October 15, 2019

Torque Tubes Installation

I spent about 3 hours getting torque tubes installed – the majority of that time was making small adjustments here and there to ensure the tubes moved smoothly. To accomplish this, I had to grind down some of the slots that the tubes’ bushings fit into. I also put some effort into polishing the tubes where the bushings fit over, to minimize friction. This helped a little, but the bigger contributor to ensuring smooth movement was to ensure the slots were wide enough for the bushings to slide in without getting squeezed, and to make sure all the slots line up.

Flap and elevator torque tubes set in place
I used 400 grit followed by 1500 grit sandpaper (with water) to smooth the surface of the torque tubes that come in contact the Vesconite bushings. You can see how much shinier the surface is where I sanded!

I had to ask for help to figure out the purpose of metal bushings that are on some of the torque tubes. My guess was that they are used to secure the tubes in place so that they don’t shimmy out of the bushings. TAF was able to confirm this, and they provided this advice: “Please place the rivets 180 degrees or as much apart as you can.” Midwest Sky Sports had also responded to a post on Facebook where I asked the same question, and they came back with the same response, also adding: “the recommended qty of rivets per collar would be 2. Placed as equally to 180 degrees from each other as possible. In some instances having them directly across from each other can be difficult so do your best. Ensure there is not too much slop or movement fore or aft, but try not to make them so tight to the Delron bushing that it binds. M4 rivets is what is recommended.”

These are the aluminum bushings / collars on the torque tubes
Picture from TAF technical support, showing where to set a 4.0mm rivet into the torque tube and lock collar
Picture of where the other bushing on the joystick torque tube gets located and then riveted in place

I also asked TAF about some extra bushings that came in the subkit bag labeled Elevator Control Tube 2, specifically asking where do they go? They came back with the following answer:
“CT-BSH-008-X-A-0 Flap Connector bush is used for the same purpose on CT-PPE-015-C-C-0, CT-PPE-014-C-C-0, or CT-ASS-FLAP-002-X-A-0.”

So, in this case, the bushings go onto the end of part CT-AEL-002-C-C- (Elevator Torque Tube Short) as shown on page E7. However, in the picture they sent me (out of the finishing manual I believe), this tube is identified as part CT-PPE-014-C-C-.

From page 4a of the finishing kit manual – you can see the metal collars go onto the end of the short elevator torque tube (the one underneath the rear seat).

In my post on 23 Sept, I mentioned that I needed to remove a bunch of metal from brackets that lock the joysticks into place, but wasn’t quite sure what tool to use. Fellow builders on the FaceBook group recommended that I use a nibbler or a half-round file. I would up using both to do rough removal, and then a polishing wheel on a Dremel to smooth it out. I think the result is pretty good, and it now fits properly.

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