Avionics Cooling from the Fresh Air Vent

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

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Hours Logged This Session: 1
Total Hours: 1883.75

Exchanging the Flightcom 403b Intercom for the PSEngineering PM3000

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

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Hours Logged This Session:
Total Hours: 1883.75

Weather Stripping

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

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.

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!

Moving the Fuselage to HKY

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

Carb heat duct

Carb heat duct


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

New Vent Location


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

New Vent


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

FAB front seal


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

Prop Wrench


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

Cowling on


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

Setting up the saw horses


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

Fuselage on the trailer


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

New temporary home


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

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Hours Logged This Session: 13
Total Hours: 1883.75

Instrument Panel Labels

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

Felt Padding

Felt Padding


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

Skylight Panels


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

Drill Press


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

Fireproof Bowden Cable Fittings


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

Making Labels


And sticking them onthe panel

And sticking them onthe panel


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

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Hours Logged This Session: 8.6
Total Hours: 1883.75

Doors and Locks

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

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Hours Logged This Session: 7.2
Total Hours: 1883.75

Pulling Off Tapes

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

Blue Parts

Blue Parts


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

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Hours Logged This Session: .3
Total Hours: 1883.75

Removing Tapes

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

Painting the Last White

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

Rough Cut Angle

Rough Cut Angle


Finished Mount

Finished Mount


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

Baffle extensions


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

One side in pieces


One side done

One side done


Both sides done

Both sides done


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

Preparing for White Paint

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

Skylight and Cowling

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

Antenna cover in progress

Antenna cover in progress


It's a race!

It’s a race!


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

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


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

Tail Pipe Hole


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

More interference


This is the final hole size.

This is the final hole size.


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

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

Boot Cowl Rivets Continued

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

Bolt Blanks

Bolt Blanks


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

Threaded Bolt


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

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Hours Logged This Session: 4
Total Hours: 1883.75

Boot Cowl Riveting

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

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Hours Logged This Session: 5.9
Total Hours: 1883.75

Left Wingtip Fitting

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

Back Cargo Door

Back Cargo Door


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

Both Cargo Doors

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

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.

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Hours Logged This Session: 6.4
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

Reassembling the Front Seats

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

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Hours Logged This Session: 1.8
Total Hours: 1883.75

Door Assembly

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

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Hours Logged This Session: 3.1
Total Hours: 1883.75

Pieces to Bend

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

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Hours Logged This Session: .4
Total Hours: 1883.75

Priming Wingtips and More

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

Gascolator hatch

Gascolator hatch


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

Left wing, but not liberal.


Blue fuselage with the engine on

Blue fuselage with the engine on


Both together

Both together


Here are the parts that I primed

Here are the parts that I primed


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

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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

Final Boot Cowl Continued

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

Left Side Overview

Left Side Overview


Right Side Overview

Right Side Overview


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

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Hours Logged This Session: 6.9
Total Hours: 1883.75

Roof and Boot Cowl

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

Short roof

Short roof


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

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Hours Logged This Session: 3
Total Hours: 1883.75

Bending the Roof

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

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Hours Logged This Session: .2
Total Hours: 1883.75

Fairlead Pliers

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

Fairlead Pliers

Fairlead Pliers


In Action

In Action


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

Corner Cut


Corner cut, second view

Corner cut, second view


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

Bent side


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

Ready to prep and weld


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

Welded bracket


Inside view

Inside view


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

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

Making Windows

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

Skylight Polycarbonate

Skylight Polycarbonate


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

Safety wired bolt heads


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

Posted on
Hours Logged This Session:
Total Hours: 1883.75

Straggling Wires

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

Finished wire bundling

Finished wire bundling


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

Nose light connector


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

Drilling bolt heads


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

Polycarbonate Window


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

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Hours Logged This Session: 9.5
Total Hours: 1883.75

Bundling and Securing

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

Wire bundling

Wire bundling


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

These panels can be attached now with screws.


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

The fly cutter makes the first holes…


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

…then the forstener bit makes for a good flat center


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

From Above


From Below

From Below


I was quite pleased with the results!

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Hours Logged This Session: 13.2
Total Hours: 1883.75

Engine Installation Again

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

Engine Installation Again

Engine Installation Again


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

Coax antenna


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

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

Engine Preparations

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

Engine on the lift

Engine on the lift


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

Oil Line Routing


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

Baffle hole


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

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

Brake Lines and Blue Paint

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

Painted Parts

Painted Parts


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

Main Landing Gear Holes


Upper Support Ring

Upper Support Ring


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

Lower Trapezoid Hatch


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

Upper Panel in Place


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

Brake Lines


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

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Hours Logged This Session: 16
Total Hours: 1883.75

ANR Headset Jacks

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

LEMO Jacks

LEMO Jacks


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

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

PVC Pipe clamps

PVC Pipe clamps


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

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

Final Wiring

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

Posted on
Hours Logged This Session: .7
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.

