Flap Locks

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

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

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

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

External Control Lock

Flap up lock


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

Compass Module Direction Swap

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

More Odds and Ends

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

Engine Adjustments

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

Filling the Fuel Tanks

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

Final Tech Counselor Visit

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

Rigging the Ailerons

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

MLG Width Adjustment

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

Adding Oil to the Engine

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

Final Wing Bolt Torque

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

Carb Heat Overflow

Carb Heat Overflow

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

Pitot Tube

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

Installing the Wings

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

Wings On

Wings On

Installing the Ailerons

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

Moving the Wings

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

Wings on the trailer

Wings on the trailer


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

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.

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Hours Logged This Session: 8
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

Left Wingtip Fitting

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

Back Cargo Door

Back Cargo Door


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

Both Cargo Doors

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

Fuel Tank Prep Continued

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

Antenna lead termination

Antenna lead termination


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

Ready to Spray


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

Gloss Black


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

Partial Removal


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

Broken California Bracket


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

Completed California Bracket


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

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

Clean and Reinstall Left Tank

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

California Bracket

California Bracket


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

Fuel Cap


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

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

Reinstalling the Tail Pieces

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

Wingtip Filler

Wingtip Filler


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

Left Wing Plumbing


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

Tail Installation Hardware


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

The stripes line up!


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

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

Wing Rotisserie Removal

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

Sleeve side 1

Sleeve side 1


Sleeve side 2

Sleeve side 2


Pitot and AOA lines

Pitot and AOA lines


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

How it comes together


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

Wingtip Shortage


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

Aluminum tube extension


Extension applied

Extension applied


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

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Hours Logged This Session: 9.5
Total Hours: 1883.75

Striping for Blue

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

Right Side

Right Side


Left Side

Left Side


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

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Hours Logged This Session: 6.1
Total Hours: 1883.75

Painting White

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

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

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

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Hours Logged This Session: 3.5
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.

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Hours Logged This Session: 13.1
Total Hours: 1883.75

Nutplates and Wingtips

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

Window screen to keep the birds out

Window screen to keep the birds out


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

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Hours Logged This Session: 7.4
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

Brake Lines and Blue Paint

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

Painted Parts

Painted Parts


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

Main Landing Gear Holes


Upper Support Ring

Upper Support Ring


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

Lower Trapezoid Hatch


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

Upper Panel in Place


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

Brake Lines


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

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Hours Logged This Session: 16
Total Hours: 1883.75

Preparing to Spray Blue

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

Left Wing Ready for Blue Paint

Left Wing Ready for Blue Paint

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

Painting White on the Left Wing

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

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

Masking the Left Wing

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

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Hours Logged This Session: 4.4
Total Hours: 1883.75

Priming the Left Wing

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

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Hours Logged This Session: 2.1
Total Hours: 1883.75

Fuselage Plumbing

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

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Hours Logged This Session: 5
Total Hours: 1883.75

More Wing Preparations

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

Left Wing

Left Wing


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

Vince cuts circle panels


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

Jack installs the coax end


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

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Hours Logged This Session: 13.7
Total Hours: 1883.75

Parking Brake Warning Light

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

Parking Brake Switch Bracket

Parking Brake Switch Bracket


Parking Brake Switch Bracket

Parking Brake Switch Bracket


Parking Brake Switch Installed

Parking Brake Switch Installed


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

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Hours Logged This Session: 8.4
Total Hours: 1883.75

Another Round of Primer

The weather today was good enough for priming, and I finally have a big enough pile of parts ot make it worthwhile. I etched all of the parts and the instrument panel, then primed them.

More little parts to paint

More little parts to paint


On the items that will need both sides painted, I only painted one side today.

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!

Blue Paint for the Rudder

Today I moved the fuselage out of the paint booth. In the cool hours of the morning I finished drilling the rear cargo door skin holes to final size (#30) and prepared the rudder and right flap for painting this afternoon.

It looks great out in the sun, especially from this far away.

It looks great out in the sun, especially from this far away.


I also have a new paint gun to try. The previous coats have been with the Graco that came with the HVLP that I was able to borrow. The Graco gun is certainly nice, but is a suction feed cup, which is under the gun. By design, there is quite a bit of unusable paint with each batch. I found a reasonably priced gravity-fed gun to try. It’s sold under the “Sprayfine” brand from Turbine Products. After taking apart the gun, I can see that it is made with less quality when compared to the Graco. This is probably why it sells for so much less. For example, parts on the Graco were plated after machining, but several parts on the Sprayfine were plated and then machined. I deburred a few pieces so that they will be less likely to catch bits of paper towel as I clean the gun.

When it warmed up in the afternoon, I sprayed the blue paint on the rudder and right flap. The left flap wasn’t ready to paint yet because I have to stripe it when I stripe the left wing.

Making Tiedown Rings

I have always had some reservations about the durability of our Maule tailwheel, so when Georg was selling his lightly-used Bob-designed tailwheel for a good price, I was glad to buy it. Today I did a trial fit to the spring to make sure it would fit, then disassembled it. I’ll paint it white to match the fuselage, and to promote crack detection.

