12/31/2010 - 6.5 hrs
Day 1 of a planned busy weekend in the workshop actually panned out. I got started by working on the end and counterbalance ribs (E-703 and E-704) for both elevators. I was able to do the customary edge finishing and fluting on all four ribs. I decided to do these first because I want to be able to cleco the skins to the skeleton. These ribs are the only ones in the elevators that need to be straightened so I can do that.
But before I can do that, I need to bend the trailing edge so the angle of the upper and lower skin matches the angle of the ribs that support them. This needs to be done on both elevators. Van's was nice enough to provide a rough drawing of a simple bending brake in the preview plans. So I headed out to Home Depot for some 2x8's, door hinges and wood screws. After a little bit of work, here is what I ended up with.
With the bending brake done, it was time to bend the elevator trailing edges. Thanks to Mike Bullock's www.rvplane.com site for the excellent tips on how to get this done right the first time. His advice saved me a lot of what would have been wasted time. I set the angle pretty much by eyeballing it next to the ribs that create the final angle. His advice to place the trailing edge almost back to the hinge really did the trick. Although I didn't need to lean on it with a ton of force to get the trailing edge bent to the correct angle. But it did take me a couple of tries to get the angle correct. I was worried if I applied to much force that I would either crease or crack the trailing edge. Once I got the angle close to what it looked like it should be, I would do a quick trial fit of the rib making sure the area near the trailing edge wasn't bowed in or out.
After the right skin was done, the left skin went much easier since I had an idea of what needed to be done. But here you can see how they turned out. The ruler is laying relatively flat on the skin. It's not perfect as there is a small gap towards the middle of the skin but I'm going to call this one good enough for now.
Now time to cleco the skeleton together for the right elevator. Parts were put together in the following order: E-704 counterbalance rib to E-703 end rib. Then that assembly to the E-702 spar. Then finally the E-709 root rib to the spar. Then I slid the skeleton into the skin and clecoed them together.
The process then moved over to the left elevator. It was very similar to the right one except the cutout for the trim tab results in the interior root rib being shorter so it can attach to a small spar that is needed to support the skin directly in front of the trim tab. In the picture below, you might notice the counterbalance rib is missing. When I did a trial fit of the counterbalance skin, the holes didn't line up very well. That meant I have some more fluting to do to get the skin to fit better. I had just removed the skin and counterbalance rib when I took the picture.
With a good part of the initial assembly done, I decided to call it a day and start fresh tomorrow.
 |
 |