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

Audio Problem Finally Resolved

Today was a good day for progress- I finally got to the bottom of the last audio problem. I isolated all of the inputs from the audio amp except for the music, which works fine. The circuit is designed to use resistors to control the volume level of each channel. I gathered from the directions that anything from 30-500 Ohms would be required. When I connected the Dynon audio to the iso amp, it was just super loud, to the point of being very distorted. I figured I would give the circuit a chance by using higher resistance, without regard for any norms about what should be required. I stuck in incrementally higher values until I made it all the way up to a surprising 3000 Ohms. At that level, the circuit worked fine. I reconnected the Garmin nav output and repeated the same strategy. You can imagine how surprised I was to find that it required 68,000 Ohms! With those very high value resistors in place, everything works exactly as it is supposed to, which is a big relief.

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

Audio Troubleshooting Still

The results of yesterday’s ground problem correction were good. Everything in the system works except for the channels that go through the iso amp. I took a break from troubleshooting to install the aft 12v SAE jack, and run a few cabin wires. I installed the dimmer for the instrument panel flood lights. The dimmer came from All Electronics, but is also available from Aircraft Spruce for about four times the price.

Pulse Wave Modulation Dimmer

Pulse Wave Modulation Dimmer


The dimmer has a sub-optimal wire connection method. The back of the dimmer is potted with some white rubbery stuff, so I removed the potting in the corner where the green terminal block was attached. I cut the leads off from the block, which liberated the block itself, then used the soldering iron and needle nose pliers to remove the remainder of the leads.
Dimmer ready for new wires

Dimmer ready for new wires


Then I soldered tefzel wires into the holes where the terminal block used to be. One wire comes in from the fuse (which is on the battery bus), then one goes to the central grounding point. The other two go to the front cabin flood light. The light in the back is controlled by a switch near the right rear passenger headsets, and it is on or off only, no dimmer.
The front light is selectable as red or white, with the switch that is right next to the light. I took the output from the dimmer to the center post of the switch, then took the red input from one end post and the white input from the other post.

Posted on
Hours Logged This Session: 10.2
Total Hours: 1883.75

Audio Troubleshooting Continued

The audio problem still continues. The good news is that today I have a better troubleshooting plan, thanks to the AeroElectric list. The most frustrating thing about this problem was that I just didn’t have a good plan for how to isolate the problem. One list member suggested pulling all of the pins out of the connectors, and assembling them one circuit at a time to try and isolate the problem. First I removed all of the wires coming into the intercom except for the front left seat. That didn’t fix the problem. Next I used little alligator clip test leads to connect the left front seat input on the intercom directly to the headset plugs, bypassing the aircraft jacks. The problem was gone! I reconnected the airframe microphone jack on the front left, and the test was still good. I reconnected the audio jack on the front left, and the problem came back. A little bit of investigation led me to the problem- the audio jacks weren’t grounded. This happened through a series of events. First, our project’s previous owner had connected the audio jacks without any ground wires. He was planning to ground them through the airframe, as was I. While microphone jacks must not be grounded to the airframe, audio jacks can be. Some time later, I learned that while the audio jacks may be grounded via the airframe, it’s better if they are not. When I learned that, I drilled the holes to a larger diameter and installed insulating washers like the ones on the microphone jack. The only problem is that I didn’t come back after the fact to add a ground wire connection. The good news was that the shielded audio cable had an extra conductor available, so I was able to add the ground by shortening the cables a few inches on each end. It took me several hours to perform this soldering surgery, but as of the end of today it’s all ready to plug in and test. I’m just glad to have it figured out.

Posted on
Hours Logged This Session: 6.6
Total Hours: 1883.75

Instrument Label Planning

This evening Tabitha and I both came out to the hangar so that she could see how the panel is coming together. We worked some on making a list of labels that we’ll need for the panel. I plan to use a label printer that we have on hand, at least at first. We may decide to make some changes to the labels, so I want to be able to make those changes in-house.

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

Audio Troubleshooting

Today the audio troubleshooting continues. First I swapped the power supply. My fancy battery charger has a “power supply” mode, so I had been using that for test power. Just in case that was related to the audio problem, I installed a temporary SLVA battery and tested again, with no change in results. I tried removing the plug from my audio amplifier circuit with no change. I didn’t have many other ideas for troubleshooting the audio right then, so I moved on to configuring the avionics to talk with each other. It was pretty neat to be able to see the course change on the 430 by turning the knob on the HS34. I connected a GPS antenna to a length of coax, then tossed the antenna out through the gap under the hangar door. After a few minutes, the GPS found itself, which was also quite rewarding.

