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!

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.

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Hours Logged This Session: 8.1
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.

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Hours Logged This Session: 5.5
Total Hours: 1883.75

Horizontal Stab Fairings

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

Making Fairings

Making Fairings


Making Noises

Making Noises


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

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Hours Logged This Session: 8.5
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.

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Hours Logged This Session: 12
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

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!

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Hours Logged This Session: 9.5
Total Hours: 1883.75

Removing Masking Tape

Tabitha especially enjoys removing masking tapes, so we both came out today and finished removing the tapes from last night’s paint session. She compares it to unwrapping presents.

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Hours Logged This Session: .5
Total Hours: 1883.75

Spraying Blue on the Tail Pieces

This afternoon I was able to get the correct combination of software, drivers, and cables to update the firmware on the Dynons. The D100 had been in service before, so it was only a few versions old. The D180 was factory new, and the firmware was very old. I also updated the HS34. Then I cleaned out the paint booth and taped the horizontal tail pieces for blue paint. I sprayed those in blue, cleaned the gun, and left after dark again. Some of these paint nights tend to run pretty late.

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Hours Logged This Session: 6.5
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.

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Hours Logged This Session: 4.5
Total Hours: 1883.75

Spraying the Interior

I’m thankful for being able to spend some serious hours in the shop this month. Today was a good painting day, at least in the afternoon, so I spent the morning wrapping up a few more prep tasks on the fuselage interior. I couldn’t come up with an easy way to mask the floor area. Then I had the idea of using the floorboards. After all, they are cut just to the right shape. I didn’t want them to get covered with overspray, so I masked them with a very thin plastic sheeting.

Floorboards as masking

Floorboards as masking


The fuselage was ready to spray, but it still wasn’t quite the warm part of the day yet, so I started preparing the horizontal stab and elevator for their white coat. Our paint scheme uses Bob’s measurements on the rudder and vertical stabilizer, but instead of painting the horizontals white, we put the same type of burst scheme on the top and bottom of those surfaces too. To make them look harmonious, I measured the overall perimeter of the rudder, then the overall perimeter of the elevator. Not surprisingly, they are actually very close to each other, within a few inches. I applied a small correction factor to the measurements, and assembled the tail pieces to lay out the stripes.
Something about this arrangement makes me think of DaVinci.

Something about this arrangement makes me think of DaVinci.


This is a really critical step, since the final paint scheme will fall where these tapes fall. I spent a couple of hours getting both sides of the stab done, then added paper to a couple of the pieces. I was out of time and paint booth space for today’s round, so I stopped there and sprayed Juneau White Aerothane on the interior, both trim tabs, and the left elevator. Then I cleaned the gun, which is a ritual that is becoming more and more familiar. I sit on the paint booth floor with my space man mask and white bunny suit and clean each of the pieces right away, since I won’t have any way to get the paint off of them after a day or two of sitting.

Painting Little Parts

I’m taking advantage of this relatively warm weather to get as much painting done as possible. Today was a long but productive day that started with getting the ailerons and right flap safely stored in the ceiling.

Storing the painted parts

Storing the painted parts


The rudder is looking festive

The rudder is looking festive


I covered those parts with plastic to protect them from dirt and overspray that might escape the booth.
Yesterday I wrote about the Sprayfine gravity gun. Today I learned about the packing nut that seals the needle. It was leaking pretty bad on my last round and I had to switch back to the Graco gun. I noticed that several of the o-rings in the gun were not holding up well, so I wondered if the leak was from those. I called the company to ask their tech support folks. The most surprising aspect of that call is that the person who answered the phone also answered my question. There was no menu structure, no receptionist, just a knowledgeable person on the phone. He said that any o-rings in the gun should be removed, as it was designed to function without them. I’m not sure how it is that I ended up being the person to have to remove them, but I was just glad to get the gun back up and running with no downtime waiting for parts. It turns out I just needed to tighten the packing nut a little. The supplied wrench for removing the nozzle was designed to also work on the packing nut, but due to manufacturing tolerances the slot wasn’t quite big enough. I fixed that with a dremel, but soon found that the metal that the wrench was made of was a little too soft to be effective. Instead I just started keeping a small crescent wrench in the paint booth with the gun tools.
Starting the next round of prep

Starting the next round of prep


The next round of parts included the lower door frames, rear cargo door frame, one of the upper front window frames, some of the rudder cable guards, the rudder pedal assembly, the control sticks, the seat adjustment levers, the flap handle parts, one of the wing struts, and likely a few others that I’ve forgotten about. After painting an airplane, the number of parts becomes especially apparent!

Second Coat of Polyspray

This afternoon I did a little bit more prep and sprayed the second coat of Polyspray on the fuselage, landing gear, rear seat back, scrap panel, and the patches on the tops of the horizontal stabilizer.

