Finish elevators - 23/08/2011

Work continued on the rolling of the left elevator.

You may remember that I completely messed up during the weekend on the rolling of the leading edges. Large openings, insufficient bending, curtain style match between the skins and last but not least, some serious dents in the skin by trying to bend with the pliers.

My girlfriend came up with a fantastic idea on removing the bumps from the skin. She used a marble (and a lot of patience and strength) to roll out the bumps. The marble will not create new bumps as it's surface is round and nicely follows the contour of the already made bend. Just push locally when the marble passes over the bump. It requires a lot of strength in the fingers to do so but the result is really remarkable. The bumps have almost completely disappeared.

The star with the marble:

For the first time since the build started, I have deviated from the original plans. The picture below shows then front side of the left elevator where the electric trim engine is installed. The electric engine has a threaded push rod that moves in and out of the engine and meanwhile makes the actual motion of the trim tab. On the plans, the threaded push rod that moves out when the engine is completely pushed in share the same hole as the electric wires to control the engine. Threaded rod and electric wires through the same holes sounds like suicide on the long run. It may not happen right away, but be sure that at some point in time, the wire will scarf the rod and might create a short circuit, or blockage of the motor. You can only hope the trim is not at full extention at that time.

To avoid such problems, I decided to surf other builders websites and found some people that had the same scary ideas about this as I had.
The best place to put the additional hole was in the lightning hole of the elevator horn. I drilled it for a SB437 snap bushing. The snap bushings seemed a little loose to my likings and I added a bit of RTV to secure them in place.

View from the front:

View from the inside:

I then continued to roll the leading edges using the PVC tube I used before for the right elevator.

This improved the original bends quite a bit. However, they were not perfect yet.

I first tried to 'massage' the edges in an attempt to make them flatter. This is hard and painfull to the hands.

Finally came up with a better alternative. Using a small plier (flat jaws used for electricity), I was able to slightly bend the edge of the outside edge skin on the last 3 to 5 mm so that it pushes nicely to the other skin when pulled in by clecoes.

Finished it of by drilling the 1/8 holes and installing the AD-41-ABS pop rivets. Two of them don't sit completely flush to the skin so I might drill them out later.

Once the curve it made, I installed the rod end bearings. There are a lot of examples for tools that help with installing rod end bearings but I used something much simpler that I found on the site of David De Ridder. David all credit goes to you on this one.

Use the cleco pliers and take a piece of cloth to put between the rod end bearing and the cleco plier. It works very wel and the jaws of the cleco pliers fit nicely around the ball in the rod end bearing.

Once that was completed and measured to 13/16", I torqued the 4 nuts on the counterweights of both elevators to 25 lbs/inch and marqued the position of the nut with sealant lacquer.