More Odds and Ends

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

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!

Weighing

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

Bunny Book

Bunny Book


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

New Cowl Fasteners


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

Mains are on


Scale pad

Scale pad


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

1328 pounds empty


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

Fuel Flow Test and Engine Run

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

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

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


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

Fuel Flow Attitude


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

Dynon agrees


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

Tied down securely


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

Ladder vantage point


Cowl off for the first run

Cowl off for the first run


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

Paint Scheme


Paint Scheme

Paint Scheme


Paint Scheme

Paint Scheme


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

Rigging the Ailerons

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

MLG Width Adjustment

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

Main Landing Gear

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

Pitot Tube

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

Installing the Wings

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

Wings On

Wings On

Moving the Fuselage to HKY

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

Carb heat duct

Carb heat duct


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

New Vent Location


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

New Vent


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

FAB front seal


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

Prop Wrench


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

Cowling on


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

Setting up the saw horses


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

Fuselage on the trailer


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

New temporary home


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

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

Instrument Panel Labels

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

Felt Padding

Felt Padding


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

Skylight Panels


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

Drill Press


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

Fireproof Bowden Cable Fittings


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

Making Labels


And sticking them onthe panel

And sticking them onthe panel


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

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

Stripes on the Cowl

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

Cabin heat diffuser in paper

Cabin heat diffuser in paper


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

Flat aluminum blank


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

Bent aluminum blank


This is where it sits:
Ready to drill and rivet

Ready to drill and rivet


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

Cowl Reinforcements

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

Cowl Reinforcement

Cowl Reinforcement


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

Cowl Reinforcement


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

Fiberglass Surface Work

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

Sanded Filler

Sanded Filler


Sanded Filler

Sanded Filler


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

One more round


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

Preparing for Fiberglass

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

Foam Indicators

Foam Indicators


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

Foam Spikes


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

Sanded Windshield Fairing


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

Foam


Spray Foam

Spray Foam


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

Velcro Strips


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

More Foam


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

Steel Blanks


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

Rough trim

Skylight and Cowling

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

Antenna cover in progress

Antenna cover in progress


It's a race!

It’s a race!


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

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


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

Tail Pipe Hole


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

More interference


This is the final hole size.

This is the final hole size.


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

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

Installing the Exhaust

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

Oshkosh Loot

Oshkosh Loot


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

New Rami Antenna


Rami AV520

Rami AV520


Another big box finally arrived!
Exhaust system

Exhaust system


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

Wood denting form


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

Vice attempt


Side view of the system

Side view of the system


Drain Plug Dent

Drain Plug Dent


Intake Tube Dent

Intake Tube Dent


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

Tailpipe


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

Bottom View


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

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Hours Logged This Session: 8
Total Hours: 1883.75

Boot Cowl Rivets Continued

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

Bolt Blanks

Bolt Blanks


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

Threaded Bolt


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

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Hours Logged This Session: 4
Total Hours: 1883.75

Horizontal Stab Fairings

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

Making Fairings

Making Fairings


Making Noises

Making Noises


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

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Hours Logged This Session: 8.5
Total Hours: 1883.75

Boot Cowl Riveting

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

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Hours Logged This Session: 5.9
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

Nutplates and White Paint

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

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Hours Logged This Session: 5.5
Total Hours: 1883.75

Painting White

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

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

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

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Hours Logged This Session: 3.5
Total Hours: 1883.75

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

Fairlead Pliers

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

Fairlead Pliers

Fairlead Pliers


In Action

In Action


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

Corner Cut


Corner cut, second view

Corner cut, second view


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

Bent side


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

Ready to prep and weld


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

Welded bracket


Inside view

Inside view


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

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Hours Logged This Session: 8.4
Total Hours: 1883.75

Brake Lines and Blue Paint

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

Painted Parts

Painted Parts


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

Main Landing Gear Holes


Upper Support Ring

Upper Support Ring


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

Lower Trapezoid Hatch


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

Upper Panel in Place


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

Brake Lines


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

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Hours Logged This Session: 16
Total Hours: 1883.75

Fuselage Plumbing

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

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Hours Logged This Session: 5
Total Hours: 1883.75

More Wing Preparations

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

Left Wing

Left Wing


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

Vince cuts circle panels


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

Jack installs the coax end


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

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Hours Logged This Session: 13.7
Total Hours: 1883.75

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.

