Fuselage panels

Another quick post to mention that I reinstalled most of the fuselage panels. Had to trim a little bit the side panels around the gear area since it shifted forward about 1/16".

Still need to install the cabane panel and bottom panel... The wall of parts on the left is getting empty. I like where this is going!

Side panel brackets

Flight tests at work being quite demanding lately, I can barely work on the Pitts. Last week-end, I had a few hours to work on the aluminium brackets that snap on the top longerons to attach the side panels.

They originally had nyloc nutplates. I decided to change them to all metal nutplates for multiple reasons:

- The rivet holes on the brackets were not dimpled, therefore the rivets were chafing with the aluminium panels

- Nyloc may not be reused if the nylon doesn't provide enough friction (AC43-13)

- All metal nutplates are smaller and lighter

Took me a few hours to drill the old rivets, dimple all rivet holes, dimple all new nutplates and squeeze all the new rivets in place. I used a hand rivet squeezer from my friend Scott both for doing the dimples and rivet squeezing. My friend Marc also helped in replacing the nutplates on the rear brackets. Thanks Scott and Marc!

Here is the new vs old nutplate comparison:

I may have to partially tap the nutplate threads as they are pretty tight. I'll see once I will try to reinstall the side panels. Here is the result once snapped on the fuse:

Will stick some anti-chafing tape on the brackets before reinstalling the panels. I'm thinking of replacing  nutplates also on the vertical braces (right of the above picture), but the access may be challenging for dimpling and riveting. 

Mission for next work session at the hangar: install the main fuel tank.

Sidelugs

One of the last steps of the welding process is to weld the sidelugs on the bottom longerons. I've contacted many local sheet metal shops to see if they could bend the 0.025" thick 4130 sheet I had. The bends required are close to each other and shops were generally reluctant in doing the job. I therefore decided to make them myself.

My initial design looked like this:

 

The original sidelugs did not include the step as you can see above. I needed to add this step in order to accomodate the new thickness change of the lower longerons. However, making this out of one piece with the few tools I have was a little complex so I decided to split it into two parts:

 

 

Had to make a holding tool to make sure that the metal was securely held in place. I used two pieces of 3/8 thick mild steel with a little radius on the corner of one of them. Here is what my bending setup looked like:

 

 

 

 

I used screws going through both plates to provide additional clamping force near the edges. The bar you see on the right is a piece of 1/2" thick steel I used to hammer the base of the protruding part of the sheet metal. It took a lot of effort to bend this only with a hammer. After two nights of work, I had the four pieces bent the way I wanted:

 

 

 

The last step before welding to the fuse is to trim the excess material used to clamp them in place. I left this job to my welder since he is going to determine their final location and might need extra length.

 

Next post will be about the final welding and if everything goes well, about the ferry back to my home airport!