Thursday, February 21, 2019

Canopy Parts (3)

3 hours

Tonight I assembled the canopy frame, which was pretty straightforward since the four holes were already all pilot drilled.  The frame is pretty rigid!  More than I expected at least.  Then I built most of the other little parts involved in the canopy installation.


Tuesday, February 19, 2019

Main Spar Tunnel & Misc Riveting (2.5)

2.5 hours

I reassembled the main spar tunnel and riveted those parts in.  I also riveted a few things I hadn't done earlier, like the upper gussets on the fuselage side panels and the seat support angle on each side.  Now there aren't many holes left in the side panels that don't have rivets in them!


I have no idea how I would have pulled these rivets without this handy little tool!



Engine Mount Bolts (0.5)

0.5 hours

I finally got the correct length AN5 bolts for the engine mount, so I put the plane on a sawhorse again and swapped them out one at a time.  I guess I forgot to take any pictures!



Monday, February 11, 2019

Aft Spar Carry-Through Installation (3)

3 hours

With the holes that fix the wings in position drilled, it was just a matter of getting everything riveted in place.  I pulled the aft spar carry-through out, and disassembled what wasn't already riveted previously, and deburred everything.  I riveted the shear angle on the bottom edge before reinstalling everything.


Riveting the shear web to the fuselage crossmember was pretty tedious given the lack of space, but it wasn't too hard.


I then reinstalled the attach angles and riveted them to the side skins.


Done!  I ended up swapping the long elevator pushrod to the left side of the idler because it cleared the hole better on that side, but otherwise I didn't run into any isssues.


Saturday, February 9, 2019

Wing Rigging (6)

6 hours

It's finally time to get these wings rigged!  I got a couple of helpers to come over and give me a hand this weekend, and we kncoked it out in about six hours.  That includes several coffee/pizza/beer breaks, and a quick trip to Home Depot to buy some longer drill bits.  Overall the process wasn't too bad.

We started by rolling the fuselage out onto the driveway, lifting it onto a sawhorse, and then leveling it in both directions.  Then we slid both wings into the fuselage.  It took a little bit of messing around to get them into position.  I had to file a tiny bit off of the fuselage side skin on one side for clearance in the spar tunnel, and we loosened a couple of the nuts on the aft spar carry-through to allow the aft spars to fit in a little easier.

Eventually we got both wings installed and I bolted the spars together through the three 1/4" holes that I originally bolted through when I mated the spars.  I pinned the aft spars to the carry-through with some temporary 3/16" lynch pins.



With the wings installed enough to support themselves, we set about taking all the measurements that the plans directed before drilling the holes for the pins that will eventually locate and retain the wings in the fuselage.  There are essentially four things to measure and/or check: centering the main spars in the fuselage, leveling the wingtips relative to each other, setting the angle of incidence, and checking the wingtip-to-tail distance.  Once the spars were mated, everything was spot-on except leveling the wingtips to each other.  We used a length of clear tubing taped to the wingtips and filled with water as a giant level to check this measurement.  Initially, the right wingtip was about 10mm higher than the left, so we filed down the delrin bumper that the right main spar rested on until both wintips were within about 1mm of each other in height.  This took a few iterations, but eventually I think we got it about as perfect as we possibly could.

Next it was time to drill the 1/2" holes that will locate the main spars within the fuselage.  This was actually pretty simple; since the main spars already had 1/2" holes drilled through them, all we had to do was insert the provided drill guide into one of the main spar holes, drill front-to-back through the aft spar tunnel with a 3/8" bit, remove the guide, updrill to 1/2", pin that side with a 1/2" pin, and repeat on the other side.  Then we re-installed the forward tunnel zee and all the associated brackets, and repeated the whole process drilling from back-to-front.  This was where we had to run to the store and get a longer 3/8" bit, since the overall assembly is pretty huge at this point!  Eventually we got the whole stack drilled to the final 1/2" size, and installed the big pins that'll hold the wings in.



Next was the aft spar.  This was actually more of a pain than the main spars!  The carry-through was already cleco'd into the fuselage when we started, and then when we installed the wings we pinned the aft spars to the carry-through with temporary 3/16" pins.  The next step was to install the brackets that fixed the carry-through to the sides of the fuselage.  In order to do that, we had to clamp the bracket to the carry through with everything in place, which was tricky in the tight space it was in.  Then I drilled and cleco'd the brackets to the carry-through and the fuselage side skins.  We disassembled and removed the carry-through and brackets, cleco'd them back together on the workbench, and drilled the 3/16" holes from the carry-through into the brackets.  Then we re-installed everything, and updrilled the 3/16" holes to 1/4".  This was the tricky part, since there wasn't any direct access to this hole to drill it directly.  I ended up removing the front half of the aft fuselage floor since it was still only cleco'd on (thankfully), and crawling up into the aft fuselage to drill the holes from back-to-front with an angle adapter on the drill.




With the aft spar holes drilled, the position of the wings was finally set, so we pulled them back off and put them away.  Now I can disassemble everything, deburr all the parts, and reassemble for the final riveting!

Wednesday, February 6, 2019

Wing Rigging Prep (2)

2 hours

I want to try and get the wings rigged this weekend, so I did everything I could think of to be ready for that.  I removed the forward spar tunnel zee and associated brackets, updrilled the three holes in the aft web for socket access so I'd be able to bold the wings spars back together, cleco'd in the aft spar carry through, detached the flap tube to provide access to the aft spar holes, created the delrin blocks that the main spars will rest on, and got the wings out of storage.  Now if I can get some helpers this weekend we'll be ready for the rigging process!





