3.3 Hours -
The second sentence on the flaps section of the instructions states, “The flaps are the easiest control surfaces on the RV-7/7A to build.” I’m going to have to strongly disagree with this statement. In fact, I would say that they are the most difficult. It’s not that they are complicated, but there is a fair amount of fabrication, and the instructions are the vaguest instructions thus far. Because of this, I had to take a few steps back today in order to complete a few things I missed (actually, I didn’t miss them, the plans just weren’t clear on when they needed to be done!).
I still needed to finish the fabrication on the FL-706A angle and the FL-706B plate. The angle needed five holes drilled in it and then it needed to be matched drilled to the spar.
I drilled 5 holes in the FL-706A angles per the plans prior to match drilling to the spar.
The rest of the holes in the FL-706A angle are drilled using either the spar or the FL-706B plate as a guide.
Once the angle was in place, I turned my attention to FL-706B. These plates need to have a slight bend put in them. The plans call for one to be bent up 6.3 degrees and the other down 6.3 degrees (this creates a left and a right piece). I’m not sure why they don’t say 6 or 6.5 degrees…who’s going to be able to get 6.3? Even with a digital level, like I’m using, it’s not that accurate. Even if the display reads 6.3, it’s not exactly 6.3. Anyway, I clamped each plate into my vice and used some wood scraps to gain leverage on the part. In the end, I had one bent to 6.0 degrees and the other to 6.2 degrees on my digital level. Once the plates are clamped to the rib/spar, I’ll be able to finesse them further if needed.
The FL-706B plates need a slight bend...the plans call for 6.3 degrees. This is my bending setup.
6.2 degrees on the digital level should be close enough. The other one came out to 6.0.
Next, I drilled the plate to the inboard rib and FL-706A angle. I had to do this with the spar and ribs clecoed to the bottom skin so that I would know the inboard rib was at the correct angle to the spar. The angle of the plate matched the rib perfectly. Once the plate was drilled to the rib, I enlarged the aft hole to 1/4″ for the AN4 bolt that will attach the flap to the actuator. I also drilled the holes for attaching the nutplate using the nutplate as the guide.
FL-706A & B are drilled to the inboard rib and spar.
The aft hole on FL-706B is enlarged to 1/4" for a nutplate.
Fabrication of the left flap is pretty much done now, so I disassembled everything and deburred the holes in all of the parts except for the skins. I also countersunk the bottom of the spar. The spar is countersunk to accept the dimples in the skin, and the hinge is left untouched.
The bottom side of the spar is countersunk to accept the dimples in the skin. The hinge isn't countersunk or dimpled, but I used it as a guide for the countersink cutter.
Next, I built a flap assembly jig to help with riveting the flap together. For this, I just screwed a couple of pieces of scrap wood together, traced the outline of one of the outer flap ribs, cut the v-shape out of both pieces simultaneously, and then attached each piece to a base. I was able to reuse my aileron assembly bases as the bases for the flap assembly jig. Although I’m calling it a jig, it is really nothing more than a stand for holding the flap in an optimal position for access during riveting.
I also made some v-brackets to hold the flaps during riveting. I screwed to pieces of wood together so that I could cut both sides at once.
The bases for my v-brackets are the stands I used for riveting the ailerons.
Finally, I wrapped up the day by removing the blue vinyl from the skins in order to prepare them for finishing.
The last thing I did for the day was to remove the blue vinyl from the skins in order to prepare them for deburring and edge finishing.