Wing white paint

Wing white paint


I also removed the tapes from the right wing and started taping for the blue coat.
Taping for the next coat

Taping for the next coat

Wooden Ribs

There is some discussion in the Avipro building manual about adding spacers to the ribs. I made these out of poplar on the bandsaw and belt sander.

Wooden rib shims- I ended up not using the top set

Wooden rib shims- I ended up not using the top set


I thought these turned out pretty well.

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Hours Logged This Session: 1.1
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.

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Hours Logged This Session: 11
Total Hours: 1883.75

New ELT Antenna Bracket

Back a few years ago when I made and installed the antenna bracket for the ELT, I never got around to putting in a fairlead bushing. Now that I have, it’s a pretty loose fit. This is the third strike against this setup, with the incorrect height and limited cable clearance being the other two. So with three strikes, it’s out.

Old ELT antenna bracket is out

Old ELT antenna bracket is out


The new bracket is just a trapezoid of .032 aluminum that will share fasteners with the stringers.
New, much simpler ELT bracket is in

New, much simpler ELT bracket is in


By putting the antenna off to one side slightly, I was able to eliminate the interference issues with the feedline and the elevator trim cable.
Lateral Offset

Lateral Offset


Here’s a nice wide-angle picture of where we are these days.
Overview and messy hangar

Overview and messy hangar

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Hours Logged This Session: 4
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

Control Cables and Fuel Lines

In the last entry I mentioned that the lower right fuel line was going to need an extension. This morning I added that extension and made a line from the fuel valve to the gascolator. Next I routed the upper flap cables, made new rudder cables, and routed the elevator trim cable. It became immediately obvious that the elevator trim cable was going to need to occupy the same space as the aileron cable. If I had put the aileron cable turnbuckle somewhere other than in the middle of the cabin, this wouldn’t have been an issue. Bob Barrows says that an offset of the aileron turnbuckle is usually enough to provide clearance. If not, it would be acceptable to split a few inches of 3/16″ Nylaflow tube and attach it to the aileron cable with some Pliobond. I think I’ll follow the path of Bearhawk builder Gavin Chester and add a fairlead just above the junction. After a break for dinner I came back to the hangar and made the left front fuel line again. This latest version looks like it will work just fine. I installed the elevator and trim tabs again so that I can verify the operation of their associated cables and such. Back when I was covering the horizontal stabilizer I sanded through the covering at the outboard end of the elevator trim torque tube. I was worried that this was going to be an ongoing problem, so I cut an access hole to see what was going on. Here is the view:

Sharp Edge

Sharp Edge


This would explain the issue. Ours is welded on instead of bolted on, and I’m not sure if that’s something that Avipro did at the factory or our previous owner did. In any case, the welding seems like a good idea, since the bolt would have been inaccessible without a hatch. My plan is to dress the edge a little, then put a patch on the hole before painting the color coats. I was going to have a patch there anyway since I had the sanding issue, but this way we’ll have less chance of abrasion once we’re operating the airplane.
Dull Edge

Dull Edge


Now a little bit of primer on the steel, and a little bit of MEK to remove the old patch, and it will be ready to repatch. I’ll be able to spray the area when I have the equipment out to spray the fuselage and landing gear later this summer.

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Hours Logged This Session: 10.3
Total Hours: 1883.75

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.

Rudder Cable Decisions

This morning I spent a while organizing and cleaning up. I connected the rudder cables again, and found a slightly better way to connect the return spring. Instead of having it attach in line with the rudder cable, I drilled an extra hole in the pedal arm and moved the aft attach point down.

New Rudder Return Spring Location

New Rudder Return Spring Location


In the old configuration the spring was squarely compressed at full rudder deflection, but in this arrangement the spring is able to bend at an angle. This reduces some binding and makes for a more smooth pedal action at full deflection. I measured my remaining stock of control cable and found that I don’t have enough on hand to make the flap cables. I also don’t have enough turnbuckles, since the Wicks kit did not include enough to use turnbuckles in the rudder cables. I can’t really see why the rudder cables need turnbuckles anyway, since the system only has real tension when the pilot puts his feet on the pedals. The cheapest course of action is going to be to remove the existing rudder cables, convert them into flap cables (with the same turnbuckles) and remake a set of continuous rudder cables without turnbuckles. This solution requires purchasing more cable, but not more turnbuckles, which are much more expensive and much heavier than cables.

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.

Flap Trailing Edge

This morning I used the irons to smooth the rudder and prepare it for spraying. I’ll wait until the flaps and ailerons are done before I start spraying, since that process is better suited for larger lots. Speaking of the flaps, I started on those today too. I put the left flap and aileron on the wing, drilled out the temporary pop rivets, and checked for alignment per the Avipro manual instructions.

Left Flap Trailing Edge Adjustment

Left Flap Trailing Edge Adjustment


I made a slight adjustment and riveted the flap trailing edge in place. I wiped off the accumulation of dust from the flap and brushed a coat of polybrush onto the leading edge. I’m not sure if this is required or not- the manual says to precoat wing leading edges, and this seems like a miniature wing.
Left Flap Ready to Cover

Left Flap Ready to Cover


Leading Edge Pre-Coat

Leading Edge Pre-Coat


I also added a bit of anti-chafe tape to the trailing edge rivets, and I had to stop there for today.