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Hours Logged This Session: 8.3
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.

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.

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!

Spraying the Fuslage Blue

This afternoon the weather was finally good enough to paint again. I sprayed the blue coat on the fuselage, then removed the tapes to check for problems.

It looks great with the tapes off!

It looks great with the tapes off!


The paint ran under the tape a little at each point where the pinked edges intersected the tape seam. I was able to remove the larger part of these with MEK, since the blue had not yet cross-linked.
Bleeding under the masking tape at the fabric tapes

Bleeding under the masking tape at the fabric tapes


Just to exhonerate the 3m fine-line tape, the same thing happened under the vinyl registration number mask.
I also got a little bit of bleeding under the vinyl mask.

I also got a little bit of bleeding under the vinyl mask.


They end result is far from perfect, but it certainly meets my goals. I’ll just not be able to park right next to Dave or Georg!

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.

Making Tiedown Rings

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

Tailwheel Assembly

Tailwheel Assembly


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

Tailwheel tire size


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

First Bend


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

Second Bend


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

Welded Tiedown Rings


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

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

Fuselage Blue Prep Continued

This afternoon I continued with preparations to the fuselage for the next coat. This kind of work is more time consuming and tedious than I had anticipated. Since I’m painting in parts, I have to make sure that all of the stripes are located very precisely. We decided to use a pattern as follows: starting from the blue top, next we have a 2″ white stripe. Then there is a 3/4″ blue stripe, then all white. This pattern is very similar to Peter Stevens’s N27PS, and is essentially the standard “Bob” stripes minus one. I started by establishing the 2″ stripe, since I can measure everything else from there. My goal was to make the stripe parallel to the split of the front windows, and to have the stripe arrive at the engine cowling right at the air inlet.

Horizontal Stripe Reference

Horizontal Stripe Reference


As you can see in the picture below, I did quite a bit of head scratching to figure that all out. I temporarily installed the front windows to mark the location of the split. I used a copy of the early Beartracks issue where Bob lists his measurements for the stripes he used, and also had a copy of the 2013 Bearhawk Calendar handy so that I could reference Zane’s picture of N27PS.
Stripes get complicated

Stripes get complicated


I decided to use a paint mask from Higher Graphics for the registration numbers. Our numbers are a simple block style, which we chose to compliment the vintage-like lines of the Bearhawk. I didn’t realize it until I read Russ Erb’s observation about it, but the aesthetic cues of the Bearhawk fuselage and tail remind me of older airplanes. Maybe that’s part of why it looks so appealing to me. I’m sure I could have made the numbers out of tape, but using this mask kept the numbers all consistent and parallel. I located them with consideration for the horizontal stabilizer and cargo door, but still ended up with some of the last “B” on the cargo door. For a while it will be TP instead of TB. I followed the directions that came with the mask, and it all went exactly according to plan. First I sprayed the area with a mist of water, then I taped the top of the carrier sheet in place with the backing still on. That held the numbers in the right spot.
Applying the Mask

Applying the Mask


From there I was able to reach up from below and remove the backing, thus applying the adhesive of the letters and the carrier sheet onto the fuselage side. Once the letters were stuck, I just peeled off the carrier sheet and here is the result.
Right Side Registration Number Mask

Right Side Registration Number Mask


Left Side Registration Number Mask

Left Side Registration Number Mask


While this stage is tedious and quite consequential to the end result, it is also a phase with lots of visual progress.

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 on the Fuselage

This afternoon my Mom was in town, so we all came out to the hangar to get a few things done. They helped me move the fuselage into the paint booth. I later learned to put wheels on the front wood pieces, but back then it was still a three person job. After they left, I sprayed the white paint on the fuselage and one of the struts, and also did a little bit of touch up on th the elevator trim pushrod and main landing gear where I had missed some spots. I painted the bottom of the fuselage, the white stripes on the vertical stab, and most of the sides of the fuselage. My usual back-taping strategy was too complicated on the fuselage sides, in part because of the registration numbers and in part because of the horizontal stripes.

