Dynon Roll in Wing/TruTrak in Belly

I am looking at autopilots and was wondering if there is any difference in how each performs. Also, can you mount the Dynon on the belly by using a TruTrak bracket.

This is on an RV8A.

Thanks

Dynon and TruTrak servos are mechanically compatible and can use the same install brackets.

Trutrak brackets

Trutrack is getting tired of builders using their brackets for another company's autopilot. I just installed the Dynon/AFS servos in an RV8. Dynon only makes the wing mounted bracket kit for the roll servo. I thought this needlessly complicated in a flying airplane, so I contacted Trutrack to buy their center section bracket kit. $200!!!!

So I made my own. It is not difficult. Cost under $30 and used mostly scrap materials. Only problem is that you will probably need to TIG weld the tab on the bracket that attaches to the roll torque tube.

Trutrak has a actual size diagram of the bracket kit on their website so you can get all the measurements you need.

Jim
N37PK

Installing the Dynon roll servo bracket is terribly easy. Took me less than 30 minutes, though my wings are still on the stand (finished).

Does it make any difference where you place the roll servo? I have heard that it is better operationally if placed under the cabin, but do not know if that is true.
Thanks for the responses.

Shadetree said:

Does it make any difference where you place the roll servo? I have heard that it is better operationally if placed under the cabin, but do not know if that is true.
Thanks for the responses.

Click to expand...

Other than CG, I can't think of a reason why it would matter. Plus, I would think installation in the floor would be much more difficult. I know the trim servo was a PITA.

Shadetree said:

I have heard that it is better operationally if placed under the cabin, but do not know if that is true.

Click to expand...

On an RV-8 or RV-4 it does not matter.

On a side by side RV, a mounting the servo out in the wing is slightly better.

This is because it is very difficult to position the servo so that the
mechanical interconnect is directly on axis to the motion of the roll control system (servo pulling on the control column directly to the side). Because of this, it can be inducing a small amount of pitch input when it tries to move the ailerons in choppy turb., etc. Particularly if the airplane has a nicely set-up, low friction pitch control system.
Since the 4 and the 8 have a control column that rotates in the roll direction instead of the pitch direction like it does on the side by side RV's, inputs from a servo mounted inside will not effect pitch.

My Dynon roll servo with the Dynon install kit went under the copilots seat. Works great.