Posted on
Hours Logged This Session: 3.8
Total Hours: 1883.75

Wiring the GNS430

Here’s the rudder. All of the taping is done and it’s ready to smooth.

Rudder ready to smooth

Rudder ready to smooth


I connected several more wires to the 430 today. It has a bunch of them, and it would have been many more if I were using a remote annunciator and indicator. The connectors on the back are divided into the three main functions of the unit- VHF Communication, VHF Navigation, and GPS. The VHF Comm connector uses standard size d-sub sockets, except for the power in. Garmin calls for slightly larger wires on the power inputs for the Comm, so they use these fancy connectors that are a bit longer and allow for the bigger wires. Each of the three connectors includes two power inputs, though I think the duplicates are more for power delivery than redundancy. It was tempting to connect one to the ebus and one to the main bus, but Garmin says that each pair should be connected to the same bus. Some folks connect the two power inputs to a single splice just forward of the connector and then run a single cable to the fuse block. I ran two separate cables all the way to the fuse block and gave each one a fuse.
GNS430 Power Wires

GNS430 Power Wires


I connected all of the wires for the GPS function of the 430, which are routed through the high-density D-sub connector with lots of holes. Most of those holes are for functions that I’m not going to need, so that job went pretty quickly. The transponder is all done except for the power feed, since I ran out of that size of wire. I’m trying to minimize my orders to Stein and B&C, but that’s easier written than done. So as of today the 430 GPS wiring is done, the VHF Comm has power only, and the VHF Nav is still empty.

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

Rudder Lacing and Taping

These nice weather days have provided an excellent opportunity to spend some time in the hangar. Here’s the rudder after the first coat of polybrush:

Bearhawk Rudder

Bearhawk Rudder


Rudder Rib Reinforcements

Rudder Rib Reinforcement Tape, 3/8 inch


I finished the rudder rib stitching in about an hour and a half. This is one of those skills that gets faster with experience.
I marked the areas for taping and brushed on the pre-coats of polybrush for the tapes. While that was drying I made a few more wires. Next up are the RS232 wires that connect the transponder to the 430. These cables allow the GPS to tell the transponder when we are moving so that it can automatically transfer between Standby and Mode C.
It was time to get back to the taping:
Rudder Taping in Progress

Rudder Taping in Progress


Rudder Rib Stitching Done

Rudder Rib Stitching Done

The picture above shows the pre-coat areas for the tape, the reinforcing patches around the hinges, and the chordwise tapes.
The next few pictures are documentation for the seat upholsterer. I’ll include them in case you might need them for the same purpose.
Front Seat Area

Front Seat Area


Seat Position Adjustment

Seat Position Adjustment


Outboard Seat Track

Outboard Seat Track


Inboard Seat Track

Inboard Seat Track


The Dynon sensor for manifold pressure has 1/4″ mounting holes. I didn’t want to use heavy 1/4″ bolts to mount it, since the smaller 3/16 bolts would still be very much structural overkill. Also, as I found with the shunts, 1/4″ nutplates are much more difficult to find and work with. I cut some aluminum tube bushings to reduce the hole size and adhered them to the sensor with a little bit of JB Weld
Dynon Manifold Pressure Sensor

Dynon Manifold Pressure Sensor


Dynon Manifold Pressure Sensor Back

Dynon Manifold Pressure Sensor Back


Once the epoxy cures I’ll trim it flush.

Posted on
Hours Logged This Session: 6.7
Total Hours: 1883.75

Covering and Wiring

Today I shrank the fabric on the rudder and applied the first coat of polybrush. While I was waiting for one side to dry I returned to the wiring. My 430 rack was a second-hand find, and the previous owner chopped off the wires right behind the connectors. I took all of those little stubs out today, which would be the first step in putting in the new wires.

While I was studying the diagram for the architecture wiring I found that I had incorrectly wired the alternate ebus feed to the main bus instead of the battery bus, so I fixed that. I also returned to the wing wires. Richard had populated each conduit with two black wires and three white wires. There are essentially two circuits in the aeroflash unit- position lights and strobes.

I’m not interested in being able to turn on the aft-facing white position light without also turning on the corresponding red or green position light, so I only need two leads. Both units are safe to ground locally, so there’s no need for a ground wire to come all the way through the wing. This was a handy change, since I was running a bit short on 18-gauge wire and was able to use much of it in the wiring from the panel to the wing roots.

I also added the wires for the Dynon OAT sensor, which I’ve decided to locate just aft of the left wing strut where it meets the wing. This is a high-drag area already, and the sensor will be in the shade for an accurate reading. It will also be out of the way so I won’t bump my head on it!