Laying out Fin Stripes

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

Wing in the Sun

Wing in the Sun


Tabitha removes the last few tapes

Tabitha removes the last few tapes


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

Second Coat of Polyspray

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

Wing white paint

Wing white paint


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

Taping for the next coat

Sanding the Fuselage

Today I had a visit from local EAA friend Skip. Skip is thinking about building a Bearhawk LSA and wanted to try some welding practice. While he did that I sanded the fuselage Polyspray, ironed down a few bits of tape that lifted, and in general got ready to spray the next coat.

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.

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.

Repairing the Small Iron

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

Failure Point

Failure Point


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

Brazed Reinforcement


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

Brazed Reinforcement again


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

I added a zig and a zag


Then added the spanwise brace that catches the AN4 bolts.

Then added the spanwise brace that catches the AN4 bolts.


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

Priming the Right Wing

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

A few small parts

A few small parts


One big part

One big part


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

Wing Masking

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

Masked wing root

Masked wing root


Masked trailing edge

Masked trailing edge


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

Still wet, but very clean


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

Wing Preparation

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

Right Wing Prep

Right Wing Prep

Wing Rotisserie Continued

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

Wing Rotisserie

Wing Rotisserie


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

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


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

Dusty wing


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

Temporary hole covers


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

Clean wing bottom


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

Half clean wing top


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

Tabitha taping


Eventually Felicia came out for a visit too.

Eventually Felicia came out for a visit too.

Wing Rotisserie

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

Tabitha the riveter

Tabitha the riveter


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

Wing goes here


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

Paint Booth Details

Previously I wrote about building the paint booth, but today I added the airflow system. There was an old furnace under our house that had a nice big blower. I spent some time under there with the reciprocating saw and extracted it for the paint booth.

Dusty Blower

Dusty Blower


A couple of 2×4 scraps and a stub of electrical wire brought it back to life.
It works!

It works!


My plan is to use that blower to pull air out of the booth, and this large stand fan to force air in.
First I tried just pointing the fan at the filters

First I tried just pointing the fan at the filters


The airflow was pretty good with having the fan just pointed at the filters, so I didn’t bother with anything else. I stopped by the Sherwin Williams store to pick up some paint can lids with pour spouts (nobody else seems to have them) and looked in the clearance corner. They had this nifty stick-on zipper for $10, which seemed worth a try.
Adhesive zipper

Adhesive zipper


I wish I'd gotten two!

I wish I’d gotten two!


The hole in the end won’t be big enough to get the large pieces like the wings and fuselage in, those movements will be fairly infrequent. Next I marked the lines and precoated for tapes on the top of the fuselage.
Ready to tape

Ready to tape


It’s not easy to mark a line parallel to a curving stringer! Fortunately accuracy isn’t super critical for these lines.

Inspection Rings and Tapes

Note from the future: I had to add several more rings than you see here. For example, I had to add another hole in the top of the cabin, another three or four holes in the tail area, another on each landing gear leg, and that’s not to mention that I forgot to account for the elevator trim horns all together. If you are deciding where to put rings, I would suggest making a visit to a flying airplane with a similar configuration to yours to take detailed notes about where they need to be.

The elevator halves join behind fabric, and I think it will be much easier to get in there to install and inspect those bolts if I have an opening that’s larger than the usual ring. I made a larger rectangular ring for the right side, but used a standard round ring on the left. The round ring will use a spring cover, while the right ring will use nutplates and screws.

Custom Inspection Ring

Custom Inspection Ring


I also embedded a small piece of aluminum in the tail. I’ll rivet the dataplate to this plate after painting.
Data Plate Mounting Pad

Data Plate Mounting Pad


Left Rear Inspection Rings

Left Rear Inspection Rings


The interior will need inspection rings near the headset jacks.
Interior Inspection Hole and Tapes

Interior Inspection Hole and Tapes


More Interior Tapes

More Interior Tapes


Tapes, tapes, and more tapes!

