how to go about an airplane electric trim thumbwheel

spencer's picture

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Joined: Oct 23, 2021

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how to go about an airplane electric trim thumbwheel
October 23, 2021 - 11:10pm

Hi,

I'm trying to figure out how to put together a yoke mounted electric trim thumbwheel for my airplane. As of now there is a momentary thumb paddle style switch-- forward push the trim tab goes up, reverse trim tab goes down. (The trim tab on an airplane just controls the pitch of the airplane on a very fine scale, just like pushing or pulling on the control yoke but millimeters at a time.)

I've seen a lot of thumb wheel switches but they are return to center style. I don't like the paddle style switch and prefer the tradional feeling of being able to flick the wheel- so to speak- to adjust the trim. The switch just controls a simple servo that actuates the cable/pully system that adjusts the trim tab.

I'm pretty ignorant when it comes to electronics. Is there a way to do it in just a electro-mechanical way? Maybe a hall effect rotary wheel or something? The crux to me seems like it would be having the switch be able to diffienterate forwards and backwards regardless of position and also open the circuit after the trim tab has reached its limit of travel, so the servo doesn't keep trying to move the cable when it can't anymore. I'm just looking for a basic idea on where to start. There is a lot of stuff on flight simulator trim wheels, but that is all arduino/digital stuff.

Long question I know-- anyput input is much appreciated.

Sourav Gupta's picture

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Joined: Feb 12, 2018

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Can you share some images? So it will be better to understand?

spencer's picture

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Don't know if I'm too late, sorry it took so long to get back to you. Please excuse my awful drawing. I hope this helps. Thanks!

 

electric_trim_0.jpg

Sourav Gupta's picture

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Joined: Feb 12, 2018

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I am not sure if you can achieve this without the digital system. mommentary paddle switch is easier to interface as it will not produce a lot of data or has resolution. But for the thumb wheel it is quite difficult to achieve.

spencer's picture

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thats what I thought, thanks for taking the time!