Tailwheel Assembly

Tailwheel Assembly


This wheel uses a 10-inch tire, so I took this picture so that I could remember the tire size, which is 10×3.5-4.
Tailwheel tire size

Tailwheel tire size


The tiedown rings are intended to mount to the bolt that holds the top of the strut to the wing. I started with mild steel 1/4″ rod, which I heated and bent around a piece of scrap steel that was about 1.5″ in diameter.
First Bend

First Bend


Rather than fight with a small piece of metal, I just added the second bend right on to the first. It was easier to do with more straight stock to hold on to.
Second Bend

Second Bend


I made the flat plates out of 4130, and as you can see, I left the 1/4″ rod a little bit long for the welding. That makes it a little bit easier to control the heat at the end of the bead.
Welded Tiedown Rings

Welded Tiedown Rings


I’ll still need to drill the holes, but that will have to happen on another day.

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

Wingtip Prep

It was too cold to paint today, but I was able to work on preparations for the wingtips. I filed some of the filler off, and also cut out the aluminum skin on the front cargo door for its window.

Spraying White Parts

Here’s a picture of yesterday’s masking work:

Vertical Stabilizer Masking

Vertical Stabilizer Masking


This afternoon I cleared out a few small parts to make room for the fuselage. Today’s parts include the main landing gear legs, shock struts, rudder, right flap, elevator trim pushrods, tailwire brackets, and the right hub cap.

Laying out Fin Stripes

Today we both came out so we could get the wing moved out of the paint booth.

Wing in the Sun

Wing in the Sun


Tabitha removes the last few tapes

Tabitha removes the last few tapes


Then we spent a while laying out the white stripes that will go on the vertical stabilizer and rudder. We’re using Bob’s measurements so that our stripes will match his, but even with those measurements it was still fairly difficult to get the tapes to sit where we wanted. The complex curves near the front base of the vertical stab make for some strange taping patterns.

Wing Blue Paint

Today was a fun day, removing the tapes from yesterday’s paint. It’s nice to see the two colors together with crisp lines.

Painted Right Wing

Painted Right Wing


Tabitha and my dad both helped. We also removed the tapes from the fuselage, since I won’t be spraying any more silver.

Spraying Blue on the Right Wing

Today I carried on with the spraying theme. I put the new tapes on the top of the wing in the morning, and then wet sanded that second coat of Polyspray. Later in the day when the temperature was back up I sprayed the final coat of Polyspray, then sprayed the blue paint on the right wing.

Fuselage silver is done

Fuselage silver is done

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

White Paint on the Right Wing

As promised, I added paper and masking tape to finish preparing the right wing for spraying.

Ready for white paint

Ready for white paint


Then I sprayed the first of our Aerothane. I learned several things, some of which I’ll include here. First, I set up the fresh air box inside the hangar, near the HVLP turbine. This was acceptable, but it makes much better sense to put it outside and upwind. Next, the paint both that I built really isn’t big enough to comfortably paint the wings. It’s 10 feet wide, and the top arches are made with two 10-foot pieces. If I were to do it again, I would have made it wider, taller, and longer. Each bay should be 4 feet long, but I used 1/3 of 10 feet, since I was trying to minimize waste in the 10 foot lengths. Here are a few more lessons from later sessions that I’ll include here for easier organization and reference. First, standing or sitting on the fresh air hose will greatly diminish the flow of fresh air, and as such, is a bad idea. Also, the hose can become kinked if it gets twisted around very much. On the topic of diminished flow of fresh air, I also found out by experience that leaving the air compressor switch on is a bad idea. Since the paint booth uses two lights, a big fan, the HVLP turbine, and the fresh air box, our limited electrical circuit can’t handle much more. When I forgot to turn off the compressor, all was well until it leaked down enough to turn on. The lights dimmed, the fans slowed, and a few seconds later the breaker tripped and it all shut off. This is problematic in the middle of a paint job! Finally, it’s a good idea to keep plenty of extra clean gloves and rags in the booth, since the gun cleaning process usually consumes one or two.

Wing Paint Prep

While the Polyspray is drying a little I worked on wing preparations. I built the left wing rotisserie so that I could get the wing off of the rack, and made a few parts for the pitot tube mount. I’ll see if I can get my friend Alan to weld the aluminum parts, since that will make for a nice lightweight and simple mount. I started sorting parts into various buckets for painting the different colors. Now that the primer is on the right wing I installed the inspection covers. Our stripe scheme is going to be complicated enough that I’m going to paint with the panels in place. Finally I set up the fresh air supply and HVLP turbine and made sure that they both work.

Repairing the Small Iron

One downside of using model airplane irons to smooth covering imperfections is that they really aren’t designed for that kind of pressure. I’ve damaged a few of them now. This wooden handled iron failed right in the very thin spot where the shoe top joins the handle.

Failure Point

Failure Point


To reinforce that area, I brazed in a small piece of steel tube that would fit inside of the cheap stamped and rolled handle.
Brazed Reinforcement

Brazed Reinforcement


I spent a little bit of time at the grinding wheel to clean it up:
Brazed Reinforcement again

Brazed Reinforcement again


Then I reassembled the iron and tried it out. It works much better now, since I can transmit plenty of smoothing force onto the covering without worrying about damage to the iron’s neck. Next I installed and top coated the few remaining fuselage reinforcement tapes. The next important task was to come up with some way to support the back end of the fuselage. So far I’ve just been resting the back end on the strong structural points, but that’s not going to be an option when I start spraying the covering products, since those areas will be wet. Instead I used some scrap 1.5′ square tubing to make a stick that will bolt to the tailwheel spring attach points.
I added a zig and a zag

I added a zig and a zag


Then added the spanwise brace that catches the AN4 bolts.

