Avionics Cooling from the Fresh Air Vent

I’ve been having some GPS problems that I suspect might be related to the box getting hot. The first step was to install a vent in the boot cowl up above the stack, but that didn’t seem to help. After considering options like fans and extra exterior vents like Cessna did for a while, the best option seemed to be tapping off of the air that is already coming into the cabin. The easiest way I could think to do this was a tee fitting with 2-inch flanges on the through ends and and 3/4-inch flanges on the short end. Somebody may make these, but I couldn’t find them. Thankfully, my friend Alan is a good welder of seemingly anything weldable. I brought him a 2″ diameter tube and a 3/4″ diameter tube:
Alan Welding
And he fixed it right up.
IMG_0120
After his welding I trimmed all of the flanges to about 1″ long, cleaned up the edges, and drilled the hole in the side of the 2″ diameter tube. I figured drilling this hole after the fact would help with the thermodynamics during welding, and make it so that we didn’t have to try and hit a predetermined spot with accuracy. I started with a 3/8″ diameter hole, which could be enlarged for more flow.
IMG_0126
Then I removed the old scat hose that connected eyeball the the NACA scoop, and replaced it with the new tee in the middle.
Avionics Cooling Tap
A foot-long piece of 3/4 scat connects the tee to the avionics, with support from wire ties.

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Hours Logged This Session: 1
Total Hours: 1883.75

Symptoms of Contamination in the Carburetor Float Bowl

Things were going well and running fine until I decided to take my friend James for a ride. He had never been in a small plane before, so he brought his daughter, who is about the same age as our oldest, and we took off for a sightseeing hop. After about 15 minutes, the engine coughed really hard. This caught my attention and called for a calm reaction. The engine was running fine after the momentary power loss, so I selected the mixture to full rich and started heading for the airport. We landed uneventfully until it was time to taxi up the hill to get to the hangar. The engine ran fine in the idle range, but it wouldn’t run above 1500 RPM or so. Since we needed more than that to taxi up the hill, we shut down the engine and pushed the airplane back. This was certainly not the best impression for a first-time airplane ride.
I downloaded the diagnostic data from the D180 and uploaded it to Savvy Analysis. After much consideration and consulting with Bob Barrows on the phone, I decided that it must have been a carburetor ice event. The main symptom was that the carburetor’s main jet was plugged, but the problem had gone away. The carburetor air temperature indication did not support this theory, but then again I’ve heard other folks say that theirs indicated higher than actual temperatures. At the time, the ambient conditions weren’t exactly prime for carburetor ice, but it was cloudy and about 50 degrees. I ran the engine for half an hour on the ground, making passes up and down the runway to make sure it was operating correctly. I flew solo for a short flight, and then flew for almost an hour with another friend. The carb ice theory was starting to become the most plausible.
That is, until I went flying with another young couple that I had met recently. This time we were planning to fly for about an hour, but just as I was turning on what would have been a crosswind leg if we were staying in the pattern, we lost power again. Just as before, the power loss was very temporary. It was running again by the time I could do anything, without any input from me. This time we were within gliding distance of the airport, so I landed promptly, assuming it might quit temporarily or permanently at any time.
After landing, the symptom was the same. Any power application above the idle range would cause the engine to quit. This time I had the forethought to try and determine if the problem was a lean mixture or a rich mixture. I advanced the throttle into the quitting range, and then rapidly pumped it back and forth over about one inch of travel, to work the accelerator pump. This worked, indicating that the problem was fuel starvation. I used this technique to taxi up the same hill to the hangar, and sheepishly apologized to yet another set of passengers. They were more understanding than I expected.
This was all that I needed to stop flying the airplane until I was exactly sure about why these symptoms were popping up. I did lots more research, and found an old service bulletin about modifying the carburetor to deliver more fuel. The RV guys call this the “Mooney Mod” and it dates back to the 1960s. I asked Bob about this, and he said that was probably not related. He offered to swap carburetors with me, which was generous. I asked what he would do in such a situation, and he said he would take the float bowl off of the carb and see if anything looked suspicious in there. We knew that it had a brass float, but I wondered if it had begun to deteriorate somehow.
I felt comfortable with this, being armed with a detailed parts diagram and plenty of non-airplane carburetor experience. I didn’t really see how there could be anything in there though. After all, fuel flows from the tank, through a finger strainer, to the gascolator (which would separate out just about anything), and through a fine screen right where it enters the carb. The gascolator and carb screen were spotless, as usual.
I took the carb off, which was about a 30-minute job, and cleaned off a section of work bench for surgery.
MA4-5 Carburetor Float Bowl
I carefully collected the fuel from the float bowl, wanting to be sure to document any debris. There were a couple of little floaties, but nothing significant. Then, I looked into the float bowl and found the evidence I was looking for:
MA 4-5 Float Bowl
You might have to click on the big version of the picture to see the little piece of red RTV. I am pretty sure that this little bugger was what was causing all of the trouble. But how did it get in there? It’s way too big to get through any of the screens, and how could it be rattling around in there for 130 hours without any other symptoms? Well, regular readers may remember a time that I removed the float bowl drain under less than ideal circumstances. The best explanation that I have is that this was when the piece was introduced. Of course that was 60 hours ago… but maybe the piece just finally eroded to a point where it could cause trouble.
I put everything back together, though I misaligned the mixture parts, so the mixture didn’t work. I had to drop the float bowl down again and carefully ensure that the mixture adjusting piece sticking down from the throttle body was engaged in the tube at the bottom of the float bowl. After that, everything ran great. It has been running great for around 30 hours so far, with no more problems.
The takeaway is that we should be extremely careful when messing with the carburetor float bowl drain. There are so many defenses in place to keep contaminants out of there, but when the drain plug is out, those are all bypassed.

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Hours Logged This Session:
Total Hours: 1883.75

Exchanging the Flightcom 403b Intercom for the PSEngineering PM3000

One of the complaints that I have had from the start with our airplane is the inadequate audio system. This is no surprise, since the audio system was one that I understood the least about, and it was the most difficult to integrate. Further complications came from our project coming with the Flightcom intercom already, so I never did any research to select the best intercom for our application. The end result was that I had to adjust the squelch every time I applied takeoff power. To be fair, our cabin is exceptionally noisy; I wouldn’t even consider flying in it without a headset and/or earplugs. I’m sure that the 403 is well-suited for an airplane with an average noise level. Research led me to the PM3000, and discussions with the folks at PS Engineering led me to believe that it would be a better choice. So did I call them up and buy one? No, actually. There are several sub-models of the PM3000, depending on how the unit is set up to isolate. I wanted the one that would allow us to isolate the back seaters from the front seaters, and that model number is 11932.
IMG_7146
From the front, it looks like a pretty straight-forward swap. Just drill a few new holes, and be glad that the new one is bigger than the old one! From the back though, there is this:
IMG_7147
Hmmm… it would have been handy if the gender of the d-sub pins was the same. Fortunately, we have handy access at the top of the instrument panel:
IMG_7149
It ended up taking me a couple of afternoons to get everything squared away. One challenge was removing the stereo/mono toggle switches that the Flightcom had required (for reasons unknown to me). Another was routing wires for a second audio input, which is to be used by the back seat passengers when they are isolated to themselves. While I was in there, I considered a few options for integrating Bluetooth, and/or a USB port that would be able to charge my phone and use it for audio content. I have this arrangement in all of our cars, and it would be handy to have in the plane too. I have a circuit candidate on hand, but it needs more testing and modification before I trust it enough to make a permanent installation. It was very inexpensive and not intended for this kind of use.

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Hours Logged This Session:
Total Hours: 1883.75

Isolating 3.5mm Audio Jacks from the Airframe Ground

Back when I was first assembling our panel and wiring everything up, I had a hard time finding non-conductive shoulder washers for our two 3.5mm “earbud” size audio jacks. The big 1/4″ jacks had washers like these to isolate them from the airframe ground, but not the little guys. Well, this was a case of too much thinking and not enough information. I recently replaced our Flightcom 403b intercom with a PSEngineering PM3000 to better handle the high cabin noise level, and while rewiring much of the audio system, I learned that these little jacks are already set up for this. Look closely at this picture:
Isolating washers for 3.5mm audio jacks
Notice that just under the silver part is a little black plastic shoulder. The way this is supposed to work is that we are to drill a hole in the panel that is the same diameter as that black shoulder part, not the silver threaded part. Then, we just need a flat non-conductive washer that will isolate the nut from the panel. I made my own out of an old hotel room key. Wasn’t that easy?

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Hours Logged This Session:
Total Hours: 1883.75

Replacing the OEM Dynon Thermocouple Connectors with Omega Connectors

All of my Dynon temperature probes worked well for about 100 hours. Then, I started getting intermittent readings on some of the EGTs. My research indicated that I might have been lucky to have not had problems sooner! Many builders have found that the Dynon-supplied connectors just aren’t up to the job, for a combination of reasons. One is that the thermocouple wires don’t fit well into the crimp-on terminals, and they don’t crimp securely. In an age where almost anything is available at our fingertips, why should we be flying around with problem connectors? Omega makes connectors that are designed to work with thermocouples, so I ordered a set of five HMPW-K-MF connectors.
Omega Thermocouple Connectors
I removed the old spade connectors and stripped back enough wire to get to.
Omega Thermocouple Connectors for EGT
The little dark red donut goes over the wires first to provide a seal and strain relief.
Here it is ready to close:
Dynon alternative thermo couple connectors
Here’s the final result:
Omega EGT Connectors
So far all of my intermittent indications have gone away. I’ll follow up here if they come back. I only replaced the EGT connectors, but it would probably be a good idea to replace the CHT connectors too. It looks like they use type J thermocouples for the CHT, so the Omega part number would be HMPW-J-MF for a male-female set. These were cheap and easy to install, and seem to be a great alternative to the OEM Dynon thermocouple options.

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Hours Logged This Session:
Total Hours: 1883.75

(not) Fixing The Broken Micro USB Port on a First Generation Stratus ADSB Reciever

The first-generation Stratus

The first-generation Stratus

I’ve enjoyed using the first-generation Stratus ADSB receiver to get in-flight ADSB inputs like METARs, TAFs, and radar returns. Life was going well until the day the female micro USB jack came out with the charging cord! It turns out this is a fairly common thing to have happen on these, and a subsequent redesign effort addressed the problem. Having the tools to open the case, and being fairly experienced with a soldering iron, I didn’t see much to lose by opening it up to attempt a repair. Spoiler alert! I wasn’t able to fix it very well.
This is what the back of the unit looks like before any opening attempts. Where are the screws?
Screws for disassembling the stratus
Here they are:
First Gen Stratus Screws
Note that one is under the sticker, right over the “Serial” in the serial number. A torx t-10 bit fit the screws in mine, revealing this:
Inside the first-gen Stratus ADSB Receiver

Inside the first-gen Stratus ADSB Receiver


The red, yellow, and black wires connect the giant silver battery to the green circuit board.
Stratus ADSB circuit board battery connector
I applied force away from the circuit board, and the white connector popped off.
Stratus ADSB circuit board battery connector
This allowed me to work freely with the circuit board. Now, about that connector! Here it is, as “removed.”
Circuit Board Mounted Micro USB Connector
There are six relatively large pads that seem to serve no electrical purpose. These were all that held the jack to the board. In my case, the solder joints did not fail. Instead, the pads just pulled right off of the circuit board. I used the soldering iron to remove the remaining bits of copper from the jack:
Circuit Board Mounted Micro USB Connector
You can see two of those copper pieces to the right. Don’t let the imagery fool you- these are some very tiny parts. The tip that I’m using in my Metcal soldering iron is around 1/16″ diameter. Here is where the connector used to attach to the circuit board.
Stratus ADSB broken USB
There are five little tiny contacts in the middle of two of the large pads, and that is where the electrical connections are made. I carefully crafted a diagram to show the pinout of the micro USB:
Micro USB Pinout
My plan had been to attempt to strip the end off of a surplus USB cable, and then solder the wires from that cable directly to the board. The problem that I found was that even though the wires inside the USB cable were quite fine, they were still huge compared to those five little pads. The next best solution was to try to attach short lengths of extremely fine wires to the pads, which I could then solder the USB stranded wires to. Here’s how that looked:
Tiny wires
Tiny Wires
As I tried to solder these to the five little pads, I found that the pads were too fragile. The slightest movement would cause them to break off of the circuit board. I traced each to where it made its next contact, and then soldered the wires there. Here’s what that looked like:
Soldered Wires
This sort of worked. The connections were made. Before soldering everything up, I drilled a hole in the case of the Stratus and ran the USB cable through the hole. I tied a knot for strain relief. I tried to very carefully place everything back into the case and closed it up. Upon plugging it in, the unit would power up, but it gave the red flashing indication that the charge current was inadequate. This might have been related to the extremely tiny wires.
So my conclusion is that I didn’t really fix it. It might have worked OK, but it was suboptimal. In the end I got lucky and was able to exchange it for an overhauled version for a fee.

Posted on
Hours Logged This Session:
Total Hours: 1883.75

Symptoms of Losing the Idle Mixture Screw

We had some complicated plans for getting to Oshkosh Airventure 2014. The problem was that we had a wedding to go to in Boston on the Sunday before Oshkosh, and we had to be back at Oshkosh in time to set up the cookout on Tuesday. The plan we came up with was for me to position the airplane to Oshkosh in advance by myself, then to airline to Boston to join the girls. Then after the wedding, we would all airline back to Oshkosh and enjoy the show. I’m oversimplifying the plan here, because there is obviously no airline service to Oshkosh, but if I explain the whole thing here you’ll likely get bored and quit reading. So to get back to the Bearhawk part of the story, I loaded everything up that we would want for our trip but not need in Boston, and set out on Thursday morning for what should have been about 6 hours of flying. For some reason, the first trip to Oshkosh for several Bearhawks has historically been an unlucky one. If mine had been uneventful, I wouldn’t bother writing this entry, but as you will see, it was not.

Weather for the first half of the trip was so-so; it was good enough to go, but it was less than ideal. My plan was to stop just northeast of Lexington KY at a small airport with cheap fuel. From there I could top off and fly all the way to Brodhead WI to camp for the night, then fly the short hop to Oshkosh on Friday morning to pick up a rental car. As I made my way over the mountains towards Kentucky, I was easily able to maintain VFR conditions above variable cloud covers below. At one point I climbed as high as 11,500 briefly, and the airplane was performing well in spite of a substantial load of “stuff.”

The forecast called for clearing conditions in the Lexington area when I was scheduled to get there, but as I got closer, I could see that those improvements were running a bit behind. I was on top of a flat but solid layer that I could see was breaking up to the north. I was showing a fuel quantity on board of around 8 gallons, and while that’s an hour of flying, it’s not much! One plan was to call Lexington approach and file a pop-up IFR to get through the thin layer. Once underneath, I could cancel and proceed VFR to my original destination. The only problem with this plan was that for some reason, my primary radio (the only panel-mounted radio) was not transmitting my voice. Are you starting to see how a superstitious person might be able to wonder if these glitches were related to my destination? The only way to use that plan would have been to revert to my handheld radio, which didn’t seem wise for IFR in Class C airspace. So I looked at the map, and saw that Frankfort was the next option past Lexington. It was farther than I wanted to go, but based on wing root sight gauges and Dynon fuel flow-based calculations, I had enough fuel to get there with legal reserves.

I was flying right over the top of the LEX Class C airspace as I saw for sure that the clouds were not going to be a problem. The clouds and the airspace led me to stay higher than normal, instead of making a power reduction to start descending towards FFT. Once clear of the outer airspace ring, I reduced the throttle to near idle to start what would need to be a circling descent. That’s when the engine started missing. It wasn’t entirely obvious at idle, because in that condition the relative wind is driving the prop and engine, rather than combustion. As I opened the throttle a little to see if it was indeed missing, I confirmed that the engine was running intermittently.

This was not cause for dire concern for a few reasons. One was that because of my high descent profile, I had enough energy to make it to FFT without any engine power. Another was that I had enough altitude to tinker with it while I was on the way. Keep in mind that the power-off glide in our Bearhawk is on the order of 500 feet per minute, allowing around one minute of glide per thousand feet of altitude. This meant I had around 8 minutes to sort it out. While these factors meant the power loss was not a dire concern, it was still a pretty serious concern, mostly because I didn’t know why it was happening. I assumed that the most likely cause was fuel delivery, because I had not yet ever flown the airplane with so little fuel on board. Maybe it was sloshing around somehow and not getting to the engine. Of course I realize now that I could have ruled this out if I had checked the fuel flow gauge, but at the time I didn’t think of that.

The situation became doubly undesirable when I finally had the FFT runway in sight. It was well within my gliding range and beautiful to see, except for the two big X marks. That’s right, it was closed for resurfacing. At that point, I had no intention of landing anywhere else. An off-airport landing is much less desirable than an off-runway airport landing, and while it was not exactly safe to land on a closed runway, I could see that the runway was clear of any personnel and equipment that I might have endangered by landing there, and since I was exercising my emergency authority, coloring outside of the usual lines was allowed to get the airplane on the ground safely. If the runway had not been clear, I could have made use of the taxiway, or even the surrounding grass.

I landed uneventfully and coasted off of the runway, and attempted to restart the engine to taxi onto the apron. It would run, but not well. The airport manager met me at the airplane to amicably express his discontent for me having just landed at his closed airport. I explained that it was an emergency landing, and that we’d sort it all out, and he agreed. We pushed the airplane to a tiedown spot and I started recalculating my complex travel plans. The airport manager said that he wouldn’t be able to let me depart from the closed airport, which was really going to complicate things. Fortunately, the construction project was nearing completion, and the airport might end up reopening on Saturday, or more likely Monday. The only viable option was for me to leave the airplane there and get to the wedding, then return after the wedding to fly the airplane to Oshkosh.

After an explanation to the friendly (and quite reasonable) local FSDO inspector who wanted to hear why it was that I felt like landing at the closed airport was the safest course of action, I took a taxi to the Lexington airport. My plan was to catch an airline flight to Chicago, with plans to catch a second flight to Appleton. From there I’d try and figure out how to get to OSH, then try to figure out a place to sleep there for one night, then wake up on Friday morning to pick up the rental car and resume the original plan. Notice that the details of that plan start getting sketchy at the end. That’s part of the adventure of flying a GA airplane on a long trip- one is never really sure that he’ll get there at all, much less according to the original plan.

The flight to ORD was uneventful, though a little bit delayed. Fortunately the crew that worked that flight was also the crew for the Appleton flight, so it was also delayed. While in the gate area I noticed one of my coworkers, Mark; this is one of the few perks of having to all wear the same flammable work clothes. We had not met before, but we talked for a little while and he explained that he was picking up a rental car in Appleton to drive to Oshkosh upon arrival, and offered me a ride. This turned out to be most useful. I figured if I could get to the show grounds, I could find a place to sleep, even if it was under Chris Owens’s Camper RV, which he had pre-positioned in his usual campsite. As we flew from Chicago, I looked out the window to see the beautiful green countryside, blue sky, and calm winds. I really wish I had been able to fly the Bearhawk instead! Conditions were just perfect. I had a great visit with Mark as we drove from Appleton, and he dropped me off in the campground at OSH. It was somewhat surreal to be on the grounds before the start of the show. Things were certainly ramping up, but the airplane parking areas were primarily empty and there weren’t any crowds.

After sizing up the grass under Chris’s camper, the scant clothing that I was wearing/carrying, and the forecast overnight low, the option of sleeping there was becoming less appealing. I had brought a tent for sleeping at Brodhead, but I was having to travel light, so it was still with the airplane. Then it occurred to me that it was Thursday, and while the local hotels are historically unobtainable during the show, I thought it would be worth asking what the rate would be. When I called the Super 8 the lady told me that they had plenty of room, and the rate would be $70. I didn’t need to take a second glance at the grass to make my decision! I started walking in that direction, enjoying the memories from the special place, the beautiful sunset, and the mild temperature. I was not enjoying the airshow that the mosquitos were putting on around my head, but they only served to remind me of 100+ good reasons for an indoor sleeping space.

After checking in I walked over to Friar Tuck’s for a hot crock of french onion soup and a roast beef sandwich, my first consequential food for the day. The next morning I woke up and continued with the travel plans, including procuring a used child seat for the rental car. The seat I had planned to use remained in the airplane, a casualty of our fragmented plan. The logistics of all of this trip would have been complicated without the need for carseats! It’s fun to have little kids, but they step up the travel complexity significantly. I drove the car down to ORD and parked it as planned, and took a flight to Boston. From there I took a bus to Cape Cod to catch up with the rest of my family tree, arriving in the middle of the night. We had a great time at the wedding on Sunday, and well before the sun came up on Monday, Tabitha’s parents took us to the airport so that we could get back to the Midwest. The girls flew to ORD to pick up the rental car, and I flew to ORD to catch a flight to LEX. After another expensive car ride to FFT, I was finally back in position.