First Fix

First Fix


I also finished replacing the ELT remote antenna, since it took me until now to get the replacement battery lined up.

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

Spraying Blue on the Tail Pieces

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

Posted on
Hours Logged This Session: 6.5
Total Hours: 1883.75

Reinstall Intercom

I was feeling pretty good about my wiring, right up until I hooked up the intercom. All of the audio is just really weak. I did a little bit of troubleshooting before tabling that problem, pending more research. I installed the aft dome light, which will be able to serve either the baggage area or the back seat. When I installed the tab to support that dome light, I wasn’t planning on covering the ceiling the way that I did. In retrospect, I would have rather had the tab on the lower tangent of the tubes, rather than the upper. As it is now, the base of the light is under the fabric.

Dome Light

Dome Light


I also spent a little while pulling off the masking tapes from the last load of white paint parts.

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

Powering Up the Avionics

I started today by preparing and painting the tailwheel spring. I suspect that the paint will be somewhat short-lived on this part, but if it starts to come off, I’ll just paint it again. I cleaned off the light surface corrosion and applied a flat black rustoleum.

Preparing the Tailwheel Springs for Paint

Preparing the Tailwheel Springs for Paint


All of the tailwheel parts were ready to assemble, so next I put them together.
Tailwheel Assembly Parts

Tailwheel Assembly Parts


Assembled Tailwheel

Assembled Tailwheel


I also picked up a nice grease gun from Amazon to use on the various grease fittings.
Grease Gun

Grease Gun


When I mounted the tailwheel and spring, I used 39 foot pounds on the big bolt. Mark G had this bolt come loose once, so I made an extra effort to make sure that it was installed correctly. I found that I had to grind a slight bevel on the aft end of the spring to clear the weld fillets on the tailwheel body.
Installed Tailwheel Assembly, minus wheel and tire.

Installed Tailwheel Assembly, minus wheel and tire.


Next I reinstalled the instrument panel, with its fresh paint. That made a few easy tasks available, such as installing the annunciator lights, headset jacks, and switches.
Bearhawk Instrument Panel

Instrument Panel Progress


Back when I wired the Garmin boxes the first time, I separated the multiple power inputs to separate fuses. In retrospect Bob N. recommended that those two power leads be combined to a single wire and fuse, so I made that change. I installed each of the avionics boxes, connected them, and powered them up for a test in unison. Did you know that the ELT remote has its own little battery? I sure didn’t, until someone happened to mention it in passing. Since our ELT has been sitting on the shelf for a little bit longer than initially expected, I thought it prudent to replace the battery now.
ELT Remote Battery

ELT Remote Battery


I was glad to see all of the panel lit up, and no smoke released. I’ve been using this battery charger in its “supply mode” to power the electrical system for this sort of testing.
Bearhawk Instrument Panel

Bearhawk Instrument Panel


The intercom is the only remaining box that isn’t installed at this point. Tomorrow I’ll start with testing.

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

Painting White Pieces

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

Masking Paper

Masking Paper


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

Inspection Covers with Flush Rivets


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

Mouse Door Hinge Rivets


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

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

Rudder Pedal Changes

Yesterday’s efforts to strip the tailwheel fork were not fruitful. The abrasive that I was using was too fine and the coating was too tough. Today I was able to remove it with the die grinder and a scotchbrite wheel. I had previously painted the rudder pedal assembly, and while it turned out quite nicely, there was just an engineering change that suggested additional welding. I did that welding today, then prepped the welded portions for paint. In this round of priming I sprayed the other side of yesterday’s parts, plus the tailwheel fork, and the rewelded rudder pedals.

Posted on
Hours Logged This Session: 3.8
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.

Still More Fuselage Reassembly

Today I tied up a few more loose ends of wires. I started with the ELT remote. The remote uses a cable that looks just like a phone line. I wanted to shorten it, so I clipped off the old end several months ago. This also made it much easier to fish the cable through grommets on the way back to the ELT. Today I crimped on a new end. Then I returned to the instrument panel and countersunk all of the holes that I drilled yesterday.

Countersinking the Dynon Trays

Countersinking the Dynon Trays


These angles hold the Garmin trays in the panel

These angles hold the Garmin trays in the panel


I riveted the trays to the panel with -4 rivets, then worked on the window frames. I deburred those and started making the covers for the inspection holes in the horizontal stabilizer area.
Front Stab Cover

Front Stab Cover


Right rear stab cover

Right rear stab cover


Both of these will need slots that will allow them to come on and off without removing the horizontal stab. Note from the future: I have since learned how to use a shrinker, and I could have made a nicer inspection panel by shrinking the edge a little. I also wish now that I had made the hole on the right side a little bit further up vertically, and/or made a similar size hole on the other side too. It turned out that connecting the elevator and trim mechanisms was pretty tricky with this arrangement.