Fabric Taping

Now it’s time to start down the long road of reinforcing tapes. I started with the round doilies for the inspection rings. I found a good deal on some of these fancy pinking shears:

They cut a continuous line and are very well suited for these shapes.

They cut a continuous line and are very well suited for these shapes.


Danny stopped by and tried them out, and liked them so much that he cut out all of the doilies for me. Next I started on the lengthwise tapes.
Left Fuselage Side

Left Fuselage Side


While the fuselage tapes were drying I started on the landing gear leg.
Left Landing Gear

Left Landing Gear


More Tape Detail

More Tape Detail- Note: Don’t copy my ring placement. I ended up having to add several more later.


The 1-inch tapes that I’m using on the stringers are very hard to keep straight. The stringers aren’t straight though, so using wider tapes might be counterproductive.

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

Building the Paint Booth

It will be time to start painting soon, so I built a paint both out of plastic and PVC pipe. I used 10-foot lengths of PVC electrical conduit, which was cheaper than the white stuff. I found a roll of plastic that was 10-feet wide, so that made for easy layout.

Paint Booth

Paint Booth


Update- The booth isn’t quite big enough. The 10-foot width is ok, but it really needs to be longer. I used 1/3 of a 10-foot piece for each of those bays, but I should have used 4 feet instead. That would have added an extra 40 inches to the booth. Afterwards I spent a few minutes to finish the rib stitching. My big bucket of covering supplies is slowly diminishing, and now I’m putting the rib stitch needles and thread away for the last time.

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Hours Logged This Session: 4
Total Hours: 1883.75

Polybrush on the Fuselage

It’s finally time to start putting some new colors on the fuselage. I wiped the fuselage fabric with MEK and then brushed on a coat of Polybrush.

It's Pink

It’s Pink


It's Pink from this angle too

It’s Pink from this angle too


Next I applied the reinforcing tape to the VS ribs.
Ready to measure for rib stitch

Ready to measure for rib stitch


Plastic Reinforcing Rings

Plastic Reinforcing Rings


Rib Stitching Done

Lower Rib Stitching Done


I finished the lower rib, and will pick up with the upper rib next time.

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.

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.

Envelope Continued

Today we continued with cementing the envelope.

Cementing the right side of the fuselage

Cementing the right side of the fuselage


Once the bottom was cemented for most of the back end, I did some preliminary shrinking on alternating sides of the seam to help smooth out the most severe wrinkles and make sure that we’d be able to get a good final shape.
Preliminary shrinking on the VS.

Preliminary shrinking on the VS.


Scrap Panel

Scrap Panel


I’m planning to finish this scrap panel with the whole process up to the final coats. That way we’ll have something to cut small patches from later on.

Installing the Envelope

Most of the fuselage fabric is in a one piece envelope from Jim and Dondi at Aircraft Technical Support. The envelope is made of two pieces of heavy duty fabric, sewn together so that a seam runs along the leading edge of the vertical stabilizer and the left top stringer. The best way to start was to locate the seam along the leading edge of the vertical stabilizer.

Note the clothespins on the leading edge of the VS

Note the clothespins on the leading edge of the VS


Then we draped the rest of the envelope close to where it was supposed to be, and gradually moved it closer to the final position.
Front of the Envelope

Front of the Envelope


As we pulled the edges down, these clothespins would have to come off

As we pulled the edges down, these clothespins would have to come off


Next we pinned the trailing edge of the VS

Next we pinned the trailing edge of the VS


One possible shortcoming of the envelope is that it’s just barely big enough to cover the right side of the fuselage. For someone who doesn’t have the cargo door, this envelope wouldn’t work. Of course Bob’s prototype is the only one I’ve seen without the cargo door.
Right side of the Envelope

Right side of the Envelope


Felicia checks out the progress

Felicia checks out the progress


Looks good!

Looks good!


We started cementing at the leading edge of the vertical stabilizer, then the trailing edge.

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.