We added some fuel to the airplane, though not a top-off due to the high fuel price. The airport was not open yet, but it was expected to be open that afternoon. This gave me some time to troubleshoot the voice problem with the Garmin 430. My research over the weekend suggested that removing and reseating the radio in the tray might fix the problem, and fortunately it did. I prepared the airplane so that I could hop in and go as soon as the airport opened, and after a few hours of waiting, the manager finally gave me the thumbs up. I hopped in and started the engine, and it wouldn’t run. This was most frustrating.

It was acting like it wasn’t getting fuel. If I pumped the throttle it would stumble along, and if I got the RPM above 1500 it would run reasonably well. A local airport patron named Gene was hanging around, and he helped me with some troubleshooting. He was a long-time owner, pilot, instructor, and home builder, and was immensely useful. One problem that I found was with standing water in the airbox. The FAB instructions say to drill a hole in the back to allow water to drain, and somehow I had omitted that step. Shortly after Oshkosh, I saw a mention in one of the magazines that said this is a very common problem to pop up at Oshkosh, since so many of us keep our airplanes outside for the first time while there. I drilled a 3/16″ hole and allowed a cup or so of water to run out onto the ramp, hopeful that I had fixed the problem. I hopped back in and started the engine, only to find no change.

I’ll save you a lengthy review of everything that we checked, including draining the float bowl, which required removing the airbox, which required removing the cowl. With all of that stuff out of the way, I happened to look at the back of the carb to see a hole where the idle mixture adjustment screw was supposed to be! This explained the problem. The engine would run fine at high power settings, when the idle circuit was not in use. At low power settings, the idle circuit was running very lean, since there was a 1/4″ air hole where the needle was supposed to be. The friendly local mechanic loaned me a needle off of one of his grounded airplanes, and after reassembly, everything ran great. It turned out to be harder than I expected to replace his needle. I started the process of ordering a replacement at the Aircraft Spruce booth, but it ended up taking several weeks, in part due to the complicated nature of ordering carburetor parts from ACS. This ended up creating a most-confusing situation in the subsequent weeks, where when I saw the shipment finally leave ACS, I sent the mechanic his original needle back, but at the same time he called ACS and redirected the new needle back to FFT, presumably assuming that I had run away with his needle, etc. Our carb is the ubiquitous 10-3878, but it’s not readily clear which variants of the MA4-5 use the same part number for the needle.

The good news was that I had a running airplane and another hour or two of daylight, so I finally got out of FFT and headed north. OSH closes at night during the show (and I don’t fly the Bearhawk at night anyway), so I knew I wasn’t going to be able to make it all the way, but I also knew that closer was better. I stopped in Indiana for the night, topping off on cheap fuel and sleeping like a king in my little tent. I wasn’t sure if camping was allowed at the airport, so I asked the tower controller when the first folks started coming around in the morning, and set my alarm for a few minutes prior. The next day I was cranking the engine just as the first car was arriving, and just as the dawn sky was lightening.

I flew from there to southern Wisconsin, where I topped off on fuel again. I didn’t want to have to worry about fuel while at OSH. I arrived at about 9:30 in the morning, and taxied to the Bearhawk Aircraft display booth. Mark’s other options for display airplanes fell through, so he put ours to use. My late arrival meant that we wouldn’t have time to clean out the airplane, or otherwise make it any more presentable. While at the show, I stopped by the Precision booth to ask if they’d ever heard of the idle mixture screw falling out. They said it can happen if the needle is backed out to a point where the spring is no longer applying good pressure to immobilize the needle. This was likely the case on our carb, because I had it backed out pretty far. The guidance about how to set the idle mixture says to look for a 50 RPM rise during shutdown. I incrementally backed the needle out looking for that rise, but never saw it. If you find that yours does not seem to respond to input, be wary of backing it out too far.

Using WordPress as a Building Log

Who doesn’t like WordPress? It’s fast, stable, and ubiquitous. I have used WordPress to power this building log, and it does a great job. There are so many folks using WordPress in so many ways that online help is abundant- which is part of why I’ll direct you to those sources for questions about how to install the software and implement a theme.

Once you have done those things, you’ll find one key feature missing, and that is hour tracking. How can you log hours with wordpress? I got around this with a little help from my programming friend Wesley. This strategy assumes that you are using a WordPress Post for each building session. By the way, did you know that you can publish a post with any date? I use this feature to batch post building log entries after the fact. I select the date and time that corresponds to the end of the building session, and that keeps everything organized. When you are composing the post for your building session, scroll down to the “Custom Fields” dialog at the bottom. Create a custom field called “Hours” and enter the decimal version of the number of hours you have logged with that post. This will store your build time in the WordPress database, right beside your post content.

Now, we just need to fetch that number from the database when we want to show the number. In your child theme’s style sheet (stop right there if you don’t know what a child theme is- Google it, and make one, because if you make these changes in your main theme files and then update the theme, the changes will be overwritten), create the following:


.post-hours {
[insert your css here]
}

.hours {
[insert your css here]
}


Just be sure to replace [insert your css here] with your css styling that you would like to use. http://www.w3schools.com is a great source for CSS syntax.

Now, decide where you want the number of hours to show up, and find the right file to edit. This is going to vary from theme to theme. Most themes use a file like post.php or content.php to display posts. You may want the number to show up there, perhaps in the post meta data as I do on this log. You may want it in a sidebar. The key is to find the file that you think you want it in, copy that file into your child theme, and then put some sort of sample flag (perhaps a word like “Fish Sticks”) in place to make sure you are controlling what you want to control. If your fish sticks are showing up where you want for your hours to show up, then that means you are editing the right file.


<div class="post-hours">
<p>
<span class="hours">Hours</span>
<span class="hours"><?php
$thesehours = 0;
$thesehours = get_post_meta($post->ID, "Hours", true);
echo "Logged This Session: $thesehours";
?> </span>
</p>
</div>

This was the relatively easy number to display. If you want to change the text, carefully edit the “Logged This Session: area without deleting the preceding quotation mark or the $ in front of $thesehours.

To display the total hours for the project, use the information here.

For a while I had a different method listed here, but it stopped working after a WordPress update.

As with everything else on this website, the above information may be totally wrong. Definitely back up your files and database before you attempt to implement the above changes!

Flap Locks

As we prepared for our first trip to Oshkosh, we were concerned with preparing the airplane to live outside for a while. This involved making plugs for the air intakes, weather stripping the windows and doors, and coming up with a way to hold the flaps in the retracted position.

Since the Bearhawk uses one-way cable tension to hold the flaps down and spring tension to hold the flaps up, a gust of wind from behind can extend the flaps. This can subject the flaps to damage, especially if the gusts are strong.

My first attempt at a control lock was to make a v-shaped piece of aluminum out of a 1/8″x2″ extrusion. I bent the aluminum to a radius that would fit outside of the flap and trailing edge at the wing root, allowing for some foam padding. This didn’t work very well, because the 2″ bar was too narrow. The same idea might work if the bent piece was much wider, maybe 6″ or so.

It was important to minimize the weight and space of the lock device, since I was going to have to be carrying it around, so a 6″ taco shell wasn’t going to be optimal. Instead, I expanded and copied a design that I saw on a Kitfox at Oshkosh one year. I started with a scrap of 3/8″x2″ hard plastic, probably Delrin.
Flap Lock Parts
I drilled two holes to accommodate two 3/8″ dowels, then padded those dowels with some hardware store tubing. Before applying the tubing, I spray-painted the whole assembly bright pink to make it more obvious during the preflight exterior inspection. Finally, I connected a short and small bungee cord that will hold the lock in place. The lock would probably stay in place without it, but I didn’t want to risk having it come off.
Bearhawk Flap Lock

External Control Lock

Flap up lock


I think the bright color looks quite nice, though it hasn’t been too durable in the sun so far.

An RV Builder’s Guide to Building a Bearhawk

I love the RV series of two-seat airplanes. They have revolutionized home-building, recreational flying, and perhaps even the overall world of GA. As far as airplanes go, they are pretty useful in that they go fast, handle well, and don’t have any bad flying habits. While they are useful as far as airplanes go, they aren’t as useful as transportation tools, especially if you plan to fill both seats. They are like sports cars- fast, fun to drive, and visually appealing, but short on trunk space, and with no back seat.
This shortcoming is something that often comes up in discussion with RV builders who see my Bearhawk. They look at the baggage area, and while it is still fairly small by car standards, it is cavernous by RV standards. While they are thinking of all of the stuff they could carry in there, I tell them that they could load 900 pounds of people and stuff in that big cabin (when the tanks are full) and still get a 500-1000 fpm climb rate on 180 horsepower, the gears really start turning.
There is a trap though for RV builders who have not built any other airplanes. It’s easy to not realize how streamlined the construction process is for the RVs. If an “RV only” builder extrapolates his builder experience with the RV and assumes that building a Bearhawk would be pretty much the same, plus a little fabric work, he would be in for a surprise.
Part of the success of the RV series is the quality and quantity of the engineering that goes into the builder experience. With thousands (perhaps soon, over ten thousand) examples flown, there are plenty of resources to devote to creating a thorough instruction manual. If there is a mistake in the manual, or if directions aren’t clear, the staff at Vans is going to hear about it. They have developed very specific instructions that make for a high completion rate with many satisfied builders.
This is where the Bearhawk is a different animal- a much more rare animal. There may be 200 examples of the line of Bearhawk airplanes flying, but I doubt there are more than that. Perhaps half of those are scratch-built from plans only, and not from a kit. I wasn’t around to know for sure, but I suspect that back when Van had 100 examples of planes from his kits flying, his instructions were probably not quite so well-developed either. The designer of the Bearhawk and the owner of the kit factory are receptive to customer feedback, and they are always refining their materials, but there is just not anywhere near as much information coming in.
Here are some examples. The Bearhawk wing is built much like an RV wing, with a few large exceptions like the strut support and the removable fuel tank. When the designer Bob Barrows specified the rivets to hold vertical rib stiffener angles to the ribs, he specified the alloy, head, and diameter of the rivet, and not the length. The intent is that the scratch-builder should be able to work out which length of rivet to use. Contrast to Vans instructions that specify rivet length for each hole, with associated symbols on the plans. Currently the Bearhawk plans are hand-drawn, and they are rich in detail and well made, but there is not as much information available as in the Vans package.
Personally, I try not to put a value on this difference to say that one is better or worse, since that judgement depends on perspective. The detailed instructions probably lead to a better completion rate. Once a builder has started construction, the detailed instructions are going to help that builder finish, especially if he does not need to deviate from the instructions. Prospective shoppers can look at a kit with more detailed instructions and perhaps be less intimidated by the prospect of building an airplane, and that probably leads to higher builder starting numbers. I wonder if that leads less-dedicated builders to start construction and later give up, but I don’t know if the numbers back that up. On the con side, someone can build an RV without having to do as much problem-solving and fabrication from scratch. To over-generalize, it seems to me that the RV builder community is more often a “buy it and bolt it on” group. That’s not to say that there aren’t plenty of exceptions, especially in folks who deviate significantly from the plans (such as by adding retractable gear or floats). Likewise, it would not be fair to say that the RV builder doesn’t still do plenty of fabrication. I think it is fair to say that an RV builder can produce a good quality airplane without having to learn many of the skills that a Bearhawk builder would need to have. Indeed, this is probably what has led to the popularity of the airplanes. It’s like the joke about whether Navy pilots are better than Air Force pilots: the Navy pilot says “I can land and stop on a tiny pitching carrier deck.” The Air Force pilot says “I don’t have to.”
In this regard, building an airplane like a Bearhawk is a different project than building an RV. The whole mindset is different. For example, you can’t “just buy a tail kit.” Another big appeal of the RV series is in the option to sneak up on construction, buying partial kits incrementally. With the Bearhawk, this isn’t an option. The tail parts are not difficult to make for someone who knows how to weld, but in the current kit production process, they must be custom-fitted to a fuselage, and delivered with a fuselage. In theory one can buy a set of wings separate from the fuselage, and the wing parts will line up with the fuselage parts, but there is a significant cost premium with this strategy, a large part of which is shipping. So when it comes to building a Bearhawk from a kit, there isn’t any toe-dipping to test the waters of building- it’s a head-first jump into the deep end. This also has its benefits. Builders have all of the parts on hand from the start, and need not be stuck waiting for parts, or try to roll the dice on sub-kit lead time.
Another big difference that may surprise some RV builders is the level of kit completion. The Bearhawk kit only includes Bearhawk parts. Nuts, bolts, fuel lines, washers, control cable, wheels, brakes, fabric, turnbuckles, pulleys, and paint are all purchased separately by the builder. The positive side of this is that a builder only needs to pay for exactly what he wants. Since there is so much variation in how builders finish Bearhawks, any hardware package provided by the factory would inevitably include lots of unused components. When the builder orders what he needs, he knows what goes where. This saves the trouble of having to sort out where everything in a big pile of little parts goes. The negative aspect of this arrangement is that in the end, builders are likely paying slightly more for the hardware than the factory would be able to buy in a large volume. In some cases, this savings might exceed the risk of wasted/unused parts, but with the way that Aircraft Spruce prices things so low these days, I think that is unlikely in most cases. For example, if the kit factory could provide bolts at 10% off of the ACS price, then a builder would need to have less than 10% loss, after correcting for the effort of having to figure it all out. This is another drawback, that the builder has to spend the time to figure out what he needs and where it goes, which is a direct opposite to the “knowing where it goes” benefit.
For a builder who is building for his own recreation and education, as I hope we all are, the Bearhawk will provide plenty of education opportunity to an RV-only builder. The quick-build kit comes with the wing almost entirely skinned, except for the section of the top skin aft of the main spar. This means that the wing shape is already locked in at the factory, and the remaining rivet holes are already deburred, dimpled, and ready to rivet once the builder is finished making connections inside of the wing. So in that regard, there is very little of the tedious aluminum work that an RV builder has already mastered.
Similarly, the quick-build fuselage is completely welded, so a builder does not necessarily need to be able to weld. Some Bearhawk builders chose to make minor modifications that do require welding, usually increasing the build time and complexity. Even without welding, working with steel is a new skill set. Then of course there is fabric covering. This should not be intimidating at all, because much like working with aluminum, there is plenty of information available on how to get the job done safely. The most important part of a covering strategy is to choose one system and follow that system’s directions exactly, and not do much wandering off of the map. The Polyfiber and Stewart systems are both likely to produce a result that will last decades. These are just a few examples of differences, and there are certainly plenty of others too.
To summarize, an RV builder should realize that the RV building process is very refined. The path that a builder takes is smooth, paved, and well-maintained. If an RV builder starts thinking he’d like to have an airplane with a little more space and payload capability, the RV-10 is not the only option. The Bearhawk is worth consideration for a builder who is willing to step off of that well-paved construction path onto a scenic hiking trail, in return for a little bit more of a challenge and a substantial cost savings.

Using the GoPro on the Bearhawk

I’ve always been fascinated with the GoPro cameras. I had one of the early versions, and it was cool, but not very functional. It required AAA batteries, and could only handle a 2gb SD card. There was no preview to tell what the image frame looked like, and the on-camera buttons were the only way to control it.

Enter the later generation of cameras, as pictured here. I use the “white” edition to take all sorts of interesting pictures and videos. The version that I have is wide angle only, and having the option to go to a narrower angle would also be nice.

This little guy solves so many of the problems of the original. First, it uses a proprietary lithium battery. While I’m not usually keen on proprietary batteries, the lithium technology lasts so much longer than the aaa cells did, and it is fast to recharge. And now days with the folks in China not having any regard for intellectual property, it is easy to get a knock-off extra. I have ordered a three-pack and a two-bay USB-powered charger, though I haven’t had enough test time yet to be sure that they are worth recommending.

This new version uses better SD card technology that allows for much larger capacities. I use this one, but if you are shopping for one as of today I’d do a little bit of searching. The prices on these seem to fluctuate quite a bit from one packaging variant to another. I’ve never come close to filling up one of these. I suppose if I recorded a few hours of flying at one time then I might, but honestly the video would probably be pretty boring.

The real deal-sealer of features for me on the new generation of GoPro cameras is the wifi control. With a camera mounted on the exterior of the airplane, it’s nice to be able to start and stop the video (or take still shots) from the iPad or iPhone. Gone are the days of having to turn on the camera and record from start up to shut down (or more likely, battery death or card exhaustion).

Mounts

The Bearhawk presents a mixed blessing of mounting options. On the wing, it’s very easy. I have a mount that is on the inspection panel where the front, outboard aileron pulley is. I applied the standard sticky mount to the inspection panel with the sticky adhesive, after making sure that I liked the angle and position. Then I removed the inspection plate and drilled two small holes through the black plastic and the inspection panel, and countersunk the holes in the plastic. I used two #6 stainless screws to double up the adhesive, since I’d rather not have the camera fall off in flight. Don’t get me wrong- the video would be spectacular, but I’d have to find the camera in order to get the video, and that seems unlikely to happen. As you can see in the picture below, this seems to be a very nice distance from the cabin, so that there is a little bit of background showing in front of and behind the airplane, but the fuselage mostly fills the frame. I point the camera fairly low so that the wing doesn’t dominate the top of the frame.
DCIM773GOPRO

Cabin Mounting
Another easy situation is mounting the camera inside of the cabin. This time it’s easy because the risk of having the camera fall off are low. There is a little bit of concern for making sure that the camera doesn’t get in the way of something important or pose a risk of injury. I found that I really liked having it just aft of the aft carry-through tube, which in our case is also just aft of where the skylight ends. Here is what the frame looks like there:

Go pro in the cockpit

Go pro in the cockpit



Tail Mounting
This is where it starts to get much more difficult. Mounting the camera on the aft end of a Bearhawk is complicated because there’s not a good way to mount to the fabric. I’ve tried mounting on the aft handle like this with a handlebar mount:

Aircraft Go-Pro Mount

This has worked out fairly well, and here is what the pictures look like:

Tail View Wide Angle

Tail View Wide Angle



This view demonstrates how the wide angle view has its drawbacks. At first glance this may look like the horizontal stabilizer, but it’s actually the wing. With the wide angle view, the camera probably needs to be situated a little bit further away from the fuselage to make a meaningful image.



Video
Here are some video links that I’ll add to as I get more edited and published.




37 Hours – Oil Cooler

Here’s an update from about 37 hours since the first flight. I found a few hours ago that I was getting high oil temperatures. This turned out to be an indication of several minor factors that were working together. First, the ambient temperatures started rising with the arriving spring season. Second, I didn’t really come up with an optimal mount for the oil cooler. I had it right next to the cylinder, but it’s really better for there to be some space between the cylinder and cooler. Also, I had the cooler mounted in such a way that it could trap air. A better arrangement would have been to have the inlet down low and the outlet at the highest point, which would naturally purge any air from the cooler. Another factor is that the 7-row cooler that I started with is probably a little bit too small. Bob seems to think that it should be adequate, but I read about many other installations where the 7-row proves to be too small for the angle-valve 360s.

To help resolve the problem, I’ve made several changes to the oil cooler arrangement. Note from the future- I’ve subsequently moved the oil cooler to the firewall. See this post. First, I found a 9-row unit. It is the same width as the 7-row, just a little bit taller. I removed the back left baffle and fabricated a new mounting system. The new mount scoots the oil cooler back about an inch, and also rotates it closer to horizontal. One thing that I haven’t yet done, but plan to do, is to flip the cooler over so that the outlets are on the top. A better arrangement would be to have the oil cooler sitting with the long dimension running vertically, but I’d have to make more extensive changes to mount it that way.

I have completed almost all of my data gathering. A few days ago, I flew down to Shelby to get some fuel. When I had topped off the left tank, I tried to install the fuel cap but found that the threads had seized. I had not lubricated the threads with anything, but Bob suggests a regular application of fuel lube to keep the threads from galling. I borrowed a vice from the friendly folks at the maintenance shop, and was able to use my onboard crescent wrench to apply enough force to snap the center male threaded part in half at the o-ring gap. This allowed me to separate the parts of the fuel cap. I borrowed the airport courtesy car and drove a few miles to the hardware store, where I picked up a 3″ long 6-32 screw and nuts. My plan was to drill the center vent hole and cut threads in the lower portion, allowing me to hold the cap together with the 6-32 bolt. The hardware store didn’t carry thread cutting taps, so instead, I drilled the vent hole up to the major diameter of the number 6 threads, and just used a nut on the bottom.