Fuselage Reassembly Continued

It’s nice to have enough painting done so that I can start putting things together again. This morning I started with the firewall. When I painted the fuselage, I just balled up the wiring and wrapped it in a plastic bag. Today I untangled that big ball and started reconnecting the connections on the firewall. I disassembled the instrument panel, which involved removing the avionics racks from the panel blank itself. Those were drilled to #40 size and held together with clecos, so I drilled them to final size and deburred the holes.

I’ve never been very happy with Dynon’s mount for the HS34. The problem is that the holes are already drilled in the flange. The shape of the bracket makes it impossible to match drill the bracket to the instrument panel, which in turn makes it impossible to get a good hole location in the panel. If the flange were not drilled at all, then I could drill from the panel side and everything would match up. While I was at the Sebring LSA expo back in January, we had stopped by the Dynon booth to look at their displays, and I noticed that their display panel had a box-style mount for the HS-34. I was immediately excited and asked where I could buy one. It turns out that the mount is actually the one that they sell for the autopilot module, and I was able to order one.

Dynon's mount for the HS34

Dynon’s mount for the HS34


Dynon's mount for the AP74

Dynon’s mount for the AP74


The AP74 mount will require some modification in the back to make room for the connector, but I’ll do that later.

Reinstalling the Landing Gear

This morning I used a little bit of fuel in a steel bowl to clean the old grease out of the wheel bearings. Then I packed them with fresh Aeroshell grease and put the wheels back together.

Cleaning out the old grease

Cleaning out the old grease


Here's the bearing number in case I need it later

Here’s the bearing number in case I need it later


While I had the wheels in my hand, I checked to be sure that they would fit in the wheel pants that I picked up last summer at Oshkosh.
The tires fit in the wheel pants

The tires fit in the wheel pants


If only it were this easy!

If only it were this easy!


I’ll have to figure out a mounting bracket for them, but I might just wait until after the plane is flying.
With the plane back on its main wheels I pulled off the remaining masking tapes in the fuselage. Then I started working on a few remaining wires in the cabin. I cut out the inspection holes and installed the rear seat intercom jacks. I connected the static ports to a tee fitting in the middle of the fuselage and added some an adel clamp to hold it in place. Then I made an adjustment to where the ELT mounted. It mounts to a little piece of floorboard that sits aft of the cabin on the right side. I moved it as far aft as it would go, then riveted the bracket in place. That bracket had originally been attached with screws.

Preparing for Landing Gear Assembly

This afternoon I finished assembling the cargo door latch that I started yesterday. I also made a little aluminum plate that will cover the center of the mechanism, hopefully reducing the odds of getting a finger caught in there on a cold and windy night somewhere. Then I drilled the holes in the front cargo door to final size and deburred the holes in the frame.

I have noticed that when I had #40 holes in these parts, there were a few little bits of steel chips that I could hear
rattling around in the tubes. When I enlarged them to #30, the holes became big enough to evacuate those little chips by shaking the frame around with the holes pointed down.

Next I reassembled the main landing gear shock struts. I had taken them apart to paint the strut tubes, and to inspect Richard’s work. I figured it wouldn’t hurt to replace the automatic transmission fluid while I was at it, since the old fluid had been in there for a few years now. Isn’t it amazing how this 2-year project is going on 4? And to think, that’s after Richard had been working on it for a few years. I can completely understand why he decided to not continue with construction. One has to really enjoy this process in order for it to be worthwhile.

I set out all of the parts to reassemble the landing gear, in part to make sure that I had all of the right pieces, and in part just because it was fun.

Landing Gear Hardware

Landing Gear Hardware


Also, the axles had picked up a little bit of surface rust after being exposed for a while, so I polished them with a green Scotchbrite wheel in the die grinder.

Assembling Parts

One important mental changeover is switching from a temporary assembly mode to a more permanent assembly mode. In the past, I knew that anything that I put together was going to have to come apart again. Now I’m starting to assemble some parts that will probably be together until at least the first flight. Today I assembled the control sticks, rudder pedals, and rear cargo door latch.

Control Stick Assembly

Control Stick Assembly


I used the die grinder with a scotch brite wheel to clean the paint off of the part of the cargo door pins that will go into the fuselage holes. This should help keep them from binding.
Cargo Door Latch

Cargo Door Latch


I wasn’t able to paint today, but it was nice to take a break and do some relatively easy assembly, or I guess more accurately, reassembly, since all of these parts have been together plenty of times before.

