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.

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.

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.

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.

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

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

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

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

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

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.

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Hours Logged This Session: 5.5
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

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.

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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.

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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.

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Hours Logged This Session: 7.7
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.

Posted on
Hours Logged This Session: .7
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

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

Painting White Pieces

This afternoon my Mom was in town again, so she helped by adding the masking paper to tail pieces. I use 3M fineline tape to mark the final edge, and then use regular cheap masking tape to hold masking paper onto that tape. It can be a little bit confusing sometimes to make sure that we mask the correct color section, especially since these are all smaller parts that are going to come together to make the final scheme.

Masking Paper

Masking Paper


While she did that, I added rivets back on to the inspection covers and reassembled the paint gun. The inspection covers came with universal rivets, but I took them apart to switch them to flush rivets.
Inspection Covers with Flush Rivets

Inspection Covers with Flush Rivets


This also allowed me to prime both sides of the retaining spring to help prevent corrosion. I also added rivets to the hinge on the door skin that will support the mouse door.
Mouse Door Hinge Rivets

Mouse Door Hinge Rivets


After a late lunch break I came back and painted white Aerothane on the inside of the door skins, the tailwheel fork, the tailwheel body, the elevator, horizontal stabilizers, and tiedown rings.

Posted on
Hours Logged This Session: 4.5
Total Hours: 1883.75

Firesleeve Clamp Tool

Today was a short session, but I wanted to try out my new tool for installing the steel bands on firesleeve ends. It came from Aircraft Spruce, but is branded as a CV joint band tool. This is it from Amazon.

It works very well.

Last Polybrush

The pile of empty cans is getting bigger and the pile of full cans is getting smaller! Today I did a little bit of touch up ironing and sprayed what will hopefully be the last of the Polybrush on the fuselage and landing gear.

Spraying the Fuselage

This afternoon I finished the last bit of heat smoothing in the interior. I had to add a little bit more reinforcing tape to one spot on the left side of the cabin where the large window is. That’s a complicated transition and a seam in the fabric makes it more complicated than it should be. The extra tape will help. I spent a few hours applying masking tape to the areas that I’d rather not have to clean off later.

Ready to spray

Ready to spray


Then I sprayed the first coat of Polyspray on the fuselage and landing gear.
First coat of Polyspray

First coat of Polyspray


I’m also spraying the exposed portion of fabric on the back seat, and a 3×3 foot swatch of spare fabric that I’ll prepare for emergency patches.

Still More Fuselage Tapes

A full day of adding fabric reinforcing tapes to the fuselage has just about finished that process. I have just a few left to do.

Fuselage Bottom

Fuselage Bottom


Interior Ceiling, Fuselage is upside down

Interior Ceiling, Fuselage is upside down


After applying the last of the 1″ wide reinforcing tapes, this is how much I had left on the roll.
Not much extra!

Not much extra!


Fuselage right side

Fuselage right side

Still More Cementing

The new can of cement came in so Tabitha and I resumed our covering. While Tabitha finished the fuselage edges I started to prepare the horizontal stabilizer for a new patch. This was an area that I’ve patched before, but needed to patch again after grinding off the sharp edge on the elevator trim mechanism.

First, I drew a circle

First, I drew a circle


Then I used MEK to remove the coats around the patch area

Then I used MEK to remove the coats around the patch area


Here are the sheets of polycarbonate for the windows and skylight

Here are the sheets of polycarbonate for the windows and skylight


The landing gear legs have a brake line that hides under the covering, so I installed the brake lines in both.
I'll have access to remove the lines later, but it's easier to put them in now.  Note!  in this picture, they are upside down.

I’ll have access to remove the lines later, but it’s easier to put them in now. Note! in this picture, they are upside down.


Tabitha works on cementing the left side of the fuselage.

Tabitha works on cementing the left side of the fuselage.


Those dark blue gloves are extra thick ones from Harbor Freight, which work much better than the regular ones.

Shrinking Interior Covering

I started off by installing those two remaining triangles in the cabin area roof. Those were the last pieces of the interior, so I started shrinking those areas to make sure that it was all going to work. I didn’t shrink the ceiling pieces yet, since they aren’t stitched. Next I started cementing the belly piece, which is a single strip of heavy-duty fabric.

Belly Piece and Interior

Belly Piece and Interior


Belly Covering

Belly Covering


The rotisserie arrangement sure is important at this stage!

More Disassembly

Today I carried on with the disassembly, in a marathon building session that would indicate that Tabitha is out of town. I took out the control sticks, elevator bellcrank, rudder pedals, headset wires, and other things like that.

Getting back to bare bones

Getting back to bare bones


The wiring was going to be too much trouble to take out completely, so I just balled it all up and wrapped it in a trash bag.
Protected wire bundle

Protected wire bundle


I removed the landing gear legs and set the fuselage on sawhorses. I welded on a tab to support the fire extinguisher, which will mount on the floor just in front of the main carry-through structure. Since we’re planning to leave the wing root section uncovered in the fuselage, the wing root fairing doesn’t have anything to collide with where it meets the fuselage. I added a few tabs there to allow for a vertical portion of the wing root fairing, which will seal the gap. I started with a long strip, then welded the end of the strip in place. Next I trimmed the strip off to determine the length of the tab. This made it much easier to hold the pieces in place for welding.
Weld the tab on, then cut it to length

Weld the tab on, then cut it to length


Here's the finished row of tabs

Here’s the finished row of tabs


Next I modified the landing gear trailing edge to allow for larger tires.
Here's the original arrangement

Here’s the original arrangement


Here's the desired arrangement, before welding the lower section

Here’s the desired arrangement, before welding the lower section


Here's the final product, ready to blast and paint.

Here’s the final product, ready to blast and paint.


With both of those done, I needed a way to get the fuselage around by myself. This is what I came up with:
1-man wheelbarrow fusleage transport

1-man wheelbarrow fusleage transport


The fuselage is resting on a 2×4 that sits on the wheelbarrow. There is a strap that runs under the wheelbarrow handles, which makes it possible to lift the rear end of the wheelbarrow by lifting the tail.
I tied the front down for stability

I tied the front down for stability


I tied the front down for stability

I tied the front down for stability


these will make up the front portion of the rotisserie, which is a necessity for the next few building steps. I learned several months later that it was not a good idea to use the airworthy AN bolts. The moisture in the wood led to a little bit of corrosion on the bolts.

Posted on
Hours Logged This Session: 11.5
Total Hours: 1883.75

Taking it All Apart

My last session in the shop included putting almost all of the parts on the airplane, and my last entry here included flying in Dave’s Bearhawk. From those two highs, it’s time to carry on with progress and see a few lows. First I dug through my tubing scraps and was pleased to find one that will fit nicely inside of the axle. This will help when it is time to bend the axles to align the wheels. Next I marked and trimmed the fiberglass fairings that cover the junction of the lower strut end and the fuselage. Since I’m not planning to have the wings on for a while, this is good to do now.

Lower Strut Fairing

Lower Strut Fairing


Next I cut the aluminum on the right upper front window frame to match the steel where the lock cylinder will go.
Right window lock mount

Right window lock mount


With those things done, I started taking things apart. After about 6 hours of work, this is what it looks like:
Almost all apart

Almost all apart


Wade and Danny helped with getting the wings and engine off. Tomorrow I should have everything removable off of the fuselage to prepare for blasting and painting.

Posted on
Hours Logged This Session: 11
Total Hours: 1883.75

Photo Session

This morning I reinstalled all of the sheet metal on the front end, especially the tunnel and lower boot cowl. This is all part of the plan to make sure that I don’t have any interference problems.

