I drove into Seattle yesterday and visited with another RV builder (he's building a RV7). It was nice to be able to take a look at a project that is a little further along (the RV7 fuselage is actually the same as the RV9). He is letting me borrow his longeron bending dies, which I put to use today.
First things first, I went back to the bottom aft skin to try to get it and the bulkheads shaped appropriately. This skin is very thick and it took quite a bit of bending, but I finally got it to the correct angle. After seeing the RV7 tailcone, I figured out that the two aft bulkheads I have are simply severely under bent, so I also bent those flanges so they match the skin angle better. I slid the J stringers out of the way and clecoed the skin into place.
After the bottom skin was in place, the 710 bulkhead was next. I looked at it and thought "this will just slip into place." Boy was I wrong. For being such a simple piece, somehow it was a bear to get in.
The aft two bulkheads, which I thought would be the tougher ones to get in, actually went in pretty easily. I did have to put them in and take them out a few times to get the flange angle bent to the skin correctly though.
I decided to give the longeron dies a shot with the second longeron (I'll still need to correct the first one I already started). The dies do exactly what my previous method did, but the difference is that they capture the top portion of the angle. This keeps the angle from bending out of plane so much when a curve is put in. It was 100x easier than the method Van's uses! I finished up with the main bend of the longeron in about 15 minutes. I still need to correct a tiny bit of out-of-plane bending that happened, but it was very minimal compared to doing it without the dies. The first longeron that I already started needs to be corrected yet. I'll try that tomorrow when I'm fresh on patience. Since it's already been bent in multiple planes, I'm still going to have to do the back and forth approach to inch in on the correct bend.
