Mon Apr 26 2010

Fitting elevators

Today it was time to drill the holes in the elevator horns which will connect the pushrod to the elevators. I located the aft-most elevator horn (the left one in my case) and drilled a #40 pilot hole per the dimensions in the plans.


Prior to removing the elevator, I had measured the distance between the two elevator horns. It was 0.930 inches. I didn't have any oak that thick, so I found a piece of 5/8 thick oak flooring, cut it in half, and glued the two halves together. I'll cut this down to the correct dimensions once the glue dries.

Whle the glue was drying, I ran back over to the hobby store to pick up the next two sizes of brass tubing. You may recall I had previously made the three drill guides on the left. The two new guides on the right will allow me to drill through the center bearing on the horizontal stabilizer. Notice the right tube has been polished on the outside. I needed to turn it down to about .249 for it to fit into the bearing.

I also made a handy dandy bolt installation tool. Hopefully this makes it easy to install the elevator pivot bolts.

Once the glue was dry, I planed the oak down to the correct thickness.

Using the drill press, I drilled a #40 hole perpendicular to the surface...or so I thought. Apparently my drill press has enough wobble that this first hole was drilled at a slight angle.

The second attempt worked better.

Then, with the elevators reinstalled and the block clamped between the two elevator horns, I used my long #40 drill bit to drill through the opposite horn. Afterwards, I removed one elevator, used the drill bushings to create a pilot hole through the bearing and one elevator horn. Same for the other elevator. The holes for the bearing as well as the pushrod were opened up with each elevator removed. Let me just say the L pins I made for fitting into the pivots are really working well. It's very quick to install and remove the elevators. Very important when you're putting them on and off multiple times.

I got the elevator pushrod out and set the bearings to the dimension as indicated on the plans.

With the pushrod attached to the elevator horns and the elevators held "in trail", it took a few iterations to adjust the rod end bearings until the bellcrank was vertical. Notice I'm using a socket to locate the bottom bolt relative to the access hole in the center rib.

With that dimension set, I torqued the jam nuts (105 in-lb) and applied torque seal.