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Hours Logged This Session: 5.9
Total Hours: 1883.75

Rudder Covering

I took advantage of another great weather day to work on the rudder. I applied the fabric and it’s ready to shrink. This is a short entry, but it was a short day in the hangar too.

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

Electric Cables and Polyspray

I made a few more crimps on the large conductors with the whack-a-mole crimper, but none are really any better than the first. On a more productive note, I sprayed one last round of Polyspray on the tail pieces.

Instrument Panel

Today I finished enlarging the center hole in the instrument panel and attached the two Garmin racks.

Garmin 430 and 327 Racks

Garmin racks in place.


Instrument Panel Switch Clearance

I cut some reliefs in the attach angles to make room around the holes for the switches


I added the Dynon trays, but did not yet cut the left flange off of the right tray. I’m planning to wait until I get the HS34 and its mounting hardware.
D180 and D100 Racks

D180 on the left, D100 on the right.


Next I enlarged the holes for the throttle, prop, and mixture.

Colors!

Colors!


I added a few more items to the panel layout, including the annunciators. To finish up, I sprayed a coat of polyspray on the side of the horizontal stabilizer with the patch.

Polyfiber Patches

I stopped by today to smooth out the patches with the iron/teflon combination and to add a bit more polybrush to fill the weave. At this point I’m waiting so that I can get the patches ready for the next spraying.

Polyfiber Patch

Here the patch is ready for smoothing

Second Polyspray

I masked off the area where I sanded through on the last work session. I used a rag with MEK to clean the fabric in that area down to a bare surface. I can see why the polyfiber products are so successful- this whole process was much easier than I expected.

Patch Area

The masking tape made for a nice clean edge.


The damaged area needs at least one inch of overlap, so I made the patch to those standards.
Polyfiber Patch

The patch is ready to apply with some polybrush.


Since the patched side of the elevator isn’t going to be ready for spraying, I sprayed all of the other surfaces with their second coat of polyspray.

Seats Ready for Covers

I started wet sanding the first silver coat today while Tabitha carved the last bit of foam. They are ready for transfer to Mississippi for covering. I also spent a little while carving down the wingtip foam to prepare for the first layer of superfill that I added to the wingtip for the position light.

Sanding Polyspray

This is what the polyspray looked like after sanding.


I forgot about the elevator trim torque tube and its corresponding sharp edge under the fabric, and sanded right through. It really does just take a couple of passes with the paper to cut the fabric! Now I’ll have to learn how to make a patch.
Hole in the Fabric

Here's my chance to try patching fabric.

Rough Cut Foam

The foam will hold the position light mount in place until I can build up enough filler and fiberglass to hold it permanently.


Test Fit

I installed the light fixture just to be sure that it all still fit properly, and it did.


Smurf Extract

The filler makes me think of the Smurfs, so I refer to it as Smurf extract.


That should be ready to sand/file on my next visit to the hangar.

Seat Foam and Silver

Tabitha came out today and we glued the foam together for the back seat cushion. I had planned on a 3″ thick bottom cushion for the back seat, but with a little bit of testing we realized that the headroom would be limited with a full 3″ cushion. Instead, Tabitha carved out much of the 2″ foam to make the cushion 2″ overall. While she was working on that, I was putting together the paint shaker and stirring the polyspray.

Back Seat Foam

The little cut marks will disappear with the 1/4" layer of foam that we'll have quilted to the upholstery.


The silver polyspray was a lot of fun to stir! I could just stir and watch the little swirls all day long.
Stirring Polyspray

Isn't it just amazing to watch the swirls?


I sprayed the first round of silver and called it a day!

Spraying More Polybrush

The Polyfiber manual suggested that small runs or imperfections in the polybrush could be fixed with a sheet of teflon under the iron to spread out the sharp spots in the iron shoe and reduce tracks. I tried the technique on a few little runs and had good results. I also sprayed the next coat of Polybrush. I haven’t been taking a lot of pictures, in part because I’ve been getting out of the hangar right after spraying. The respirator starts to get uncomfortable after an hour.

Spraying Polybrush

The Polyfiber manual suggests spraying a diluted coat of polybrush in cases where the the brushed coats have been sitting for a long time. I sprayed that coat this morning, then sprayed the first regular coat this afternoon. This schedule works out well with the temperatures, since it is usually too hot in the middle of the day anyway.

Finish Heat Smoothing

In two sessions today I finished the heat smoothing on the rest of the parts that are ready to go. I rigged up a way to hang the parts from the ceiling so that I can spray them all in one round.

Tail Parts Ready to Spray

I have a system of ropes, strings, and sawhorses holding the tail parts in place.


One strategy that I came up with for handling the problems with the wingtip-wing junction was to adhere a strip of aluminum that would overhang the junction. Today I got it ready for that operation.
Wingtip Aluminum Strip

Here's the aluminum strip, ready to adhere.

Heat Smoothing

More ironing! Today I spent an hour and finished heat smoothing and ironing the tape edges on one elevator and both trim tabs.

