Mon Jan 12 2009

Fitting gear weldments

Today I called Van's to discuss the fit problem I have with the gear leg weldment. Ken was very nice and we talked about the situation quite a bit, but essentially his advice came down to "beat the crap out of it until it fits...and use a shim if necessary." (Note that I'm paraphrasing here) Anyway, I didn't think that would come out very well, so I talked to Mark, one of the welders at work and he said he could help me out with making a modification to the flange. So once I made it down to the shop, I got out the die grinder and an abrasive disc and hacked the flange off.

With the flange off, I was able to fit the weldment without this arm pushing outward on the F-7101 web. I used the flange to draw some marks on the sides of the tubes and then sanded it to the correct angle.

Now with the tube sanded down, the flange just fits between the arm and the F-7101 web without preloading the structure. I marked on the flange around the end of the arm so that Mark would know the correct positioning. I'll ask him to tack it in place tomorrow. If it's in the right position, I'll bring it back and ask him to tig weld it all around.

After that, I figured it was time to get to work on fitting the right gear leg weldment. First order of business was to remove three nutplates. I also trimmed the threaded studs just like I did on the left side (but didn't get a picture of that).

Next, I trimmed the center section skin and flange of the forward F-704 bulkhead to clear the gear weldment. This took about six or eight fittings to get right. Much faster than the left side.

As on the other side, I needed to make some clearance for one of the rivet heads.

With the weldment temporarily in position, I can see that I'm going to have a similar (but probably less severe) problem with the flange that lays atop the F-7101 web.

I'm also going to have to open some of these holes up like on the other side to eliminate some small interferences with the rivet heads.