Then added the spanwise brace that catches the AN4 bolts.


This little tailspring substitute looks like it will work quite well.

Priming the Right Wing

This morning I added some fabric tapes to the right side of the fuselage, then prepared for a round of priming.

A few small parts

A few small parts


One big part

One big part


Since we have a complicated striping pattern, I’m priming the access hole covers now, so that we can apply the top coats with them in place.

Wing Masking

Since I’m not planning to paint the wing root, tip, or trailing edge areas, I added some masking paper and tape to block them off.

Masked wing root

Masked wing root


Masked trailing edge

Masked trailing edge


I finished the metal prep on the top of the wing:
Still wet, but very clean

Still wet, but very clean


Then I moved it into the paint booth with some help from Tabitha, Danny, and Jeff. I finished the day with a little bit of heat smoothing on the main landing gear legs.

Wing Preparation

Today I continued with paint prep for the right wing, while Tabitha worked on more fuselage taping.

Right Wing Prep

Right Wing Prep

Wing Rotisserie Continued

Today we were both back out at the hangar. Tabitha continued with adding tapes to the fuselage, while I continued with getting the right wing onto the rotisserie. Here’s what one end of the rotisserie looks like. The double 2x4s stick into the wing by at least two center ribs to spread out the load. The lag bolt in the center is long enough to go through the double chord-wise 2x4s.

Wing Rotisserie

Wing Rotisserie


Here's the other side, though I still need to cut off the too-long spanwise 2x4s so that they will clear the a-frame.

Here’s the other side, though I still need to cut off the too-long spanwise 2x4s so that they will clear the a-frame.


The wings sure are dirty! This is a picture of the bottom even.
Dusty wing

Dusty wing


I taped the inspection holes to keep the various solutions out of the inside of the wing.
Temporary hole covers

Temporary hole covers


The process is to first wash it with the Polyfiber alkaline cleaner and a fine scotchbrite pad, then a phosphoric acid-based etching compound. The biggest hassle has been removing the residue from the plastic adhesive that had been on the aluminum to protect it from scratches. There were several very small spots that became obvious after etching, since they were still shiny when the rest of the aluminum is dulled slightly.
Clean wing bottom

Clean wing bottom


Here’s a before and after on the top of the right wing.
Half clean wing top

Half clean wing top


While I did that, Tabitha worked on taping the right side of the fuselage.
Tabitha taping

Tabitha taping


Eventually Felicia came out for a visit too.

Eventually Felicia came out for a visit too.

Wing Rotisserie

Tabitha came out today to help get the right wing ready to go on the rotisserie. That involved riveting the tip rib back onto the skin, since I recently drilled those rivets out to remove the flush mounting strip.

Tabitha the riveter

Tabitha the riveter


My strategy for getting the wing onto the rotisserie was to start with it on sawhorses.
Wing goes here

Wing goes here


She helped me move it there, then started working on the fuselage top tapes while I worked on the rotisserie.

Wing Repair Continued

Picking up where I left off last time, I finished the wing repair

Ready to Rivet

Ready to Rivet


Ready to prep and paint

Ready to prep and paint


While I had the air drill over on that side of the hangar, I also removed the metal strip that I had installed in the wing tip to allow for flush mounting of the fiberglass tips. At this point it just makes more sense to use the much simpler overlap method instead.

More Priming

I went out today to touch up a few more paint spots, but when I reached for an unopened can of catalyst I was surprised to find it was empty! Unfortunately it leaked sometime in the past couple of years, so I’ll have to take a break from
painting until I can get more.

Painted Tubes

Painted Tubes


Instead I worked on the wingtip filler and the position light mounting pad.
More filler on the position light pad

More filler on the position light pad


A little filler on the wingtip leading edge

A little filler on the wingtip leading edge


I’m starting to wonder if I’ll be able to get all that I need from the first can of filler!

Posted on
Hours Logged This Session: 2.8
Total Hours: 1883.75

Wingtip Light Mount

I stopped by today for one more measurement to make sure that the landing gear alignment is within tolerance, and it is. I cleaned up the hangar in preparation for round 2 of sandblasting, and applied a coat of smurf extract to the right wingtip position light mount and the stringer that required a relief cut. It’s time to go to Oshkosh soon, so building will be on hold for another week or two. Next time I’ll have a few more parts and plenty more motivation, though at this point I’m not facing a shortage of either.

Posted on
Hours Logged This Session: 1.5
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

Antenna Planning

I was only out for a little while today, but I cleaned up the hangar and measured for a few of the coax cables. I was planning to use RG-58, but it turns out that some of the low-cost cable that I found wasn’t very good quality. Additionally, Bob Nuckolls has a pretty good deal on some RG-400 equivalent, and his pricing is very good. In some cases it will work out better to have a 90-degree end, which he offers as an option.

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

Preliminary Control Rigging

With the flap cables in place, I was able to work on adjusting the flap rigging. I adjusted the pushrods until the flaps came up to zero degrees under spring tension. I started to adjust the aileron cables and realized that my loop is just a little bit too short, and I’ll need to make a new version of one of the back cables that’s about 3/4″ longer than the current one.

