Trim wheels
Rotary encoder
Interfacing circuit

Rudder and Elevator trim wheels

The rudder and especially the elevator trim wheel function is a very nice addition to the cockpit controls. Since elevator trim is used a lot, I have tried to make it come (somewhat) close the the real thing found in light aircraft. The whole assembly is mounted below the throttle/prop/mix section, and elevator trim is quite easy to reach. Rudder trim is somewhat low, as I needed to place the small keyboard for radio frequency input as well.

The trim interface is via rotary encoders, to a pulse shape circuit, to the keyboard trim up/down/left/right keys. Update: I suggest to use MJOY-16 interface for rotary encoders.

For the elevator trim, there is a small gear section that makes the turn sensitivity more realistic. Rudder wheel is directly mounted to the rotary encoder. The wheels need some friction, so I used dishwasher sponge (don’t laugh) in between the wheel and the wooden frame.

Rear view drawing of the trim wheel section

Update I:

In the Simpit construction I had to move the trim wheel to the left side. This construction is shown below:

Trim wheel is placed next to throttle handle. The rudder trim has been omitted. Same gear and rotary encoder is used.

Update II:

I have added electric trim function to this construction.



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