Interior Covering Continued

Today I continued with the fabric covering for the interior. I divided the cabin area roof into four sections, with the first being as shown below:

Cabin area ceiling

Cabin area ceiling


I didn’t account for my back seat shoulder harness tab when I did this piece.
Shoulder harness tab

Shoulder harness tab


When I do the other side I’ll cut a small slot and slide the fabric over the tab during installation. On this side I’ll have to cut a pretty big hole to make room for the tab. It will be hidden behind a big reinforcing patch anyway.
Starting on the other side of the rear ceiling

Starting on the other side of the rear ceiling


Done with the cargo area ceiling

Done with the cargo area ceiling


This section of the roof is a concave shape- the only one on the airplane. That’s why I’ve arranged the covering into these triangle shapes. The next pieces will require some stitching to keep the panels from pulling off when I shrink them later.
This is what we came up with for the left rear window

This is what we came up with for the left rear window


Left rear window continued

Left rear window continued


The area around the front of those two big triangles gets a little bit weird because of the overlaps.
A wide piece of tape will cover this void, hopefully.

A wide piece of tape will cover this void, hopefully.


Next roof piece

Next roof piece


I’ve marked this triangle to fit in on the front section of the ceiling. This piece will go on as an overlap joint with cement, since there aren’t any tubes to wrap around.

Interior Covering

Today we were both out at the hangar to get started on the fuselage fabric covering. The first step was to cover the interior, since some of the interior pieces need to overlap under outside pieces.

Interior Covering

Interior Covering


Alan stopped by for a visit and some supervising.

Alan stopped by for a visit and some supervising.


We started with the easy pieces and went from there

We started with the easy pieces and went from there


This process of covering the interior is more time consuming than I would have thought.

This process of covering the interior is more time consuming than I would have thought.


After our work session I read back through Eric’s manual and saw that he was also bogged down a little with the interior covering. One tool that helped with trimming around the tubes was a little pair of scissors that I ordered from China. They have small, pointed blades that are spring loaded to the open position.

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.

Posted on
Hours Logged This Session: 5.2
Total Hours: 1883.75

Installing Stringers

I was glad to be done with painting for a little while, and ready to start reassembling things! I sanded the filler on the wingtip and applied a coat of gray automotive primer to check the progress.

The first coat of paint tells many tales

The first coat of paint tells many tales


I think it will do.

I think it will do.


I installed the stringers with long blind rivets. These were all aluminum and are very lightweight.
They were also fast to install.

They were also fast to install.


The other side

The other side


Here's the part number and specs from McMaster Carr

Here’s the part number and specs from McMaster Carr


This shot shows the notch to clear the fuselage tube.

This shot shows the notch to clear the fuselage tube.


Since we’ve decided to use the Dynon pitot tube, we’ll need to route static lines from the back of the fuselage. These static ports came from a kit that I got from Avery while we were in Oshkosh. The little aluminum plates will hold the ports in place.
Static Ports

Static Ports


Inside (left) and outside (right)

Inside (left) and outside (right)


Mounting holes ready to countersink and dimple

Mounting holes ready to countersink and dimple


Countersinking and dimpling done

Countersinking and dimpling done


Here's how the ports mount to the stringers.

Here’s how the ports mount to the stringers.


I put them close to an attach point so that they wouldn’t wiggle as much.

Next I routed the VHF navigation antenna feedline from the vertical stabilizer. I put a joint in the line so that we can replace the antenna if it doesn’t work, or if it quits working in a few years.

VHF Navigation Feedline

VHF Navigation Feedline


Here's the best way I could find to secure the coax cable

Here’s the best way I could find to secure the coax cable


I also did a few more pre-covering jobs, such as adding nutplates to the areas that are going to be harder to get to after covering.

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Hours Logged This Session: 5
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

Cleaning Stringers

This morning I shaped some of the filler from yesterday.

More Filler

More Filler

Over the past few years the stringers have gotten pretty nasty, and the texture of the paint was a little rough, so I cleaned them with some fine sandpaper. Now they are clean and smooth. This should help prevent catching and fraying the fabric when we put it on.
Clean Stringers

Clean Stringers


The stringers have taken a little bit of a bend already. If I were starting fresh I’d use the heavier stringers that Mark G. sells.

Posted on
Hours Logged This Session: 2.5
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!

