Stjohn's RV-7

3 hours.
Going through the construction manual and looking over all the steps sometimes reveals things that weren’t done by the quickbuilders, which is why it’s a really good idea to check their work as if it was your own. For one thing, I ran into the fun and exciting process of setting up the tailwheel spring mount, WD-409. This device comes partially assembled in the QB kit. The mount and spring are match drilled and the tailwheel fork is matchdrilled to the spring. What’s not done for you is installing the mount between the F-711 and F-712 bulkheads, a process which was definitely not easy, for such a simple task. First I had to heat up the mount to get the spring loose. I gave it a few licks with the propane torch and finally managed to twist the spring out of the mount. AFter the mount cooled down i was ready to try fitting it in the fuselage. Well, guess what. You have to drill out a bunch of temp rivets and take the F-712 out so you can drill the holes for the two keeper rivets that hold the mount in place while you drill the holes for the verticle stab bolts. And then, friends and neighbors, you have to get the thing back in. This is not easy. And there is a trick to it. For one thing, if you rivet the mount to the F-712 bulkhead first, you’re hosed. You won’t be able to get the bulkhead into the magic position that lets you get all the tabs inside the skins. Even then, it’s a really tight, nasty fit. Cutting the “mouse hole” where the tube sticks out of the lower aft skin makes it even worse. I wound up drilling off the rivets on the side between the F-711 and F-712 bulkheads, which helped a little, but it was still a royal pain. Methinks nobody brought this up when the qb kits went into production, and even if they did, it’s not like there’s much you can do about it. The WD-409 has to distribute its load between two bulkheads, because just one wouldn’t stand up to the stress of 3-point landings and taxi-ing down force for all that long. Of course, me being the dumbass that I am, misread the plans for the keeper rivets and wound up using 1/8 rivets instead of 3/32. No big deal, I’m sure, but those keeper rivets are going to stay kept.

Here’s the F-712 bulkhead clecoed back into place after my tender attentions with the drill.

This is the WD-409 mount after a coat of paint. The hole in the top is where the bolt goes through to hold the spring. It’s extremely important to get this vertical, because side forces on the tailwheel fork suck.

Here’s a shot down through the top deck. You can see the mouse hole down there in the lower skin, which is cut to clear the mount tube as it angles down and outward.

This is the section of the drawing that shows how it all goes together. One of the notes off to the side is “Some parts removed for clarity.” I wonder why.