Lower front sheet metal

Lower front sheet metal


With those parts and the cowl on, I rolled the airplane outside for a few photos. It looks so close to being done, but it’s still so far from flying!
Bearhawk Before Covering

Bearhawk Before Covering


Bearhawk Before Covering


P1020910


Axle Nut Width
I also measured for the size of the wheel axle. This is the first time that I’ve needed to take the wheel off, and I’m not sure about what the best tool is going to be. The nut is 1-3/4 inches, but it’s recessed inside the wheel so that it’s not really accessible by a wrench or socket. I’m not sure whose idea that was. I did more initial checking of the main landing gear alignment and have come to the conclusion that I’m going to need some better measurement methods if I’m going to get repeatable results. I tried using some 1/16″ aluminum angles that I had on hand, but they’re just too wiggly.

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

Adjust Seatbelts

I found a great deal on a set of seatbelts on eBay. These are military surplus Amsafe units that were stocked by the military for off road vehicles. These are almost the same as the ones that I use in airliners, with the only difference being that these don’t have a release option for the shoulder harnesses only. The buckles are 5-point, but the eBay auction only included the parts for the 4-points. I’ll have to buy a few extra parts to make these work just as I’d like, but hopefully in the end it will mean a significant cost savings over the other options, and a much nicer finished product. I started with the front seats. When I bolted in the lap belt and buckled it up, this is how much slack was left over:

Front Seat Slack

Front Seat Slack


Obviously that’s not enough. While I’m not as skinny as I used to be, I’m still fairly skinny by comparison, so we’ll need more adjustment here. The solution is to put the shoulder harnesses in as lap belts, since I’ll be replacing the front shoulder harnesses with inertia reels anyway. The only problem with that plan is that the left lap belt is permanently attached to the buckle. This seemed like something that I could overcome, so I started taking the buckle apart.
First I removed the Amsafe logo in the middle, exposing the allen bolt.

First I removed the Amsafe logo in the middle, exposing the allen bolt.


Here's what's underneath.

Here’s what’s underneath.


To get the buckle out, I loosened the 6 torx bolts, then pressed down on the latch from above. Then I put the shoulder harness buckle in instead:
Shoulder Harness Becomes Lap Belt

Shoulder Harness Becomes Lap Belt


Now I just need to round up a few more buckles and some inertia reels.
As I mentioned in a previous entry, the threaded-end mixture cable that I was planning to use wasn’t going to work. I was able to trade with a local EAA Chapter member for a bare-wire mixture cable, so I put it in today to make sure it was going to work. I also got a good deal on a pair of aluminum eyeballs, though they were 1/8″ holes. I enlarged the holes to fit the mixture and throttle cables.
Enlarge Eyeball Holes

Enlarge Eyeball Holes


I used a letter B bit for the final hole.
Here they are in place

Here they are in place


While I was there I did a few other minor things, including a preliminary check of the landing gear alignment and installation of the quick release pins for the back seat.

Posted on
Hours Logged This Session: 4.3
Total Hours: 1883.75

Measuring for the Seatbelts

Now that the seats are in I was able to measure how long our seatbelts will need to be. I used the form from the Aero Tuff website. A few entries ago I made the oil cooler lines. Today I applied some high-temp RTV to the ends to help keep the oil and debris out. I’ll add the special stainless clamps once I can find someone who can loan me the tool that they require.

Firesleeve Rolled Back

Firesleeve Rolled Back


High Temp Goop

High Temp Goop


Ready for a Clamp

Ready for a Clamp


Oil Lines Installed

Oil Lines Installed


I also repositioned the fuel valve one last time, I hope.
Fuel Valve Location

Fuel Valve Location


I was concerned about having it in the way of grabbing the flap handle, but after sitting in the seat and making a few practice grabs, I found that for the first couple of flap settings my hand didn’t go to the end of the handle anyway.

Posted on
Hours Logged This Session: 4.5
Total Hours: 1883.75

Oil Hose Pressure Testing

I purchased some surplus reusable hose ends from B&B Aircraft Supplies a few years ago at Oshkosh, so I figured I would use those. They were new and very inexpensive ($5 each), but I didn’t know much about them. It turns out that they were Stratoflex 676 fittings. A few hours of research turned up that they are designed to work with Stratoflex 156 hose, which is a braided stainless type of hose. I ordered a few feet of hose from the Sacramento Sky Ranch and assembled the lines. Since I was operating on intuition instead of instruction, I thought it would be prudent to pressure test the lines before installing them.
With an afternoon to kill in Charlotte, I sat down with Google maps and started calling hydraulic shops around the area. The first few weren’t set up to do any testing at all. One would test them at their hourly shop rate of $100 per hour, with an estimated test time of 1.5 hours. Another would test them for $35, but wasn’t sure when they would have time to do it. Eventually a shop put me in touch with Rick White, at Brown and Miller Racing. On the phone I asked Rick if he was set up to test lines, and he said “Sure.” Did he have 1/2″ 37-degree flare fittings? “Of course.” How long would it take? “A few minutes. You can come back into the shop and watch.” When can you do it? “When can you be here?” That was all of the convincing that I needed. The only problem was that I was in Matthews and he was in Concord, and it was 4:00. Their closing time was 5:00, so I headed over there directly. I arrived at 4:45 to find a very polite and accommodating Rick. He showed me his test bench and explained how it worked. It uses a specially filtered water to apply a specified pressure anywhere up to 5,000psi, then closes the valve to check for loss of pressure. He tested the lines up to 500 psi and they held fine, which was a relief. It’s always nice to have my own work validated! I also needed a flexible fuel line for the firewall-carburetor connection. Rick priced a fire-sleeved Teflon line with crimped-on ends at just under $30. Then, he made it with his fancy machinery (and pressure tested it) in about 3 minutes. In short, I was impressed with his capabilities and amazed with the level of service he provided, even though I walked in the door a few minutes before closing time. If you are in the area and need to test some hoses or have non-PMA hoses made up, I’d recommend giving Rick a call at 704-793-4319. His shop is next to the Charlotte Motor Speedway is certainly worth a visit.

Posted on
Hours Logged This Session: .5
Total Hours: 1883.75

Oil Cooler Lines

A few days ago when I finally got the right oil filter installed, it became pretty obvious that the straight AN fitting that I was going to use for the oil cooler line wasn’t going to clear the filter. I swapped it out for a 45-degree nipple instead, which works much better.

AN823-8D Fitting

AN823-8D Fitting


I made the second oil cooler line out of the remaining piece of stratoflex, and started to think about measuring the deflection of the flight controls.

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Hours Logged This Session: 1.3
Total Hours: 1883.75

Stratoflex 156

This afternoon we tried a little bit of family hangar time. The weather was nice, so they enjoyed the shade while I made use of some new parts. A box arrived from the Sacremento Sky Ranch with the Stratoflex 156 hose for our oil cooler and a new oil filter. The new filter fits the adapter correctly. I found a good deal on a stainless steel oil line for the prop governor, and it also arrived recently. I tried for a few minutes to put it onto the engine, but quickly realized that it wasn’t going to happen without separating the engine from the engine mount. I picked up some reusable hose ends from Oshkosh a few years ago, which came attached to a short piece of hose. I disassembled those today and put one on the end of our new hose, and by then, Tabitha was ready to go home again.

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

Prop Governor Gasket

Back when I was making a new bracket for the prop control, I had to remove the back of the governor to ajust the angle of the control arm. This disturbed the gasket from that area, so I tried to find a replacement. I wasn’t having much luck with Google, so I just called up an “experimental friendly” prop shop and gave them the governor model. In a few minutes and for less than $10 I had a new one on the way, which I installed today. I installed the lower left fuel line that goes under the front door, and remade the aft line that goes behind the front door. The first version was too wiggly, and I made it before the wings were on, so it didn’t end in the right place. I’d recommend to others that it’s probably better to wait on making fuel lines until the wings are on. I added a tab halfway down the door post to support the aft vertical fuel line and meet the 16″ support requirement.