Spraying the Interior

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

Floorboards as masking

Floorboards as masking


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

Something about this arrangement makes me think of DaVinci.


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

Prepping the Interior

The fuselage paint has had plenty of time to crosslink, so today I started masking so that I can spray the interior. I
didn’t spray it back when I was spraying the white on the outside of the fuselage, in part because we hadn’t decided on the interior color. In retrospect it would have been easier to spray all of the white at once.

Masking the outside of the fuselage

Masking the outside of the fuselage


A few other tasks today included putting wheels on the bottom of the fuselage rotisserie so that I can move it by myself. I don’t know why I didn’t do this sooner! I also prepared the wing tiedown parts so that I can paint them in the next round of primer.

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.

Door Frame Preparations

It has been too cold to paint, and I haven’t been spending many hours in the hangar. Today I finished cleaning up the tiedown rings, and started drilling the door skins and frames to final size. They were all drilled to #40, but I’m planning to use 1/8″ rivets to hold the skins on the frames, so I started drilling them out to #30. Today I did the right front top and bottom, lower left door, and started on the rear cargo door. The larger holes made it much easier to shake out the little chips of steel that were rattling around in there.

Fuselage Blue Prep

Today I removed the masking tapes from the fuselage, and started adding paper to the front end of the fuselage for the upcoming blue painting. Here’s the result of the taping:

Vertical Stabilizer

Vertical Stabilizer


Registration Number Area

Registration Number Area

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.

Polyspray on the Fuselage

This morning Tabitha came out to help with laying out the masking tapes on the right wing. We are planning to only paint the areas that are going to show, so instead of painting the whole wing white and then masking off the blue areas, we’re going to mask off the white areas, spray white, then mask off those areas, and spray blue. This will require more labor and tape, but it will save weight and paint. Weight and paint are more expensive than labor and tape at this point. We applied the fine line tape, which establishes where the lines will be. Later I’ll come back later and finish with cheap masking tape and paper. I took the ends off of the wing struts so that I can paint them while I have the white paint mixed. After lunch I came back and sprayed the first coat of Polyspray on the fuselage.

Polyspray on the fuselage

Polyspray on the fuselage


This picture also shows the section of the back seat that I mentioned earlier.

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.

Last Polybrush

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

Spraying the Fuselage

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

Ready to spray

Ready to spray


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

First coat of Polyspray


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

Interior Smoothing

I only had a few minutes to work today, but I was able to finish the smoothing on most of the interior. All that remains is the left side of the baggage area.

Fuselage Smoothing

Today I finished heat-smoothing the exterior of the fuselage and one side of the interior. I found that the iron shoe was getting pretty gummy with baked-on Polybrush, so much so that MEK wasn’t really getting it off. The green scotchbrite pad in the die grinder worked pretty well though, and left behind a nice polished finish. I also removed the elt bracket from the floor panel that goes aft of the rear cabin bulkhead. I’m planning to move it to the back of that panel, so that I’ll have a place for my feet in case I ever try to sleep in the cabin.

Still More Fuselage Tapes

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

Fuselage Bottom

Fuselage Bottom


Interior Ceiling, Fuselage is upside down

Interior Ceiling, Fuselage is upside down


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

Not much extra!


Fuselage right side

Fuselage right side

Visitor Day

I hadn’t planned to have so many visitors today, but it sure was nice! I started out early in the morning with the rest of the remaining fuselage cementing. Skip stopped by in his Kitfox and visited for a little while. I had sent a message out to our EAA chapter members to invite folks over who wanted to learn more about covering. Jack took me up on the offer and I put him to work on one of the landing gear legs.

Jack cements the fabric on the right landing gear leg

Jack cements the fabric on the right landing gear leg


Left landing gear ready to shrink

Left landing gear ready to shrink


I worked on the left landing gear leg while Jack worked on the right, and it didn’t take long to finish them both. We shrank the covering on those legs, and Jack started working on the first coat of Polybrush while I shrank the fuselage.
Jack applies the first coat of Polybrush

Jack applies the first coat of Polybrush


Then fellow Bearhawk builder Hari stopped by from out of town for a visit. Hari was able to take some pictures of our
progress and give us an update on his. Other visitors that afternoon included Jim, Danny, Paige, and Bradley.
Bradley flew in for a visit

Bradley flew in for a visit


The weather was perfect, which might have been part of why so many folks came by. I was able to finish the shrinking on the fuselage, which is looking very nice.

Still More Cementing

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

First, I drew a circle

First, I drew a circle


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

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


Here are the sheets of polycarbonate for the windows and skylight

Here are the sheets of polycarbonate for the windows and skylight


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

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


Tabitha works on cementing the left side of the fuselage.

Tabitha works on cementing the left side of the fuselage.