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

Priming Continued

When I got back to the hangar today I found a few spots where the paint was a little thin. I also saw that the texture under the paint was pretty rough in areas where the sandblasting started and ended. I sanded those spots in areas where they would show, then sprayed another coat.

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Hours Logged This Session: 6.9
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

Wingtip Light Mount

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

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Hours Logged This Session: 1.5
Total Hours: 1883.75

Final Gear Alignment

Today was the day to bend the landing gear to fix the alignment. Here’s a picture of the measuring jig:

There's one small problem here

There’s one small problem here


Can you spot the problem with this arrangement? The right side sawhorse is in the way of the right axle. It’s going to be hard to get in there with the BATPISS to bend the axle. BATPISS is Russ Erb’s acronym for the bending lever. I forget what it stands for, but you’ll probably have no trouble finding it with a google search. I used a 1″ piece of black pipe that’s about 10 feet long. I put a snug-fitting piece of 4130 inside the axle, then put the black pipe inside of that. I dusted off the trigonometry to figure out how much travel I needed to have at the end of the bar to get the toe-in angle correct. This was really rather pointless, because the pipe flexed quite a bit. Part of what makes this job so complex is that the wheels need to be off while heating up the landing gear junction, but they have to be on to measure to see if the angle is correct. That means heating the junction, bending until it seems about right, waiting quite a while for the cluster to cool, reinstalling the wheel, and measuring again. Fortunately I only had to go through that cycle twice per wheel. I used a giant rosebud tip on the industrial OA torch that had a terrific flame- I didn’t take a picture, but it’s about 1/2″ wide and 4″ long.

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Hours Logged This Session: 2.7
Total Hours: 1883.75

Gear Alignment Continued

Today I was able to try measuring the main landing gear alignment with more sturdy steel angles. When I was shopping for them, I tried to find the straightest two in the store. The tiles on the store floor made a nice straight edge. Just to be sure that I didn’t have any bends in the angles, I repeated my measurements with several different configurations, and they all came up the same. The right wheel needs just a little adjustment, and the left wheel needs quite a bit. Felicia stopped by to see how things were going:

Felicia sizes up my measurement

Felicia sizes up my measurement


She says it looks like a lot of trouble. It is!

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Hours Logged This Session: 2.25
Total Hours: 1883.75

Main Landing Gear Alignment

Today I was able to start in earnest on the main landing gear alignment. I used three tiedown straps per side to make a rigid mount for the fuselage. One strap runs from the firewall station to the floor tiedown (which is right about where it would need to be to serve as a wing tiedown). Another strap runs from the tiedown to the tailpost. A third runs from the tiedown to the top of the fuselage, near the rear wing attach bolt. The same pattern is on the other side, so I was able to end up with a very sturdy fuselage position. The final strap runs from the top of the vertical stabilizer to the ceiling, and holds the tail up to a level attitude. One challenge of doing these measurements on a dirt floor is that it’s hard to make marks. The best solution that I could come up with was to use two sheets of plywood, attached to each other with 2×4 lumber. This simulated floor allows me to make a chalk line for the fuselage centerline. Fortunately I’m working in the part of the hangar where we put extra gravel so the left-right level is pretty close even on the bare floor. I removed the tires from the wheels and put the wheels back onto the axles, then positioned the main landing gear so that the wheels were spread apart as described in the information from Bob. In the process of trying to measure the toe-in angle, all that I’ve been able to determine is that the thin little aluminum angles that I have been trying to use just aren’t going to work. I need to get some beefier steel angles that will not flex when I try to measure with them.

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Hours Logged This Session: 3.5
Total Hours: 1883.75

Soda Blasting

This is the third and final day in my bachelor building binge. The girls have been out of town and my goal was to press on to get the fuselage primed and ready for covering. Unfortunately this hasn’t worked out for a few reasons. The first is that I’m out of reducer for the expoxy primer. This stinks, because I need to paint the fuselage right after it’s blasted. My original plan was to go rent a compressor and sand blaster today, but earlier this week I was talking with a friend who asked if I had looked into soda blasting. Soda blasting uses baking soda as a blasting media with equipment that seems very similar to sand blasting. The soda is not as harsh as sand, which means less likelihood of blowing holes in the thin steel tubing. I figured I should at least get a quote, which came to $100. That was less than I was going to have to spend to rent the other equipment, and that’s not to mention that I wouldn’t have to do the miserable job of the blasting.