Posted on
Hours Logged This Session: 2.1
Total Hours: 1883.75

Aileron Cable Turnbuckle

I noticed that the turnbuckles that come in the Wicks hardware kit (or at least, the ones that came in ours) are all the same. They have a pin eye on one end and a cable eye on the other.

Pin Eye on the left, cable eye on the right

Pin Eye on the left, cable eye on the right


In all but one of the cases on this airplane, that’s exactly what is needed. The exception is in the aft aileron cable, since the turnbuckle there joins two cables. It may be possible to use the turnbuckle as provided if I were to put it on one end of the cable, and then build a continuous cable all the way across the airplane to the other wing. This would be terribly inconvenient when taking the wings off though. Instead I ordered a replacement cable eye, so that now the turnbuckle has a cable eye on both ends. I also ordered a second -23 adel clamp for the oil pressure sender, so that I can attach it to two engine mount tubes. This seems much more secure than one.
Oil pressure sender

Oil pressure sender


I also rerouted my carburetor heat cable and removed the mixture cable. I had both of these exiting the firewall down low in the middle. The problem with that location is that there is a very short straight stretch between the firewall and the respective control.
Very short cable run

Very short cable run


Since the engine moves around in its shock mounts, this is going to transfer all of that motion to a short length of cable. The solution is to route the cables so that they exit the firewall about a foot higher, then form a nice sweeping bend down to the forward end. This is easy for the carb heat, but not so easy for the mixture. I’m going to need to swap my threaded end cable for a plain end cable so that I can have more clearance between the control and the firewall. I’ve also decided to remake the fuel lines again, in hopes of getting a better end result. I started with installing the lower right fuel line, which I’ll not need to remake. Our new baby finally came about a week ago, so my hangar time has been a little bit sparse!

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

Manifold Pressure Tap

In the last episode we left off with a failed attempt to get the manifold pressure from the engine to the sensor. Today was more successful, thanks to some inventory from hangar neighbor Danny. He had one of these fancy restrictor fittings that will go in there nicely:

Manifold Pressure Restrictor Fitting

Manifold Pressure Restrictor Fitting


The idea behind using a restrictor here is that if the line between the cylinder and sensor fail, it will create a vacuum leak for the number 3 cylinder. The restrictor reduces the size of the leak from a 1/4″ hole to a .040″ or so hole. The larger hole would likely lead to some engine roughness, but the smaller hole probably would not. To get that fitting in, I had to disconnect the oil line:
This is where it goes.

This is where it goes.


There, see?

There, see?


That fitting is a 37-degree flare fitting, and I need to end up with 1/4″ tube. The best idea that I could come up with also solves another problem, which is how to bend the hose around the relatively steep corner and keep it clear of the cowling. I used 1/4″ 5052 aluminum tube to make the first 6″ or so of the line, then used an angle bracket attached to the baffles to change over to a 1/4″ Tygon hose.
Here's the bracket and the fitting

Here’s the bracket and the fitting


Bracket and 2" hole with flange

Bracket and 2″ hole with flange


The only bad thing about this plan is that the area where the bracket will attach is where I was also planning to put a 2″ hole to bring air into the exhasut muff for carb heat. The solution was to move the hole over to the right instead. By having the hole low in the baffles, it helps pre-heat the air as it flows over the cylinder fins.
All was well until I reinstalled the baffle and realized that I had put the port right next to the intake area, where there aren’t any fins, and there probably won’t be very much airflow.
Oops, that's not going to work very well.

Oops, that’s not going to work very well.


So I patched the hole with an aluminum piece, and I’ll make a new hole up above the cylinder later.
Problem fixed

Problem fixed


Next I mounted the manifold pressure sender, near the top of the firewall and slightly to the right. This high location will help any liquid contaminants drain back towards the engine. I finished up a few other items that were outstanding, like supporting the prop control.
These clamps secure the prop governor control- I think I might have to change the clamp on the cable to one that doesn't have the rubber padding.

These clamps secure the prop governor control- I think I might have to change the clamp on the cable to one that doesn’t have the rubber padding.

Flap Shackle Bushings

Today I welded more on the oil cooler support tube. I made a nice little foot on the end that should help distribute the force and vibration.

Oil Cooler Support

Oil Cooler Support


As I mentioned in an earlier entry, the flap cable terminates at the torque tube in an interesting way. Bob specified a shackle with a 1/4″ hole, but a 3/16″ bolt. I made some bushings for this junction earlier, but I didn’t make them correctly. It turns out that each shackle requires two bushings, and the flap horn itself still keeps the 3/16″ hole. To help make the bushings as true as possible, I cut them with the circular pipe cutter. To help reduce the stress on my hands, I chucked up the 1/4″ 4130 tube in the drill and let it do the turning. That method worked pretty well.
Using the drill with the pipe cutter

Using the drill with the pipe cutter


I dabbed a tiny amount of JB weld on the bushings where the join the shackle. The goal here was to keep from losing the bushings between now and flying time. Once the airplane is assembled, the bushings will be held in place by the bolt.
Completed Bushings

Completed Bushings


Next I tried a few different ideas for installing the tap for the manifold pressure. I need to go from 1/8″ pipe threads to 1/4″ hose, which leaves me with plenty of options. The cylinder end is going to be exposed to some fairly high temperatures. When the engine is running the temperatures should be fairly moderate, but after shutdown that area will probably be at least 200 degrees.
This straight fitting isn't going to work, it's too close to the oil drain line.

This straight fitting isn’t going to work, it’s too close to the oil drain line.


This straight barbed fitting isn’t going to work, and I’m not sure that a 45-degree barb fitting will be able to turn in the confined space.
Here are a few pictures that I took to send to the exhaust folks to see if they think a muffler will fit. I’m including them here for reference.
Sump from Below

Sump from Below


Sump from Left

Sump from Left


Left Side

Left Side


Right Side

Right Side

Drilling the Flap Tube

Yesterday I installed the oil filter adapter, but didn’t have a socket big enough for the vernatherm. Today I have the socket, so I torqued it to specs and installed safety wire. I welded the aft end of the brace tube for the oil cooler, which will go between the engine case above the number 2 cylinder and the back left baffle.

Oil Cooler Brace Tube

Oil Cooler Brace Tube


I removed the rudder cables and turnbuckles to turn them into flap cables. I wanted to try and get the length of the two cables as close as possible, so I used a rope to tie the triangular junction to the fuselage.
Rope support for flap cable

Rope support for flap cable


The outboard ends of our flap tubes were not drilled yet, so I spent a while looking at the plans. There isn’t a lot of room for error in the geometry of the wing root end, so I measured carefully to get the angle of that inboard horn
correctly. The most accurate dimension that I found to measure was the distance from the center of the hole to the rear spar, measured with a square. I used that method to position the tube angularly, and shifted it left-right to line up with the cable. Then I drilled a small #40 hole at the outboard end of the tube. I installed a cleco and drilled the other side, then enlarged those holes to 3/16″ for the AN3 bolts.
Flap Tube Drilling

Flap Tube Drilling


This is certainly an instance that calls for measurning twice.

Oil Filter Adapter

Back in September I wrote about our oil filter adapter. Today I installed it, which required removing each of the mags in order to get to the nuts. While I had the right mag off I also put a drilled rivet into the fitting to act as a restriction.

Oil Filter Adapter

Oil Filter Adapter


I also drilled the firewall for the prop governor control and carb heat control, and started cutting apart the right rudder cable so that I can turn it into a flap cable.

Prop Control Support

The baby is running behind schedule, which is a good thing. It means that I’m in town with a clear schedule, which translates to getting lots of things done. I started with deburring the prop control support bracket that I started making yesterday.

New Prop Control Support Bracket

New Prop Control Support Bracket


The new bracket is very similar to the old one, with a few notable differences. First, on the end that is on the right side of the picture above, I’m adding a little flange to bend up. This will support the cable in a more secure way than an adel clamp. The new bracket is thicker, simply because the aluminum that I had on hand was a little thicker. I bent flanges along the edges as in the original, and they add quite a bit of stiffness. I drilled a few lightening holes in it and installed the whole contraption onto the prop governor.