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

Cementing Continued

This covering stuff takes a while! Today I worked until I ran out of cement (two quarts so far in the project). I installed a piece on the lower right side under the cargo door. Since I’ll have to order more cement, I spent time today to make sure I have enough reinforcing tapes too.

Fuselage Covering

This morning I finished cementing the belly fabric in place. I shrank the fabric to 225 degrees and it looks much better.

Shrunk Belly Fabric

Shrunk Belly Fabric


With the distractions of the rest of the fuselage hidden by the fabric, I see that the stringers aren’t quite straight. I probably managed to bend the standoffs a little while handling the fuselage. At this stage it was easy to fix- I just reached in from the sides of the fuselage and gave the stand-offs a little tap with a hammer. That made the stringers look much better too. Next I added the rib stitching to the cabin roof:
Reinforcing tape in place, stitch holes punched

Reinforcing tape in place, stitch holes punched


Stitching in place

Stitching in place


Here's another shot from the nose to show the progress.

Here’s another shot from the nose to show the progress.


I left the area behind the tailwire attachment point open to allow for airflow in the fuselage. To help deter mice and the animals that eat mice from getting in through that opening, I added a swatch of window screen.
Tail vent hole

Tail vent hole


Looking up at the inverted fuselage

Looking up at the inverted fuselage


I used a little dab of fabric cement to hold the screen in place.

Shrinking Interior Covering

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

Belly Piece and Interior

Belly Piece and Interior


Belly Covering

Belly Covering


The rotisserie arrangement sure is important at this stage!

Anti-Chafe Tape

There are a few more things that I need to have done before we can start covering. For example, the lower fuel lines that cross under the front door sills need to be in place.

Left Lower Fuel Line

Left Lower Fuel Line


I installed those lines and added a nutplate for a clamp that will support the right rear vertical line.
Fuel line tab

Fuel line tab


With our covering strategy I don’t think I’ll need to have the vertical lines in place prior to covering. I routed the rear passenger headset cables and tied them neatly in place. I added the anti-chafe tape to a few spots on the fuselage that seemed like good candidates for it, and I started repairing the hole in our wing root.
Wing Root Repair

Wing Root Repair


How did I end up with a hole in the wing of an airplane that isn’t even flying yet? I’ll tell you- I cut that hole. I was thinking of a way to get airflow to the back seats, and copied an idea that I saw on another airplane. Then, after I had the hole cut, I saw something in the Avipro manual about not putting big holes in the .032 portion of the wing skin. So I called Bob, who confirmed that there really shouldn’t be such a big hole there. He said that I should patch it with a doubler underneath, using -4 size flush rivets spaced 1 inch apart. In the picture above you can see the beginnings of just that. I used a square and a ruler to lay it all out, cut out the hole to a rectangular shape, then match drilled the skin and the doubler.

Covering Prep

This morning I mixed up a batch of epoxy, which I used to laminate a strip of unidirectional carbon fiber to the inside of the wingtip. Hopefully this will keep the scalloping down.

Wingtip Carbon Fiber Strip

Wingtip Carbon Fiber Strip


Carbon fiber looks like a snake

Carbon fiber looks like a snake


Top carbon strip

Top carbon strip


Antenna feedline and ELT remote cable

Antenna feedline and ELT remote cable


I also used the epoxy to secure the wooden ribs to the vertical stabilizer steel rib.

Nutplates that will be burried in covering

Nutplates that will be burried in covering


Here are a few more nutplates that are easier to get to now than later. These include the front strip on the lower sides, plus the back of the skylight hole. I only have a few more things to do before we can start covering.

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Hours Logged This Session: 5.2
Total Hours: 1883.75

Priming Small Parts

The new can of catalyst arrived today, but I couldn’t get the top off. The neck broke free from the can and was spinning with the lid. I poked a hole in the cap and forced the cap and neck off in one piece. I had a clean empty can from another product and was able to transfer the catalyst to that can.

Priming Small Parts

Priming Small Parts


I prepped the fuel tank bay cover and sprayed it and a few other odds and ends, and a few touch up spots on the fuselage.
Fuel tank bay cover

Fuel tank bay cover


Rudder cable covers

Rudder cable covers


That should wrap up the fuselage painting and start the clock on our 7-day waiting period for covering.

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Hours Logged This Session: 1.8
Total Hours: 1883.75

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!