Fabric Covering on Tail

One of the elevators still needed a little bit more reinforcing tape, so I finished that up today. Now I’ll just need to finish heat smoothing and I’ll be ready to spray.

Posted on
Hours Logged This Session: 2.3
Total Hours: 1883.75

More Position Lights

I stopped by Laney’s fly-in towards the end of the event, but there were still a few airplanes left, including a new Maule. I liked the step on the landing gear, and perhaps it’s worth investigating.

Landing Gear Step Idea

While I was at Laney's fly-in I saw this Maule's landing gear step. I wonder if a similar step on the Bearhawk would allow me to reach the fuel filler from the ground?


In the hangar, Tabitha worked on getting the seats while I started roughing in the position light mounts. The epoxy between the foam layers was rock-hard and made for some complications with the shaping.
Position light plates with foam

These foam fillers shaped nicely. The epoxy between layers did not however.


Since the weather is starting to cool off, I spent some time with the iron on the horizontal stab and elevator. I wanted to dip my toe into the heat smoothing pool to see how it would go. If all goes well, I’d like to get all of the surfaces to the silver stage before the cold weather comes.

Posted on
Hours Logged This Session: 3.3
Total Hours: 1883.75

Battery Box, Tail Pieces

Today I spent a little bit more time convincing myself that the tail alignment issues aren’t going to be important. I did find a minor difference between the kit and the plans when I measured the length of the tubes that hold on the horizontal stab pieces.

Span of the front stab tube

This is the dimension on the plans for the spanwise length of the tube that holds on the horizontal stabilizer halves.


Measuring the Tube

Here's the actual tube width.


The only potential complication from this tube being long might be with the possibility for interference with the welds inside of the stab tubes. The longer tubes would provide more support, and as Mark pointed out, the welds shouldn’t be a factor since the tail was installed correctly at the factory before the kit shipped.
Making the elevator trim horns line up

This is what the stab halves look like if I apply pressure to make the elevator trim horns line up. Obviously that isn't the right arrangement.


As you can read in the previous post about tail stuff, I’m not really worried about this stuff anymore. I can make everything line up except for the elevator trim horns, but they aren’t going to be moving very much or very often. Their misalignment will introduce a little bit of friction to the system, which it needs anyway. I moved on to the battery box, which was ready for assembly and installation, now that the kindergarden paint is dry. Why paint something black and black when you can paint it blue and yellow? Especially with the odyssey batteries being orange.
Bearhawk Battery Box

Here's the battery box, finally.


Battery box with PC680

The strap across the top does not get any paint.


I also made some progress on the flap handle change. I didn’t see any point in remaking the whole handle, since the arms and the hole reinforcements were the only parts to change.
Bearhawk Flap Handle Update

In the top of half of this picture you can see the new steel flap handle arm. In the foreground, you can see the flap handle that the kids who broke into the hangar decided to practice their dremel skills on.


Bearhawk Flap Handle Update

I made photocopies of the plans, then glued those copies to the steel plate to use as a template.


Bearhawk Flap Handle Update

After some careful positioning and measuring, I was able to mark the old flap handle with locations for where I should attach the new arm pieces.


Mark asked me to keep up with how much time I spent working on the flap handle, so I took lots of detailed pictures. Since those pictures are gone, I won’t be able to know an accurate elapsed time, but the time would probably vary considerably depending on tool availability. Having access to a metal-cutting bandsaw would have expedited these steps by at least an hour.

Aligning Tail Pieces

On a recent trip to Harbor freight I picked up another pair of adjustable height support stands to help figure out why the tail doesn’t seem to be lining up right.

I used these stands in an effort to more reliably position the tail pieces for measurement.


I leveled the fuselage left-right with a water level at the wing attach points. From there I levelled each stab half with a bubble level.
Left-Right Level

I used a bubble level to level the stab halves, carefully positioning it between rib stitches.

I also raised the tail to level the stab halves front-back and then rechecked the other measurements. I spent lots of time scratching my head, but here’s a summary on what I have so far. The stab halves seem to be built with a little bit of error in the vertical positioning of the parts. I wonder if the left and right halves were built in the same jig, such that a slight error due to gravity would be down on one half and up on the other half, thus providing the 1/8″ or so error that I see between the left and right halves. My solution is to adjust the hinge supports a little so that the elevator halves will be parallel, and just accept the error in the trim system.

Straght Trailing Edge

From this angle you can see that the trailing edges of the two stab halves are parallel.


The trim horns don’t quite line up right, so there will be a little bit of binding and friction. Since the trim system needs a little friction anyway, this will work out well. Also, the trim horn only moves slightly, so I don’t know if the binding will even be noticeable in the range of motion that it will see in service.
Trim Horn Alignment

Note the trim hole alignment as I rotate the horn.


Trim Horn Alignment

Notice that with the horns turned 90 degrees, the misalignment is still only vertical.