This arrangement worked to seal the tank, but not to allow for any venting. While flying on one tank is not an optimal arrangement (indeed, it is even advised against by Bob because of concerns about unporting the feeding tank during uncoordinated flight), it was sufficient to get me home for a 10-minute flight. The right tank was completely full, so unporting the inboard side was highly improbable.

Once I got back home, i was able to salvage the bottom piece of the cap, and of course all of the o-rings. I chucked the bottom piece of the cap into the drill press vice so that the vent hole was in line with the drill chuck, then I started increasing the size of the vent hole. I used about four sizes to get up to the minor diameter of the 1/2″ threads, which left just a few small pieces of the old male threads in place. I was able to pick out most of those pieces with a scribe, at least enough of them to allow me to get a thread cutting tap started. I worked it back and forth slowly and the threads cleaned up just fine. I used a steel bolt from the hardware store with coarse 1/2-13 threads to make a temporary center post. I drilled a 1/8″ hole through the middle of the bolt, which will allow the cap to vent. Since the bolt has a hex head instead of the airfoil-shaped vertical blade, cap removal requires a wrench. This gets me back to a flying condition while I wait for a replacement cap to arrive. You can be sure that I have since added some lube to the threads on the other cap too! I’ll use the repaired old cap as a spare, which I’ll carry in my onboard tool kit.

Posted on
Hours Logged This Session:
Total Hours: 1883.75

Mobile Phone-Controlled Preheat

Now that I’m flying with some regularity, I’ve found all sorts of inconveniences that are wanting solutions.  One example is the engine pre-heat.  This is a little bit of a princess complaint, since the airport is only a mile from my house.  Still, I don’t want to have to get in the car, drive to the airport, open the gate, drive down the bumpy road, and all of that, just to plug in the heater and come back home.  Many of my data-collection flight tests require smooth air, so I’ve been making some very early morning flights.  The reality is that I end up rushing the preheat, which isn’t doing the engine any good.

The low-hanging fruit that I could pick to solve this problem is The Switchbox.  This fellow sells them ready to use, with short extension cords in place and a decorative logo.  He advertises on many of the type-specific message boards, which tells me that he knows how to find customers.  The only downside of his unit is the price.  As you may know if you have read much of my building log, I’m quite frequently able to spend way too much of my life trying to not spend a dollar.  This happens even when I make a conscious effort not to! A little bit of Googling pointed me to another option for a cell phone-based switch, and an excellent opportunity to see if I could save money by doing it myself.

I’m willing to report that I do think I saved money, but I’m not ready to be sure that someone else in the same position would agree.  The short answer, in case you don’t want to read about all of the details, is that I believe that I’ve created a functionally-similar unit for about half the price, with the investment of about one hour of shop time and half a day of research.  With any luck, I’ll be able to save you most of that research, depending on how long it takes you to read all of this, and depending on whether you fall asleep in the middle of reading it.  For someone who is not comfortable stripping wires and going to the t-Mobile store, the ready-to-use Switchbox will probably be a superior value.  There may also be some functionality that the Switchbox has that my unit does not have, so I’ll stop short of saying that mine is exactly the same- not because I have reason to believe it isn’t, but rather just because I don’t know for sure that it is.

So here are the details, about how I did it, and about how you could too.  First, I ordered the circuit box from China.  In the days of the internet and the global economy, I find myself ordering things from China with some regularity.  The company that markets the box is called “Wafer Star” and they call it the GSM-AUTO-AC.  GSM is of course the name of the type of cell phone network (don’t get the box for CDMA if you are going to use the tMobile service).  The AC at the end is also very important, because it is designed to be powered by AC.  They also have a unit that is powered by DC, and lacks an on-board transformer to power the circuitry.  You don’t want that one for this application.

The best deal that I could find was on eBay, though you can also find similar products on Amazon.  If you go that route, be sure that you are getting the AC version and the GSM version.  The total was $140 with shipping.  I was ordering right in the midst of the Chinese New Year, and the eBay arrival date estimate was around 3-4 weeks.  I was willing to wait this long, but I was already starting to see how The Switchbox was able to score some value.  A few days later, my wife mentioned that when she checked the mail, she had a box from China that our cat was very interested in.  I didn’t remember ordering anything else, but figured there was no way that the GSM-AUTO would have arrived so quickly.  When I got back home, I was glad to see that it wasn’t a kilo of high-end Cantonese Catnip, but rather a very-quickly shipped package that promised to meet all of my preheating needs.

The unit, quite cleverly, ships without any electrical cords.  This probably poses at least two big benefits to the manufacturer.  One, he doesn’t have to try and supply area-specific plugs.  Two, he knows that the person hooking the box up is going to at least need to know which end of a screwdriver to use.  I went to the hardware store and purchased an 80-foot extension cord for $16.  (Total cost now $156).  This cord came with a male and female end, as they usually do.  I could have made use of just those ends, but the GSM-AUTO has two different relays.  I figured I might as well make both of those relays available, so I also purchased a female plug. (now $160)

I measured the distance from my electrical outlet to the area of the hangar over the engine compartment.  I applied an extra yard or so of error margin, then cut the same length off of the male end of the extension cord.  Then, I measured the distance from that ceiling location down to where I would want to plug in the heater.  I cut that same distance off of the female end of the cord.  Then, figuring that I wouldn’t need to have the second relay attached to something very far away from the engine, I cut the remaining bit of cord to match the female end and applied the female plug to one end.

Next, I stopped by the local tMobile store.  Keep in mind that the store-bought Switchbox comes with a SIM card already in place.  I gather that the other store-bought option (from Reif) does not.  Reif suggests calling tMobile to have them send a card, but I was fortunate enough to have a local store at my disposal.  The card costs $10 to purchase, and I also purchased the minimum $10 of prepaid credit.  The GSM-AUTO can operate in a few different modes.  One mode turns on the relays when you call the unit.  This method doesn’t consume any of the prepaid credit, since the unit never answers the call.  The other method is to operate by text, which does consume the credit.  I figured that since the credit is only good for 90 days, I might as well operate in text mode and use it before it expires.  The total cost was now up to $182 with tax.

Back at home, I called T-Mobile to have them disable the voice mail option.  One thing that I didn’t do, but probably should have, was to pop that SIM card into a phone, and register/activate an account online with t-Mobile.  If you are in a position to do this, now is a convenient place to do so.  The online account should in theory allow for automatic renewal of the expiring balance, among other things.  If you don’t have an unlocked or t-Mobile phone to do this with, you could probably have the folks at the store help.  Once the sim card is in a phone, go to the website to register a new account.  That site will ask for your mobile number, then it will send a secret code to your phone by text.  Enter that code, and it will know that you are authorized to create the account.  As of my writing this post, I haven’t completed these steps, because with the box installed in the hangar ceiling, I have to move the airplane out of the way and climb up there to pull the card back out.

With that step done (or disregarded), I put the card into the card holder on the circuit board.  Next, I connected the incoming AC to the appropriate threaded terminals on the board, in my case, the far left two.  Don’t forget to thread the incoming wire through the little compression nut first, then the box cover second.  Once you have the wire attached to the terminals, this won’t be very easy.  From that point, I wanted to test the operation of the unit before I went any further.

Upon powering it up, I used the instructions on the Wafer Star website to start communicating with it.  One communicates with the box by sending texts.  It came with a serial port option for programming by computer, but I haven’t had a serial port available for many years.  I didn’t try using the Dynon serial converter that I use for communicating with the 100-series boxes, because I didn’t have it on hand.  I sent a command to the box to have it change the password first.  Then I had it establish that my number was the only one on the white list, so that an errant wrong number wouldn’t make any relay changes.  The Wafer Star instructions are pretty good about learning how to make these commands.  From the iPhone, I used the copy and paste functions to save from having to type each command repeatedly.  I did not find that their iPhone app worked, which might be related to the iOS7 upgrade issues.

Next I sent a command to have it turn on relay 1.  A second or so later, I heard a click.  Another second later, I got a text back that confirmed that the relay was on.  How cool!  I unplugged the incoming power, and took a cookie break.  I’m always a little bit nervous about working on AC-powered devices that have been recently powered.  I don’t know what kind of capacitors there may be in there waiting to shock me, or worse, some poor component on the circuit board that I wouldn’t be able to fix.  After all, I an heal, but as of yet, electronics can’t.

Next came the hardest part of the whole venture, which really wasn’t that hard- connecting the wires.  After I ran the two bare ends of the female wires through the little nuts, then the top cover, I stripped them to expose about 2″ of inner black and white wires.  My extension cord had a ground conductor, which I cut off as close as I could to the end of the outer shell as to limit the possibility of shorts.  Then I cut two pieces of the scrap wire to about 4″ each, and removed the conductors from the outer green shell.  That  yielded 8 ends that needed to be stripped.  I happened to have a nice stripper that made quick work of those ends- she had them ready to go before the first song finished and I ran out of singles.

Now is the time for concentration.  Starting with the left-most terminal, put the black incoming power conductor and two of the black 4″ pieces under the first screw.  Under the second screw, put the incoming power neutral (white) with a 4″ piece of white scrap.  The way these relays work is that they are only switches.  The terminals are what you use to interrupt the power on its way to the heater.  So that means the outgoing white wires will join together with the 4″ stub that just went under the second screw on the left.  Another option would be to eliminate the 4″ stub of white wire and just put all three white wires under the left-most screw.

Now, run one of the 4″ black wires to the “COM2” terminal and run the other one to the “COM1” terminal.  If you want for your relays to turn on when you send a text (as opposed to having them turn off when you send a text), disregard the “NC” terminals.  You would use those if the default/fail-safe position was going to be on, or “closed” as the relay would say, if relays could talk.  In the case of a preheater, I definitely want the default position to be “off.”  So, if you are following along, run the two outgoing black conductors to the “NO2” and “NO1” terminals.  You can follow the electrons in your mind- you want for them to start at the wall outlet, then swim along to the left-most screw, then from there to the “COM2” terminal, then if the relay is on, to the “NO2” terminal, and to the heater.  If you object to my oversimplified metaphor for swimming electrons, then you probably know enough to hook the box up without needing to read my article, so go be an electrical engineer someplace else.

After making those connections, I did one final test before closing up the box.  Everything was good, so I attached it to the wooden trusses in the roof structure.  I suspended the incoming power and routed it to an outlet, and left the female outgoing plugs dangling.  I tossed a string over a part of the door hinge on the side of the hangar, and tied the other end to the female plugs.  I use that string to raise and lower the outlet cords.  This keeps them up and off of the floor, and also out of the way of the airplane as it comes and goes from the hangar.

So in all, I would say that I saved on the order of $100 by going with the direct-from-China option.  If you figure that I would have had to still buy extension cords to go with the store-bought Switchbox, then the cost is right around half.  If you are in the market for a similar setup and are willing to do a little work, you might consider going the route that I went.  If the above description for how to connect the wires is at all confusing, you’ll probably be better off going with the pre-made, plug and play, hassle-free option.  Keep in mind too that the Reif option is also available.  While my box appears to be identical on the outside to the Switchbox, it is different from the box that Reif shows on his website.  His price is only slightly more than what I’ve spent, unless you happen to be buying one of his heaters at the same time, in which case his price is a no-brainer.

Gross Weight Testing

Today I continued adding ballast to the Bearhawk to test how it performs at heavier weights.  My ballast is 80 pound bags of concrete, so I started with 160 pounds in the back seat.  The weight wasn’t really noticable during a few stalls and some phugoid tests.  Since I was flying with close to half tanks on that flight, this weight gain was not much above my solo full fuel weight.  On the next hop I added 160 pounds to the front right seat.  As with before, this weight didn’t seem to matter very much. 

For the next flight I added two more bags to the back seat.  By now, the pitch stability was still pretty good, though the phugoid definitely started to show a higher amplitude.  The takeoff roll was noticably longer (perhaps 700 feet or so) and the uphill back-taxi required much more engine power.  The latter indicator might have also been related to the somewhat soggy runway.  For the first time, I was able to land tailwheel-first.  The landing flare was much easier.

For my final configuration, I added 105 pounds to the baggage area and another 80 pounds to the front right seat.  To recap, that’s 240 pounds in the front right seat, 320 pounds of concrete (plus another 20 pounds of fly-away-kit), plus 105 in the baggage area.  I was at about 1/3 fuel, which would mean that when I flew up to HKY to top up the tanks, that would put me about 8 pounds short of the max gross 2500.  I should mention that with each additional weight increase, I also measured the main landing gear tread.  As the weight increases, the gear spreads out.  Bob advises that the center-to-center distance of the main landing gear tires must not exceed 72″ at max gross, an fortunately mine did not.  

That heavy configuration had my CG at 21.88 inches by my calculations.  Bob specifies a limit of 22.5 inches, but I didn’t really care for flying it at 21.88.  If I encountered a little updraft, I found myself working the elevator control back and forth to maintain level flight.  If I trimmed for level flight at around 80 knots, bumped the stick aft about 2″, then let go, the resulting pitch up was 1.6g all the way up to around 25 degrees.  While I thought all of this through over lunch at HKY, I decided not to test any further aft.  Instead I made a note that 21.5 will be my operational limit.  To get there for the next flight, I moved the 80 pound bag from the baggage area to the back seat, and left the 25 pounds of kitty litter in the back.  Then I topped off the tanks and took off.  As before, the most noticable difference was the longer takeoff roll and climb rate.  

I had intended to fly around the pattern a few times, but all of this extra weight made it apparent that my tailwheel tire was a little bit low on air.  On the second landing (which was not one to be especially proud of anyway), the tailwheel started to shimmy as I slowed through about 25 knots.  I attributed the shimmy to the low tire pressure and departed for home.  On the way I tried to validate my calculated high-altitude performance with a climb to 10,000 feet.  I had to level off several times along the way due to high CHT and/or oil temperature.  This tells me that I need to improve the effectiveness of my cooling, since the OAT was right around freezing.  I have made a few adjustments and am going to try again on another day.  

In summary, I would say that the fully-loaded Bearhawk, particularly at a fully-aft CG, is a whole different animal than an almost-empty one.  This is the case with every other airplane that I’ve flown in both conditions, so I’m not surprised.  The good news is that from the family-hauling standpoint, I won’t be that heavy or that far aft.  My concrete family is at least 300 pounds heavier than my regular family, at least as of now.

Russ Erb Visit

I had a long overnight in LAX today, so I checked in with Russ Erb.  His schedule was available for me to stop by for a visit, so I rented a car and drove up to the desert.  I was excited about getting to catch up with Russ and discuss a few flight testing strategies, and I was also eager to see his plane up close again.  I’ve seen it several times over the past few years, but I’ve noticed that each time I see a completed Bearhawk, I have different things to look at.  When I was doing fabric work, I was looking at fabric work on other Bearhawks.  Now that I’m seeing how mine is working out in service, I look for similar information on others. 

Just yesterday I had a long overnight in IAD, and I spent the afternoon at the Air and Space Museum.  Similarly, I can go to a place like that and see the same airplanes that I saw there 9 years ago, yet my life experience has changed enough to give me something totally new to look at.

While I was exited about visiting with Russ, I was also very excited about his gracious offer to take me flying in his Bearhawk.  Upon arrival in Rosemond, Russ drove us out to where his Bearhawk lives.  It’s a very nice airpark with a paved runway and everything.  I picked his brain with all sorts of questions about how he has best found to operate his Bearhawk in the past 300+ hours spread over 4 years while he prepared a few last-minute things.  We got in and he started the engine for a brief warm up.  

There are several unmistakeable differences in Russ’s cockpit and mine.  First, his is much more festively decorated in yellow and red.  Second, he has quite a few more gadgets at his disposal.  He commented about this, being aware of the very full pilot toolbox.  This was my first experience in a 540-powered Bearhawk, so I wasn’t quite sure of what to expect from a performance standpoint.  The takeoff roll was comparable to what I’ve experienced with my Bearhawk, but there are several things to consider in that comparison.  First, we were operating at a heavier weight than I have been operating in my solo flight tests.  I suspect that we were around 400 pounds heavier than my usual weight, because of the extra passenger weight and higher empty weight.  Second, and perhaps most importantly, we were at a much higher density altitude.  The airport elevation is much higher than I’m used to, and so was the temperature.  Those factors combine to explain why the performance seemed only somewhat better.  I’m interested in doing more comparison work someday where I can better quantify the difference, using tools other than intuition and the seat of my pants.

Seeing all of these factors in play, it makes much more sense to me why Russ chose to equip his Bearhawk as he did.  After all, it was January!  In the summer, I can imagine that he sees much higher density altitudes.  The departure density altitude is an issue, but so is the need to climb high to clear the surrounding terrain.  In the short hop over to his glider airport, I saw why he explained that any cross-country trip of length is going to require a cruise altitude in the 10,000 foot realm.  I’m especially interested to get our Bearhawk into this kind of environment to see how it does, but I haven’t yet.

I had a great time riding with Russ, and I learned a bunch about how he operates his Bearhawk.  To top it all off, his wife made a home-made supper that couldn’t be beat, and I got to visit with one of his fellow TPS friends and hear about their Oshkosh trip.  That area is crawling with a bunch of really smart airplane folks, and I could certainly imagine an alternate life where I could live around them and have lots of airplane fun.  Overall the trip was absolutely worth the effort, and I’m looking forward to applying the experience and some measurements from Russ to make a much more numerical comparison between the capabilities of the 540 and 360 Bearhawks.

Flying Update

I have found that the engine is running a little less smooth than I think it should. This is a challenging problem, in part because it may be running just fine. I have a fair amount of experience in single-engine piston airplanes, but most of it is not in recent times. At idle, I hear an occasional miss, even with the mixture leaned. The other day, I took off with the intent to fly for a few hours, but at 2500 RPM and full throttle, it was running rough enough to make me turn back towards the airport. To be fair, I’m not sure if a non-pilot passenger would have noticed it. I leaned the mixture a little bit and the roughness went away, but this didn’t make sense, because it was exceptionally cold that day, and the density altitude was probably well below sea level. On another day I found 150 RPM drop during a ground mag check, when I turned off the left mag. I tried running the engine up a little bit and leaning aggressively, but had no change. I taxied back on the rough mag and hopped out to check the exhaust pipe temperatures. All except number 1 were around 350 degrees, while number 1 was more like 300. I swapped the bottom plug from that cylinder to the top, and tried another mag check. This time the drop was on the other mag, confirming that the plug was to blame. I replaced it with a spare that I had on hand and took off to conduct an inflight mag check, as described by Mike Busch.

His process involves using the EMS data logging, so I figured getting that started would be a good first step. I had noticed earlier that when I went to the data logging menu in the D180, instead of the usual choices of “on” and “off”, I had a message that said “Error 4.” With me not having the tools to address that problem right then, I took off anyway and conducted the check as Mike describes. I wrote down the EGT changes, but as he points out in his articles on the subject, that’s not really enough information. The good news is that during those checks, I didn’t get any significant roughness. The bad news is that I had some wacky EGT numbers. The cylinders were all fairly even when running ROP, but one was about 300 degrees lower when running LOP. I resolved to get the data logging working, then fly on another day to get more valuable numbers and see what’s going on. I never have installed the little blocking plates in front of the front two cylinders, since the Vans baffle kit instructions say to not install them unless you find that you need them. I have been reading reports from Husky owners that they get much better LOP operations with similar plates in place, because the cylinders run more similarly to each other. So that’s another avenue to explore.

To address the “Error 4” in the data logging menu, I did some Googling to find that it is a bug with the Dynon. Speculation is that the data log file becomes corrupted. The fix is for Dynon tech support to send a file, which I then send to the D180 as a “restore firmware backup.” The repair file is firmware version specific, and Mike at Tech support sent the version that corresponds with the latest firmware. I was due for an update anyway (though I didn’t realize it just then) so I downloaded the latest support program and went back out to the airport. I went through the usual ritual of powering off both the D180 and D100, then updating the HS34. Then I updated the D180, then the D100. After all of the firmware updates, the Error 4 message was still there, so I sent the repair file. The good news is that the new file fixed the problem, but the bad news is that there wasn’t any log file there. The D100 did have a good file though, and it has been extremely fascinating to study. Now I’m looking forward to getting to fly again and get some good data from the D180, which will be much more valuable, since it should have EMS data too.

In fact, with having so much information available in the logs, I think I’ll plan to redo the bootastrap glide tests, to try to provide better numbers for the data plate.

