January 16, 2006

In the right wing, we needed to mount the autopilot servo. Here’s the start of the basic design. The end plates are 0.063", and the angles are 3/4"x3/4"x0.063". There’s an angle piece at the far end too, but it’s not on in this pic.

This is the plate that it will mount to. The plate will be riveted to the wing rib, then the angles will screw to the plate.

Here’s the pushrod. We were experimenting a bit with the pushrod hole positions, and settled for the one closer to the pivot. It took some working out to get the swings right, as you don’t want the servo to over centre.

Here’s the servo’s first mounting in the wing. Now, access is going to be fun when the skin is on. Ultimately, the mounting plate will have a cutout in it around the first rib lightening hole. The whole contraption can the be unscrewed from the access bay and slid through the lightening hole and out of the access hole. I know it’ll fit, coz I’ve already tried it with the skin off!

Here we are all riveted and screwed into place. This is pretty rigid, and will be even more so when the lower skin is on. It ain’t going anywhere in a hurry!

Here you can see the safety tab which is there to prevent the arm coming off if something comes loose. You have to be really careful here with the tab, because you need room for the arm to swing through the appropriate range of motion.

Another shot of the arm end.

We threaded the conduit through the holes we made previously. This was fun. The conduit is actually 3/4" OD irrigation tubing. Its smooth, a little flexible and light. Perfect for this application. Available from the aviation isle at Home Depot (Orange Hell). In this pic, the wings are almost finished.

Stuff left to do… Countersink the rivet holes on the main spar, and put the skins on. Here, the skin is just clecoed and hanging in place. You didn’t think we were done did you?!

I got Dave to make soem rings for the aileron pushrod boots. While he was busy doing that, I countersunk the spar.

And put the wiring in for the aileron servo. I had to cut the cable to do all this. The joints will be made inside the fuselage. There are 12 wires inside the sheathing. I labelled them all before cutting them!