Tabitha stopped by to say hi and Felicia says "Oh Dad, why aren't you done with this yet?"

Tabitha stopped by to say hi and Felicia says “Oh Dad, why aren’t you done with this yet?”

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Hours Logged This Session: 1.6
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.

Posted on
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.

Posted on
Hours Logged This Session: 10.3
Total Hours: 1883.75

Flap Cables

Today was a brief session, but I was able to drill the left flap tube up to the final 3/16″ size for both bolts. I measured the length for the upper flap cables and made both of those, and started on the latest rework of the left aft fuel line that runs from the tank down the back of the front door opening.

Posted on
Hours Logged This Session: 1.7
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

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.

Aileron Control Cables

This morning I finished replacing the last of the hinge bolts for rivets. I made the aft aileron cable, which goes across the back of the cabin. When I made it, I put the turnbuckle right in the middle. This turned out to be a mistake- I should have put it off to one side instead, or perhaps even in the wing somewhere. I’ll explain why in a few days when I point out the interference with the elevator trim cable. With all of the aileron cables complete I was able to check for interference with the ribs. I found several places where the aft cable was rubbing on the ribs, so I filed those holes to enlarge them accordingly. That took much of the grinding noise out of the system and freed things up a bit. I welded a little more on the exhaust pipes too.

Improving the Nicopress Crimpers

After some consultation with more experienced builders, I found what part of the problem with my cheap nicopress tool is. If you look at this picture, you’ll probably see it too:

Cheap Nicopress Tool

Cheap Nicopress Tool


The outermost contact point on the inside of the jaws is too big. That’s making an air gap between the contact points at the other positions in the die. I used a file to remove enough metal from that spot to allow the dies to finish closing, and the end result was much better. All of test subjects now pass the no-go gauge, so I made the front cable for the left aileron. I replaced a few of the hinge bolts with rivets on the right side, and started going through the right wing to check for proper hardware and torque. In the whole process I only found one bolt that was the wrong size, but it was easy to fix. I started on the right front aileron cable before I had to quit for the day.

Checking the Wings

Last time I set the big rivets in one of the aileron hinges. I started out today by polishing the faces of my hammers so that I could do the same job without leaving any marks on the shop heads of the rivets. I started at the belt sander, removing enough material to get a consistently scratched face. Then I used a coarse scotch-brite wheel in the die grinder to smooth those scratches out. A medium scotch-brite wheel yielded a surface that wasn’t quite as shiny as a mirror, but certainly very nice.

The face on this hammer used to look like the sides!

The face on this hammer used to look like the sides!


This newer hammer only needed the scotch-brite treatment.

This newer hammer only needed the scotch-brite treatment.


Here's another hinge with the bolts...

Here’s another hinge with the bolts…


...And now with rivets.

…And now with rivets.


There are five of these rod joints per wing, and I finished the replacement for the ones on the left wing. I also spent a little time cleaning the dust out of the trailing edge area, which was fairly thick from me storing the wings nose-down in their cradle for a while. Next I went through the left wing systematically, checking to be sure that the right bolts were in there, and that they were torqued correctly. I found that one of the bolts on the aileron bellcrank was hitting the rib, so I removed a little material.
Aileron Bellcrank Clearance

Aileron Bellcrank Clearance


The next job for today was to make some little steel bushings for the shackles that attach the flap cables to the inboard flap torque tube arms. For extra clearance Bob calls for a #4 size shackle here, but only a 3/16″ bolt and a 3/16″ hole in the arm. This means that I’ll have to make some steel spacers to bush the 1/4″ hole in the shackle down to the 3/16″ size of the bolt.
Shackle Bushings

Shackle Bushings


I made a few practice nicipress fittings in anticipation of making the aileron cables. I’m not really impressed with how they are turning out, so I’m going to see if I can get away with modifying my inexpensive crimping tool.
Bad Nicopress

Bad Nicopress


The one above is bad because I didn’t keep the thimble inside of the sleeve. Some of the others were too big to fit into the no-go gauge.

Aileron Hinges

The aileron and flap hinges are made from rod ends that are attached to steel tube structures, which are bolted to the wings. Eagle-eyed John Wigney was visiting our hangar last spring and pointed out that the plans call for 5/23″ rivets in that joint, but our previous builder had 3/16″ installed bolts instead.

Bolts in the hinges

Bolts in the hinges


After John pointed out the difference, I asked Bob Barrows about the substitution. He said that the bolts would be fine, but that rivets would be much lighter. He said it would be no problem to swap out those bolts for 3/16″ rivets, so that’s what I’m working on today. Those are -6 size rivets, which are the largest in the whole airplane. My little 3x gun and pneumatic squeezer aren’t really beefy enough to set rivets that big, so I had to come up with some other options. First I drilled a 3/16″ hole in the anvil on my vice. This hole perfectly fits the rivet set that will cradle the manufactured head of the rivet.
Vice Modification

Vice Modification


Rivet set in the vice anvil

Rivet set in the vice anvil


A regular anvil would have been better than the vice, but I don’t have a regular anvil. I removed one of the bolts and put in a rivet:
Rivet in place

Rivet in place


Then I used a hammer to form the shop head of the rivet.
Formed Rivets

Formed Rivets


These turned out pretty well. It took some serious hammer wacks to form the rivets though!