The Bootstrap Method of Performance Analysis

The first part of flight testing was relatively easy to plan.  For the first few hours, I was just interested in getting the airplane safely into the air and back on the ground.  I began to find the edges of the center part of the envelope in as incremental of a way as possible.  After those few hours, what was to come next?

I’ve read several articles, books, and Advisory Circulars that all have good guidance, but what I really wanted was a good way to start fleshing out the performance data that would come in the POH of a store-bought airplane.  I have read about sawtooth climbs and other “fly and record” approaches, but I didn’t see how that was going to give me as much detail as I knew I would want to have available.

Fortunately, some searching led me to a series of three articles by John T. Lowry in the Avweb archives.  Those articles led me to other articles of his, and to his book, Performance of Light Aircraft.  I’ve read enough of his writing to appreciate his approach and his style.  He is a physicist, but he is also a pilot.  He finds an excellent balance between the theoretical world and the actual world, and takes an approach to performance calculations that knows its limits so to speak.

He describes a method that he calls The Bootstrap Method of Performance Analysis.  The short version of the strategy is that we use the measured performance from one set of conditions, combined with his math-rich spreadsheets, to create predicted performance for many different conditions.  I’ll let you read the articles to learn how the strategy works.  If you’d like a little bit more detail, I’m planning to put an updated article in the first quarter 2014 Beartracks issue.  If you’d like to have much more detail, see if you can find a copy of his book, in which he goes step-by-step through his derivation of the various formulas.  Good luck finding a copy, since it has aparently been out of print for a while unfortunately.

The good news about his method is that it doesn’t take very much flight testing to get started.  The even better news about his method is that airplanes with constant-speed props have even fewer measurements to make.  The airborne flight tests amount to just a series of glides.  These glides do require a calm day with no convection, which means either an early morning, or an overcast, stable day.  

The first round of glide tests have shown that the minimum sink speed is somewhere between 50 and 55 knots indicated.  Lowry points out that the curves in most GA airplanes are very smoothly shaped, which is another way of saying that the glide performance difference between 50 and 55 is likely to vary little.  I’m planning to do more tests to see if I can pin down the specific speed, but for now my sample size is too small to say definitively whether it’s 52, 53 knots, etc.  

I’ll have much more to write about the method, especially if it works well.  The great thing about it gives me some insight about how various factors impact performance.  I’m less interested in knowing exactly what my climb rate will be at a particular circumstance.  I’m much more interested in knowing if, for example, the temperature were 20 degrees warmer, how much I should expect the rate to change.  Will it be 10% lower, or perhaps 80% lower?  Short of intuition or actual flight testing, I don’t have any other way to know.  

The Bootstrap Method also allows for comparing input factors like engine horsepower.  What if my engine produced 15 more horsepower at the same weight?  How would that impact my maximum level speed?  Similarly, what if I had installed a Hartzell 80″ prop instead of a 76″?  You can see how this method, even though it does make a few underlying assuptions, will be very useful in helping elaborate on how the Bearhawk can perform under certain circumstances.  Look for much more to follow, if not here, then perhaps elsewhere.

Transponder Check

Yesterday’s flights went very well, and after a second thorough inspection, the airplane still looked like it was ready to fly. I took off and climbed up above the airport again, and all was still well, so I flew over to the avionics shop to get the transponder checked. This will allow me to turn the transponder on, which will greatly enhance safety with ATC and other airplanes. The folks at the avionics shop fixed it right up, and I flew back home. Instead of landing back at Hickory, I landed at our home airport just south of town. I’m glad to have the airplane back in our own hangar, where I can work in more relative comfort and convenience.

First Flight

Last week I drove down to Charlotte to pick up the airworthiness certificate. I got back into town with it just as a cold front did, and it took these 9 days to get a day with the right combination of me being in town and the weather being good. The weather was perfect all day today, and the flight went well. I flew for about half an hour, then came back to do a thorough inspection. I found a few more minor items to correct, such as the direction of the elevator trim. It worked backwards to how I thought it should work, so I just flipped the wheel around to reverse it. In that process, I noticed that the nut in that bolt had no cotter pin, which goes to show that even with several sets of eyes looking over an airplane, things can get overlooked! Everything looked good with the inspection, so I put it all back together and flew again. On the second flight I repeated much of the first, though I expanded the initial stall testing by adding flaps. At the end of the flight, instead of ending after one landing, I flew around the pattern for 5 more. The challenge with test flying a new airplane is that there are several goals to achieve. One is to validate the airframe and systems, but another is to train the pilot. The landings were more for the latter goal, though of course they also helped with the first. I feel very confident with the directional control on the ground, which was one of my main concerns about the flight testing. I find that I have a little bit of a heavy wing, and a few other minor things to fix, but that’s what the next 40 hours are for.

FAA Airworthiness Inspection

Today was the much-anticipated, rescheduled FAA inspection. I came out early to take off a few inspection panels and tie up the last few items. One was to add safety wire to the prop governor stop screw. Since I wasn’t sure that yesterday’s adjustment was going to be exactly correct, I hadn’t safetied it yesterday. When it was time for my appointment with the inspector, I went to the FBO and waited patiently, for an hour. After an hour, I called the inspector. After a brief discussion, we came to the conclusion that he had made a scheduling error and was not on his way. Fortunately though, he found someone else to do the inspection and sent him right up. I took a lunch break and waited for the new appointment time. The inspector was very professional, and had some suggestions for minor things that I could make better. He found the airplane to be ready to fly, and we did the paperwork. Since he didn’t have any advance notice about doing the inspection, he had not prepared the airworthiness certificate or operating limitations, and said that they would be ready in the next day or so. This was a bit of a setback, because the weather has been perfect these days. The good news is that the airplane passed, and the paperwork should be easy to remedy.

Weather Stripping

This morning I added some weather stripping to the cabin doors. I also installed small rivets on either side of the front window latches, as Eric Newton did. Hopefully these will keep the window from coming open on its own. I also endorsed the logbooks with all of the required endorsements. Now it’s just a matter of trying to get the inspector in to issue the airworthiness certificate.

Taxi Checks

Today was supposed to be the day of the airworthiness inspection, but the FSDO had to cancel it. I spent a few minutes working on a few minor things, such as installing the new Dynon backup battery that arrived, and replacing the GPS data card with a new database. I also adjusted the prop governor stop screw to try and increase the static RPM. I taxied around for a while, working at first on verifying that the RPM increase was good. Then I worked up and down the runway, increasing my taxi speed by about 5 knots each time. It occurred to me that I had not yet done a compression check on the engine, so I did that while it was hot and found all good numbers. At this point, the airplane is pretty much ready to fly, at least mechanically.

Compass Module Direction Swap

I’m back to working solo today. I started by making some extensions for the rear seat center seatbelts. I used 1/8″ 4130 to make little dog-bones, which would move the attach bolt outward by 1″. Then I cut a piece of tubing that was as long as the attach bracket in the seat structure. I ran one bolt through the seat bracket and both dog bones, then ran another bolt through the seat belt brackets, the dog bones, and the spacer tube. A picture would help with making sense of all of this, but I didn’t take one, sorry! Yesterday I found that the compass readings were 180 degrees off. It turns out that I installed the compass modules backwards, which would explain that problem. I took off the left wing tip and swapped the modules around, which was a tedious 2-hour job.

More Odds and Ends

Today we worked more on the odds and ends. Dad installed seatbelts while I took the stainless tunnel under the boot cowl off. This part was vibrating when the engine ran, so I adhered a piece of 1/4″ thick closed-cell foam to try and dampen the vibrations. The rear seat belts have fairly large fittings on the ends, and they interfere with the structure at the center of the back seat. I’ll have to make some extension fittings for that spot. We installed the fire extinguisher and the carbon monoxide detector, and added a few more color markings to the EFIS setup for the airspeed. Next I did more taxi testing, this time to calibrate the compass. The headings are 180 degrees off, so I’ll have to investigate why.

Engine Adjustments

It has been really helpful having my dad in town to help with these final preparations. Today we drilled holes in the outboard aft corner of each fuel bay hatch. These holes will allow the fuel to drain more readily if the tanks begin to vent like they did yesterday. I also added the labels to the top of the wing that show the fuel tank capacity. I did a final check of the fuel fittings to make sure that none had been leaking overnight, and we took a lunch break. After lunch we ran the engine for a while to make adjustments to the carburetor for idle mixture and idle RPM. The theory is that the mixture adjustment should be somewhere between 1.5 and 2 turns out from fully closed. I was aiming to set the idle at around 700 or so. We made those adjustments, and while the EAA videos talk about looking for a 50 RPM rise when the mixture is fully leaned to stop the engine, we were seeing around 30. I taxied out to the runup area to check the static RPM, which was 2600. This should be 2700, so I’ll start by adjusting the governor stop to see if that is the limiting factor. If it isn’t the governor, then it might be the low pitch stop.

Filling the Fuel Tanks

This morning dad came out to help again, and we finished up the wing root fairings. I used pliobond to attach velcro to the fuselage tubes in the area where the back cabin bulkhead attaches. I noticed a very small oil leak around the prop governor control head, and a few days ago I ordered a new gasket for that spot. We worked together to replace the gasket and re-safety the screws. I added the final magnets for holding the windows open- it took three behind the wing skin and one on the window. The one on the window is about 3/8″ in diameter, while the ones behind the skin are each about the size of a nickel. After those few things, I taxied across the airport to the fuel pump and we topped up the tanks. I wanted to get an accurate picture of the tank capacity, so I filled them all the way up. This proved to be problematic, because the fuel expanded and started venting out of the tanks as it warmed. Before I realized that this was what was happening, I was concerned that I had a leaking tank. I was relieved to find that it was just running out of the cap!

Final Tech Counselor Visit

Today my dad and I worked on shortening the list of final things to do. We started with installing the top wing root fairings, which I designed to use nuts. Nutplates would have made the work a one-person job, but since these will only come off when the wings come off, I figured that the reduced work of not having to install nutplates would probably provide a net gain over the occasional need to have some help. Our local EAA Technical Counselor Wesley came over to look over things too. He found a few good things to fix, such as my incorrect routing of one of the ammeter wires. I made good notes of all of his suggestions. After that, dad and I got back to the wing root fairings. I attached a few cosmetic fabric patches over the elevator trim arms and the flap pulley bolts, while dad reinstalled all of the wing inspection panels except for the fuel panels. We also lubricated the prop per Hartzell instructions.

Weighing

I’ve spent some time trying to come up with a good way to hold the airworthiness certificate and registration in place. The most light-weight option that I could come up with was to use pages from a small photo album. A trip to the Mighty Dollar yielded a little bunny book that I took two pages out of.

Bunny Book

Bunny Book


While I was in there, and now that we’ve had a successful engine run, I closed up the top access panel over the instruments. I started installing the left wing root fairing, but will need some help backing up nuts to finish it. I sealed the firewall grommets with 3M Fire Barrier 2000+, and worked on the cowl for a while. I decided to switch to screws on the front seam that had originally been rivets. I located the holes in the same way that I did the first time. I used spacers to create a gap with the spinner, then started in the middle and worked my way out one hole at a time. In this case, I used a strap duplicator to match the holes to the underlying fiberglass. Since I’m switching from rivets to screws, I also increased the spacing.
New Cowl Fasteners

New Cowl Fasteners


The good news is that I was able to remove all of the old material that had the rivet holes in it. The front edge of the aluminum is not painted, but there are plenty of other flaws that a discerning eye would see in my paint job before something like that becomes apparent. Jim and Danny came by to help get the airplane ready to weigh. As much as it is a moment of truth, there isn’t much to the actual procedure. I placed all of the access panels and fairings over their respective holes, drained the little bit of fuel from the tanks and lines, installed the back seat and back seatbelts, stuck the spinner in place, removed everything else from the cabin (which is usually my work space), and connected the engine lift to the tail handle. We powered up the scales and zeroed them out, then rolled the mains up onto their scales.
Mains are on

Mains are on


Scale pad

Scale pad


Then we lifted up the tail to level flight attitude and built up a stack of stuff to support the tailwheel scale at the right height. Then, I looked at the scale to find what I think are pretty good numbers.
1328 pounds empty

1328 pounds empty


I was expecting 1350, and hoping for under 1400, so I’m quite pleased.

Fuel Flow Test and Engine Run

Much of the work lately has been sequential. I have a list of tasks that can’t really be done out of order. Today I was finally to the point on the list where it is was time to test the fuel flow. I did it in almost the same way that Eric Newton did, although I used a little bit different method for lifting the wheels. I used the calculations in AC90-89A and Eric and Russ’s test descriptions to arrive at a fuel flow requirement of around 24-25 gallons per hour. I used the engine lift and a webbing strap to lift the left wheel high enough for a concrete block underneath. I was surprised at how low the right wingtip was during this arrangement, and it was quite clear that I was going to have to set one block per side at a time.

With one block in, it sort of reminds me of the Husky display at Oshkosh.

With one block in, it sort of reminds me of the Husky display at Oshkosh.


So that’s what I did. Once the left wheel was under a block, I moved the lift to the other side and lifted the wheel high enough for two blocks. Then I moved the lift back over to the other side and added the second block on the left.
Fuel Flow Attitude

Fuel Flow Attitude


I disconnected the fuel line at the carburetor and rigged up a gas can at the same height as the carb inlet. I put my little digital scale under the gas can. I zeroed the scale, ran around and turned on the fuel valve while starting the time. After a minute, I turned off the fuel selector and went back around to check the fuel flow. Even with the sensor in place, I was able to get a pretty consistent 24-25 GPH. That’s not much above the minimum required, but the minimum already accounts for a 50% margin and essentially empty tanks.
Dynon agrees

Dynon agrees


With a few successful tests producing repeatable data, I lowered the airplane back to the ground and breathed a sigh of relief to know that it was back on the ground safely. Since the test was successful with the fuel flow sensor in place, I secured the wires for it and reinstalled the stainless tunnel after one more leak check. I did find a minor leak on the parking brake valve fittings, but was able to snug those back up and stop the seep. I used a length of 2″ SCAT tubing to create the duct from the carb heat muff to the carb heat inlet and secured it with hose clamps. Tabitha stopped by to help with the first engine run, and to bring some delicious lunch. We pushed the airplane out onto a tiedown spot, and tied it down very securely with our own ropes.
Tied down securely

Tied down securely


We conducted a thorough briefing about what she should expect to see, what she should expect not to see, how she would communicate the most important information, and how she would stay safely clear of the prop. I positioned a fire extinguisher off of the left wing, and she carried one on the right wing. She positioned a ladder so that she could see the top of the engine too.
Ladder vantage point

Ladder vantage point


Cowl off for the first run

Cowl off for the first run


She took a few more pictures just to show off the paint scheme.
Paint Scheme

Paint Scheme


Paint Scheme

Paint Scheme


Paint Scheme

Paint Scheme


With all of that preparation out of the way, there wasn’t anything else to do but start it up. I conducted a pre-start flow (fuel on, mixture rich, prop low pitch, throttle cracked, carb heat off, master on, right mag off, left mag start) and after a blade or two it fired right up. I carefully scanned the engine instruments to confirm oil pressure, and looked to my observer to be sure that everything looked good to her. She said all looked good, so I let the engine warm up for a few minutes while I conducted a few function checks. First, I energized the primary alternator and verified that it increased the bus voltage from the battery range to the alternator range. Then, I closed the ebus alternate feed and turned the master off. I turned on the standby alternator and verified that it was providing power. I returned the electrical system to the normal configuration (standby off, master on, alternate ebus open) and cycled the prop a few times. It took a few cycles before the oil filled the prop, but by the third one or so it was working well. I kept the RPM around 1000, and verified that the CHTs stayed low, and the oil pressure stayed up. I checked the mags one at a time and saw a slight drop, and also turned off both mags very briefly to verify that the p-leads were functioning. The engine was smooth and ran well. It does appear that the RPM is indicating half of its actual value, but this is adjustable in the EMS settings I believe. After about 7 minutes I shut it down with the mixture control. I consider it to be a successful run, and now that the alternator wiring is validated, I’ll be able to seal up the firewall. Tabitha helped me push it back into the hangar, and I worked on getting the cowl to fit properly.

Rigging the Ailerons

I started to set up the ailerons for their final rigging, and realized that when I routed the cables yesterday, the ends at the turnbuckles were twisted and not quite right. This made the cables about 1/2″ too long, but I was able to correct this by carefully removing the nicopress, shortening the cables, and recrimping with a fresh sleeve. I set them to their final tension and added safety wires to the turnbuckles. I added cotter pins to the bolts, and made a careful end-to-end inspection of each of the control cables. I’ve often thought that the handle on our Newton SPRL fuel valve is a little bit ambiguous in its pointer design. I had the label maker out to label the elevator trim and flap handle, so I also made some little arrows for the fuel valve to help eliminate the ambiguity. I installed the remaining floorboards and belly pieces, and found that the fuel flow wires were going to need a new routing. I had routed them outboard of the steel tube near the floor, but that means that the wires could rub between the tube and the boot cowl. I disconnected each of the wires and moved them to eliminate this problem, but I can’t reconnect them until I bring the heat shrink tubing from the other hangar.

MLG Width Adjustment

After a few days of work at my regular job, I was glad to get back to Bearhawk preparations. I installed batteries in the ELT and armed it. I set up to make the adjustments to the landing gear width as instructed by Bob. First, I tied a rope around the bottom of one axle, so that it would not be able to slide up the axle. Then, I connected a heavy-duty ratchet strap to the other side. Bob suggested a come-along, but I didn’t have one handy, and the ratchet strap is larger than usual, with 2″ webbing. I connected the strap to the rope and applied tension until the shock struts seemed to be neutral. I had to roll the plane back and forth a few inches to let the gear slide in. Once the tension was off of the shock struts, I could remove the lower bolts, then remove the bottom end of the strut. Then I could rotate the whole strut to change the thread engagement of the bearing at the top. I spent a while trying to figure a few things out, and I had to call Bob for a little bit more clarification, but eventually I was able to get the gear set up correctly. Here are a few tips. First, I used a second ratchet strap between the gear leg and the rope. This allowed me to set the second strap so that it was a few inches longer than the first. When I needed to let a little bit of tension out, I would release the first strap and let the second take up the load. Next, let me elaborate a little on how the gear is supposed to be configured. If the gear is built to plans, then the axles will be coliniar when the tread width is 72″ at the center of the axle. Since the tires are not perpendicular to the ground, I was measuring the tread width from the center of one tire to the center of the other, with my measurements happening in the vertical center of the tire, in the front of the tire. I found that I had to have the rod end threaded pretty far out to get the width wide enough. Bob says that the minimum thread engagement should be 1/2″ to 5/8″, with his preference being 5/8″. He said if the threads were really tight, then 1/2″ would probably be ok. He pointed out that since the thread pitch on the bearings is 20 threads per inch, then one could be sure about the engagement by threading the bearing all the way out and counting the turns. The overall thread length of the bearing is 1.5″. Bob suggest 68″ from center to center with no load on the shock struts, and requires no more than 74″ width at max gross weight. There are several things that occur to me here. One is that I’m not positive that the center of the tire is coincident with the center of the axle. The other is that until I load the airplane up to max gross weight, I won’t have any way to verify that I haven’t exceeded the 74″ limit. When I get to that stage, I’ll be sure to measure again. When the gear is splayed beyond the 72″ neutral point, then the gear is toed out. When it is narrower than 72″, it is toed in slightly. This caused a minor short term panic, because after I finished the adjustment I rolled the airplane forward and backward to check for changes in the width. I found that at the empty condition, the wheels were toed in a little. I was under the impression that any toe-in was bad, and had flashbacks of the complicated job of aligning the gear all over again. Fortunately, it turns out that because my tread was so narrow in the empty condition, the gear is supposed to be toed in a little. Bob says that this is the way he likes it, and that upon rolling backwards, the gear width shouldn’t change by much more than an inch or inch and a half. After setting all of that up, I added cotter pins to the bottom of the shock struts. I made the new aileron cables out of the new stuff that came in, but I left the dead ends long until I finish the rigging completely. I don’t want to wait yet another week for replacement cable!