Trim Horn Alignment

Finally, here is a shot with 180 degrees of rotation. These pictures convince me that the trim shafts are straight but not coaxial.


In the end there might be a slight difference in height between the left and right stab halves (1/8″ or so) but both will be level with reference to the wing attach points, so I’m not really concerned.
Right Tube Verification

I verified that the removable pieces were installed correctly on the right...


Left Side Verification

... and on the left.


I spent some time getting the aluminum part of the flap handle finished. I drilled holes where the notches would go, and plan to take the piece home to cut out on my wood cutting bandsaw. I started making up the fuel lines that connect the tanks to the inboard rib. Tonight at the EAA meeting Wade brought his punch and cut out the lightening holes in the battery box.
Wade Punches

The picture is a little bit blurry, but here Wade is punching the holes at the EAA meeting.


The conduit punch had no trouble with the thin steel.

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

Elevator Trim Pushrods

Today the river of airplane parts is flowing again with the arrival of my Oshkosh Aircraft Spruce order. I added the dimpled nutplates to the little boot cowl piece, and used my new fuel lube to install several NPT thread fittings that were on hold pending its arrival.

Here's the parking brake valve and it's NPT fittings with fuel lube.


And the fuel selector (which I subsequently decided not to use after all)


And the Gascolator


Since my repaired elevator trim pushrods didn’t bend so well, I also ordered more tubing to make new ones. This time I started with the bend, figuring that I could do the trimming and welding afterwards. This made much more sense than trying to get an accurately located bend after the ends were already in place. I tried making the bend on my imperial tubing bender, though it is certainly not designed for that kind of abuse. I used the specifications in the Beartracks issue to make a cardboard template, then put one arm of the tube bender in the vice. It took a fair amount of force, and I wouldn’t want to do it more than twice, but it worked pretty well.

Here's the bent elevator trim pushrod, ready to trim and weld the ends.


Isn’t it fun when all of the new parts come in?

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

Try Swapping Stab Halves

Just to be sure, I tried swapping the left and right stab halves today. It didn’t seem to work out well. The holes in the front mounting tube did not line up correctly. I’m going to keep investigating, though my working time will be limited for the rest of the month. I’ve got to go sell some motorcycle parts in Ohio, then lots of vacation and travelling including the usual Clinton Brodhead Oshkosh circuit.

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

Welding and Priming

The only parts that didn’t survive the move when we purchased the project were the tail struts. I haven’t been able to find them anywhere, and neither has Richard. This is unfortunate, since they are fairly expensive. I was able to buy another set from Mark, though he cautioned that they may need a length adjustment. After getting everything level for the tail pieces, I realized that one of the the struts was just a little bit too short. As you can see below, I removed the original end and welded in a new end that Mark also provided.

Adjusting the length of the tail struts

Adjusting the length of the tail struts


New end in place

I also added a small patch tab to the part of the tube where the old fitting was.


I never was able to understand why the two engine control tabs are mounted where they are. I am going to have three engine controls, and I’d like to have the prop control centered in the panel. Since these two tabs are situated around that location, it would be hard to use them. The solution was to cut them off, make a third tab, and put them where they needed to be.
Cut them off

Step one- cut the existing tabs off


Step Three- Put them where they should have been

Step Three- Put them where they should have been


Step 4- finish weld

Step 4- finish weld. Don't they look like little tombstones?


Shiny Tombstones

Shiny tombstones, ready to prime


I also cleaned up and primed several other welding areas. The bare steel rusts so quickly that it makes sense to prime these areas as soon as possible after cleaning them.
Control Stick Ends

Here are the cleaned and primed control stick ends


Panel adjustment area

Panel adjustment area cleaned and primed


After some more considerable measuring and head scratching, I noticed that when the elevator halves are joined at the middle, they don’t line up with each other.
Right Elevator

Right Elevator aligned with Stab


Left misaligned

...means that the left half doesn't line up with the left stab.


Elevator Trailing edges

Here is the same view of the trailing edges. Note that the left is lower than the right by a measurable difference.


I’m still not really sure about exactly what is going on here. The suggestions from Mark and others are to make sure that all of the pieces are installed correctly, but it certainly seems as though they are.

Posted on
Hours Logged This Session: 4.4
Total Hours: 1883.75

Test Fitting the Tail Pieces

Before I proceed with any of the covering steps, I want to be sure that I understand exactly how the tail goes together. To check all of this out, i tried a test fit.

Tail Pieces in Place

Tail pieces installed, not quite lined up yet.


I repositioned the engine lift over to the downhill side of the airplane so that I could level it left-right. Our hangar floor has a bit of a slope to it- about 18 inches over the 42 foot width.
Airplane Leveler

Here's my technique for leveling the fuselage left to right.