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Hours Logged This Session: 2.8
Total Hours: 1883.75

Sand Blasting

Funnel Top

Funnel Top

We had a great time at Oshkosh as usual. We saw several old friends and met new ones too. It was hot, as you can see in this picture:
Hot Ladies

Hot Ladies


I found a great deal on a set of Cessna style wheel pants. I’ll have to make the inboard brackets, but that shouldn’t be too hard. I also picked up a different nut to support the outboard side.
Wheel Pant Axle Nut

Wheel Pant Axle Nut


It was finally time to sandblast the fuselage, so I made arrangements to rent a 180 CFM compressor and pressure pot.
Diesel Compressor

Diesel Compressor


The pressure pot was very simple, but it had one serious inconvenience. The top is shaped like a funnel, which makes it easy to load, but it’s very hard to empty. The previous renter had been using a different type of media, but I didn’t know what it was or how coarse it was. I dumped out what I could, and just ran the nozzle out into the air until my quartz started flowing.
Sand Blast Pot

Sand Blast Pot


As advertised, it was a hot and miserable job. I only blasted the areas where I had removed paint previously. In retrospect, I probably should have removed more, because the transition from old paint to bare metal ended up showing through the new paint. I started setting up at 12:00 and was done by 15:30. When I was done I turned the fuselage over several times to make sure I didn’t miss any spots. I moved it back into the hangar and took the compressor back, since I was paying by the hour. I used a total of 150 pounds of medium quartz. I was back in the hangar by 17:40 and sprayed paint until after 10:00pm. Those tubes sure are tricky to paint- there are so many different angles that have to be covered. I used almost two quarts of EP420 to get it all covered, and most of that ended up as overspray.

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Hours Logged This Session: 8.2
Total Hours: 1883.75

More Disassembly

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

Getting back to bare bones

Getting back to bare bones


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

Protected wire bundle


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

Weld the tab on, then cut it to length


Here's the finished row of tabs

Here’s the finished row of tabs


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

Here’s the original arrangement


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

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


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

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


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

1-man wheelbarrow fusleage transport


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

I tied the front down for stability


I tied the front down for stability

I tied the front down for stability


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

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Hours Logged This Session: 11.5
Total Hours: 1883.75

Taking it All Apart

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

Lower Strut Fairing

Lower Strut Fairing


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

Right window lock mount


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

Almost all apart


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

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Hours Logged This Session: 11
Total Hours: 1883.75

Photo Session

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

Lower front sheet metal

Lower front sheet metal


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

Bearhawk Before Covering


Bearhawk Before Covering


P1020910


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

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Hours Logged This Session: 3.1
Total Hours: 1883.75

Adjust Seatbelts

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

Front Seat Slack

Front Seat Slack


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

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


Here's what's underneath.

Here’s what’s underneath.


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

Shoulder Harness Becomes Lap Belt


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

Enlarge Eyeball Holes


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

Here they are in place


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

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Hours Logged This Session: 4.3
Total Hours: 1883.75

Seatbelt Tabs

This morning I made and installed some mounting tabs for the front seat belt crotch straps. I used 1/8 inch 4130 steel.

Seat belt tab blanks

Seat belt tab blanks


I removed much of the metal to save weight.
Shaped Blanks

Shaped Blanks


I had a hard time coming up with a good mounting method that would put everything in the right place. This is the best that I could come up with.
Tab mounting location

Tab mounting location


A while back I shorted the SD-8’s ammeter shunt while I was working on something under the cowl. After a discussion with Bob Nuckolls on the AeroElectric list, I decided to replace the fuse link that was there to protect that shunt. He recommended a fuse instead of a fuse link, since that’s what’s in the Z13/8 drawing now. I ordered this fuse holder, which uses a gasket that is very similar to the weatherpack connectors.
Waterproof ATC Fuse holder

Waterproof ATC Fuse holder


It’s a good thing that I replaced the fuse link. Here’s what it looked like when I took it out of the fiberglass sheath.
Overloaded fuse link

Overloaded fuse link


Afterwards I killed a few minutes by peeling more of the protective plastic off of the wing skins.

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Hours Logged This Session: 2.4
Total Hours: 1883.75

Final Fuel Lines

Tonight I finished making the last of the fuel lines, hopefully for the last time.

Looking up at the fuel lines from belowFinal Fuel Lines

Looking up at the fuel lines from belowFinal Fuel Lines


Final Line Routing

Final Line Routing


I put the stainless steel tunnel in place and it looks like it just barely touches the fuel valve:
Fuel valve interference at tunnel

Fuel valve interference at tunnel


I haven’t decided yet if I’m going to try to make a bump in the tunnel or try to secure the valve to the tunnel. The first option is the most appealing so far. While I was at the hangar, I also weighed our new fabric aft cabin bulkhead and our old aluminum bulkhead to see how much weight we saved. The fabric weighs 11 ounces, and the aluminum weighs 3 pounds 1 ounce. Yikes!