Main Landing Gear

I started today by adding a little bit of fuel to the tanks. I wanted to see if there were any leaks, and there were a few. I was able to stop the leaks by snugging up the nuts a little. One of the necessary adjustments is to set the width of the main landing gear. That is going to require a few steps, so I started today on preparing to make that adjustment. First, I removed the main wheels, one at a time. I needed to do this so that I could set those last few rivets on the access hatches at the bottom of the gear legs. Next I put the wheels back on and started to put in the cotter pins, but I soon realized that there weren’t any holes in the axles yet! So I took the wheel back off and drilled a hole through the axle, using the axle nut as a guide. I reinstalled the wheel, installed the cotter pin, and repeated that process for the other side. I put cotter pins into the bolts at the top of the shock struts, since they won’t need to be removed during the adjustment. I removed the belly panels so that I can get better access to the shock strut tops, and stopped there, being that our new hangar doesn’t have lights to speak of, and the days are getting shorter.

Timing the Mags

With finally having all of the right tools in place, I was able to time the mags this afternoon. I started with the right. When I got to the left, I found that I didn’t really have enough adjustment. I could get the light on the timing box to change only when I was right at the edge of the adjustment, and only when I applied a little bit of force beyond there. I called Bob for advice, and he said that the gear on the front of the mag is designed to be installed in one of two ways, just for this purpose. Here’s what it looks like.

Left Mag and Impulse Coupling

Left Mag and Impulse Coupling


While this picture is blurry, you can see that it is the left mag because it has the impulse coupling, there between the gear and the mag. Note how the gear has a slot in the back where it mounts to the impulse coupling. Now check out the next two pictures.
Slot aligned with slot

Slot aligned with slot


Slot aligned with tooth

Slot aligned with tooth


Notice that on the first picture, the slot on the back of the gear is aligned with a slot between gear teeth. In the second picture, the slot is aligned with a tooth. Since there are 13 teeth and 13 is an odd number, it works out that the gear is not symmetrical. I removed the cotter pin and castle nut, then removed the gear. I reinstalled it 180 degrees different in rotation, torqued the nut, and reinstalled a new cotter pin. Upon reinstalling the mag, I found that the timing light changed right in the middle of the adjustment range. I finished timing the left mag, and both are set right to 25 degrees btdc. With that work right next to the mags done, I installed the battery. This allowed me to test the wingtip lights, which I had been waiting to do before I installed the tips. I didn’t want to have to take the tips back off if the lights weren’t working! I mounted the lights onto the tips, and then installed the tips. Tabitha came out for a few minutes and we verified the calibration of the oil temperature sensor and the CHT sensors by dipping them into ice water and near-boiling water. In the case of the oil temp sensor we had to dip the sensor for a while, then wipe it off and stick it back in the hole so that it would ground in the right spot. All of the sensors were very close, certainly as close as they need to be. While she was there to keep an eye on things, I cranked the engine over with the spark plugs removed to prime the oil system. After about 45 seconds the oil pressure was up to 60 psi. I reinstalled the top spark plugs and torqued all of the plugs to 35 foot pounds. Then I spent a few minutes going through the menus on the Dynon units setting up the limits, color ranges, and other things like that.

Adding Oil to the Engine

While I wait for the new aileron cable to come in, I removed the old cables and used one of the front cables to make a replacement for the left rear. This will allow me to get the flaps on. Doing more things like this helps increase the odds that I’ll find unforeseen errors. Fortunately there weren’t any that turned up with the flaps, which are working well and as expected. I secured the flap turnbuckles at the back of the cabin with safety wire. I still haven’t figured out exactly what happened with the cowl alignment, but somehow the top piece is too long. I drilled the rivets that held the top aluminum panel to the top of the nose bowl, and started to think about how I would be able to adjust. With the cowl off I started preparing to time the mags. I started to remove the spark plugs, and realized that I didn’t have a spark plug socket with me. This gave me an excuse to go visit the other hangar for a little while. Once there, I used my little pneumatic tool engraver to engrave the stainless steel data plate with the information that’s on our registration card. When I got back to our second hangar, I added oil to the sump, one quart at a time. I waited several minutes after each quart, then removed the dipstick to graduate it. Some of the odd jobs that I did while I waited included verifying the torque of the exhaust nuts, torquing and safetying the alternator bolts and prop bolts. In the case of the prop bolts, I used the little prop wrench as an adapter. I calculated the required settings for the torque wrench based on the formulas in AC 43.13 and torqued each bolt to 40 foot-pounds, then to 60. The safety wire was pretty slow going, but after an hour or so it was done. I doubt that it takes an experienced A&P two hours to install a constant-speed prop, but that’s about what it takes me. I added a total of 7 quarts to the sump, and made marks up to 6.

Final Wing Bolt Torque

Today an order came in from Aircraft Spruce. When I ordered the new aileron cable, I ordered 3/32″ diameter instead of 1/8″. This was a frustrating mistake, but fortunately they are going to accept a return on the 3/32″. I installed the wing tiedown rings at the top of the wing strut, which required removing the bolts and putting them back in. I torqued all of the remaining wing bolts and applied some torque seal paint. The paint isn’t without its own shortcomings, but there is a chance that it might indicate a bolt loosening problem sometime. Another one of the suggestions that came from our EAA Chapter project visit was to route the cabin heat overflow away from the battery. In my original arrangement it was pointed directly at the battery. I ordered a huge Adel clamp that would go around the 2″ tube, and installed it on one of the bolts that holds the parking brake valve in place.

Carb Heat Overflow

Carb Heat Overflow

While I was working there I also noticed that the engine ground cable had a long floppy section that wasn’t supported so well, so I added a clamp to stabilize it better.

Pitot Tube

This morning I finished with installing the pitot tube, and connected the AOA and pitot lines. I installed the VHF comm antennas in the top of the wings, and secured the wires for the right side wing rooth. I finally connected the front left upper fuel line at the wing root, since it needed a little bit of adjustment.

Installing the Wings

The timing of this whole relocation effort has worked out pretty well. Tonight was the EAA meeting, so we made it a project visit. Before the meeting, I spent a few minutes checking out the cowl clearance problem, and installing the rigid tube portion of the engine breather line. Lots of folks came out to see how the project has been coming along, and with all of that help, we put the wings back on. Things went together nicely, and it was good to see the airplane looking more like an airplane again.

Wings On

Wings On

Installing the Ailerons

Back at our first hangar, I loaded up the flaps, ailerons, wingtips, and a few other things to move to our second hangar. I unloaded those things and started making the connections that had been waiting on the wings. I connected the flap cables and fuel lines, excepting the front left fuel line, which wasn’t cooperating well. I connected the aileron cables and installed the pulleys near the sticks, and started investigating the known rigging problem. When I first made the cables, I overestimated the amount of turnbuckle travel that I would need to tension the cables. I built the cables with about half of the threads showing, so when I tightened them to 30 pounds of tension, I still had most of those threads exposed. The limit is three threads exposed, but at the time I figured it would be best to wait until now to remake the cables. I had planned to remake one of the two rear cables, but today’s investigation showed that I’m going to have to remake three out of the four cables, including both front cables. I’ll be able to reuse one of the front cables to make the shorter rear cable, but I need to order about 35 more feet of cable. Last night when we put the wings on, we just put the bolts in place with no nuts. Today I added nuts and torqued the lower ends of the struts, and the front wing bolts. I had two holes to patch in the firewall, and I had intended to do so with a stainless patch. Jack was at the meeting last night, and he suggested filling the holes with bolts and washers. That sounded like a great idea, so I did that too. The holes were about 1/2″ each, so I used AN3-3 bolts with AN970 washers on either side of the firewall. Finally, I started working on the pitot tube install. The access hole there is pretty small, so it’s slow going.

Moving the Wings

After the harrowing fuselage move, we left town for a few days of vacation. Now that we are back, it’s time to move the wings. These should be easier to move than the fuselage. The process included taking each wing off of the rack and putting them on saw horses. Then we put the rack onto the trailer and secured the bottom of it. Then we moved each wing back onto the rack, and secured the wings to the rack and to the trailer. Here is what it looked like:

Wings on the trailer

Wings on the trailer


Danny was instrumental in getting this done. We moved the whole package to the airport, including the struts (which Danny took in his car) and many of the tools. We are expecting a crowd tomorrow evening at the EAA meeting, so for now we just took the whole trailer into the hangar and left the wings loaded on it.

Moving the Fuselage to HKY

Our little airport is going to be a great place to base our Bearhawk, in part because it is really close to the house. It’s a small airport though, and not really well suited for a safe first flight. As such, the plan has been to move the airplane to the municipal airport about 5 miles to the north for final assembly. Today I worked on a few remaining jobs that are easier to do here, and spent some time meeting with the folks at the big airport to finalize our hangar spot. After a lunch break I came back to work on more final items, starting with the carb heat inlet on the airbox. Here’s the arrangement that I came up with:

Carb heat duct

Carb heat duct


The duct for the right side cabin air vent was really in the way of the electrical distribution panel, but I thought I was going to be able to make it work. After a few different attempts, it became clear that this wasn’t going to be the case. The easiest corrective action at this stage was just to move the vent down a few inches to clear the panel.
New Vent Location

New Vent Location


After locating the hole with great precision and accuracy, I cut out the aluminum section and riveted the vent into place with blind rivets. I used washers on the back of the blind rivets to help spread the load out on the plastic vent, instead of making an aluminum ring like I had for the first vent. I also made an aluminum blank to cover the old hole, and next time I do some painting I’ll drill the rivets and paint this piece to match the rest.
New Vent

New Vent


Next I installed the font seat seatbelts. They went in exactly as they were supposed to. I installed the two-piece stainless shields on the firewall where there were grommets, and made a rubber sealing strip to go on the front of the filtered airbox.
FAB front seal

FAB front seal


I added the remaining belly panel for easier transportation, and installed the prop. I didn’t set the final torque on the prop yet, in part because I have an interference problem with the cowl that I didn’t expect. Installing the prop sure is a pain in the rear, though the special wrench did help some.
Prop Wrench

Prop Wrench


I got the wrench from Anti-Splat Aero, and it probably saved about 45 minutes on the job. I was still able to get the cowl on, though it was rubbing the spinner on the top of the junction.
Cowling on

Cowling on


I installed the ELT antenna on the top of the rear fuselage, and used wire ties to secure the coax all the way down to the ELT. I also used temporary ropes to secure the flap cables and the electrical wires that go out to the wing root. From there all that was left was to load the fuselage up on the trailer and drive away! You can be sure it was much easier to say than to do. Fortunately, I had some help from Tabitha. For all three wheels to sit on the ground, the trailer would need to be 18 feet. Mine is 14 feet, which means that it goes from the main wheels to the handles on the fuselage. The trailer has a gate on the back, which we left in place initially. We rolled the mains onto the ramp, then hooked up big ratchet straps to the main landing gear. I disconnected the trailer from the truck so that we could tilt the whole thing back. This allowed the ramp to sit flat on the ground. Then I advanced the ratchet straps until the mains were up over the axle. Once there, we were able to set the tongue of the trailer back down to the normal height, and push the fuselage by hand up to the front of the trailer. Once there we detached the ramp, since it was going to be too tall to fold up. My plan had been to build some wooden shoring to keep the tail up, by running a board under the handles. What I didn’t realize is that the stringers protrude down below the handles. I was pretty sure that they didn’t, but I was wrong! Tabitha came up with the idea that we ended up using, and she called it the hammock. We set a saw horse on each side of the fuselage, as far back as we could. We stabilized those saw horses with diagonal braces fore-aft, horizontal braces across the front, and one long brace across both in the back.
Setting up the saw horses

Setting up the saw horses


Then we ran straps from the outer edges of the trailer bed, up over the saw horses, and then to the handles. These carried the weight of the tail sort of like a suspension bridge. Then we ran a big strap over the top of the whole contraption to hold the tail down. I used large ratchet straps to hold the main wheels in place, and made control locks out of bolts and very large washers. I installed those on the counter balance areas of the elevator and rudder. One should note that it’s not really prudent to carry the fuselage on a trailer with the horizontal stab and elevator in place. The span of the stab is 10 feet, and in my state (and probably yours too) the max towing width is less than that by a little. This was part of the reason that we conducted this big move in the middle of the night. The more important reason was that we wanted to minimize the number of other cars on the road, both for the safety of the cargo, and as to not create too much of a spectacle. Here it is all ready to go:
Fuselage on the trailer

Fuselage on the trailer


We stationed Tabitha and sleeping Felicia in a car in front, then Alan brought up the rear in his truck. Tabitha’s job was to scout out oncoming cars so that I could pull off of the side of the narrow two-lane roads. I only had to do this a time or two. Alan’s job was to make sure that the load remained secure. We briefed to establish communication methods for all of these roles, and proceeded very carefully to the other airport. When we got there, Jim came out to help with the unloading. Here is the result:
New temporary home

New temporary home


To say the least, it was a nerve-wracking experience that I hope I’ll not have to repeat.

Posted on
Hours Logged This Session: 13
Total Hours: 1883.75

Installing the Landing Light

The only trouble with those fancy firewall pass-throughs that I made yesterday is that it’s hard to install them this late in the process. If I had installed them back when the boot cowl was still off, I would have been able to do it by myself. Since that’s not the case, it’s a two-person job. Fortunately Danny was able to help. Those all-metal lock nuts are pretty stiff to operate, especially from under the instrument panel. I was glad to have coarse thread bolts, since that meant fewer turns! next I attached the longitudinal skylight strips to the roof piece, with two rivets each. This allowed me to finish installing the skylight panels and associated sealant. I started a few days ago on making the rubber baffle seal attach points for the front of the cowl. Today I finished making those.

Right Front Baffle Seal

Right Front Baffle Seal


Next I installed the landing light into the empty bracket. I connected the wires and used an adel clamp to provide strain relief.
Landing Light Wires

Landing Light Wires


I installed the cabin heat box a few days ago, but had to think for a while about how to connect the control cable effectively. This is what I came up with:
Cabin Heat Control

Cabin Heat Control


It’s just an l-shaped bracket with a small angle bracket to stiffen it up. I also reinstalled a few leftover panels, such as the ones that sit under the front doors, and the horizontal stab root fairings on the right side. I made up a wire to put into the left mag blast tube to give it the proper aim.
Magneto Blast Tube

Magneto Blast Tube


Back when I removed the straight breather fitting to install and angle fitting, I had to remove the safety wire that was securing the tach drive cover. I redid that safety wire this afternoon, and called it quits for the day.

Posted on
Hours Logged This Session: 8.1
Total Hours: 1883.75

Instrument Panel Labels

Since the roof and skylight materials are done, it’s time to get the windshield in place for good. I used the felt tape that came with the windshield to pad the bottom.

Felt Padding

Felt Padding


The left and right post fairings worked pretty well, and the fiberglass fairing fits nicely. I used a bead of Lexel to try and keep the rain out. A line of masking tape on either side of the bead helped keep the lines straight.
I used the same stuff to apply a bead on the outboard side of the skylights.
Skylight Panels

Skylight Panels


I had been wondering aobut the best course of action for getting the various small control cables through the firewall. I found a great thread on vansairforce.net about using bolts. Bolts are inherently fireproof, and while not super lightweight, they are cheap and available locally. The thread author used 1/2″ diameter fine thread bolts, but that sounded pretty heavy. Instead, I used 3/8″ coarse thread bolts. The smaller size will still have plenty of edge distance and some weight savings, and the coarse thread makes it easier to find the bolts locally, along with all-metal lock nuts. Also in the VAF thread, the original poster used a lathe to make the hole in the middle. I don’t have my own lathe, so I tried it out with the drill press instead. There’s no need for that center hole to be perfectly concentric, so the lathe is probably a little overkill.
Drill Press

Drill Press


Here are the first two, ready to install.
Fireproof Bowden Cable Fittings

Fireproof Bowden Cable Fittings


This afternoon, Tabitha came over to help with a few things. We worked together for about two hours and made all of the instrument panel labels. I would tell her which ones to make, and she would take care of spacing them to minimize loss of the label tape on our little Casio label maker.
Making Labels

Making Labels


And sticking them onthe panel

And sticking them onthe panel


After she left, and now that we have an enclosed, locking cabin, I reinstalled the avionics and hooked up the pitot, static, and AOA lines.

Posted on
Hours Logged This Session: 8.6
Total Hours: 1883.75

Doors and Locks

I made a little bit more progress this morning on the rubber seals for the front baffles. I decided to make an attachment for the horizontal portion of the front baffles that starts on the nosebowl, allowing the rubber to extend to the aluminum portion of the baffle and float freely there. So far I bent some aluminum angles and used the shrinker to make them match the shape of the nose bowl. I came up with a new carb heat duct flange that uses a 45-degree angle, and started attaching it to the FAB. It still needs a little work. With the paint done, I was finally able to install the rear left window with blind rivets and some sealant. I used clevis pins and cotter pins to attach the front doors and windows, and attached the lock cylinders to the front windows. While I was working on cabin items I also adhered the 2-inch “Experimental” decals so that they are in view from all of the doors. After lunch I installed the horizontal stabilizer root fairings on the left side.

Posted on
Hours Logged This Session: 7.2
Total Hours: 1883.75

Pulling Off Tapes

This morning I stopped by to pull off the blue tapes and make sure that I didn’t have any problems to clear up.

Blue Parts

Blue Parts


I had a few spots to clean up, but since the paint is so fresh, it was not entirely crosslinked and MEK wiped it off well.

Posted on
Hours Logged This Session: .3
Total Hours: 1883.75

Spraying Blue

This morning I finished the masking work on the cowling.

Cowl Stripes

Cowl Stripes


With the cowling in place I found that I needed to trim my new extended front baffles just a little, so I did. I added the rubber seals onto the front of the side and rear baffles, and installed the new 45-degree breather fitting that came in the mail.
New Breather fitting, AN844-10d

New Breather fitting, AN844-10d


I had to trim a little bit off of the end so that it could thread in and clear the engine mount. If the engine had not been in the mount, I would have been able to thread it on without trimming. I finished adding stripes to the window sealing strip and horizontal stab fairings, then mixed up a batch of blue paint. This is the last round of blue paint before the first flight.

Posted on
Hours Logged This Session: 5.5
Total Hours: 1883.75

Stripes on the Cowl

At this stage of the building process I’m tying up lots of loose ends and checking things off of the to-do list. I started by making a length of coax that will go where I had intended to put the balun in the previous antenna arrangement. I mounted the cabin heat box in the hole that I made last time, and came up with a diffuser to help direct the air down a little bit. I suspect that I’ll want to make something more substantial later, but it may take some testing to decide for sure. To make this version, I started with poster board.

Cabin heat diffuser in paper

Cabin heat diffuser in paper


Then I flattened out the paper and made an aluminum version
Flat aluminum blank

Flat aluminum blank


Then I bent that aluminum blank to shape.
Bent aluminum blank

Bent aluminum blank


This is where it sits:
Ready to drill and rivet

Ready to drill and rivet


After a lunch break I drilled the diffuser and the firewall and installed the diffuser with rivets. I took apart the Vans carb heat flange, since I’m going to need to change the angle of the incoming duct. I made a few holes in the baffles for the rivets that will secure the rubber to the top of the baffles. Later in the afternoon Tabitha came over and helped mask the cowling for stripes.

More Baffling Accessories

Today I started by finishing the front baffle work. I installed the flange for the blast tube that will help cool the alternator. Next I reconnected the oil pressure wire and started to install the breather tube at the engine. The fitting that Bob supplied for this purpose routes the hose too close to the engine mount, so I’m going to need another fitting that will provide the right clearance.

Breather interferes with the engine mount

Breather interferes with the engine mount


After lunch I was able to cut a hole in the firewall for the cabin heat box, and started connecting more of the last few wires left to connect, such as the thermocouples on the left side of the engine for CHT and EGT. I made some heat shrink strain relief for the carburetor air temperature, since there isn’t a good place to attach the wires close by.
Carb Air Temp Strain Relief

Carb Air Temp Strain Relief


Next I installed the duct flanges for the magneto cooling tubes, and made the holes for the blue plastic ignition lead grommets.
Ignition grommet holes

Ignition grommet holes


Ignition lead holes

Ignition lead holes


I made an effort to route the cables so that they were twisted and tangled as little as possible. I took a break for supper and then came back to connect the thermocouple wires on the right side fo the engine, and securing the firewall forward wires in general.

Removing Tapes

Today I made a quick visit to remove the masking tapes from the door and window frames. I wanted to be sure that there weren’t any other peeling problems with those parts, and to minimize the time that the masking tape and papers were on the polycarbonate. Everything looks good.

Painting the Last White

Before painting time I worked on two dangling firewall forward tasks. The firs twas to make a support for the tailpipe where it passes under the firewall. This is totally made up by me, so it may not work. I started with a few inches of angle aluminum. Two holes are matched to the holes that are occupied by screws that connect the tunnel to the firewall. The other two holes are to be occupied by springs. Then I just removed material that wasn’t around the holes.