My first impression after adding the tail pieces is that something isn’t quite right. The left half seems to be slightly higher than the right half. It’s hard to get an accurate measurement of where the pieces need to be exactly, so I need to come up with some better methods. While I was doing all of this, Tabitha was finishing up the nutplates on the floorboards for the rudder cable guards.
Rudder Cable Guard Nutplates

Rudder Cable Guard Nutplates

Posted on
Hours Logged This Session: 8.3
Total Hours: 1883.75

Rudder Pedal Springs

Sometimes building an airplane involves taking three steps forward, sometimes it means taking a couple of steps back. Today I spent a little while adapting some springs for the rudder pedals, but I don’t really like them. I also spent a while making the third version of the boot cowl panel, and also made it wrong again. This is the couple of steps back day.

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

Test Fit Engine

Today was a busy day at the hangar. I started by drilling the holes in my new rudder pedal-cable straps. I wanted to be sure that the four straps were match-drilled, so I used a scrap piece of aluminum angle and some c-clamps to hold the straps stacked in place. After the first hole I added a cleco to keep the straps from sliding around. The aluminum angle didn’t survive very well, but it did the job.

Holding the Straps for Drilling

System for holding the straps down for drilling


End result- matched holes

The result was a set of nicely matched holes.


Now I just needed to know what kind of rudder pedal springs to shop for. I measured the distance with the rudder hooked up.
Measuring for the Rudder Springs

Measuring for the Rudder Springs


Since welding the skylight tabs was on the horizon, I used some scrap pieces of steel to weld up a jig. This is inspired by one that Eric shared, though it is slightly different. The key is that the middle leg is shorter than the other two, and that each tine is slightly bendable. The idea is that the outer two tabs will rest on the parent tube, while the tab will rest on the middle tine.
Tab Welding Fixture

Here's the crude tab welding fixture


With Oshkosh coming, I wanted to measure the length of the engine controls that I’ll need so that I can be on the lookout for some bargains. I tried taking measurements with the engine off, but it wasn’t working too well. I got some hardware store bolts to use as temporary fasteners while I wait to order the AN bolts at Oshkosh. This was all that I needed to get the engine temporarily in place, both to measure the cable runs and to inspire more progress. It was really a fairly simple job. I positioned the fuselage close to the engine on the pallet, propped the tail up so that the fuselage was close to level, and added some weight to the tail (just to be sure that it wasn’t going to nose over).
Positioning the Engine

Positioning the Engine


I used the lift to position the engine, then started sticking the bolts in. It was a strange feeling to lower the lift and let the fuselage and mount carry the weight of the engine for the first time. Of course it is strong enough to carry this weight at 6 g’s or more, but it just seems so strange at first.
Engine Installed

Engine Installed- for the first time.


My measurements were a little bit easier with the engine in place. I figure that 48″ will work for all three of the controls, depending of course on how I route them.

Posted on
Hours Logged This Session: 3.8
Total Hours: 1883.75

Rudder Pedal Geometry

In our last episode, I was moving the rudder pedals forward to address the potential over-center problem that Mark at Avipro brought to our attention. Back when Richard was building, the consensus was to locate the rudder pedals for ergonomics. Subsequent experience led to a new recommendation to locate the rudder pedals exactly as depicted on the plans. To meet those requirements, I ended up moving the pedals forward just about as far as they could go.

New Rudder Pedal Location

Here's the new location, and you can also see the old hole.

After moving the rudder pedals, I noticed right away that the brake cylinders would be touching the forward-most tubes when the pedals were at max deflection. I wanted to measure the rudder deflection so that I could see if the pedals would stop before reaching that point. To measure the rudder deflection off of a theoretical fuselage centerline, I needed to measure the angle formed by the fuselage sides so that I could subtract it from the desired total deflection.

Figuring out the angles

Measuring the angle of the fuselage sides so that I can create a template for measuring rudder deflection


Final Answer

Here's the final answer- 40 degrees on the template; 10 for the fuselage side and 30 for the deflection.


After all of that hassle, the final answer was that the rudder was at exactly the right deflection when the horn hit the stop (with no bolts in the tubes). Also, the brake cylinders do not contact the tubes at max deflection, but they are close!
Rudder Stops

Perfect deflection with no added bolts. For some reason I thought that I was supposed to have bolts in there- I guess not!


While I was thinking about it, I wanted to measure the rudder horn to see if it was the original design, or the temporarily different design. At one point there was a change in the rudder horn, then a few years later it changed back to the original design again. I believe that we have the interim horn size. Eric says that this change was simply one of control sensitivity, and that his is also the shorter interim length. The shorter length here means less pedal movement for the same amount of rudder deflection. I’m not planning to change the horn back to the original length, since I didn’t think that the rudder was too sensitive on Eric’s airplane, and since the change is optional.
Measuring the Rudder Horn

Measuring the Rudder Horn


With all of that head scratching done, I took a break to get a few things done at home. I came back later in the afternoon to start work on the steel tabs for the skylight structure. I wanted the option of using nutplates in the tabs, so I sized them with that goal in mind. (Mysterious note from the future: I subsequently decided not to use nutplates on most of the tabs, just because the skylight screws are going to be very rarely removed, and because access is easy with another person comfortably seated in the cabin)
Planning the tab size

Planning the tab size


Pile o tabs

Here's a pile of all of the rough cut tabs.