Baby Building

Tabitha came out today and worked on deburring the window frames. While she did that I started making a new bracket for the prop control at the governor end. Our used governor came with a used bracket, but it looked fairly well abused. It made a good template for the new bracket, which will support the forward end of the control.

9 months pregnant and deburring still

9 months pregnant and deburring still


What makes Tabitha’s visit to the hangar so remarkable isn’t that she’s here, it’s that she’s here while she’s pregnant with a baby that’s due tomorrow.

Planning for Prop Control

Today I reinstalled the horizontal stabilizer. The strategy at this phase of construction is to add as many of the existing parts as possible onto the airplane to try and fix any interference issues that may have crept up. I spent some time planning for the routing of the propeller control and prop governor oil line, and I spent a little while welding some of the exhaust pipes.

Install Prop Governor

This afternoon I installed the propeller governor for hopefully the last time. I used star lock washers and plain nuts. The documentation that I’ve found calls for 200 inch pounds of torque, which seems very tight. I set up the wrench and started tightening and felt like I should probably stop long before I got to the full 200. I did a little bit of research and confirmed that the setting is correct, and that several other builders have also had the same feelings. I measured the length of oil cooler lines that I’ll need, coming up with 11-13 inches for the short one and 23-26 inches for the long one.

Aft Wing Root Fairing

As I mentioned yesterday, the aft portion of the wing root fairing is the most difficult to make. One challenge is that the must intersect the fabric, which isn’t on the airplane yet. I used contact paper to simulate the fabric:

Simulated Covering

Simulated Covering


This allowed me to mark and trim the inboard side of that fairing and drill it to match the wing root. After a short lunch break I came back and got most of the right wing root fairings done, and welded more on the exhaust pipes.

Posted on
Hours Logged This Session: 5.4
Total Hours: 1883.75

Dynon Remote Compass Sensors

Today I spent a few hours of my birthday doing one of my favorite things, building airplanes. While I had the airplane leveled for wing measurements, I installed the Dynon compass sensors. The Dynon instructions say that the compass sensors and the D100-series units should be aligned within one degree or better. I’m using two compass sensors, one for the D180 and one for the D100. This will provide redundancy in the event of any number of small failures. I attached the two units together with brass screws and brass nuts. The brackets are built out of aluminum, so there aren’t any ferrous parts around. To start, I positioned the airplane so to be level left-right, and so that the bottom of the D180 mounting tray was level front-back. Then I used an angle measuring gauge and the level to find out what angle I needed to have between the wing bottom skin and the bottom of the sensor.

Wing incidence

Measuring the Relative Angle


With that measurement in hand, I attached the little foot bracket to the inboard side of the stack. It would have looked cleaner to have a single piece of metal bent to form this part, but it would have been very difficult to get the angles just right. In this case, I drilled one hole and installed a cleco, then adjusted the angle, clamped the parts together, and drilled the second hole through both at the same time. The horizontal portion of this “foot” will be riveted to the wing skin. The inboard side of the bracket will be riveted to the tip rib, so it doesn’t need a foot.
The foot

The foot


The next challenge was finding a way to drill the wing skin to match up with that foot. The easiest way would have been to drill down from the top, but there isn’t enough room in there for a drill. Instead, I drilled the holes in the skin first, based on an approximation of where they needed to go. Then I marked the edges of the foot so that I would be sure that I was close enough to the middle to avoid edge distance issues.
Edge distance indicator

Edge distance indicator


I put the whole assembly into the wing, then scooted it around until I could see aluminum through the holes, but no black marks. Then I aligned the assembly in the other axes, and match drilled the foot through the holes in the wing skin. Then I added two rivets above and two rivets below the units on the tip rib. The whole thing is lined up very well and feels plenty sturdy.
Note from the future: This installation is not correct, since I have the wires coming out of the back of the unit. The heading indicated 180 degrees off in this arrangement. Be sure to mount yours the right way!
Dynon Compass Sensor

THIS IS WRONG! Don’t do it this way! The wires need to be facing forward. In this configuration the heading indicates 180 degrees off.


I also added another layer of filler to the intake scoop and windshield fairing, again.

Checking Wing Alignment

I started off with what has become a bit of a hangar ritual, sanding the fiberglass parts and adding more filler. It’s looking better, but still needs more work.

Intake Scoop

Intake Scoop


We didn’t drill our wing attachment points, since our project’s previous owner already had. I wanted to be sure that the wings were lined up correctly- not because I doubted Richard’s work, but because if there were a problem, it would be a hole lot easier to fix now, before we cover the fuselage. And of course, if it was off, we would have no choice but to fix it sometime. To simplify the check, first I leveled the fuselage left to right with the water level. Then I raised the tail until the bottom of the wing was level. I checked along the length in several places to be sure that we had the same incidence angle on both wings, and no warps from the factory. All of that checked out perfectly. Next I checked dihedral by measuring the height difference between the wing root and the wing tip with the water level. I was getting a slight difference between the two wings, and after much head scratching I realized that the struts are probably on backwards. I think I have the right strut on the left wing and vice-versa. I looked back at pictures from Richard’s log to see that in his pictures the bolts are pointing down, which confirms this suspicion. Next time we put the wings on I’ll swap the struts and check again to verify the dihedral.
Leveled for measurements

Leveled for measurements

Left Rear Window Continued

This morning I finished welding the top track for the aft window. The more difficult section is the aft side of the window. I started that section by moving the stringer attach points. THe lower stringer is going to be out a little bit further, while the upper stringer is going to be in a little bit from original. The aft edge of this window will be the forward end of both stringers now. The aft flange is not a track, since if it was, I wouldn’t be able to get the window in. Instead, it’s a joggle. It will get an aluminum mate later that will capture the window and shape the outside of the window aesthetically. I used a bead roller to make the joggle.

Bead Roller with Joggle Dies

Bead Roller with Joggle Dies


.030 Steel Joggle

This is the result after a few practice runs. It’s not perfectly straight, but it won’t be visible once the airplane is done.


Here's how it comes together at the bottom

Here’s how it comes together at the bottom


And here's the rest

And here’s the rest


I would have preferred to have a straighter finished product on the top half, but all of that should be covered by the aluminum trim piece, so it won’t show.

Testing the D100

In another stressful moment of truth, today I powered up the D100 for the first time. I started by verifying each pin in the wiring again. Here’s the unit that I found on eBay. It’s slightly used but in great shape:

Dynon D100

Dynon D100


Here’s where the backup battery hatch is. I was surprised to see a battery in there, since the seller didn’t advertise it as being included. This little hatch is on the right side near the bottom.
Dynon Backup Battery

Bonus backup battery


Here’s what the pack looks like:
2200 mAh 18650 Lithium Cells with Charging Circuit

Bonus backup battery


With no other excuses, I put in a fuse and turned it on.
D100 Powered Up

Powered up


It works just like it is supposed to, except that the backup battery doesn’t take a charge. That’s probably why it wasn’t advertised as included! I’ll try taking the pack apart to see if I can replace the cells. In this case at least I have the connector and onboard charging circuit to harvest from the old pack. While I was waiting to see if the pack was going to charge, I installed the nose bowl to be sure that the landing aluminum wasn’t going to interfere with the starter. Here’s how it looks:
I'll need to trim a little off of the top.

I’ll need to trim a little off of the top.