Rough Cut Angle

Rough Cut Angle


Finished Mount

Finished Mount


I also needed to extend the top of the front baffles a little above the standard Vans height. Since those guys usually use a prop spacer, their cowling is probably a little bit shorter at that station. I started with posterboard extensions, since posterboard is much easier to cut and replace.
Baffle extensions

Baffle extensions


It was really hard to try and match the bends in radius and location, so I made the extensions in pieces.
One side in pieces

One side in pieces


One side done

One side done


Both sides done

Both sides done


Then I mixed up a batch of white paint and sprayed the cowling, the underside of the roof, the door tubes that previously peeled, and the front edge of the horizontal stab root fairings. Those will end up with a tiny triangle of white paint where the stripe continues.

Preparing for White Paint

The primed parts are still in the booth from the last session, but I have a few that are due for white paint but not primer. Today I prepped those so that I’ll be ready to paint in one batch. These parts included the front door and window assemblies that peeled due to inadequate abrasion before their last paint, and the exposed portions of the back seat frame. The new parallel-port cabin heat muff arrived a while back, so I installed it today to make sure it would still fit. When I tried to connect the carb heat duct I realized that I’m going to have to come up with another routing for it. The standard Vans fitting comes straight up out of the FAB top, but that puts the duct too close to the number 4 exhaust pipe.

Last Round of Primer

Today was a long run to get the last round of parts into the paint booth for priming. I say the last round, but I actually mean the last round before the first flight. There are still a few bonus parts like fairings that we’ll paint later, after the plane is flying. I started with more work on the skylight. I drilled a few extra holes to make the fastener spacing 4″ on the outboard side of the outboard skylight panels. These fasteners will go through the wing root fairings and the polycarbonate, into the square channel under the skylight edge. Where the bottom wing root fairing meets the wing, I made some aluminum strips to serve as a landing point for the rubber gasket on the wing root fairing. I added tabs for this strip some time ago, before blasting and painting the fuselage. Today’s effort was just a matter of drilling the aluminum and steel, and adding a rivet at each tab. Next I prepped the parts that will go into the booth in this round. That starts with wiping with a solvent, scrubbing with phosphoric acid, and then washing. Only the aluminum parts get the acid step.

Clean Parts

Clean Parts


Next I riveted a few parts together. This included the upper nosebowl to the cowl top, the lower u-channels on the lower cowl, the doublers in the thin areas on the lower cowl, and the fiberglass scoop and bump for the intake and exhaust clearance. When I put the cowl on for one last check, I found a problem with the steel cowl supports. I had made them long enough to host a standard nut plate, but it became clear that I should have instead made them to support a one-lug nutplate.
You can see here that the steel is too long to the aft.

You can see here that the steel is too long to the aft.


The solution was to remove the two-lug nutplate, cut off some of the steel, and install a one-lug nutplate.
Much Shorter

Much Shorter


Here’s what the lower cowl looks like all riveted together.
Lower Cowl

Lower Cowl


And now that the steel problem is fixed, I can put on the whole cowl to make sure it all fits.
Whole Cowl

Whole Cowl


Then I took it all apart again (at least to the big pieces) and sprayed the last of my supply of EP420 on to them. I had just a little bit of paint left over in the end, but since it is a two-part epoxy it will cure in a matter of hours. I’ll have to order more when it is time to paint the next parts!

Nose Light

The cowl work continues. I drilled holes for attaching the new fiberglass bump. I installed yesterday’s nose bowl backing strips with a little bit of JB weld to hold them when the screws are out. I returned to the nose light bracket. I made a lens out of spare window polycarbonate, but didn’t like how it turned out. The fit wasn’t very tight, so I made another that fits much better. I installed nutplates in the aluminum strips along the sides.

Nose Light Bracket

Nose Light Bracket


The angle will be adjustable to a certain degree by sliding the two top pieces. On to the skylight, I finally was able to come up with a system that I like. I’m using 1.25″ wide 1/8″ aluminum strips in the middle. I was having a hard time drilling these acurately, until I realized that I could remove the clear skylight panes and drill without them. Since the holes in the polycarbonate are well oversized anyway, they don’t have a role in the match drilling. These strips will be thick enough for the screws to be countersunk, and stiff enough to make a nice straight line.

Cowl Fasteners

I had initially planned to only install four camlock fasteners, but upon visiting David Bice, he pointed out that the seal between the cowl door and the lower cowl could be a potential leak of cylinder cooling air. That sounded wise enough, and since the fasteners had come in a pack of 10 instead of 8, I had two extras burning a hole in my parts drawer.

Cam Fasteners

Cam Fasteners


I started with a test in just the u-channel. This just required a 1/4″ hole in the aluminum to allow the body of the fastener to pass through.
Fastener test

Fastener test


It looks like the length is just right. I used the receptacle as a drilling jig to drill the rivet holes. Then I enlarged the center hole with the step drill. All that was left was to add the rivets.
Fastener Rivets

Fastener Rivets


On subsequent fasteners I riveted through the channel and the cowl material, for a couple of reasons. First, if i ever need to replace one of these receptacles, I’d rather drill two rivets than the whole line that attaches the cowl sheet to the u-channel. Also, my plan to dimple the lugs on the receptacles did not work so well, so the two layers of aluminum provide a better countersink medium.
Cracked Receptacle

Cracked Receptacle


I think the crack was in part because the receptacles were pretty old. Some of them dimpled fine, but two cracked. I installed the rest, and ordered replacements for the others.
Finished Camlocks

Finished Camlocks


Finished Camlocks

Finished Camlocks


After those were done I made some aluminum backing strips for the nose bowl at the horizontal split.

Cowl Reinforcements

In some areas of the cowl, the exhaust clearance holes have caused some pretty narrow sections. I can see that those might be potential crack areas, so I made some doublers to help them out. The first is for the area between the scoop and the exhaust tailpipe.

Cowl Reinforcement

Cowl Reinforcement


The second is between the scoop and the area that will be covered by the bubble.
Cowl Reinforcement

Cowl Reinforcement


I worked on deburring and dimpling some of the holes in the cowl metal that will later be filled with rivets and screws, and also cut countersinks into the windshield fairing.

Fiberglass Surface Work

Tonight I sanded the filler that I applied yesterday to the new fiberglass cowl bump and the windshield fairing.

Sanded Filler

Sanded Filler


Sanded Filler

Sanded Filler


The windshield fairing is ready to go, and the bump only needs a little bit more.
One more round

One more round


The amount of work required to finish the bump was much less than on previous parts. I would definitely recommend the finer cloth on the exterior, since it was so much easier to finish. Tonight I also made the aluminum strips that will support the rivets on the lower nose bowl. Those strips will help distribute the load of the rivets quite a bit.

Cowl Work Continued

This morning I made it to the hangar well before sunrise. It’s a nice time to work, on occasions when I would not rather be sleeping. I removed yesterday’s fiberglass handiwork and started with the finishing process.

Finished Bubble

Finished Bubble


I used the belt sander to trim the edges clean, and applied the first round of filler. While I had the filler mixed up I also applied a little bit more to the windshield fairing.
Trimmed Bubble

Trimmed Bubble


With those parts ready to cure for a little while, I started working on the cowling structure. I installed the steel support strips that go in the ends of the aluminum channels. I also trimmed the channels so that they are flush with the fiberglass or firewall flange, as applicable. I drilled the holes in the cowl at the firewall station to make them the right size for screws. I also did more work on the landing light mount in the nose bowl. I’m going to use the shrinker to make a curved bracket that will fit the shape of the nose bowl and support the top of the light.

Fiberglass Bubble

This morning the foam was well-cured so I did a bit more shaping. I covered the foam with masking tape so that the final fiberglass part will not show where the voids are in the foam. Another option would have been to fill the voids with filler, but since this is a small part and since I have plenty of tape, this seemed easier.

Tape on the mold

Tape on the mold


When I made the scoop flange and windshield fairing, I used a pretty coarse fiberglass cloth. This made the finishing more difficult than it needed to be. For this job, I decided to lay the last layer on in a finer weave cloth.
Coarse and fine fiberglass cloth

Coarse and fine fiberglass cloth


I cut the coarse pieces into strips about the size of candy bars. This would allow me to lay them over the complex curves without wrinkles. I rubbed on a generous layer of wax to the mold and mixed up a batch of epoxy. I added the strips in the usual way to build up about three layers, then added the fine cloth as a single piece.
Finished product

Finished product

Preparing for Fiberglass

The exhaust clearance problem is going to require a little bit of fiberglass work. My strategy is to build up some foam on the pipes so that I’ll have a safe gap, then lay the fiberglass up right on that foam. To help make sure that the gap is a consistent 3/4″, I made up a few little foam pieces.

Foam Indicators

Foam Indicators


These are 1/4×1/4×3/4″ blue foam pieces. I applied a contact paper masking to the cowl, pipes, and scoops, and then glued the spikes in place.
Foam Spikes

Foam Spikes


While I waited for that glue to cure, I sanded the windshield fairing again. I painted it a few sessions ago, but it really didn’t look very good. When I wet sanded the paint away, I could tell why.
Sanded Windshield Fairing

Sanded Windshield Fairing


I just didn’t have a very good surface prep before the last paint job. Look at how many low spots are still blue, and how many high spots go right down to the original filler. A few rounds of sanding, priming, and filling will be worthwhile on such a high-visibility piece.
Since the glue was cured on the blue foam pieces, I came back and added a substantial blob of spray-can foam to the area where I’ll be doing the fiberglass work.
Foam

Foam


Spray Foam

Spray Foam


I’ll leave that to cure for a little while. I had a few jobs that were waiting on rivets, so I started those today. One was to rivet the covers on the main landing gear where I had to make access for the brake lines. I couldn’t quite reach all of the rivets with the tires on, so there are a few left for next time I have the wheels off. I also attached the strips to the aft cabin station. These will give the fabric bulkhead a little more stability.
Velcro Strips

Velcro Strips


I carved off some of the foam to find that there was a big hollow bubble in the middle, so I added a bit more.
More Foam

More Foam


I should have probably applied much less, and that would have prevented the interior problem. Next I cut out the steel pieces that will support the cowl at the u-channels.
Steel Blanks

Steel Blanks


I did a little more rough trimming on the foam, and it’s starting to take shape.
Rough trim

Rough trim

Visit with David Bice

Today was a real treat- I was able to visit with David Bice while on a visit to ABQ.  David’s Bearhawk is of particular interest to me because it is so similar to mine.  I even used the same paint colors as he did!  His has an angle-valve 360 with slightly lower compression than ours, and he used a McCauley prop vs our Hartzell.  The empty weight of his Bearhawk is extremely low, below 1200 pounds.  I’m sure he’ll have at least a 100-200 pound advantage over ours, in part because he made his almost as light as he could.  For example, he equipped it for day VFR only.  It has one radio and a transponder (small panel-mounted Becker units), part 91 required instruments plus single-cylinder EGT and CHT monitoring, and maybe just a few other things.  He uses an SD-8 alternator as his primary charging source, and a PC680 battery. He has the back seat installed, but said in practice he really only uses it as a place to store stuff.  He’s using 800×6 tires and single-puck brakes, and a Scott tailwheel.  The fabric parts are covered with Polyfiber products.  The fuselage metal is painted with enamel and the fabric with Polytone.  His wings are bare aluminum, and while he hasn’t made an effort to polish them yet, you might not be able to tell.

David is a very interesting fellow who has a very methodical and safety-oriented approach to building and flying.  He took me up for a local flight to see the beautiful New Mexico scenery and to show me how well his airplane flies.  I was especially interested in seeing how his airplane performed at such high density altitudes.  The airport elevation was over 6000 feet, and when we were flying around at 8500 feet the OAT was 60 degrees F. Keeping in mind that 59 degrees F is standard temperature at sea level, we were seeing density altitudes on the order of 10,500 at 8500 MSL.  I would estimate our gross weight to be on the order of 1900 pounds.  Even still, the performance of his Bearhawk was quite respectable.  After takeoff the climb rate was a solid 500-700 feet per minute at airspeeds ranging from 70-80 miles per hour.  At 7500 feet with the economy power setting of 19″ MAP and 1900 RPM we were seeing 100 MPH.  His oil and CHT temperatures were also very low.  The oil temperature is probably related to the huge oil cooler that he used, anticipating the need for extra cooling in his hot and high local conditions. I thought his airplane had plenty of good performance for the conditions, and was yet again pleased with the engine choice in our Bearhawk.

As with the other two Bearhawks that I’ve had the pleasure of flying, the inflight experience is exceptional.  The sight picture in cruise is much more nose-low than the Cessnas that I have flown.  This makes for a very nice view from the cockpit.  The slow flight and stall characteristics are very predictable and honest, perhaps even more than they should be.  David has an angle of attack monitor installed, and it gave very effective warning of the oncoming stall, just before the airplane started to break.  Full-power climbing stalls required an expectedly high deck angle, but the recovery was as simple as reducing the back pressure slightly.  Even before his AOA warning, it was very clear to me that we were on our way to a stall.  The control stick warned me with its increasingly heavy pull to lower the nose on its own, and with its abnormally aft position, just as it should.  In a power-off stall with a power-off recovery, the nose has to come down fairly low to recover, but not as low as I would have expected.  To help demonstrate the good-natured stall characteristics, David suggested that I enter a power-on stall with crossed controls.  I used what I thought to be a fairly large amount of rudder and enough opposite aileron to fix the heading.  The stall break was completely straight ahead.  He reminded me that a similar maneuver in his Luscombe would have resulted in a rapid reversal of the positions of the sky and the ground.

David also let me taxi his airplane for a little while, and I was surprised by how much brake input it required for steering.  My tailwheel experience has been in lighter airplanes, and in those the rudder has been more effective for steering on the ground.  David credits this to the landing gear geometry of the design, with the weight on the tailwheel being of a higher proportion than those lighter airplanes.  The advantage of this geometry is that the airplane has much less of a tendency to lift the tail when you don’t want it to.  The main takeaway from my discussion with David about his previous experience, and my own experience with the taxiing, is that Bearhawk pilots should probably have the brake pedals covered for all ground operations.  I’ll be interested to see how that thought changes as my experience grows.  In retrospect, I remember Dave Lenart also needing a healthy amount of brake input on the taxi when I flew with him last summer.  With this in mind, I’m also especially glad that we configured our Bearhawk for dual brakes.

I was also glad to learn about the power settings that David has found to be useful.  For economy cruise, he uses 19″/1900 RPM.  He has found that the engine runs very smoothly at that RPM.  When he slows down to take aerial photos, he adds two notches of flaps and reduces the throttle to 14 inches.  At that power setting his Bearhawk loafs along sipping fuel at somewhere around 5GPH, but still going faster than the average Cub.  

Another data point from today’s flight was accidental.  David has a crossover exhaust system without any mufflers, and I was interested to see how noisy the cockpit was.  He let me borrow his Lightspeed Zulu for the flight, which is one of the fanciest ANR headsets available.  The batteries were depleted though, so I wasn’t able to use the ANR feature.  ANR headsets that aren’t actively using the ANR are usually not as effective as passive headsets.  This is in part because the manufacturers design the ANR headsets to use less head clamping force.  While this improves comfort, it also reduces the seal effectiveness and cuts down on the passive noise canceling capabilities.  I spite of all of these factors, I still found the noise level to be quite tolerable.  I wouldn’t want to fly very long without either a headset or earplugs, but honestly, I feel the same way about every powered airplane I’ve flown so far, from GA to airliners.

Overall, it was a fantastic visit.  David showed me around the airport and told me about lots of little things he has learned from his experience.  I was especially impressed with several of his construction details, such as the metal cover for his airbox (mine is fiberglass), his rudder cable guards, the very cleanly routed wires and plumbing firewall forward.  Those details speak to his prior building experience on several airplanes, along with his experience as an A&P mechanic who has worked on planes ranging from light GA singles to the B-17.  One of the things that I appreciated most about David’s Bearhawk is that it fits his mission perfectly.  He has managed to put together an airplane that serves his needs very well.  I wouldn’t say that I need any more motivation to get our Bearhawk flying, but this trip certainly gave me more anyway.

Skylight and Cowling

I had some help today from Tabitha and her dad. They started making the plates that will go on either side of the new VHF nav antenna. These plates are basically the same as round inspection covers, except that they have a slot in the middle to clear the antenna puck.

Antenna cover in progress

Antenna cover in progress


It's a race!

It’s a race!


While they did that, I worked on making the cowl fit the new exhaust system. I’m going to need some extra clearance where the pipes go into the collector. I feel like if I had been making the system on site, I would have been able to avoid these problems, but since I had to mock it up in PVC pipe, I had to deal with the limitations of the larger pipe.
It's going to need to be at least this big.

It’s going to need to be at least this big.


I also cut out quite a bit of material to allow the tail pipe to clear the cowl. Since the tail pipe will be shock mounted, I’ll need a little bit of extra clearance.
Tail Pipe Hole

Tail Pipe Hole


Sometimes the camera makes a handy inspection mirror. Here you can see where the number 3 pipe is also hitting the cowl.
More interference

More interference


This is the final hole size.

This is the final hole size.


I’ll need to take a little material off of the scoop too.

Posted on
Hours Logged This Session: 9.5
Total Hours: 1883.75

Installing the Exhaust

On the day that I was planning to leave to drive to Oshkosh, we got a huge amount of rain, and part of our driveway washed away. We had a big mess in the yard and lots of things to clean up, so I’ve lost a few weeks worth of building time. Today I was able to get a full day in to complete a few tasks that were held up while waiting on parts. Here’s the loot pile from B&B at Oshkosh:

Oshkosh Loot

Oshkosh Loot


One of my unsolved problems was how to create the fairing around the VHF nav antenna terminals. The terminals stick out past the sides of the vertical stabilizer, so I was going to have to make a special fairing. While I was at Oshkosh I stopped by the RAMI booth to see what kind of antennas they had. One of theirs has removable elements and an internal balun, so that the feed line just connects right to the bottom of the antenna. This solves the problem all together, and since the elements are removable, it also helps quite a bit with making sure that I don’t poke my eyes out while I’m working on or around the tail.
New Rami Antenna

New Rami Antenna


Rami AV520

Rami AV520


Another big box finally arrived!
Exhaust system

Exhaust system


Here are the exhaust pipes, ready to install.
It all looks pretty good, although I’m going to have some minor clearance issues. One is around the right side sump drain. This is a plug that we won’t be removing in service, but it still sticks out a little. The other spot is where the number 3 exhaust pipe is a little bit too close to the number 3 intake tube. These areas were both tight with the PVC pipes too. If I had been able to mock up with actual diameter pipes, I would have considered routing the number 3 exhaust pipe inside of the intake tube instead of out outside of it. The exhaust builder said that a small dent in the pipe would be acceptable in these spots, as long as it was smooth.
289- This is where I need more clearance
I made a form out of wood to support the back side of the pipe evenly.
Wood denting form

Wood denting form


I tried using the vice to make the dent, but that didn’t work especially well. In the end, the round-nosed hammer was more effective
Vice attempt

Vice attempt


Side view of the system

Side view of the system


Drain Plug Dent

Drain Plug Dent


Intake Tube Dent

Intake Tube Dent


I had been holding off on completing many firewall-forward jobs until the exhaust system was on. One was to finalize the routing of the mixture cable, since it goes pretty close to the tailpipe. I finished the mounting for the mixture cable so that it is clear of the hot pipes.
Tailpipe

Tailpipe


I don’t know how I managed to mess it up, but I ordered the inlet and outlet for the cabin heat muff incorrectly. He made it just as I asked, but I asked for the wrong thing. I’ll need to have him make another muff with the inlet and outlet on the same radius.
Bottom View

Bottom View


Note in the picture above that the carb heat muff is on the number 2 pipe. I ended up moving it to the number 4 pipe, because the duct material wasn’t as flexible as I had imagined it being, and it couldn’t make such tight turns. With the system in place, I installed the EGT probes. I also replaced the pin eyes on the flap cable turnbuckles with forks, since that’s what seems to be a more appropriate arrangement.

Posted on
Hours Logged This Session: 8
Total Hours: 1883.75

Boot Cowl Rivets Continued

I’ve noticed that the control sticks have a little bit of play around the fore-aft aligned bolts that they pivot on. I thought it would be worth trying to correct this, and after considering several options, the most viable seemed to be to enlarge the hole slightly and use a specially-made bolt of a larger dimension. I started by having Alan help me make the bolts. We used his lathe to turn some 5/16 bolts down to match a piloted reamer that I found on ebay.