Since I moved the rudder pedals forward, I found the cables to be too short. My remedy was to make new steel attach straps. I used the materials and specifications from the Beartracks and Avipro assembly manual. As you can see in the picture below, I used a washer to draw the radius for the end.
Rudder Pedal Straps

Blanks for the new rudder cable straps


4 strap blanks

Here are the 4 straps- two for each side.


The next step is to drill the holes and install the straps.

Posted on
Hours Logged This Session: 4.8
Total Hours: 1883.75

Patching and Taping

Today was another reasonably cool morning, so I did more fabric work. I didn’t take any pictures, but I was able to get almost all of the taping done. When I first started applying the polybrush, I realized that something wasn’t right. I had mixed three parts of reducer to one part of polybrush instead of the other way around. I made up a new batch and things looked much better.

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

Elevator Patch and Cable Guards

Today’s efforts include a morning session of fabric work and an evening session of sheet metal work.

Richard had started the taping process on the tail pieces, but some are still in the works. Since one side still had exposed rib laces, I figured that I would check to be sure that they were spaced properly. Of course they were.

Rib Lace Spacing

I measured the rib lace spacing to confirm that it complies with the Polyfiber chart.

Elevator Overview

Here's a view of the elevator

Hard meets Soft

Since the aft edge of the lead weight is a hard spot on the soft fabric, I believe that it needs a reinforcement.


Preshrinking Fabric

Since the reinforcement is made from preshrunk light fabric, I built a wooden stand to use for the preshrinking.


Ready to Shrink

A quick lap with poly tack, 30 minutes of drying, and it's ready for the iron.


Shrunk and ready to cut

The iron really takes those wrinkles out!

The next task was to investigate the sound of something rattling around inside one of the elevator halves. I narrowed it down to the balance area, and made a cut in the fabric to investigate.

The offending piece of lead

Here's the culprit- a little piece of lead from somewhere.

I know it is counter-productive to cut off pieces of fabric before they are even completely applied, but I wouldn’t be able to live with myself if I knew that something was still in there. It’s much easier to repair now, before the aerothane starts flying.

Elevator Surgery

Fabric Removed, Ready to Clean

Lifting the Polyfiber Tape

A little bit of MEK and some rubbing made it easy to lift off the old tape.


Cleaned and Ready to Cover

Now I just need to recover the balance area.


First Comes the Fabric

First Comes the Fabric... (with adequate overlap per the polyfiber manual)

Stay tuned for the rest of the repair. This week featured especially moderate morning temperatures, which is why I’m able to do any fabric work at all in June. Even so, I’m limited to working in the mornings. Now skip ahead to later in the evening, when I came back out to the hangar to work on the rudder cable guards in the cabin.

Trimming the Aft Edge of the Rudder Cable Guard

Here I've trimmed the trailing edge of the rudder cable guard to match the angle that it forms with the aft cabin bulkhead.

What a nice fit!

What a nice fit! I'm going to replace that aft bulkhead with fabric instead of aluminum, but it will still fit nicely then too.


Left Side Guards

Here are most of the left side guards in place.


Right Side Guards

Here are the right side guards. Do you see the problem yet?


Rudder Cable Guard Interferes with Door Opening

As you can see from this angle, the aft cargo door opening coincides with the aft right guard. How am I going to fix this?


First, put the door on.

First, I should put the door on and see exactly what I'm working with.


This is how I'm not going to fix it

Here's a great idea that didn't work. I can't move the door sill up without shortening the door.

Here is where you can insert the picture of some serious head scratching. It’s time to get out some paper or card stock and try some different ideas. After a few more failures, here’s a promising possibility:

This looks better

The new and improved option.


The final result

This is the finished part.


While I was holding this part, I realized that I was unlikely to think up something like this theoretically. The only way that I was going to make something like this was to cut up some templates and mock it up on the actual airplane. I hate to waste shop time scratching my head, but sometimes that is the way it has to be.
Another View

Here's another view, just in case you are going to try to make something similar.


Working in these two separate sessions worked out well today. I find that in some cases my productivity suffers after 4 hours of continuous shop time, and during the hot part of the day I try to stay out of the hangar/oven.

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

Boot Cowl and Tail Examination

Today I cut out a new piece of aluminum to replace the one that I made wrong (and that I would make wrong again) while Tabitha dimpled the stainless exhaust tunnel and installed nutplates on the appropriate sections. I also calibrated the iron in preparation for covering and started to evaluate the tail pieces to see what all they needed.

Tabitha is changing out the dies in the hand squeezer


Here's another attempt to cut out a piece that I made incorrectly.



Posted on
Hours Logged This Session: 3.3
Total Hours: 1883.75