I shortened the back bracket by 3/4 inch or so just to provide a bit more clearance.
Here's where it will go

Here’s where it will go


I attached it at the bottom first:
Nose Bowl Light

Nose Bowl Light


I’ll make a provision for adjustment in the top bracket, which will allow me to aim the light once we try flying with it.
Nose Bowl Light Side

Nose Bowl Light Side


It was so nice to see the D100 in the panel that I also got out the HS34 to see how they would fit together. I found that they won’t fit together very well at all, at least not without more cutting.
Dynon Clearance Shortage

Dynon Clearance Shortage


The problem is that I cut the hole based on the published dimensions for each box. Since those dimensions don’t include the outer flange, and since the two share a hole, I needed to add another 1/8″ or so to the width.
648- New Cut Line
The picture above illustrates the problem. It’s not a big problem, and a few minutes with the dremel and file will have it all worked out. If only I could say the same thing for the HS34 mounting bracket! I would rather not drill new holes in the panel, so instead I’ll drill new holes in the bracket. These holes will not have adequate edge distance, so I’ll have to come up with a doubler to put in front of (aircraft forward) the bracket flange. This will make a sandwich, with the instrument panel and doubler being the bread, and the HS34 bracket being the balogna, or cheese for vegetarians.

Fuel Line Tabs

I came out for little while today to sand the last layer of filler and add another.

Scoop Filler

I worked some into a little gap at the back of the scoop


AC 43.13 says that fuel lines should be supported every 16 inches. I can’t see how it’s possible to span the distance from the aft side of the front door to the clamp on the diagonal tube under the door bottom, so I made up a little tab:
Fuel line support tab

Fuel line support tab


I welded the tab to the outside of the flange, since it was much easier to get to.
Fuel line support tab welded

Fuel line support tab welded


Since the metal part slopes inward, the weld bead should clear the fabric. While I was welding in that area, I had to figure out how to remove the headset jacks so that I could get the wires out of the way. This was the solution that I came up with:
Big hole/little hole

Big hole/little hole


The headset cables run through the little hole on the left, so i drilled the big hole on the right and connected the two with a very small version of the Erie Canal. That reminds me of a mule named Sal, and makes me think of Albany and Buffalo, which I usually don’t do on my days off.

Adding Filler

In replacing the engine mount bolts, I found that I needed a second washer to get the castle nut in the right place. I installed those washers on each one, but I didn’t put any cotter pins in yet. Odds are good that I’ll have to take the engine off again before we fly. I sanded the prior coats of filler on the nose bowl joint and scoop, and added another layer to the scoop.

Nosebowl Light Preparations

Today I continued work on the front baffles, including deburring the edges of the thick brackets. I think Vans cuts them out with an axe, or perhaps they hire that Jaws fellow from the James Bond movies. I started working on the layout for the landing light, which will go in the nose bowl.

Landing Light Layout

Landing Light Layout


The idea is that I’ll cut out the fiberglass, install aluminum strips to support a lexan panel, then make a fiberglass back to the compartment where the light assembly is.
Aluminum Support Strips

Aluminum Support Strips


Here’s the left front baffle again
Left Front Baffle

Left Front Baffle


I riveted it all together a while back, but after looking at the plans I realized that I used the wrong ones! I was supposed to use 1/8″ but I used 3/32″ rivets. I added rivets to the front right baffle also. You can see how much more narrow it is, since the number 1 cylinder sits farther forward than the number 2.
Right Front Baffle Bottom

Right Front Baffle Bottom


Right Front Baffle Top

Right Front Baffle Top


Next I sanded the filler on the windshield fairing and intake scoop again, and added another layer.
Intake Scoop

Intake Scoop


While I had a batch of filler mixed up, I also added some to the nose bowl seam. The original fiberglass parts had an uneven edge at the overlap. Rather than try to add material to the thin flange of the top, I added it to the thicker bottom piece. I masked the top half with a little bit of clear contact paper.
Filling nose bowl joint

Filling nose bowl joint


Here's a closer view

Here’s a closer view


While that cured I pulled the engine off of the mount to install the oil pressure measurement fitting. I had read somewhere that I was going to have to install it before I mounted the engine, but for some reason I never did execute that plan. It only took a few minutes to do, and while I was there I also replaced the temporary hardware store bolts with aircraft-grade AN bolts.
Oil Pressure Fitting

Oil Pressure Fitting


That’s it right in the lower middle of the picture, with the silver braided line attached.

Riveting Baffles

Today I continued with the front baffles. First I drilled the angle support that connects the side baffle to the front.

Bearhawk Cylinder Baffle

This hole is where the AN3 bolt goes, along with the odd little nut piece that comes up from the bottom to make the threads for that hole.


Right Front Baffle Assembly

Right Front Baffle Assembly


I also spent some time working on the steel structure that will support the new back left window. I needed to have a track for the bottom, so I tried bending some steel strips by hand.
Steel Strip

Steel Strip


I clamped the steel between two pieces of wood. It’s very soft, so I figured I would try bending it without a brake.
Ready to bend

Ready to bend


I used a mallet to start the bend, and then used the vice to finish it.
Finishing the bend

Finishing the bend


It turned out not to work very well at all. The bending process stretched the section opposite the bend, making a nice curved track. It looks like I’ll have to go visit my friends with the brake again.

Front Baffles

Today my friend Hari stopped by from the other side of the state. He is scratch building and had an extra sheet of .020″ aluminum. He stayed for a little while and we had a good visit.
The front area of the engine baffles are pretty complicated. I started by setting the angle of the floor on the left side. The nosebowl is off in the picture, but I had to use it to determine the location.

Number 2 Baffle

Number 2 Baffle


The other side

The other side


This little triangle bracket is a doubler for the bolt.
Vans Part number 24

Vans Part number 24


I match drilled it to the baffle, deburred everything, and riveted it all together.
Baffle Reinforcing Bracket

Baffle Reinforcing Bracket


The number 1 baffle has a long aluminum angle support that tops off a sandwich of several layers of aluminum.
Number 1 Baffle Angle

Number 1 Baffle Angle


The Sandwich

The Sandwich

Oil Cooler Continued

I added the first layer of superfil on the windshield fairing, and another layer on the intake scoop. It will take several layers and lots of sanding to make them look reasonable.

Filler on Windshield Fairing

Here’s the first layer of filler on the windshield fairing


The oil cooler support will attach at the crankcase bolt just above the number 2 cylinder. I removed the original case bolt and added a longer version, and used the torque wrench to tighten the nut.
96 inch-pounds for the 1/4" case bolt

96 inch-pounds for the 1/4″ case bolt


I welded one of the ends of the oil cooler brace, and also welded a bit more on the number 2 exhaust pipe. I added the fittings to the oil cooler too:
Oil Cooler Fittings

Oil Cooler Fittings


While I was there I did a little deburring on the number 2 cylinder baffle.

Still More Fiberglass

This evening I worked on trimming the windshield fairing. I wanted to have an equal distance above and below the fold point, so I started by drawing a line along the the fold point. I used a square and a sharpie to mark a line along the fiberglass and used the belt sander to trim the fairing to those lines. I also started making the steel tube brace that will support the oil cooler. I’m using a 4130 steel tube with flattened ends.

Fiberglass Windshield Fairing

This morning I started on the fiberglass windshield fairing. First I applied contact paper to the windshield and boot cowl so that the epoxy wouldn’t stick to the expensive bits. Then I put a nice coat of automotive wax on the contact paper to make sure the epoxy didn’t stick to the inexpensive bits either.

Contact Paper Mask

Contact Paper Mask


I built up the first part of the fairing with two layers using the technique that Eric and Bob have published in the past. I taped a big trash bag to the table and wet the strips with epoxy. Then I squeegied most of that out with a hotel room key card. Then I put those strips in place and smoothed them out.
First 2 Layers

First 2 Layers


Trash Bag Layout Area

Trash Bag Layout Area


After lunch I came back and welded a few more exhaust pipes and sanded another gasket surface.
Exhaust Pipe Detail

Exhaust Pipe Detail


In the picture above you can see the weld fillets that run parallel to the exhast flow. Bob says that these help support the circumferential weld between the pipe and the flange.

