Wing - Left Flaps and Ailerons
I continued assembling the left flap. Although Van's instructions say this is the easiest control surface to build, there are several things that can go wrong.
Problem 1 - I almost riveted the ribs to the bottom skins before I drilled the rear hole in the ribs and the bottom skins.
Problem 2 - Forgot to cleco the spacers to the end ribs before riveting.
Problem 3 - When riveting the inboard rib to the bottom skins, you cannot get a bucking bar on the rivet next to the platenut. I had to use a blind rivet after I mashed the original rivet.
Problem 4 - You need several MK-319-BS blind rivets on the bottom of the skins because it is impossible to get a bucking bar on the end rivets on the inboard rib. Van only supplies a few of these rivets. You will need quite a few.
Problem 5 - I almost riveted the flap bottom skin to the bottom of the flap spar without the hindge.
|Here's the flaps after the ribs have been riveted to the skins. Note, I didn't build the cradle for the flaps. I simply clamped two pieces of aluminum angle to the rear edge of the flaps. This kept the flaps straight and allowed the flaps to stand up for riveting. This worked good, and the left flap came out straight.|
|Looking into the flaps at one of the ribs. Don't forget to drill and rivet the hole at the very end of each rib where they fit against the lower skins. I remembered this at the very last moment, right before riveting the ribs to the bottom skins.|
|This is the only bucking bar that would fit inside the flaps to buck the last few rivets towards the end of the ribs. Same with the rivets along the bottom edge where the top and bottom skins are riveted. It's pretty tight in here, but not that hard to do.|
| Once you start riveting the end ribs to the top and bottom skins, you discover a few problems. First, it is near impossible to buck the rivet along the rib flange, next to the platenut. The right sequence would be to rivet FL-706B to the inboard rib, then rivet the inboard rib to the bottom skin, then rivet the platenut to FL-706B and the inboard rib. Or, you can just use an MK-319-BS blind rivet here, like I had to do. |
Also, those rivets at the end of the rib are not going to get bucked with any bucking bar that I have. As you can see, it is extremely tight in there. MK-319-BS blind rivets worked here, also. Van only gives you 11 of these rivets, and I used seven on the left flap.