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

Wing Root Fairings

2012 is going to be the year of fairings. And hopefully the year that we fly this airplane! Today was a step in the right direction, with a few advances in the nebulous realm of “90% to go.” Fairings are some of the little parts that have to be made, but yet standing next to an airplane, they aren’t parts that most folks would even realize are there. At least that’s the way it should be if they are made well! After sanding and filling another round on the windshield fiberglass fairing, I trimmed and installed the aluminum windshield post pieces. These will help seal the top windows and smooth the transition from windshield to window.

Windshield Post Fairings from Outside

Windshield Post Fairings from Outside


Windshield Post Fairings from Inside

Windshield Post Fairings from Inside


Next I cut out a few strips to make the wing root fairings. These will seal the gap between the fuselage and wing, a very important aerodynamic function. They will also hold the outside edges of the skylight down and provide weather sealing for that area. I’ve laid out these fairings in 4 main pieces- the one in the front that goes around the leading edge curve, the one in the back that bends around the trailing edge, and the two straight strips between those. One of the straight strips goes on the top, and one goes on the bottom. In many airplanes, these fairings will have to be removed to inspect the wing attach bolts. Since we’re not going to put any covering on the wing root area in the fuselage, I’ll be able to inspect the wing root bolts from the cabin, so our fairings should only have to come off if we need to take the wings off. The straight strips are very easy to make, so I started there.
Looking from the top of the wing

Looking from the top of the wing


I made the front fairing out of paper first, then transfered that pattern to aluminum.
Top of Front Wing Root Fairing

Top of Front Wing Root Fairing


Bottom of Front Wing Root Fairing

Bottom of Front Wing Root Fairing


The back fairing is a little bit more of a challenge for a few reasons. First, that section will be covered with fabric, and the fairing needs to meet that fabric. It’s not covered yet though. The other challenge is that the fairing has to transition from being on top of the fuselage to beside the fuselage. Fortunately my photo library of other Bearhawks helped me figure out where this transition should happen. I left off without getting the aft piece in place, but that will give me a good starting point for next time.

Posted on
Hours Logged This Session: 4.4
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

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

Covering Continued

I only had a few minutes to work today, but I was able to finish preparing the control surfaces for their next coat of Polyspray.

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.

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

Right Aileron Stitching

This morning I layed out the rib stitches for the right aileron, applied them, and drew the layout lines for the reinforcing tapes.

Right Aileron Stitched

Right Aileron Stitched

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

Right Aileron Covering

Right Aileron Covering
Today was a good covering day, so that’s what I did. The first step, as with the other primed control surfaces, was to wet-sand the outer surfaces to smooth the paint. Then I carefully cleaned off two years (at least) worth of dust and spider webs.

Clean Aileron

Clean Aileron


Next I applied reinforcing tape to the rivet heads, and precoated the leading edge skin with a layer of polybrush.
Reinforcing Tape and LE precoat

Reinforcing Tape and LE precoat


Then I adhered the fabric and shrank it, eventually to 350 degrees.
Shrunk Fabric

Shrunk Fabric


Then I brushed the first coat of polybrush.
First coat of Polybrush

First coat of Polybrush


That was all the time that I had today, so tomorrow I’ll pick up with the stitching and taping. It seems like one control surface is almost a day’s worth of work now that I’ve done a few.

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

Dynon Compass Module

I had to start by removing the carburetor this morning. This will give me plenty of room to work on the lower cowling pieces. I started preparing the sheets for the bottom. I think I’m going to start from the top and wrap them around, making the middle cut last.
I took a break from all of that to make some brackets for the Dynon compass modules. I tried to devise a system that would allow me to position the parts accurately during installation, since they are supposed to be lined up with the main box within a degree or less.

Dynon Compass modules stacked

Dynon magnetometers- one for the d180 and one for the d100.

22-
Aluminum Rivets won't bother the magnetic field

Aluminum Rivets won’t bother the magnetic field


Dynon magnet bracket

The tall piece attaches to the rib


The bottom cowl pieces haven’t been as easy as the top pieces, but here’s the start.
Cowl Bottom PIeces

Cowl Bottom PIeces

Posted on
Hours Logged This Session: 3.9
Total Hours: 1883.75

Covering and Baffles

Tabitha came out today and resumed work on the left aileron. She finished up the tapes and applied the top coat of polybrush.

Tabitha Taping

Tabitha Taping


Tabitha Coating Tapes

Tabitha Coating Tapes


We both worked on that for a while, then I started trimming the baffles to clear the cowling pieces.

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

Antenna Mounting

6/21 1015 ground shields, drill left com antenna, add tab to tail post 1235 2.4 hours
This morning I connected the rest of the audio shields to each other. I didn’t have any of the one-ended crimp-on terminals so I just used one half of a yellow crimp-on splice. I found a good spot for the VHF Communication antenna out past the fuel tank, and drilled a mounting hole for it and the grounding screw. I’ll put one just like it on the other side, which will allow for easy connection for the handheld VHF radio.