Oil Cooler Support

This morning I started by finishing the rest of the lightening holes for the headrest parts.

Head Rest Parts

Here’s a stack of parts for the headrests


Next I made a few doublers for the oil cooler area on the back left baffle. I’m really guessing here with how much support I’ll need. I’ve studied a few other airplanes and copied what I have seen.
One doubler plate ready to cut

One doubler plate ready to cut


Match Drilling

Match Drilling


Sandwich Parts

Sandwich Parts


I’ll have to add one little filler strip to take up the gap where the top doubler doesn’t continue down to the bottom.
Filler Strip

Filler Strip


Riveted

Riveted


You can see that I’ve left several holes open. These get rivets from other sources, including the pop rivets that hold the rubber to the top of the baffles, and the rivets that hold the side baffle to the aft baffle.
The other side

The other side


Here's the whole sandwich from the side view.

Here’s the whole sandwich from the side view.


Side riveted to back

Side riveted to back


Same again

Same again


I added lightening holes to each of the headrest lower brackets
Headrest parts

Headrest parts


Then I deburred all of those holes and started to prepare the boot cowl and windshield for the fiberglass fairing that will go there.

Sanding Filler

I started today by sanding the filler from yesterday. This fiberglass work is a lot like drywall- one layer at a time makes it smooth in the end. While we were at the picnic I asked Bob about how he makes the mating surface of the exhaust flanges flat. He said he uses the belt sander, so I tried the same. It worked very well, though I did have to take a few breaks to let things cool.

EMT Conduit exhaust pipe

Exhaust Pipe Flange After Welding


Exhaust Flange After Sanding

Exhaust Flange After Sanding


I tacked on the flange for the number 3 pipe:
Number 3 Exhaust Flange Tack

Number 3 Exhaust Flange Tack


And then continued with headrest lightening holes. I used the step drill to make 3/4″ holes for the punch bolt:
Pilot Holes for Conduit Punch

Pilot Holes for Conduit Punch


I thought that the finished product turned out fairly well:
Finished Headrest Frame

Finished Headrest Frame


Finished Headrest Again

Finished Headrest Again


I spent a few more hours working on more exhaust pipes and making more pilot lightening holes in the other headrest parts.

Smurf Extract

The fiberglass from yesterday was cured well, so I used the belt sander to trim the outer edge further.

Polyfiber Superfil

Doesn’t it look nice now? Don’t look too close- it’s full of pinholes and other imperfections.


Ok, so here's a closer look.

Ok, so here’s a closer look.


To fix those problems I mixed up a batch of superfil, aka smurf extract. To spread the filler evenly in the corner, I used another hotel key. These have turned out to be quite handy and useful for this kind of work.
Rounded Corner on the Key Card

Rounded Corner on the Key Card


That rounded corner gave me a nice filet of filler.
Smurf Extract

Smurf Extract


While that cured I spent more time on the headrest structure. I found a good deal on a set of electrical knock-out punches on ebay, and it turns out that they make great lightening holes in aluminum. I sharpened the old tools on the belt sander and made a few test holes. These are some of my favorite new tools, because they are so simple to use and maintain, and because they make such nice holes.
Electrical Conduit Punch

You can see how the punch works in this view


Knockout Punch Aluminum

Here’s the end result in some scrap aluminum.


Lightening Hole

This lightening hole took only a few minutes to make and debur.


While I was working on that Tabitha did more planning for the new window frames.

Exhaust Welding

We just got back from Bob’s annual picnic up in Fincastle. It was great to see a few new Bearhawks, at least new to us. Roy Glenn and Philip Johnson were there, and we got some great ideas from both. I took my first exhaust pipe to show Bob and get his input. He said it looked fine, though he suggested adding a weld bead across the first joint to help distribute the stress. So today I added a couple:

Weld Beads

Weld Beads


The first layer of fiberglass on the intake scoop was well cured by now. I used my less-favorite pair of tin snips to trim the edge. I added another 2 layers to the side that faces the airplane.
Intake Scoop

Intake Scoop

Fiberglass Scoop Flange

Yesterday I prepared the cowling for the fiberglass work on the scoop. Today I used a few adjustable rolling stands to hold the scoop in place while I applied the first strips.

Scoop Fiberglass Flange

Scoop Fiberglass Flange


While the epoxy was setting up I made a few more pieces for the oil cooler attachment.
Baffle Support Angle

Baffle Support Angle


I needed for that angle to clear the valve cover, so I trimmed it to match the existing left rear baffle. I actually trimmed it just a little bit short, by using a scrap of angle to position the piece for marking.
Spacer for Marking

Spacer for Marking


That technique worked out pretty well.
Finished Angle

Finished Angle


I trimmed the tops of a few more baffles and deburred the edges. I would have never guessed that the baffles would have taken so long to make.

Engine Intake Scoop

Since the first headrest turned out well enough, I bent the parts for the other 3. I made some measurements for what type of support I’ll need to make for the oil cooler also. Since the intake scoop is going to need a fiberglass flange to attach to the cowl, I’m going to construct it right on the cowl. I used tape to apply a big trash bag to the aluminum:

Fiberglass intake scoop

Fiberglass intake scoop


I put 3 layers of 1/4″ foam between the bottom of the FAB an the top of the scoop. This will allow some space for the alternate air door mechanism, and will also allow for engine vibration. The FAB shakes with the engine, but the scoop shakes with the cowl.
Cowl Masking

Cowl Masking

Oil Cooler Screws

When I got to the hangar together this lady was there to help:

Praying Mantis

I told her that her claws would probably scratch the aluminum, hence the look of indifference.


I realized that the oil cooler bolts weren’t going to work as I had planned. Since the left rear baffle sits right up against the cooling fins on the back of the number 4 cylinder, I would not have any room for bolt heads. I’d have to use something like flush screws instead, so here’s what I came up with. I’d not recommend that anyone else copy this idea based on my use of it, at least not until I’m able to fly for a couple hundred hours and be sure that nothing cracks. Note that the top bolts will still go through both oil cooler flanges. When the airplane is upright and flying normally, the top bolts are loaded in tension and the bottom are loaded in compression.
Dimpled Screw Holes

Dimpled Screw Holes


Dimpled Oil Cooler Flange

Dimpled Oil Cooler Flange


Flush Mounting Hardware

Flush Mounting Hardware


And from the back too.

And from the back too.


I know that I’m going to need to add some support to the back baffle. I have been researching what other folks have done, mostly on the Vans Air Force site. The problem is that unless the post is from someone who had a baffle crack, it’s hard to know what works or doesn’t. Even in the case of a crack, that tells more about what didn’t work than about what did. The consensus seems to be that extra support in the back left corner and a diagonal brace from the crankcase are both helpful, so we’ll use both of those options.

Headrest Structure

Yesterday I located the oil cooler on the left rear baffle. Today I cut out some aluminum tubes to use as the supports that will keep the flanges from bending together when I tighten the bolts. Unfortunately, I ordered the wrong size of tube! It’s too small and the bolts won’t fit through.

Oil Cooler Bolt Tubes

Oil Cooler Bolt Tubes- too small!


I finished cutting off the other headset jack tab and primed both sides.
Evidence Removed

Evidence Removed


The landing light bracket will use the four corner screws to hold the brackets together, and the two large side bolts to attach that assembly to the structure in the nose bowl.
Landing Light Bracket

Landing Light Bracket


Landing Light Bracket

It’s a rare occasion when I can use universal rivets to attach a nutplate. Usually they have to be flush.


I worked a little bit more on the first headrest, making sure that he system is going to work before I make four of them. The idea is that these headrests will retract to the point where they are just slightly taller than the seat back. This is the only way that we could think of that would allow something to be tall enough to provide decent function (crash protection) but not in the way during operations with one or more empty seats. I copied the idea from a minivan.
Headrest Structure

Headrest Structure


Headrest Structure Attach

Headrest Structure Attach


In the picture above you can see three small holes in the short bracket. Those holes will get blind rivets, as will
additional holes on the top bracket.