Tuesday, February 5, 2019

Stick (1)

1 hour

I never got around to installing the correct bushings on the stick assembly, so I removed it to do that.  While I had it out, I drilled a small hole and installed a grommet for the wiring to the push-to-talk button that I'll install later.  Then I re-installed the stick for good!




Sunday, February 3, 2019

Hours Breakdown #4

It's been quite a while since I tallied up how much time I've spent on this thing, so here goes:

General/Misc:        16.0
Tail:                        51.5
Wings:                  147.5
Control Surfaces:   45.5
Fuselage:              177.5
Controls:                21.5
Landing Gear:       14.5
Windshield:           16.5

Total:                    490.5

Saturday, February 2, 2019

Miscellaneous Riveting (1)

1 hour

Riveted a couple of things that were still cleco'd together for no particular reason.  First, the seam between the forward and aft fuselage, on the side panels:



Then I riveted the windshield skirt:


Tail Wheel Installation and Plane on the Gear! (0.5)

0.5 hours

With the main gear finally done, I slapped the tail wheel assembly on, and finally took the plane off its sawhorse for the first time ever!



Main Gear Alignment, part 2 (4)

4 hours

Back at the main gear again.  After some pondering, I decided I might as well use the full length of the gear legs and take advantage of the higher deck angle that they will provide on landings.  I tapped both legs back down to nearly flush with the engine mount, and then started working on setting the alignment.  This is the method I used to set both the toe angle and ride height at the same time:

1. Level the fuselage in both directions.
2. Clamp an 8' piece of angle (I used 1" x 1" x 1/8" aluminum angle from Home Depot) to the bottom of the lower longerons so it extends above both axles.
3. Clamp a ruler vertically to the angle so it extends down to the very center of the outboard end of the axle.
4. Put a level on the angle to check that it's horizontal, and a level on the ruler to check that it's vertical.
5. Measure on the ruler to the top edge of the angle, and that's the dimension that the plans refer to.
6. Repeat on the other side.

So that was how I set my ride height.  For the toe angle, I continued like this:

7. Install the little spacer sleeves on each axle that come in the kit.
8. Make some spacers out of scrap bar stock that are at least as long as the axles (7" was good), and thick enough to offset your straight edge forward from the axle to clear the weldment.
9. Find the most rigid, straight, at least 7' long thing you can (I used 2"x2"x1/8" aluminum angle from Home Depot...  Steel would've been better but they only had it in 6' lengths which isn't long enough).
10. Clamp the spacers to the angle stock, and then clamp the whole thing to the front side of both angles.
11.  Tap the axles forward or back until the spacers on the angle stock touch both the little spacer sleeve and the end of the axle.
12. Check that the angle stock is level in both directions.  Left-to-right probably isn't a big deal, but making sure it's level front-to-back ensures the angle is actually sitting on the front of both axles.

13. Then re-check the ride height again, since rotating the axles will change that measurement.

I went through many iterations of this, until I was satisfied that the ride height was equal on both sides and the toe angle was correct.  I ended up with one leg flush with the top of the engine mount, and the other one about 2mm up from that.  That gave me a floor-to-axle distance of 462mm.  The plans dimension is about 424mm, so that's almost 1.5" of extra clearance!

Here are a bunch of pictures showing the steps outlined above:

Measuring the floor-to-axle distance

The axle weldment is in the way of a straight line from the axle tip to the spacer sleeve, so you need a spacer thick enough to get your straight edge forward of that.  As long as the spacers you use are the same on both sides it won't affect the alignment.

Measuring down to the axle

If this piece of angle is horizontal, and the ruler is vertical, then that's the measurement!

Here's the spacer I used on each side to get my chunk of angle across the front of both axles without touching the weldments

Checking and rechecking everything many times!

If this angle is level front-to-back, that means it's on the front of the axles and not rotated partially underneath them.

I ended up with the right leg flush...

... and the left leg about 2mm up.
With all that geometry finally set, I drilled through the front of the engine mount into the legs.  This was a pain.  I needed a long bit to drill there since the engine mount itself partially block access to the hole, so my choices for drill bits were limited.  I found a random ~6" long 1/4" black oxide bit in my tool box that actually did a decent job, but it was only long enough to drill like three quarters of the way through the leg.  I have a long hex bit extension that worked, but I could only use bits in it with a hex bit on the end.  I tried a titanium "metal" bit that I had with a hex end, but it didn't work very well.  I figured maybe black oxide bits were the best bet, so I went back to HD and bought a long 12" black oxide bit.  That thing didn't work at all!  They had some other "hard metal" cobalt bits there, but they were short and none had a hex bit end so I couldn't use them.

Anyway, what I ended up doing was just use that random bit that actually worked as long as I could, and then suck it up and use the bit with the extension for the last part.  Eventually I finally got both holes drilled, but it took about an hour per hole!


Lastly, I installed the hardware!  I have heard these bolts can eventually break inside the gear leg under some circumstances, so rather than using just a cotter pin and castle nut, I bought bolts that are drilled on both ends (AN4H30), and safety wired both ends together.  Hopefully now if the bolt happens to break it'll at least not fall out.  I will probably do what some others have done and just plan to replace this hardware as part of each 100 hour inspection.  I might do the same thing on the lower bolts too, I just don't have the drilled bolts for that yet.