Bolt Blanks

Bolt Blanks


We turned the area to be threaded down to 1/4″ so that the die would work properly.
Threaded Bolt

Threaded Bolt


Then I used the die to cut threads onto one of the bolts. So far, this process was working really well. Next I enlarged the hole, first in the control stick mount. That went well too. Then I enlarged the hole in the control stick itself, which didn’t seem to go as well. I’m not sure if it was my reaming technique, or if it is that the hole is already larger than the reamer in some areas, but I still have some play there. It seems like an acceptable amount of play, so for now I’ll leave it alone. If it turns out to be excessive during flight testing, I suppose I could remove the sticks and weld additional material into the hole, then ream that with more precision. I also made some new skylight support strips out of 1/8″ thick aluminum. These should have plenty of rigidity. I found some 2″ wide strips, and used the table saw to rip them into narrower strips. I’m still working on getting these to work just how I’d like. I added rivets to the back of the boot cowl, using solid rivets where I could, and steel blind rivets where I couldn’t. I set the windshield in place so that I could make a mount for the glideslope antenna. I was trying to think of a good material to make the mount out of. The material would need to be non-metalic. Before I got to the point of buying something, I realized that my large pile of scrap polycarbonate had the answer. I used plastic wire ties to hold the antenna to the front of the polycarbonate mount, then slipped the back of that mount into the same channel as the windshield, up under the windshield. This served the dual-purpose role of holding the antenna in place and tightening the fit a little of the windshield in the channel. Since I didn’t stuff covering fabric in that channel, and since I’m using a thinner rather than thicker windshield, there is a little bit of extra room in there.

Posted on
Hours Logged This Session: 4
Total Hours: 1883.75

Horizontal Stab Fairings

Tabitha and Felicia came out to help today. We installed the new tubing in the sight gauges and reinstalled them. We deburred the previously-made wing root fairing for the right wing.

Making Fairings

Making Fairings


Making Noises

Making Noises


The girls went home for supper while I stayed to make the root fairings for the horizontal stabilizer. They attach to the inboard rib of the stabilizer, which is a very narrow spot to hit with the drill bit. I found that the best way to get the holes lined up was to drill the stab first, then use the strap duplicator to drill the aluminum. I worked for a while on the skylight aluminum strips, only to discover that my plan up until now is not going to work. I was planning to use thin aluminum pieces to hold down the polycarbonate, but the holes aren’t frequent enough for that.

Posted on
Hours Logged This Session: 8.5
Total Hours: 1883.75

Boot Cowl Riveting

Yesterday’s black paint was dry, so I riveted on the windshield support angles. I reinstalled the now complete boot cowl
pieces and riveted the front. Since those front rivets are through the firewall flange, they are very easy to get to for squeezing. The back rivets are a little bit more difficult, so I’ll do them later. I reinstalled the pulleys for the flaps and the aft floorboards, in part to help reduce the odds that I’ll drop something and poke a hole in the belly fabric.

Posted on
Hours Logged This Session: 5.9
Total Hours: 1883.75

Left Wingtip Fitting

Today I finished fitting the left wing tip. That involved installing the strobe power supply and the left aileron, then drilling with the hole duplicator strap. I countersunk the holes, which will also have special countersunk washers to help distribute the load on the relatively vulnerable fiberglass. I also sprayed flat black paint on the windshield support angles, the instrument panel access hatch, and the portions of the boot cowl that will be visible from the interior. The cargo doors are finished, so I mounted them.

Back Cargo Door

Back Cargo Door


it was a relief to see that the stripes and letters lined up with each other.
Both Cargo Doors

Both Cargo Doors

Posted on
Hours Logged This Session: 3.2
Total Hours: 1883.75

Fuel Tank Prep Continued

I needed to finish up a few more jobs before I could put the left tank back in. One was to install the Dynon OAT probe and reconnect the wires. Another was to get the end of the antenna lead sorted out. I have plans to mount an antenna on the left wing that will be dedicated to a handheld transceiver, which will be our backup and second radio. Since that antenna is the old style with the ceramic insulator, I installed the feed line and end termination while I still had good access with the fuel tank out. I stripped the coax and removed about 2″ of sheild, then crimped a ring terminal onto the shield. I crimped a second ring terminal onto the center conductor. On the top wing skin, I used a #8 screw to attach the shield terminal to the skin, but I also ran the screw through an adel clamp that supports the whole coax. This will hopefully help ensure that the ring terminals won’t have any strain in service. In case that doesn’t make any sense, here’s a picture that probably illustrates it much better.

Antenna lead termination

Antenna lead termination


With those jobs done I reinstalled the left tank and reconnected the fuel lines that run through the inboard bay to the fuselage. While I had the sight gauges apart to replace the tubing, I also installed a restrictor in the bottom fitting of each. Much like in the manifold pressure line, I used a rivet and secured it with JB Weld. Once the epoxy cured, I trimmed the head of the rivet very slightly so that it would clear the flange on the tube, then drilled a 1/16 inch hole in the middle. This small hole will help reduce oscillations in the indication, and more importantly, will slow the rate of leakage if the sight gauge fails. The smaller hole will hopefully buy an extra 15 or 20 minutes to get the airplane on the ground at an airport instead of on a dirt road, in the unlikely event of a gauge failure. I’ve also mitigated the risk of failure by keeping the gauges outside of the cabin area, so that the fuel will be less likely to end up on me in case of a leak.
Since the boot cowl blue paint was mostly cured, I prepared it for the black paint. The area under the windshield will be flat black, in the same Rustoleum that I used on the instrument panel. I also applied the Bearhawk logo to each of the side boot cowls. This was the first time for me to try using the paint masks that I sell at BearhawkStore.com. I probably should have tried them earlier to be sure that they would work! Here is the preparation. I applied the yellow portion, then masked off the surrounding area.
Ready to Spray

Ready to Spray


Then I wiped everything down with C2210, let that evaporate, and sprayed gloss black rattle-can paint.
Gloss Black

Gloss Black


After that was mostly dry, I removed the outer masking paper, then removed the perimeter portion of the paint mask. I started removing the middle of the letters, but thought I should probably take a picture of the process.
Partial Removal

Partial Removal


159- Finished Logo
The masks worked very well, and I don’t just say that because I sell them. It was really a trouble-free process, and now I have a painted-on logo that will hopefully outlast any vinyl alternative. While I was waiting for the paint to dry in the previous steps, I took out the right fuel tank and gave it the same treatment as the left.
Yesterday I showed a picture of the alternate air control mounting bracket. I made it out of a scrap of fairly thick aluminum, probably close to .060 inches. Being used to much thinner material, I underestimated the bend radius and broke it right into two pieces when I tried to bend it. So not unlike the real California, it’s broke.
Broken California Bracket

Broken California Bracket


I made another one out of .035, which I think will be plenty rigid. Here is how it is supposed to go:
Completed California Bracket

Completed California Bracket


Last night I bent the new roof piece, so today I finished the bend with the dead blow hammer. I installed the roof piece and drilled holes in it for the GPS antenna. I sanded the filler on the left wingtip again, and left the hangar before midnight. Can you tell that the girls must be out of town these days?

Posted on
Hours Logged This Session: 10.75
Total Hours: 1883.75

Clean and Reinstall Left Tank

This morning I set the tension on the elevator turnbuckles to 30 pounds and safety wired the buckles with the double-wrap method. I made some aluminum strips that will attach to the perimeter of the hole in the back of the cabin, which will give me a better surface to attach velcro to for the fabric cover that will go there. I started making a bracket for the alternate air intake control, which I’ve decided not to install on the instrument panel. Instead, I’m going to install it under the panel by the left seat pilot’s left knee. I’ve been referring to the bracket as the California bracket, can you see why?

California Bracket

California Bracket


The left fuel tank was already out to provide access to the plumbing, so I cleaned and inspected it. I poured half of a gallon of fuel into the tank, sloshed it around, then drained it through the finger strainers. I removed those strainers to be sure that there wasn’t any gross accumulation of vegetables, animals, or minerals, and similarly checked the fuel in the clean bowl that I poured it into. I also removed the sight gauge fittings and aux pluming plugs, and applied a fresh thread sealant paste to all of the threads and reinstalled all of those fittings. I used a shop vac to clean out all of the little bits of debris and aluminum from the wing interior. I’m also going to replace the sight gauge tubing, in part because I’m not positive that it’s a fuelproof tube, and in part because it has been in there for several years now. It’s starting to yellow, and it seems silly not to change it out while I’m in here. These are the same sight gauges that Peter Stevens described in the Beartracks newsletter, and he specifies using Superthane ether-based tubing, which is available by order from Amazon and several other places. Many folks who use the machined fuel caps that Bob designed have had trouble getting them to fit in the filler neck. Mine were a very tight fit, so I took them down to John’s hangar at Lake Norman. I was in town for the EAA 309 build night, and to use John’s brake and lathe. I bent the latest version of the roof metal, along with several other pieces. He chucked up the fuel cap and turned the area where the o-rings mount down to 1.325 inches. John is a very helpful guy to know!
Fuel Cap

Fuel Cap


They fit much better now, though one of them is still pretty hard to get in. I’ll need to check to see if the filler neck is slightly out of round or undersized.

Posted on
Hours Logged This Session: 6.4
Total Hours: 1883.75

Reinstalling the Tail Pieces

Today was a fantastic productive day in the hangar. I started by applying a little bit of superfil to yesterday’s wingtip extension.

Wingtip Filler

Wingtip Filler


That is really some great stuff. The jig holes in the nose ribs on the left wing were 1/4 inch. This was just enough room for the AOA lines to fit through the aluminum with no bushing. The pitot lines already have bushings that Richard installed before he closed up the wing. I didn’t want to run the lines directly through the aluminum, though odds are good that it would have not been a problem to do so. Instead, I brazed a cheap Chinese step drill bit to the end of a 6-foot piece of 1/4 inch rod. Then I used the bench grinder to grind off the larger butt end of the bit, so that it stopped cutting at the 3/8 inch size. I chucked up the other end of the steel rod and had the holes enlarged in a about 15 seconds. This worked much better than I would have expected. Since I already had the fuel tank out, it was no trouble to install the bushings and route the plumbing accordingly.
Left Wing Plumbing

Left Wing Plumbing


After lunch I started preparing to re-install the tail control surfaces.
Tail Installation Hardware

Tail Installation Hardware


Here is the hardware that I had set aside for this job. I started with the rudder, then the left horizontal stab, then the right h. stab, then the elevators. I didn’t really get the access holes in the right spot for this job, so I had to add a few more. I didn’t make any holes at all for the elevator trim torque tube on the left side, so I had to remove the control horn, insert the stab half through a small hole in the fabric, then re-install the control horn from the other side of the fabric. Overall, this job required some mirrors and flashlights, and of course a little grabber to pick up the various bits of hardware that I dropped in the process of putting it all together. After I had everything installed, I leveled the fuselage and took a few measurements. I made the adjustments to the flying wires and struts to get the stab halves level left to right and front to back, and it all turned out very well. It should have, since it has all been done before.
The stripes line up!

The stripes line up!


The best part about getting these pieces together is the photo. It’s quite reassuring to know that the stripes line up, and I’m quite pleased with how it looks. When I was done with that, I prepared for and sprayed a round of blue paint on the boot cowl, right wing tip, left flap, door exteriors, and that sort of thing.

Posted on
Hours Logged This Session: 12
Total Hours: 1883.75

Wing Rotisserie Removal

Today I started early in the morning by rearranging things in the hangar. I made a pair of large saw horses to support one of my temporary work tables, which will free up the plastic factory-made saw horses for paint booth duty, and more immediately, support the left wing. With the rotisserie parts out of the way, I was able to install the last few nutplates on the root. Having access to the front of the left wing means that I can start working on the pitot tube mount again. The challenge is making a mount that will allow for removal of the pitot tube. If I were doing all of this again from the start, I would have gone with a mast-mounted pitot. The best solution that I could come up with was a sleeve that will join the tube itself to another tube, which is welded to a flat plate that is bolted to the spar web. The connecting sleeve has some slots to allow for passage of the air lines coming from the tube.
142-

Sleeve side 1

Sleeve side 1


Sleeve side 2

Sleeve side 2


Pitot and AOA lines

Pitot and AOA lines


I added the flared aluminum fittings to those soft aluminum lines, and then connected those to the quick disconnect fittings that will accept the DOT-approved brake lines that came in the plumbing kit from Avery.
How it comes together

How it comes together


Next I worked for a while on the firewall flange, starting to install nutplates for the screws that will hold on the back of the cowl and the front of the boot cowl. Wade came over to help for a little while, and we were able to move the left wing over to the rack. I put the left aileron on and checked the wing tip for alignment. The tip came a little bit short, because as I have learned now, it was intended to be butted up to the wing skin, not overlapped with it. You might have noticed from my previous entries that I’ve wasted a lot of time and effort on the wing tip mounting. I’m already committed to an overlap installation, so I’ll just extend the aft end of the wingtip a little.
Wingtip Shortage

Wingtip Shortage


I had plenty of spare aluminum tubing left from fuel lines, so I used that for the new trailing edge.
Aluminum tube extension

Aluminum tube extension


Extension applied

Extension applied


I’m not sure why this tip needed an extension while the other did not. I figure that it must be related to the way the tip sits at the leading edge, or perhaps a difference in the manufacturing molds.

Posted on
Hours Logged This Session: 9.5
Total Hours: 1883.75

Striping for Blue

Since the boot cowl parts and door parts have their white paint in place, today I started laying out the stripes for the blue coat. In the case of the upper front windows, they didn’t get any white, since they will be all blue.

Right Side

Right Side


Left Side

Left Side


I also started working on a mount for the pitot tube, now that the left wing is out of the booth.

Posted on
Hours Logged This Session: 6.1
Total Hours: 1883.75

Reassembling the Front Seats

This afternoon I reassembled the front seats, and changed the routing of the transponder antenna feed. When I was routing it last time, I had forgotten that I’d already drilled a hole for the antenna, which the old routing didn’t reach.

Posted on
Hours Logged This Session: 1.8
Total Hours: 1883.75

Visit Mike Bundy

Today I was in southern California for a little while, so I contacted fellow Bearhawk builder Mike Bundy. Mike spent most of the afternoon with me, including transportation from the hotel I was in. He’s a very nice fellow, and has an especially interesting engine for his Bearhawk. He’s using the 409 cubic inch 4-cylinder engine, which makes 230 horsepower. If it works as advertised, he’ll have the power of a 540-powered Bearhawk with the weight of a 360 engine. Seeing Mike’s project reminded me about how much I’ve done so far, and how much he still has left to do! On one level, it sounds so easy to describe what it takes to make a kit Bearhawk airworthy. Just install the gear, make up the boot cowl, do a few other little things, then install the engine, and make the cowling, and cover it all, hook up a few things, and that’s it. Those tasks have so many sub parts that take so much time, at least they take me so much time. I’ve long since given up on trying to estimate how long it will take to complete a particular job, even though everyone’s first question is “When will you have it finished?” Visiting with Mike was a great experience, and I was in a good mood for days afterward. It’s too bad that Bearhawk builders are spread out so sparsely, since I would love to spend more time with most of them.

Posted on
Hours Logged This Session:
Total Hours: 1883.75

Nutplates and White Paint

Several days ago I ran out of number 6 nutplates, so I ordered more. They arrived today, and I spent a while dimpling their lugs and installing them on various parts, including the belly sheet metal, the boot cowl, and the wing root. I riveted together the inspection covers that I had previously disassembled for priming, and also riveted the air intakes to the boot cowl sides. I finished assembling the rest of the windows and doors, and prepared the exposed portions of the front seat tubes for paint by masking off the areas that won’t get paint. I was able to remove the vertical seat cushions and separate the seat backs from the seat bottoms, which helped. In an ideal world, I would have painted the tubes before I had the seats upholstered, but as you probably would guess, this project hasn’t taken place in an ideal world! I sprayed a round of white paint on most of those parts, finishing up in mid afternoon.

Posted on
Hours Logged This Session: 5.5
Total Hours: 1883.75

Door Assembly

Yesterday’s painting included several door parts, so today I riveted the front cargo door together. I prepared the lower front doors and rear cargo door for their exterior white paint, with the interior paint already having been applied.

Posted on
Hours Logged This Session: 3.1
Total Hours: 1883.75

Painting White

Today I sprayed white paint on the parts that I primed a week ago. I added to that pile the rear cargo door, front cargo
door parts, and other window parts.

Mr. T wanted to help, but I was concerned about his fur getting in the paint.   And besides, the respirator was too big.

Mr. T wanted to help, but I was concerned about his fur getting in the paint.
And besides, the respirator was too big.

Posted on
Hours Logged This Session: 3.5
Total Hours: 1883.75

Pieces to Bend

I thought of a few more pieces to bend, and I’m planning to make a visit to another bending brake soon. I stopped by today to cut them out.

Posted on
Hours Logged This Session: .4
Total Hours: 1883.75

Priming Wingtips and More

Today I prepared for a big round of priming, which meant more fabrication on boot cowl parts. I drilled for nutplates, which I’ll rivet on after priming. I made a support ring for the rubber gasket that will seal the shock strut. On the left side, I extended that support forward several inches. This hatch will allow for me to remove the gascolator without having to take off that whole panel.

Gascolator hatch

Gascolator hatch


I had to remove the left wing from the paint booth, which involved some hangar shuffling. I took a few pictures while I had everything out.
Left wing, but not liberal.

Left wing, but not liberal.


Blue fuselage with the engine on

Blue fuselage with the engine on


Both together

Both together


Here are the parts that I primed

Here are the parts that I primed


This is a time-consuming stage of the project. I spent over 13 hours in the hangar today, and left at 1:00am! With sore arms, I might add. Paint prep is very labor intensive.

Posted on
Hours Logged This Session: 13.1
Total Hours: 1883.75

Nutplates and Wingtips

Today I worked on the wingtips yet again. I have really made the whole wingtip process much harder than it needed to be. I added the nutplates back for overlap mounting, and reinstalled the strobe power supplies. I also added a bit of window screen to the lightening holes in the tip rib.

Window screen to keep the birds out

Window screen to keep the birds out


I also installed the remaining nutplates on the right wing root, which will allow for mounting of the wing root fairing. I added a clamp to the front of the radio trays so that they will attach to the little bar that I welded across there. Can you believe that I welded that bar on almost 2 and a half years ago? I remember it well, because I burned my hand quite smartly, or rather, not so smartly, by grabbing the still hot tube to lift myself off of the floorboard. I took all of the cowl and boot cowl off to start deburring and dimpling more holes.

Posted on
Hours Logged This Session: 7.4
Total Hours: 1883.75

Final Boot Cowl Continued

This morning I started by drilling the holes in the lower boot cowl and belly panels to final size. I cut out some new aluminum for the roof, and the strips that will retain the left rear window. I drilled the holes in the firewall station of the boot cowl (and the firewall flange) to their final size, and took a few overview pictures.

Left Side Overview

Left Side Overview


Right Side Overview

Right Side Overview


I made a few other pieces to bend for use on top of the skylight.

Posted on
Hours Logged This Session: 6.9
Total Hours: 1883.75

Roof and Boot Cowl

I started off today by finishing the bend that I started yesterday. I only bent the roof piece to about 90 degrees on the brake, because that was all it would do. This morning I used the dead blow hammer to bend it the rest of the way over.
Unfortunately, it’s too short. When I measured the length, I used the holes on the far outboard side of the cabin. Those holes sit a little bit forward of the holes at the front of the skylight, so the roof missed the latter. It looks like version three will be in the works now. The good news is that I was at least able to validate the bending process.

Short roof

Short roof


I spent the rest of the time working on the holes in the boot cowl, drilling them to final size, deburring, and dimpling the ones that were to be dimpled.

Posted on
Hours Logged This Session: 3
Total Hours: 1883.75

Bending the Roof

Today was a quick stop by the airport in Lincolnton to borrow a friends bending brake. I bent the roof piece over to about 90 degrees on the way back from work. There was a bit of confusion initially, as my mechanic friend wasn’t there. His boss was, and when I confirmed that it would be okay that I “borrow” his brake, he thought I was asking to take it with me to borrow it, and said that he was not okay with that. Once we got to the bottom of the misunderstanding, and he understood that I really just wanted to “use” his brake, it was ok. Sometimes I don’t choose the most correct words!

Posted on
Hours Logged This Session: .2
Total Hours: 1883.75

Finishing the Exhaust Mockup

Today I finished the PVC version of the exhaust and sent it off. Now I’ll be able to get back to all of the other stuff that needs to be done.