Posted on
Hours Logged This Session: 3.7
Total Hours: 1883.75

Locating the Oil Cooler

While I was thinking about the aileron control cables, I realized that my previous location for headset jacks wasn’t going to work. I cut the old bracket off and this is what was left:

Headset Bracket Weld Bead

Headset Bracket Weld Bead


I used the die grinder and files to clean off the weld bead. It’s always frustrating when I end up making more work for myself, but such is the nature of building my own airplane I guess. I picked up where I left off last week with the landing light bracket, which involved using the rotary file in the dremel to finish enlarging the center hole. This is what I ended up with (after a few attempts to get the diameter correct on the back bracket hole)
Landing Light Sandwich

Landing Light Sandwich


The idea is that there is just enough thickness in the LED unit to allow for a tight hold when I attach the front bracket with screws. I’ll need to figure out a way to attach this contraption to the nose bowl, preferably in a way that still allows for some aiming adjustment later on.
At this point I have enough of the cowling done to be able to trim the baffles to their final height. I had previously rough-cut them so that they weren’t touching the cowl metal, so all that I needed to do was make a mark where I wanted to cut. To make that line, I poked a small hole about 1.5 inches from the end of a hotel room key. Any sort of plastic would do the job just as well, it’s just that I have a pile of hotel keys available. I stuck the point of a marker in the hole, then ran the edge of the card along the inside of the cowl metal. Some of the lines ended up on the front of the baffles, and some on the back.
Marking the Baffles

Marking the Baffles


Marking the Baffles continued

Marking the Baffles continued


I trimmed the left side so that I could know where I would be able to put the oil cooler. Tabitha came out later in the afternoon to make more window plans. She laid out the new shape in the upper left window and we worked together to cut it out.
Window Thoughts

Tabitha is thinking, looking at the old window shape. In this shape, the plexiglas is layered between the skin and a backing strip. We’re going to change the configuration to put the plexiglas between the steel frame and the aluminum skin, which saves a bunch of fasteners and allows us to enlarge the window a bit.


Bearhawk Front Window Skin

Trimming around the lock mount on the front window


While she worked on that I marked where the oil cooler will go.
Back left baffle Lycoming 360 oil cooler

First, here are the mounting holes.


Marks

Then I made marks for where the opening will be.


Note! This oil cooler mounting strategy proved to be inadequate in flight testing. The oil cooler is probably a little bit too small for this engine, but more importantly, it should probably be located back away from that cylinder a little. In the end I fabricated a mounting system that moves the cooler back about one inch. Also note that the ideal arrangement would be with the oil flow vertical. The vertical arrangement would give an outlet for trapped air to flow out of the cooler.
Then I cut out the hole for the opening.

Then I cut out the hole for the opening.


Cowl Hinge

Tabitha picked up where she left off on the cowl door hinge, exchanging clecos for rivets.


We’re both motivated to keep the project moving along.

Posted on
Hours Logged This Session: 7.3
Total Hours: 1883.75

Landing Light Bracket

This morning I sprayed the last coat of polyspray on the flaps, ailerons, and rudder. I came back to the hangar after lunch to debur the left door skin and start making the landing light bracket. For a while I wasn’t sure if I was even going to install a landing light. It certainly isn’t a required piece of equipment, and while it would be nice to have for flying at night, it’s not entirely necessary. There is some benefit for visibility to other aircraft, both in daytime and at night. While I was at Oshkosh I got a great deal on a AeroLED LED unit that I can put in the nose bowl, so that was a factor in changing my mind in favor of the light. The LED also has a built-in wig wag function (or in this case, perhaps more appropriately called a “wig”). The catch is that I have to come up with some way to mount it in the nose bowl. The unit is a standard PAR 36 size, so I started by ordering a bracket from Duckworks. The Duckworks bracket holds the front of the unit in place, and it was well worth the price, since it saved me a couple of hours of work. I used the fly cutter to make a hole in another piece of aluminum, which will support the back of the LED unit.

Bearhawk Landing LIght Bracket

This over-sized piece will eventually be the back of the LED support.


I’m not sure how the duckworks bracket was supposed to work exactly, but I found that it would work really well for me if I slightly enlarged the hole. I needed about 1/8″ more radius. I lined it up carefully in the drill press and used the fly cutter to make a significant part of the cut, then will use a rotary file in the dremel to finish the job.
Enlarging the Duckworks Bracket

Enlarging the Duckworks Bracket

Spraying Silver

This morning I sprayed the last coat of Polybrush on the parts. I cleaned up the fuel flow sensor that I wrote about in the last entry:

Fuel Flow Sensor Again

Fuel Flow Sensor Again


This evening I sprayed the first coats of the silver poly-spray on the parts.

Spraying Continued

I’ve been on the fence about wanting to install a fuel flow sensor. Eric Newton found that he wasn’t able to get the required fuel flow when he had the sensor installed. I asked him for more details about that while we were at Oshkosh, and he said that when he took the sensor out he found that a little piece of debris was blocking the little paddlewheel that should normally be turning. This was a bit reassuring, since it’s certainly excusable that the sensor would not meet the flow requirements under those circumstances. I’d like to have the fuel flow information for engine diagnostic and fuel economy reasons, but it’s expensive. Since the gravity version (gold cube FT-90) is less commonly used, it’s harder to come by in a non-retail situation. The red cube is common in low-wing airplanes and is fairly easy to find. The new price of the red cube is about $150 vs $250 for the gold. This is why I was very excited to find a gold cube listed on eBay. I have a set of automatic searches saved, so that I’ll get an email whenever a listing pops up with certain search terms. This was one of those cases, and the seller had a low starting price. There were no other bids, so I was able to get the sensor and a short piece of fuel line (with reusable ends) for $25 shipped! It has certainly been one of the best bargains of the whole project, at least on a percentage basis.

Fuel Flow Sensor FT-90 Gold Cube

Fuel Flow Sensor FT90 Gold Cube


I used the iron to smooth out the runs from my previous spray attempt, and turned my attention to the spray gun to see if I could figure out why it wasn’t atomizing well. It turns out that there is a screw on the side that adjusts the amount of air available to the gun, and it was turned down too low. After a readjustment the spray was back to how I remembered from before.
Spraying Polybrush

Control Surfaces- the black plastic curtain blocks out much of the light, so lift it up when I’m there to spray.


I sprayed the first round of polybrush on everything, then took a break until later in the evening, when I came back and sprayed another coat. Another great bargain that I found recently was on an oil filter adapter. Bob delivered the engine with just the oil screen, and after lots of research and discussion with Bob I decided to go with a full flow filter instead. It seems that Bob prefers the screen for a couple of reasons. One is that he’s concerned that during situations of high oil pressure, such as right after engine start, the spring bypass might allow oil to bypass the filter completely, where the screen does not. Another concern was with the mess required for cutting open the filter and such during oil changes. The benefits of the oil filter seem to outweigh these concerns for me. The first is the diagnostic benefit of the oil filter. If the engine is having a problem with accellerated wear, it is likely to be visible in the oil filter. The second is in the improved filtration capabilities of the filter versus the screen. The final is the longer oil change interval of 50 hours instead of 25. I compared the cost and features of the various oil filter options, including the B&C angle version, the Casper Labs knock-off of the B&C, and the original lycoming straight adapter. While the angle versions make for less of a mess during the oil change, some folks have trouble with interference, especially in the case of having an Sd-8 standby alternator, as we do. One major design difference between the Lycoming adapter and the others is that the high-pressure bypass is located inside the adapter in the Lycoming version, and inside the filter in the other versions. I don’t know if there’s any functional difference between those two strategies, but one big application difference is the threads on the oil
filter. Since it would be quite problematic to install a non-relief filter on a non-relief adapter, the designers used a different thread configuration. The Lycoming adapter uses female threads, with male threads on the oil filter. The other adapters use male threads on the adapter and female threads on the filter. I didn’t realize this until I already had a K&N filter on hand with the female threads! I was able to get a great deal on this adapter, which included the gaskets and a spacer place that is not used with our engine.
Lycoming Oil Filter Adapter

