Forward Top Skin (3 hr)

Unseasonably warm here in Southern California, summer time temps on the coast and no lack of heat out here in the desert either. That said, the hangar was cooler than I had been expecting.

So today I needed to locate for myself the holes in the forward top skin which I was going to do by clamping it all together and then tracing around the firewall edges. After messing about with that for a bit and my instrument panel clamps keep falling off I realised that I would help myself by drilling the holes for the panel on the cabin frame.

Much more stable! Oh, note that the artist’s impression of the panel is old and not representative of actual future installed product. With that on, I re-clecoed the skin to the panel, clamped the front part to keep it all in place and then drew a line under the skin where it touched the firewall. I did this on the inside as well, and I did my best to mark where the crimps were so I could avoid them.

I took the skin off and laid it on the table so I could mark some hole locations. In the meantime I believe a small child entered the hangar and drew all over the skin.

So, yeah, not precision engineering here but, from the finished product, I actually did a pretty good job of going down the middle of the firewall edge, and I didn’t come close to a single crimp. Here is the top skin pilot drilled to firewall and longeron.

Note that the rivet lines don’t go far enough along towards the front so I extended the rivet lines and drilled a couple more holes on each side. Next I pilot drilled the cut out piece in place on the firewall.

I’m not entirely happy with how that piece looks. I may make a new piece, of a different shape, from some scrap before the final rivets are put in.

Next up I had top cut four l-angle pieces to go inside the skin to act as a stiffener. The holes are pre-drilled in the skin so I just had to get the right lengths, position the angles and back drill. This day really was like the fun old days of drilling, snipping and drilling again. If I’d had a second person in the hangar I could probably have done this on the plane but there’s no way to hold the angle in place while looking over the top for the alignment. So I took the skin out and installed the angles on the bench.

Yet another reinstall of the skin and instrument panel (after deburring all the skins) and I could reach under the assembly to put the angles in place, cleco, and then drill to final size. A couple of them needed a bit more snipping but other than that they were a good fit. I put a few crimps in so that they better matched the shape of the skin and that completed the forward top skin.