Posted on
Hours Logged This Session: 5.9
Total Hours: 1883.75

Exhaust System Mockup

Today I was finally able to start on the exhaust system mock up. As you can see in much earlier entries, I started with making an exhaust system out of EMT conduit, like Bob and others have. I wasn’t too pleased with how it was turning out, and I was especially concerned about excess noise and weight. I started looking at how much longer it was going to take to finish the EMT system, compared to how much it would cost to buy a stainless steel system, and realized that it was going to make more sense to go with the stainless system. I first spoke with Vetterman, since he does the exhaust system for nearly all of the RVs, and has a great reputation. He has an associate named Clint who handles all of the work on angle valve engines, which ours is. I spoke with Clint several times about trying to make a system that would incorporate mufflers. He felt very confident that he could make a system with four straight pipes, but could not make a system with mufflers. I was asking Bob Barrows about something else and the topic came up, and he asked if I’d considered a 4 into 1 system. It turns out that Clint doesn’t make those (which is really unfortunate, since I would have been glad to work with him and see him get the business), so I started looking for someone who did. One of my fellow builders suggested aircraftexhaust.net, which is the company that was featured in a Kitplanes article a few years ago. Their business model involves sending out some exhaust flanges welded to stubs, and a collector, all of which are sized to fit inside 1.5″ PVC pipe. Then the airplane builder makes up a PVC version of what the exhaust should be, and sends that to the exhaust fabricator. I especially liked this arrangement, since our engine is very non-standard. It seemed like a good way to be sure that we’d have a finished exhaust that would fit. Back in April I got in touch with the guy who runs that business, with hopes of getting the PVC setup mocked up and back to him so that he could fabricate the system while I was out of town. It turns out that he is quite a fabricator after all, in more ways than one. Fortunately I was able to figure out that he is not reliable before
he had any of my money. A little bit of Googling points to the stories of others who weren’t so lucky. While I didn’t lose any money on that situation, I did lose about a month of progress. I started looking for other companies that could do that sort of work, and then I found sonicheaders.com. There is a fellow there named Todd, and his address is not very far from one of the addresses associated with the other company. His website has pictures of exhaust systems mounted on the same type of jigs as the other company, and the text portion of his website features enough common grammar and spelling anomolies for me to think that they were written by the same person. I was a little bit worried by this, but figured I would call to see what was up. I called him and explained where I was with the situation, and he said that he used to work for the other fellow, and that the other fellow had fallen on some hard times and decided to become dishonest with his customers. He said that he could send the mock-up parts out on that same day, so I gave him my credit card number and waited a few days. The parts came right on schedule, and that leads me to today in the short version of my exhausting exhaust story. I started by going to the local big box store to load up on fittings.

Getting Started

Getting Started


The silver parts in that picture are the parts of the mock-up kit. The fittings that I purchased locally include several 90s, 45s, and 22.5s. The 270s are actually drain traps, but the 180 portion of that fitting was a tighter turn than two 90s together. Also, not pictured, is about 10 feet of straight pipe. First, I bolted the stubs onto the exhaust ports, not forgetting to include gaskets.
Stubs

Stubs


Then, I used duct tape and string to try and position the collector about where I wanted it. The challenge was to get each of the four tubes going into the collector to be an equal length, and close to 30 inches. While there is much more room for the collector behind the carb, that location would not have allowed me to get to the number 2 cylinder in 30 inches- it probably would have been more like 40. That cylinder was definitely the limiting factor in collector positioning.
Collector position

Collector position


Then I used the chop saw to cut off several short pieces of pipe, which would allow me to but several fittings up against each other.
Fitting connectors

Fitting connectors


Then, I just started playing with the pieces to see how it would turn out. It’s a hard job to start- once I got going, it was a lot easier. I just had to jump in and get started, with temporary pipe connections of course. The biggest problem with the whole arrangement was that the collector pipes were so close together. This makes it impossible for PVC to slip around the outside of all four pipes at once. I used the belt sander to remove most of the flanges of the fittings so that they would go together.
More initial routings

More initial routings


This routing makes for easy carb heat access

This routing makes for easy carb heat access


I’m going to break the chronology here a little and add in a follow-up from the future, since I can, and since I’m sure you are giddy with suspense about how the exhaust saga ended. The exhaust system turned out pretty well. In retrospect, I wish I had come up with another way to mock up the pipes right as they go into the collector. Maybe a smaller 1″ PVC running to the inside of the collector pipes would have been an option. In the end, I had to make a bump in the cowl to accommodate two of the pipes. I could have made the bump smaller if I had turned the lowest pipe up sooner, which I could have done if I was working with smaller diameter pipe. Todd at Sonic Headers turned out to be an honest fellow and a good welder.

Several circumstances led to delays that were frustrating. First, when I sent the system back, it sat for a week before he got to it, because he didn’t check the mail. He said most folks ship via UPS. Then he didn’t have enough of the tight 90-degree bends, so he had to order more of those from his supplier. I should add tha the builds the system by butt-welding pre-bent pieces, not by starting with one long pipe that gets custom bends. The two-week lead time turned into seven, and he said that he reduced the price a little to account for that. The total cost was still right around $1500. For someone else who is thinking about going with this route, I would suggest first and foremost that you avoid aircraftexhaust.net, since he’s pretty much become a scam artist as far as I can tell. If you go with Todd at Sonic Headers, you can expect a responsive attitude and quality work, but I would do the mock-up process long before you need the pipes, and give him lots of time to get the work done. I should have probably been doing this a year ago, and that would have taken the stress out of much of this process. Here ends the follow-up from the future. Tune in tomorrow to see how the rest of the mockup process went.

Posted on
Hours Logged This Session: 5.1
Total Hours: 1883.75

Fairlead Pliers

I started re-installing the control cables today, and after a little bit of trying it became obvious that I was going to need to be able to get the fairlead clips on with the limited access that I had in the fuselage. I came up with the idea of modifying my snap ring pliers so that I could apply a spreading force to the fairlead clip. I installed the removable ends in backwards, as to not damage the end intended for snap rings. I used the bench grinder to flatten the sides, then used the Dremel cut off wheel to cut a little groove into each one.

Fairlead Pliers

Fairlead Pliers


In Action

In Action


I used these, along with a few other tools to re-install the forward part of the flap cable, the elevator cables, and rudder cables. I reinstalled the two triple pulley arrays and torqued their bolts appropriately. While I had the torque wrench out, I also put the ends back onto the right wing strut. On the forward side of the firewall, I started making preparations for the exhaust work. The plate that I was using to support the mixture and throttle was designed to work with a mixture control that has a ball on the end. Since I have made plans to use a mixture with a solid wire end, I don’t really need for the bracket to stick so far aft. This is especially true since the long bracket causes the mixture cable to bend in an unnecessarily tight radius. I started by bending the original mounting flange out of the way. Then I used some poster board to come up with an alternative arrangement. I transferred marks to the bracket and used the reciprocating saw to cut the upper left corner of the bracket off.
Corner Cut

Corner Cut


Corner cut, second view

Corner cut, second view


Then I bent the side around to form a new flange.
Bent side

Bent side


I did a little bit more trimming and grinding to make a tab for the new cable.
Ready to prep and weld

Ready to prep and weld


Then I cleaned the paint off and welded a new bead on the back.
Welded bracket

Welded bracket


Inside view

Inside view


Then I cleaned the area and painted it. I installed the carburetor, and used a gasket on either side of the bracket. I installed the airbox and the ignition harness, and connected the throttle and mixture. I added cotter pins to the main landing gear bolts, except for the top of the shock struts. Those will need to be adjusted when I get everything put together, so in the mean time I ran orange lacing cord through the area where the pin will go, just so that the lack of a pin will be that much more obvious.

Posted on
Hours Logged This Session: 8.4
Total Hours: 1883.75

Making Windows

Today I continued work on the lower right door, and assembled the frame to the skin with the Makrolon in between. I cut out the blanks for the skylights and drilled holes in those pieces.

Skylight Polycarbonate

Skylight Polycarbonate


I mentioned last time that I needed to get another bolt for the carb/airbox attachment, and today I brought the new bolt and drilled it. I installed those bolts with safety wire and used a little bit of high-temp silicone to seal the holes in the top of the box.
Safety wired bolt heads

Safety wired bolt heads


I swapped out the temporary engine drain plug for the quick drain, and added safety wire to that too. Finally, I cut out a piece of .025 aluminum to use as the roof, which is the little section between the skylight and the windshield. I made one a few years back, but through an unfortunate turn of events it ended up in the middle of the street, being run over by a few cars. Let’s just say it was because of the wind. I sort of forgot that I had set the sheet metal piece on top of the car before I drove off. The wind picked up considerably as the car started going faster.

Posted on
Hours Logged This Session:
Total Hours: 1883.75

Straggling Wires

Today was a day of rounding up loose ends. I finished bundling the wires aft of the firewall, and made a few more connections forward of the firewall.

Finished wire bundling

Finished wire bundling


I installed the weather pack connector in the landing light wires that will allow for easier removal of the cowl.
Nose light connector

Nose light connector


I also connected the oil pressure wire. I started to connect the fuel flow sensor, but found that the D180 has three wires for the sensor, while the sensor actually has four. I was able to get someone in EI’s technical department to tell me that the green wire was not necessary, so I just clipped it off. I installed the rest of the fuel lines again, though I did decide to remake the left front line that connects the tee to the fuel valve. Some of these liens have been made 5 times, but I’m very happy with the current arrangement. I reconnected the starter and alternator cables, but I don’t have a good strategy yet for securing them. Vans supplied some little tabs to lock the bolt heads on inside of the airbox. These are coarse thread 1/4″ bolts that hold the top of the box onto the carburetor. Those bolts need to be extra secure because if one falls off, it could be ingested in the engine. The tabs have fallen out of favor, and I’m concerned about being able to replace them in the long run, so I drilled the heads on a the bolts. I made it through three before I broke a drill bit off in the fourth, so I’ll have to do that last one later.
Drilling bolt heads

Drilling bolt heads


After a lunch break I cut out the lexan for the left lower front door, installed the passenger warning placard on that door, cut the lexan for the right door, and drilled holes in both.
Polycarbonate Window

Polycarbonate Window


I tied up the wires for the cockpit flood light, and started routing the elevator trim cable. By that time it was pretty obvious that I’m going to need more access holes in the fuselage covering!

Posted on
Hours Logged This Session: 9.5
Total Hours: 1883.75

Bundling and Securing

I’ve done enough wire tying today to make the sides of my index fingers sore. I started with adding cotter pins to the brake cylinders in the cabin. Then I installed back shells on the instrument panel connectors that didn’t already have them. I added a few more nutplates to the boot cowl area. I secured the pitot and static lines, at least the fuselage portion, and tied up lots of wires. I used mostly wire ties in the big bundles, and for smaller bundles I used the orange lacing cord. I also used a few Adel clamps in areas where they seemed logical.

Wire bundling

Wire bundling


I secured the prop governor control, and added a few more nutplates to the boot cowl metal.
These panels can be attached now with screws.

These panels can be attached now with screws.


Next I started on the “bump” for the stainless tunnel. I needed a bump there to make more clearance for the fuel valve. Since I had a bit of scrap stainless, I figured I’d just give it a try. First, I made a mold out of some 2×4 lumber scrap.
The fly cutter makes the first holes...

The fly cutter makes the first holes…


...then the forstener bit makes for a good flat center

…then the forstener bit makes for a good flat center


I adjusted the fly cutter to slightly smaller radii, then drilled to slightly deeper depths, just eyeballing the shape of the hole. After drilling I took the worst of the ridges off with some very coarse sandpaper. The ball peen hammer also helped. Then I clamped the stainless to the 2×4, and proceeded to beat a dent into it. The first two scrap versions turned out well, so I clamped up the real part and went to town.
From Above

From Above


From Below

From Below


I was quite pleased with the results!

Posted on
Hours Logged This Session: 13.2
Total Hours: 1883.75

Engine Installation Again

I picked up where I left off yesterday by continuing with engine preparations. I added safety wire to the bottom of the baffles, to hold the front and back curved sections inward. I also added safety wire to the oil filter, tachometer drive cap, and oil pressure relief valve. Then I reinstalled the engine and put cotter pins in the castellated nuts that hold the engine to the mount.

Engine Installation Again

Engine Installation Again


I finished the glideslope antenna by covering the whole length with heat shrink tubing. I also slipped a small 1/8″ diameter wood skewer in to help keep it all straight.
Coax antenna

Coax antenna


I’ll plan to install this in the top of the windshield area.

Posted on
Hours Logged This Session: 6.8
Total Hours: 1883.75

Engine Preparations

As I prepare to put the engine on for what will hopefully be the last time before we fly, I took advantage of the easy access of having it on the lift to finish up a few jobs.

Engine on the lift

Engine on the lift


One was to install the oil line that will run from the prop governor to the fitting on the front of the engine, just behind the prop.
Oil Line Routing

Oil Line Routing


I had planned to make this line at one point, but after spending some time with this one, I think buying it premade was a better idea. The line was available for around $120 plus shipping, but I was fortunate enough to find this one from another builder who was converting an engine back to fixed pitch. I offered him $100, and I think he thought I was crazy to want to pay that much for it. It was a little bit tricky to install, and I had to cut a hole in the front right baffle to make room for the line
Baffle hole

Baffle hole


I also filled the brakes with 5606 hydraulic fluid, and started making a coax-based glideslope antenna.

Posted on
Hours Logged This Session: 7.7
Total Hours: 1883.75

Brake Lines and Blue Paint

Today was a marathon day in the hangar that spanned from 8:15am to 2:00am, with a break for lunch of course. Here’s a nice overview picture of the parts hanging from the ceiling, each protected from dust and over spray by a sheet of clear plastic.

Painted Parts

Painted Parts


I started working on the inspection covers for the main landing gear. The upper panels are easy because they are round.
Main Landing Gear Holes

Main Landing Gear Holes


Upper Support Ring

Upper Support Ring


I had orignally planned to make the lower plates round, but a little bit of thinking led me to make plates that have a
trapezoid shape.
Lower Trapezoid Hatch

Lower Trapezoid Hatch


This shape will give access to the lower adel clamp, and also give a more elegant exit for the brake line.
Upper Panel in Place

Upper Panel in Place


My plan is to rivet these panels in place, since I shouldn’t need to access them regularly. They are right in the propwash and would be more susceptible than others to getting blown off. Next I installed the rudder pedals and brakes. I connected the flexible brake lines and installed the front floorboards.
Brake Lines

Brake Lines


While I was in that area I also routed the wires for the push-to-talk in the control sticks. By then I knew that my long day was almost over, so I mixed up some blue paint and applied it to the wing.

Posted on
Hours Logged This Session: 16
Total Hours: 1883.75

Preparing to Spray Blue

I spent a little while today getting ready to paint the blue portions of the left wing. I taped the rest of the white areas and it is ready to go.

Left Wing Ready for Blue Paint

Left Wing Ready for Blue Paint

Posted on
Hours Logged This Session: 1.1
Total Hours: 1883.75

ANR Headset Jacks

I’m glad to be back in town for a few days and am looking forward to lots of hours in the hangar. Today was a good start. I started taping the left wing for the upcoming blue paint. I also installed LEMO ANR headset jacks on the panel, since they came in from Bose. I had not intended to install these jacks, but they are very small, light, and cheap, and the prospect of running an ANR headset without batteries is certainly appealing. There isn’t any circuitry involved- it just parallels the audio and mic wiring of the regular jack, and includes a power and ground.

LEMO Jacks

LEMO Jacks


I finished routing the wires for the nose light, at least as far as the firewall. I started tying up the wires behind the instrument panel (or forward of the instrument panel, depending on your frame of reference), but that process is going to take a few days.

I was having a hard time keeping the walls of the paint booth secured to the frame. Tape kept coming off. I remember seeing a magazine blurb about making clamps out of PVC pipe for other purposes, so I figured I would try them here. I started with a scrap of pipe of the same diameter as the frame. I used the table saw to cut a kerf into the pipe lengthwise. Then I sliced off little slivers by making cuts across the pipe. Here is the end result:

PVC Pipe clamps

PVC Pipe clamps


These hold the end walls on the frame very well, and they are easy to remove. This will help when it is time to take the wing out of the booth.

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Hours Logged This Session: 8.3
Total Hours: 1883.75

Final Wiring

Today was a short day, but I was only in town for a little while. I had to order more wire to use for the aft SAE jack and the landing light, and since those wires arrived while I was gone, I started routing them today. There are only a handful of wires left to add.

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Hours Logged This Session: .7
Total Hours: 1883.75

Painting White on the Left Wing

Today was a good painting day, so that’s what I did. I was able to get the white paint on the left wing and flap.

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Hours Logged This Session: 2.1
Total Hours: 1883.75

Masking the Left Wing

I had a long weekend break and was able to get home for a few days. Tabitha came over to help install the inspection hole covers on the right wing. I measured the right wing’s tip and root sections so that I could transfer marks onto the left wing tip and root. Then I connected those marks with the fine-line tape. I installed the flap and measured and marked the spots on the trailing edge where the stripes would end. Those steps positioned the edge of where the stripes would start and end. I masked the to-be-blue areas with paper and cheap tape, and then left it all there to paint later.

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Hours Logged This Session: 4.4
Total Hours: 1883.75

Visiting Graham Meise

I was in Orlando for a while this April and May to learn a new airplane at work, and while I was there I had a chance to catch up with Graham Meise at the KISM airport. Graham has a 4-place Bearhawk kit and he’s jut now starting to have time to work on it. He also gave me a fantastic tour of the museum next door. Visits like this always put me in the best mood.

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Hours Logged This Session:
Total Hours: 1883.75

Priming the Left Wing

Yesterday’s high humidity complicated my painting plans, but I have to leave town for a while and wanted to get the wing
primed before I left. This morning I got it all done in about 2 hours, which is much less time than it took me to prime the other wing.

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Hours Logged This Session: 2.1
Total Hours: 1883.75

Fuselage Plumbing

I was getting ready to prime the wing today, but it started raining. Instead I started routing the static line from the back of the fuselage up to the instrument panel. I also reinstalled the rest of the cabin fuel lines. I had originally planned to route the wires for the manifold pressure sender through the hole on the right side of the firewall, but after looking at the firewall for a little while, it made a lot more sense to route them through the hole at the top of the firewall where the secondary alternator wires go through.

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Hours Logged This Session: 5
Total Hours: 1883.75

More Wing Preparations

Today was a productive day with help from Jack and Vince. In the morning I put the casters back onto the wing rack in preparation for moving the right wing off of the rotisserie and on to the rack.

Left Wing

Left Wing


Above you can see the left wing out in the sun. The problem with talking about left wings and right wings is that the Google search results start to get a little bit strange sometimes. Vince arrived after lunch and started cutting out aluminum circles that will make the access panels on the landing gear legs. I had intended not to put in access panels for removal of the flexible brake line, figuring that it wouldn’t need replacement for a few years. Unfortunately, I installed the lines upside down before covering, so it turns out that they need to be accessed now.
Vince cuts circle panels

Vince cuts circle panels


Jack arrived later in the afternoon to come help install an end on the VHF nav coax. He ordered some ends for me since he was already going to be ordering from all electronics.
Jack installs the coax end

Jack installs the coax end


Meanwhile, I prepared the aft left cargo door for skin and frame for riveting. While I worked on routing the wires for the aft cabin light, Vince riveted the skin to the door.

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Hours Logged This Session: 13.7
Total Hours: 1883.75

Parking Brake Warning Light

Today I made a few software adjustments to try to get the EMS data to show up on the D100. I had to call Dynon for advice, and they pointed out that while the DSAB was working fine, I had to configure the default screens on the D100 to allow the EMS pages to come up during the cycling. I installed that pilot end of the carb heat cable, throttle, and parking brake. I made a bracket to hold a little normally-closed microswitch right next to the parking brake lever, so that when the parking brake is in the fully off position, the switch is opened. When the switch is closed, a blue LED is illuminated on the panel. The LED only goes out when the circuit is opened, which should hopefully only happen when the arm is in the fully open position.

Parking Brake Switch Bracket

Parking Brake Switch Bracket


Parking Brake Switch Bracket

Parking Brake Switch Bracket


Parking Brake Switch Installed

Parking Brake Switch Installed


I made the bracket adjustable, in case flex in the system makes it indicate unreliably.
Next I started preparing the left wing for paint.

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Hours Logged This Session: 8.4
Total Hours: 1883.75