Left VHF Com Antenna

Left VHF Com Antenna in Wing


I wanted to come up with some method for stabilizing the VHF Navigation feedline in the vertical stabilizer. I added this tab so that I can have something to clamp the feed to.
Tail Post Tab for VHF Nav Antenna wire

Tail Post Tab for VHF Nav Antenna wire

Posted on
Hours Logged This Session: 2.4
Total Hours: 1883.75

Wiring and Covering

Tabitha came out today to help with the covering. She drew the pencil lines for the right aileron tapes while I worked on more wiring stuff. I installed the bracket for the HS34, which was far more difficult than it should have been. For some reason Dynon pre-drilled the mounting holes. This means that I have to try and drill holes in the panel that will match their pre-drilled holes. Since the mount is bent to provide the tension that will hold the instrument tight against the panel, it is impossible to match-drill the holes from the rear. They certainly didn’t do me any favors by pre-drilling the holes! I asked the Dynon reps if they could offer the bracket without the holes, and they said no. I started wiring the front seat headset jacks. The left jack will also host the audio out jack (for recording audio later) so it was a little bit complicated. To simplify things some I decided to move the audio out jack over to the area where the headset jack is.

Posted on
Hours Logged This Session: 5.6
Total Hours: 1883.75

Covering Ailerons

The weather is starting to get warmer, so I’m starting earlier and finishing later. Today I recoated the tapes on the right flap. Now it is ready for smoothing

Right Flap Taping Complete

Right Flap Taping Complete


I added the rest of the fabric to the left aileron:
Bearhawk Left Aileron Fabric

Left Aileron Fabric


And used the iron to shrink the fabric:
Shrink polyfiber fabric

Left Aileron shrunk, ready to brush.


Then applied the first coat of poly-brush by brush:
Left Aileron Brushed

Left Aileron Brushed


And added reinforcing tapes to pepare for stitching:
Rib Reinforcing Tapes

Rib Reinforcing Tapes


I also finished riveting the right aileron’s trailing edge and balance tube in place. It is now ready to cover. I started wiring the audio isolation amplifier, which consolidates the various audio inputs into a single channel for the intercom. I finished the power and ground wires today. I’ve saved the audio system wiring for last, since it is by far the most confusing.

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

Rib Stitching

This morning I stitched the ribs on the right flap and layed out the tapes with pencil lines. After lunch I used the iron to smooth the left flap, added tapes to the right, and started covering the left aileron by cementing the sides in place.

Right Flap Rib Stitching

Right Flap Rib Stitching


Right Flap Taping in Progress

Right Flap Taping in Progress

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

Parking Brake Adjustments

Today I made a bracket for the parking brake valve. This will support the end of the cable.

Matco parking brake cable support

Parking Brake Valve Cable Bracket


I installed a cable control and found that I had a bit of a problem- it was backwards. I definitely want for the cable to be pushed forward when the parking brake is released, but in my first configuration it was the other way around. What I really needed was to flip the whole parking brake over. This would also solve the problem of the wacky curved brake lines that I wrote about earlier. Since the Dynon compass sensor is in the wing and I’ll need to be able to remvove the wings later, I needed to add a splice in each of the shielded cables near the wing root. I used a d-sub connector for both of the cables (4 conductors and a shield for each) and for the OAT sensor in the wing. In the end I’ll have the molex connector for the wing lights and the single d-sub connection for everything else. I made the connections for these cables at the instrument end, which completes the Dynon wiring. I used a little bit of rescue tape to build up the diameter of the bundle so that it will be more evenly supported where it exits the back shell.
Enlarging wire bundle

Small wires in a big hole.

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

EAA Chapter 309 Visit

This evening the EAA chapter from Charlotte came up for a project visit. I’m a member of the Charlotte chapter too, and I was glad to have so many folks drive so far to see our Bearhawk. It’s always great fun to talk about our project with other airplane builders, and of course the pizza was good too.

EAA Chapter 309

A few Chapter 309 Members


As the visit was winding down, I tested the position lights, and they work. It sounds silly to be excited over turning on a switch and seeing the lights come on, but in a project of this scale, small victories are important.
Aeroflash Bearhawk Nav Lights

The position lights work!


Left Position Light

And on the left too…

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

Taping Wing Surfaces

Today I finished the taping on the left flap.

Left Flap Before Taping

Left Flap Before Taping


I used the gallon can as a template for making a round patch.
Pinking shears and round patch

Round Reinforcing Patch


Round Reinforcing Patch

Here’s the gallon-can patch in place over the lightening hole.


Poly fiber tapes

The left flap tapes are ready to apply.


Left Flap Taping Done

Left Flap Taping Done


I brushed the first coat of polybrush on the right flap and added the rib reinforcements.
Right Bearhawk Flap

Right Flap Ready to Brush


Right Flap Before Stitching

Right Flap Before Stitching


Next step is stitching. I also finished the wiring for the strobe and position lights, and next time will see if they work.

Posted on
Hours Logged This Session: 7.5
Total Hours: 1883.75

Covering Continued

Here’s another short entry for a few hours of work. I cemented the fabric onto the right flap, finished stitching the left, laid out the lines for taping on the left, brushed on the taping precoat, and shrank the right flap. See what I mean about this being pleasantly monotonous?

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

Covering the Flaps

Today was almost all covering work. The great thing about covering is that I have very little “thinking” time. With wiring I work a while and think a while. With covering, I walk in, pick up where I left off, and work until something needs to dry. It’s therapeutic in the sense that it requires much less higher brain function.

