Lower boot cowl extensionÂ

[Nev]

Here are some pics to show how I attached my lower boot cowl extension under the doors. The kit comes with a small aluminium skin the runs back halfway along the door. I decided to replace it with a full length piece that runs to the door rear upright. The fuselage fabric will terminate on the door former under the skin. The only real issue was how to attach the underside of the aluminium skin to the lower longeron, which I’ve done using Adel clamps with tinnermans. I’ll add some adhesive to the tinnermans to keep them in position if the screws are removed. It was a simple solution that didn’t take long to install. The lower belly fabric will sit between the aluminium skin and the tinnermans (the screws will go through the fabric).

Comments and feedback welcome.

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[whee]

I like having the aluminum the full length under the door. I never could figure out what the deal was with the half panel of AL.

I don’t like the idea of the screws going threw the fabric but I’m sure it would be fine. I put my fasteners in from the side, ie the adel clamps would be oriented vertically.

[AKKen07]

I did it similarly, but welded tabs for rivets instead of screws.

[svyolo]

I am going to TIG some tabs probably, but I was trying to think of a different way to do it with Adel clamps. Maybe orient them vertically like Whee suggests, but have the vertical edge of the clamps flush with the inboard side of the longeron. Use them to secure a bent piece of .025 or .032 angle. Have the fabric ride over that angle to wrap the longeron, and the boot cowl piece attaches to it with nut plates. I have some scrap I might try it just to see how it looks.

[svyolo]

Another thing that I thought about using was some little homemade Adel style clips that I made a bunch of to hold the interior panels. I used .020, wrapped them around a tube about 30% smaller to form them, and used a nut plate to hold the whole thing together, and tight against the tube. A bit of 3m 5200 to keep it from slipping. They mostly turned out really good. On one of Rob's videos I saw he used something similar on his wing root interior panels.

.020 is probably too thin for holding the boot cowl panels, but I think I can use 3 or 4 each side, made out of .032. I will make them slightly wider to give me room to use a few rivets to hold them together a bit more securely than just using the rivets for the nut plates keep them together.

The .032 is a little tough to bend around a tube by hand, but the second one came out OK. 2 or 3 dimpled rivets plus a #6 nut plate will hold it together. You can get a 270-290 degree wrap around the tube for a fairly tight fit, plus some adhesive to keep it from moving.

[sjt]

Could you tell me who Rob is that has videos?

[robcaldwell]

Hello!! 😁

[Nev]

Here you go:

https://www.youtube.com/c/BearhawkLife/videos

[Nev]

Maybe orient them vertically like Whee suggests

Yep I agree, Whee’s idea is a good way to do this.