Lycoming Oil Filter Adapter- note pressure relief plate/spring inside


The filter side of the oil filter adapter

The filter side of the oil filter adapter

Covering Spray

Our seats are at the upholsterer, so I need to hurry up and finish the headrests. I cut out some 8×8 .032 aluminum squares to use as the face and top. I used the bench grinder to remove some of the larger bits of the weld bead from the exhaust pipe. Since the temperature has started to moderate a bit, I started with the spray coats on the ailerons, flaps, and rudder. The first step was to hang all of the parts from the ceiling. I hung a sheet of black plastic over the hangar door, with hopes of minimizing the UV exposure to the hanging parts. I sprayed a round of polybrush on the rudder, but the gun wasn’t quite working well. The atomization just wasn’t very good. I stopped there to let that coat cure, since I won’t be able to fix it until it does.

EMT Conduit Exhaust

Today I used the technique from the last entry to add a few more curves to the number 1 exhaust pipe. I worked until I ran out of oxygen, or rather until my welding oxygen tank became empty.

Number 1 Exhaust pipe

Number 1 Exhaust pipe


Welding on this EMT sure is easy. If all else fails I’ll weld these up into some sort of scupture.

Posted on
Hours Logged This Session: 2.5
Total Hours: 1883.75

Back Seat Seatbelt Tabs

With the lower cowl in place I started preparing the outer fiberglass scoop that will cover the FAB and direct the intake air to the inlet. I found an RV builder who had a scrap scoop, which was quite affordable. I only needed a very small piece of the original, so any defects or mistakes higher up were not going to be an issue. I marked the edge and used the cutoff wheel in the angle grinder to get the edge pretty close.

Vans fiberglass intake scoop

This is how much fiberglass I cut off of the scoop.


Vans Scoop

Here is the final product, ready for the new fiberglass flange.


I wrote in a previous entry that the radius of the EMT elbows for the exhaust pipes was hard to adjust. Since the number 1 cylinder is closest to the cowling, I started working with it first. I needed a tighter radius, so here is what I tried:
Electrical Conduit Exhaust System

These saw kerfs allowed me to bend the pipe to a tigher radus. It was no trouble to weld the kerfs closed.


This is my second attempt on the number 1 pipe. On the last iteration I had the pipe coming out of the flange at an angle, which made it nearly impossible to get the nuts on. Next I made the seatbelt tabs for the back seat shoulder harnesses. I started with .125 4130 tabs that were 1″ wide.
Rear Seat Seatbelt Tabs

Rear Seat Seatbelt Tabs


Rear Seat Seatbelt Tabs

I shaped them on the grinder and welded them onto the cross tube over the cargo area.


A little bit of cleanup and paint will make that look much better.

Posted on
Hours Logged This Session: 5.25
Total Hours: 1883.75

Child Labor

Windshield Installation
Since today was a nice warm day in the hangar, I started working with the windshield. I took it out of the box, set it in place, and it fit just as it was supposed to. I don’t think it is going to need very much trimming at all. I did spend a while smoothing the edges, just to help prevent cracks in the long run.

Bearhawk Windshield Holes

I peeled back enough of the protective coating around the edges to be able to drill the holes for the screws on the side posts. These holes are larger than they need to be, and each is carefully deburred. I used the special plexiglas bits and it all went exactly as advertised.


I made a few bent pieces of aluminum to add to the boot cowl just aft of the windshield. I learned that on my first exhaust pipe I didn’t leave enough room for the nut when i welded on the flange. I fixed this with the dremel, and on future cylinders I’ll use a little bit less filler metal around the holes. Tabitha’s cousin was in town, so they both came out to work for a little while.
Tabitha trimmed the cowling hinge

Tabitha trimmed the cowling hinge


Rebecca deburred hinge holes

Rebecca deburred hinge holes


Then they worked together on dimpling

Then they worked together on dimpling


Bearhawk FAB Cowling

Here’s the final position of the FAB with the bottom cowl pieces on


It was nice to have some extra help!

Posted on
Hours Logged This Session: 7
Total Hours: 1883.75

Making Exhaust Pipes

Making Exhaust Pipes
This morning I finished the heat smoothing on the last flap, so now those parts are ready to spray. While I was thinking about it, I also made a couple of cable guards for the flap cable pulleys. These are the final pulleys before the flap cable ends at the torque tube.

Pulley Cable Guard

Pulley Guard Step 1


Step 2

Step 2


Step 3

Step 3


Step 4

Step 4


I started cutting out parts for the exhaust system. (Note from the future- I’m not sure if I’m going to end up using these parts- I might end up going with a “store bought” system instead). This is like the system that Bob has used for his prototype Bearhawk and several airplanes since. It’s very inexpensive to make, and easy to repair with the tools that I have. Since the EMT comes with a galvanized finish that contains poisonous zinc, I started by soaking the parts in phosphoric acid. I found the acid in the paint stripping section at Home Depot, and I’ve also used it for other rust removal jobs in the past. As with all other new techniques, the best way to start is with scrap material. I used these two small pieces to be sure that I was going to be able to weld them well. The short length helps facilitate inspection of the back of the weld.
EMT Exhaust Test Piece

EMT Exhaust Test Piece


EMT Exhaust Test Piece Back Side

EMT Exhaust Test Piece Back Side


Since that went pretty well, I jumped right in to the real parts. I purchased the 1/4″ thick flanges from aircraft spruce, since they were inexpensive and would have been a real hassle to make. I held the pipe up to the engine and figured out about where it needed to be, then marked it and took both pieces back to the bench to weld.
First Exhaust Flange Welded

First Exhaust Flange Welded


Cylinder 1 Exhaust Pipe

Cylinder 1 Exhaust Pipe


One certain limitation of this system is that the radius of the bends is hard to adjust.

Posted on
Hours Logged This Session: 5.8
Total Hours: 1883.75

Finish FAB Assembly

I attached the steel (alloy?) reinforcing ring on the bottom of the FAB, and used a little bit of high-temp silicone to make an airtight seal.

Alternate Air Intake

Alternate Air Intake


The weather was nice so I also did a bit more covering work. I brushed the tapes on the right aileron, whch gave the RTV a little time to set up.
I sprayed a nice enamel coat of paint on the steel arm for the carb heat door, then riveted all of that stuff together.

I sprayed a nice enamel coat of paint on the steel arm for the carb heat door, then riveted all of that stuff together.


The other holes in the top of the FAB are for the duct flange for the carb heat air. The back edge will be dimpled rivets, while the front edge will be sandwiched in with the rubber. My hangar Neighbor Danny and his friend stopped by with an interesting Skylane. It has the little canard wings on the front, which seemed a bit curious with my recent cowl work. It turns out that they are actually mounted to the engine mount structure, and while I can’t speak to their effectiveness as aerodynamic surfaces, they sure do look handy for lunch.
Skylane with Canard

Skylane with Canard


I riveted the thin aluminum top to the fiberglass portion of the FAB, then heat-smoothed both ailerons and half of the remaining flap. Since I had to add aluminum pieces to fill the holes in the thin aluminum FAB top, I decided to apply a layer of silicone to help seal the thick top to the thin top. To keep the thick top from sticking permanently, I covered it with a masking plastic.
Protective Plastic

Protective Plastic


On the Bottom

On the Bottom


A nice bead around the perimeter

A nice bead around the perimeter


I bolted the top on to let the silicone form a gasket, then left for the day.

Posted on
Hours Logged This Session: 4.5
Total Hours: 1883.75