Bearhawk Left Aileron Rib Stitch

Here’s the left aileron ready to stitch


I only had 3/8″ reinforcing tape, so I used two pieces per rib. In retrospect I should have used a bit more higher brain function and ordered a wider width so that I wouldn’t use so much of it. I prepared the right flap in the same way as the left and cut out the fabric for it. I got about half of the lacing done on the left flap before I went back home. Since the flaps are the first non-propwash parts that I’ve covered, I consulted the Polyfiber manual to check for the rib stitch spacing. I have been using 2.5″ spacing in the propwash areas, and I used that spacing on the inboard two ribs of the flap. I used 3″ spacing on the other ribs, and this is what I’ll use on the ailerons.
Bearhawk Flap Fabric

Right Flap Fabric


Here are a few pictures of me lacing the ribs on the left flap, just so that you can see that it was me.
Rib Lacing Poly Fiber

Rib Lacing Left Flap


I’m wearing gloves because the thread is waxed and I don’t like having sticky fingers. That seems to be something that I inherited from my Mom’s dad.
Rib Stitching Knot

Rib stitching knots, not to be confused with stall speed in knots, or cruise speed in knots.


By now the knot is becoming pretty routine.
Mental Floss

Mental Floss


Sometimes I need to clean out my brain with a little mental floss.

Posted on
Hours Logged This Session: 3.25
Total Hours: 1883.75

Flap and Aileron Covering

I’ve been busy with work and that sort of stuff for a little while but I was glad to get back into the shop today. I started at lunch time, took a break for dinner, and finally left at 1:10am! I covered the left flap, starting with the ends:

Bearhawk Flap End

Left Flap Inboard End


Then the rest, all in one piece:
Bearhawk Flap Covering

Left Flap Covering


The previous owner of our kit located and drilled the hinge mounts, for which we are greatful. The only problem is that the bolt heads are very close to the bend and it’s hard to get to them with a socket. I found some high-strength socket-head alternatives and asked Bob if he thought they would be strong enough. He said that they would, so we’ll plan to use those in some areas. I prepped the left aileron for covering, which included riveting the trailing edge, cleaning off all of the dust, adding reinforcing tape to the rivet heads, and precoating the leading edge. As I mentioned in the last entry, I don’t really know if this is necessary on these parts.
Bearhawk Aileron Frame

Left Aileron before covering


Once the cement was dry I shrank the covering on the left flap:
Bearhawk Wing Flap

The covering is shrunk.


Here I am giving it the first coat of polybrush
First coat of polybrush on the left flap

Here I’m applying the first coat of polybrush on the left flap.


Bearhawk Flap Rib Stitching

Now the left flap is ready to stitch


I’ve been adding and removing lots of wires to the left wing conduit, and I wanted to add a full-length piece of some sort of string to allow for future wires. My orange avionics tying wrap seemed light weight and up to the task, so I used it. If I have to pull any more wires, I can pull a new length of string along with the new wire. The left side conduit is starting to get pretty full, so hopefully I won’t need to add any others.

Posted on
Hours Logged This Session: 8.7
Total Hours: 1883.75

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

Wing Wiring

Today I finished wiring the D100. The last step was to splice together the DSAB wires, which are the wires that allow the three Dynon units to communicate with one another. I also started working on the wires that run through the wing conduit. I realized that I need to order more cable for the Dynon magnetometer. This is a 4-conductor shielded cable and with the sensor mounted in the wing tip it looks like I’ll need more than 20 feet. Richard had already run the wires for the aeroflash lights, but I wanted to be sure about which one was which. To make this job easier, I used a battery and my voltmeter.

Wire Identification

Wire Identification


I labeled two wires, then taped each one to a battery terminal. On the other end I measured for voltage until I found the corresponding wires. This system works very well as long as there isn’t any risk of a short on the measuring end. While I was working on all of that I heard an airplane flying by. Our little airport doesn’t get a lot of traffic, so it’s always worth stepping outside when someone stops by. It turned out to be a very fancy Maule!
Visiting Maule

Visiting Maule


I took several pictures of a few details, including uphostery and that sort of thing. The weather was perfect, so I started preparing the rudder for covering. This was a simple matter of drilling some drain holes on the aft edge of the horizontal ribs and wiping the structure down with the polyfiber C2210 prep solvent.
I also started wiring for the transponder. It’s a very simple process compared to the Dynon units, and especially compared to the 430, which I’ll start shortly.

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

Aileron Balance and Wiring

Today I had a visit from fellow Bearhawk Builder John Rheney. It was great to have him stop by, since most of my visitors are not Bearhawk builders. We were able to talk about several of the special challenges and hard decisions in the building process. My Aircraft Spruce order from Sun-n-Fun arrived, and I got several new goodies. One is a new fuel valve to replace the Andair. The Andair is a great design for most applications, but for ours it doesn’t work very well. Since the outlet is on the bottom, the height ends up being a limiting factor. Here’s the alternative- the SPRL valve, which is available from Aircraft Spruce.

SPRL Fuel Valve Top

SPRL Fuel Valve Top


SPRL Fuel Valve

See how much shorter this one is, since the outlets and inlets are on the sides?


Tach Drive Cover

This little cap covers the tachometer drive. Since our electric EMS doesn't use a tach cable, we need to cover that hole with something.