I met the friendly blaster early in the morning and moved the fuselage out into the sun.

Ready for Soda Blasting

Ready for Soda Blasting


Soda Blasting in Action

Soda Blasting in Action


While he did that, I made some minor adjustments to one of the stringers. This one is the upper left sringer, which rubbed on one of the diagonal fuselage tubes. I cut a little relief out of the stringer with the Dremel:
Take a bite out of stringers

Take a bite out of stringers


Then I added a little dam of aluminum to help seal the area

Then I added a little dam of aluminum to help seal the area


The idea is that I’ll fill this hole with some epoxy to seal the bottom, then top it off with some Superfil.
Epoxy first

Epoxy first


Meanwhile, the kind blasting gentleman was through, and I was able to learn the second main reason why I wasn’t going to be able to prime today- the soda blasting wasn’t harsh enough. I don’t think it’s the fault of the operator, but rather the process. Soda blasting just isn’t suitable for prepping welded steel tube structures.
Soda Blasting Results

Soda Blasting Results


Note the little bits of oxidization in the low spots.

Note the little bits of oxidization in the low spots.


These were too hard for the soda to remove, but sandblasting would have yielded fresh, bare metal. I think the process is very well suited for paint removal- the blasted areas looked just like they did before I painted them with a temporary primer. This was a disappointing setback, but these have still been very productive days. I took the rest of the afternoon off and came back later in the evening to prepare for the landing gear alignment project. I would have preferred to get the alignment done before the blasting, but time constraints wouldn’t allow that this week. With my new delayed schedule, I can return to the preferred order and get the alignment done next. The first step in aligning the gear is getting the fuselage positioned at the right height and level in all dimensions. Then I need to secure the fuselage in that position so that I can make reliable measurements, and presumably be able to bend the landing gear without having the fuselage moving around. To start, I installed augers in the floor to use as tiedowns. These are in the right spot to serve as wing tiedowns later on.
Installing anchors in the floor

installing anchors in the floor


I also spent some time locating and adhering the position light mounting pad to the left wingtip.
Wingtip Position Light Mount

Wingtip Position Light Mount


I left the hangar in the wee hours of the morning, somewhat defeated, but only reminded that deadlines and goals need to be flexible with this kind of project.

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Hours Logged This Session: 4.1
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

Antenna Planning

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

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Hours Logged This Session: .5
Total Hours: 1883.75

Brake Lines

When I changed the configuration of the parking brake valve, my old brake lines became obsolete. I made new ones today out of 1/4″ 5052 aluminum tubing.

New Hard Brake Lines

New Hard Brake Lines


I also reinstalled a few more of the floor panels in the front part of the cabin.

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Hours Logged This Session: 2.9
Total Hours: 1883.75

Mounting the Fuel Flow Transducer

I’ve decided to put the FT-90 Gold Cube fuel flow transducer aft of the firewall, between the gascolator and engine. It will end up being right under the pilot’s left foot. The wires come out of the top, so I made a bracket that will provide some space between the floorboard and the cube. I wasn’t able to find much in the way of installation instructions for the FT90. What I did find explained the orientation (wires up) and suggested flex lines going to and from the sensor. I wondered if this would be necessary in a case where the sensor is rigidly mounted, so I emailed the manufacturer and asked. They said that the flex lines were intended to dampen vibrations that could cause erratic readings. Since I’m not sure if I’m even going to be able to use this sensor due to the flow issues, I’m going to install it for now with hard lines since they are available and more durable. If I get erratic readings, then I’ll know that replacing those lines with flexible alternatives will be the first step towards fixing them.