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Hours Logged This Session: 2.3
Total Hours: 1883.75

Fabric Aft Cabin Bulkhead

Back when we picked up the seats we had Russell save us a yard or so of the tweed fabric that he used. This will make a fabric version of the aft bulkhead, which will be lighter and quieter than the current aluminum version. My mom was in town to visit, so we put her to work on the sewing machine.

Sweatshop

Sweatshop


I thought it turned out pretty well, and a nice 10″ Bearhawk patch was the icing on the cake.
Aft Bulkhead

Aft Bulkhead

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

Measuring for the Seatbelts

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

Firesleeve Rolled Back

Firesleeve Rolled Back


High Temp Goop

High Temp Goop


Ready for a Clamp

Ready for a Clamp


Oil Lines Installed

Oil Lines Installed


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

Fuel Valve Location


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

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Hours Logged This Session: 4.5
Total Hours: 1883.75

Installing the Seats

I only had a few minutes free today, but I had to take out the seats and see how they looked in the airplane. They fit just as they were supposed to, and it was nice to see them back home again. Back when I made the headrests I intentionally left the vertical pieces a little bit long, so today I trimmed them to fit and put the headrests in.

Bearhawk Seats

Seats Installed

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

Fuselage Features

I mentioned yesterday that I was going to add a fairlead for the elevator trim cable at the aft end of the skylight. This morning I welded that tube on, and while I was there, I also welded on tabs for the front and rear flood lights.

Elevator Trim Cable Fairlead

Elevator Trim Cable Fairlead


Aft Flood Light Tab

Aft Flood Light Tab


Those will be LED spotlights on the battery bus. The light fixtures are adjustable so that the rear white light can point to the baggage area or to the back seat. The front is red and white, and I’ll install a dimmer on the instrument panel for it. With our new rear left window arrangement, the lower stringer interfered with the diagonal steel tube. I cut a small relief out of the stringer, and it looks like a small bite mark.

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Hours Logged This Session: 2.8
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!

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Hours Logged This Session: 3
Total Hours: 1883.75

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.

Baby Building

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

9 months pregnant and deburring still

9 months pregnant and deburring still


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

Patrol Doors

Today Tabitha joined me to work more on the doors and windows. We worked specifically on the lower front door skins, which will be mostly cut out to make room for windows. Some folks call these “patrol doors,” which makes for some especially confusing terminology, since there is a 2-place airplane called the Bearhawk Patrol that was designed by the same designer as our airplane.

Bearhawk Patrol Door

Tabitha drills the first hole to make room for the snips


I made the first pass

I made the first pass


We take turns with these since our hands get tired pretty quickly, Especially in the .032 aluminum. We cut about 1/2 inch from the line on the first cut, then make one or two other cuts to get closer to the final line. This helps minimize bending and distortion on the finished piece, because the scrap piece is able to bend more easily and get itself out of the way.
Tabitha Deburring the Window

Tabitha Deburring the Window


In the case of the window skin, we’re just enlarging the center hole slightly from the dimensions that our previous project owner had already cut the skins to. We cut out the right lower door skin and the right top window and started to debur those edges before it was time to go home again.

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Hours Logged This Session: 3.5
Total Hours: 1883.75

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.

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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.

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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

Window Lock

I only had an hour to work today, but I was able to get the right window lock structure cleaned and primed.

Priming Left Window Frame

This afternoon I cleaned up and primed the left window frame. It looks much better now!

Left Window Frame Primed

Left Window Frame Primed


I also welded on the support structure for the front right window lock.

Cargo Door Planning

This afternoon Tabitha came out and we spent a while working out the plans for the right rear windows and for the lock on the cargo door. The challenge with the cargo door lock is trying to work out a few conflicting goals. The most important goal is to be sure that the door will be available for emergency egress. In other words, we don’t want to have anyone locked in. The second goal is to be able to secure the door with some sort of locking measure to keep homeless folks and airport bums from going in there to sleep. The third goal is to be able to walk up to the door and open it, without having to open any other doors first. These are in addition to the usual requirements for light weight and simplicity. The first and third goals seem to be conflicting in most circumstances. The best solution that we could come up with is to have a lock cylinder that will secure the door in addition to the standard latch. We’ll just have to make unlocking the door a preflight checklist item, as much as I would prefer for it to not be. The front window locks will be the same, so at least there are a few reminders.

Left Rear Window Continued

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

Bead Roller with Joggle Dies

Bead Roller with Joggle Dies


.030 Steel Joggle

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


Here's how it comes together at the bottom

Here’s how it comes together at the bottom


And here's the rest

And here’s the rest


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

New Aft Left Window

I started welding the aft window frames this morning. The bottom was easy, so I did that one first.
Front of Window Bottom

Back of Window Bottom

Back of Window Bottom


I trimmed the top to length, but found that I needed more oxygen. I took a break to drive into town and then came back and tacked the top piece in place.