Lycoming Tach drive

Tach drive


While I was doing all of that Tabitha was working on her window design.
Next I installed the panel annunciator for the low volt circuit. This is especially rewarding work, since now when I turn on the master a light on the panel blinks. If you don’t know what I mean, then I’d have to ask if you’ve ever made an electrical system or circuit. Hearing the battery contactor click is exciting, but blinky lights are much more visual. I found these fancy LED mounts at SNF for cheap, but I wanted to replace their unknown wires with aircraft grade tefzel wires. This has been a strict policy of mine for all wires aft of the firewall.
LED mount disassembled

LED mount disassembled


All that I’m using from this particular mount are the three silver pieces in the middle of the picture. I have a high-intensity LED that will replace this conventional one.
Low Voltage Annunciator Installed in the Panel

Low Voltage Annunciator Installed in the Panel


I’ve made provisions to duplicate all of my annunciators. This provides extra redundancy in case one fails, and also adds to the ambidexturous nature of the panel layout.
Low Voltage Annunciator Wiring

Low Voltage Annunciator Wiring


Just to recap, the function of this indicator is quite simple. When the master is on but the alternator is off, the light blinks. This is a great way to detect an alternator failure in flight, and also a great reminder to turn the master off after flight.
I pulled the lead balance tubes back out of the ailerons and checked the weight. I had originally filled them to 6 pounds each, but after further discussion with other builders I decided to remove a little bit of that lead. I drilled out enough to make the new weight 5 pounds and 3 ounces.
I ran a few more wires, including the Dynon ammeter, ground, oil temperature, all grounds, and power feeds.
Bearhawk Wiring

The wires are slowly multiplying, one wire at a time.


D180 Wiring

D180 Wiring


D100 Wiring

D100 Wiring

Posted on
Hours Logged This Session: 10.3
Total Hours: 1883.75

Battery Bus & P-Leads

Today I continued with more wiring. I finished the SD-8 ammeter wiring that I started yesterday, and made a cable for the starter:

Starter Cable

This clear double-wall heat shrink will preserve the label for a while.


I found a covered fuse block to use for the battery bus. Since it is on the engine side of the firewall I was worried about an uncovered block getting dirty. The only thing I don’t like about it is that each fuse feeds separately. To fix this I bent all of the tabs on one side:
Covered Fuse Block Modification

The top row of tabs will become the feed side.


Then I cut a piece of brass into a 1/4 inch strip and rounded the corners a little:
1/4" Brass Strip

This was from the same stock that I used to make the forest of tabs.


Brass Tab

The tab is just a little bit longer than the contacts.


I soldered the brass piece to the bent tabs, very carefully. I was able to get good melting without any of the plastic housing.
Soldered Tab

I also potted the back side of this with high-temp silicone, just to keep out contaminants and prevent shorts.


Next I started working on the P-leads for the mags. These bendix mags use a special terminal end.
Bendix Magneto P-Lead Terminal

This is the stub of the old p-lead terminal.


New kits are available to build the p-leads, but since I have these old ones I’ll just use the parts to make mine. The far right side is a soldered end that includes a small washer. I was able to melt the solder and extract the washer from the old ends. I used shielded wire and connected the shield to a ring terminal and grounded it on one of the screws on the back of the mag housing.

I’ve also been working on the wire conduit in the wing. I cut a notch to allow entry for the Dynon magnetometer cable, but that made a weak spot in the conduit tube. I cut a piece of aluminum tube for reinforcements:
Reinforcement for Plastic Conduit

Half of this tube will make a good reinforcement. I used a reciprocating saw to make the cut, but a bandsaw would have worked well too.


Reinforcement for Plastic Conduit

I roughed up the plastic and aluminum, then attached the reinforcement with JB Weld.


I added rubber grommets to each of the holes in the wing ribs, then reinstalled the conduit.

Wire Routing

I started out today by putting the control sticks back in. I drilled a hole in the bottom of the left stick that will allow the push-to-talk switch to fit through.

Bearhawk Control Stick Push To Talk

This is the bottom of the control stick. The black grommet will pad the wire and reduce the size of the hole, which must be big enough to accommodate the body of the push-to-talk switch.

Next I attacked the 0.025″ aluminum panel that I’ve spent the last few days making. I didn’t weigh it before and after, but hopefully it saved an ounce or two.

Electrical panel lightening holes

This part is clearly Swiss-made.


I was ready to add a few wires to the left wing conduit, but it made sense to do as much work as possible while the wires were convenient and outside of the airplane.
Dynon Magnetometer Wire

I stripped the end of the 4-conductor shielded cable and separated the conductors from the shield. This quad cable is much easier to work with than the single conductor wire that I am using for the p-leads.


I added a piece of tie-wrap to use for future wire additions, then added the magnetometer wire and OAT probe wires to the left wing conduit. Lastly, I took a few measurements to see if I’ll be able to find studs for the Hartzell prop governor.
Hartzell Prop Governor Flange

I'll never be able to figure out why they designed this flange this way.


This flange design seems problematic. Even if I can get the right length of studs, it looks like installation would be quite a hassle.

Window Planning

Tabitha came out today and we did some planning for the windows. With the top of the fuselage uncovered it was hard to realize how dark the back seat area would be with small windows. So we used a few blankets and such that we had around to serve the role of the covering material.

Bearhawk Window Testing

We used blankets to simulate opaque covering.


Tabitha put some plastic sheeting on the outside of the fuselage and used markers to draw a few different window layouts.