Fuel Flow Sensor Mount

Fuel Flow Sensor Mount

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Hours Logged This Session: 3.25
Total Hours: 1883.75

New ELT Antenna Bracket

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

Old ELT antenna bracket is out

Old ELT antenna bracket is out


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

New, much simpler ELT bracket is in


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

Lateral Offset


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

Overview and messy hangar

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Hours Logged This Session: 4
Total Hours: 1883.75

Control Cables and Fuel Lines

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

Sharp Edge

Sharp Edge


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

Dull Edge


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

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Hours Logged This Session: 10.3
Total Hours: 1883.75

Fuel Lines

Tonight I finished the left rear fuel line and started on a remake of the right front fuel line.

Right Rear Fuel Line

Right Rear Fuel Line


The latest guidance from Bob says to put the T joint as low as possible, so I moved it down a few inches. The Patrol actually uses a tab that attaches in front of this station to the longeron, which eliminates the need for the aluminum wedges that I needed to make, and also lowers this junction further. Because that station is sloped aft, that means that the lower right fuel line needs to be a few inches longer. The new right rear line is much straigher and better looking than the previous iteration.

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Hours Logged This Session: 1.2
Total Hours: 1883.75

Flap Cables

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

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Hours Logged This Session: 1.7
Total Hours: 1883.75

Prop Governor Gasket

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

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Hours Logged This Session: 2.1
Total Hours: 1883.75

Rudder Cable Decisions

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

New Rudder Return Spring Location

New Rudder Return Spring Location


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

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

Cargo Door Gas Strut

I cleaned up and primed the fuel line support that I welded on last time:

Bottom Fuel Line Support

Bottom Fuel Line Support


Then I made one just like it and installed it on the right. While I had the primer out I sprayed a coat on the intake scoop to see how my fiberglass work was coming along. Sometimes it’s hard to tell without a coat of paint.
Fiberglass needs more filler

Fiberglass needs more filler


As you can see, it needs more work.
Intake Scoop

Intake Scoop


This is one of those areas where the part is certainly airworthy, but if I spend more time sanding and filling, it will look much better. Next I started working on the gas strut that will hold the forward cargo door open. The aft cargo door is held open by gravity, so it doesn’t need a strut. I found some threaded balls to use on the ends of the strut, and though the front ball will bolt onto the door sill, the rear ball will have to attach to the door frame somehow. I didn’t want to weld the ball on, since there’s no telling what kind of metal it’s made of. This seemed like a good job for brazing. Being that I haven’t ever brazed before, I tried a practice joint with some exhaust scraps.
Practice brazing

Practice brazing


I heated both parts until they were just starting to glow, then applied the fluxed brazing rod as I would solder. It seemed pretty straight forward, so I moved right on to the real parts.
Brazed on ball

Brazed on ball


Here’s the end result:
Cargo Door Strut Installed

Cargo Door Strut Installed


Cargo Door Open

Cargo Door Open


I used a 10-pound strut, which was the smallest that I could find. So far it holds the door open, but that’s without the skin or window. If it doesn’t stay open with the extra weight of those items, I’ll get a 20-pound strut instead. Both have the same external dimensions.
Here's how it falls with the door closed

Here’s how it falls with the door closed


I’m planning to use a small section of aluminum between the skylight and the windshield. I cut the piece out of .020 sheet, and installed the GPS antenna.
Roof Aluminum

Roof Aluminum


I’m planning to bend the sheet at the red line, then insert that tab into the windshield channel. The back of the aluminum piece will go over the skylight front and will be secured by the same screws that hold down the skylight.

Riveting Baffles

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

Bearhawk Cylinder Baffle

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


Right Front Baffle Assembly

Right Front Baffle Assembly


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

Steel Strip


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

Ready to bend


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

Finishing the bend


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

Oil Cooler Continued

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

Filler on Windshield Fairing

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


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

96 inch-pounds for the 1/4″ case bolt


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

Oil Cooler Fittings


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

Still More Fiberglass

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

More Fiberglass

Today was a quick session. I added two more layers of fiberglass on the windshield and one more layer on the intake scoop.

Fiberglass Windshield Fairing

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

Contact Paper Mask

Contact Paper Mask


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

First 2 Layers


Trash Bag Layout Area

Trash Bag Layout Area


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

Exhaust Pipe Detail


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