Empennage

The Empennage is done except for the fairings. There is definitely a tendency for the counter weighted stabilator to enter climb, but this is apparently normal at this stage. I used the Sky View ADAHRS F000011 template to drill and then rivet the new Sky View ADAHRS brackets to the old version of the top skin.

Fig. 1. Template F000011

I also installed the new improved trim tab wiring harness.

Fig. 2. Tail feathers awaiting AS Tabs.

Beware of trapping the rudder control string between the tail cone and vertical stabilizer.

Fig.3. Vertical stabilizer attached to the tail cone.

Fig. 4. AS Tab installed.

Once the AS tab was installed, the stabilator is almost balanced.

Fig. 5. Piano hinge wire safety wired. I ended up using stainless steel safety wire available from VANs.

The piano hinge wire was fairly easy to insert using a touch of silicone spray. Consider inserting the final wire from below :).

Fig. 6. New version of the servo tray with quick connectors.

You may need to use progressive larger drills to final drill the 1/4 inch openings for the bushings. You can use a C clamp and then a vise and a socket to press fit the plastic bushing into the 1/4 inch (0.250 inch) openings. Use the #27 Plastic Drill when match drilling the hole through the servo motor base.

The new wiring uses Molex micro-fit pins which are opened barreled. The wiring from the trim motor is 26 gauge. Here is a tutorial and another on crimping molex pins which require a special tool pictured below:

More detailed information on the GC/Waldom and Sargent tool is available here. I used a single edge razor blade to strip the insulation from the wire. I was not happy with the width of either crimping tool relative to the size of the Molex micro-fit pins used in the RV-12 trim motor connector.

I messed up squeezing the 3/32 (AN470AD3-9) rivets holding the threaded insert into the push-rod. I would recommend doing this step first, before riveting the clevis plates, just in case you also mess up. Part of the problem is that I tried to use an 1/8 inch rivet cup on a 3/32 rivet such that the cup head marred the push rod. The other problem is that I removed the second rivet before setting the first rivet. I could not insert the second rivet after squeezing the first rivet. Things went much better the second time using a 3/32 rivet set and leaving both rivets in place before riveting. Note that placing the opposing rivet holding the clevis to the push rod is more difficult than placing the first rivet. This is due to the fact that there is not enough room inside the push rod to allow the opposing rivet to be fully inserted before pulling the second rivet. Setting the second rivet with a steady downward pressure does work.

You may need to do some fine trimming of the spacers to attach the trim motor tray to the empennage. I was able to motivate the trim motor by connecting the trim motor to the empennage wiring using the quick connection and then touching the white wires at the forward end of the wiring to a 12 volt motorcycle battery. It is pretty cool to see how the AST works as you move the horizontal stabilator through its range of motion.

It was not clear to me from the drawing how to double tie the wiring. Tie wrap the reinforced area of the empennage wire that protrudes from the tail, capturing a second tie wrap in the first tie wrap. Finally, pass the second tie wrap through the provided hole in the trim motor bracket and secure the wiring without any abrading of wire on metal.

After installing all of the tail feathers, I was chagrined to read that I needed to remove them all to install the fairings. I removed the feathers and stored them with the tail cone at my airport hangar. I ordered all new bolts just to be safe.