Very excited!! Got the Arduino based trim servo working! #builditflyit #CH750STOL #dreambuildfly


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Comment by Jason R on January 31, 2020 at 7:06am

It is being used to control the elevator trim servo on my scratch built Zenith 750 STOL. It will also control the LED trim indicator on the panel.

The reasons are many but primarily I was looking at alternatives to the RayAllen trim system which is north of $400.

This led me to high torque/energy R/C servos, which will work, but require digital input and some simple programming to control and slow the servo speed. The digital control allows me to move the trim incrementally up or down but also allows for single button neutral reset. It also allows for digital output of trim position and movement, which can be displayed in the the cockpit. Currently I plan on a simple LED bar graph display like the RayAllen, but theoretically the output could be sent to a glass panel for display I suppose :)

Taking the concept further, I plan on a power up self test routine, loopback function verification and post shutdown neutral reset of the trim. Wig Wag landing lights are on my list too, likely as part of a full lighting package - landing, taxi, strobes, position, etc. The ideas are endless.

All told, I have about $20 of materials into the system so far and expect to come in well under $100 by the time it is up and running. I suppose I've got much MUCH more invested in lost sleep over it, but that is why I got into this project - to learn something new.

You can have a look at this video I posted in my blog to see an early version in action:

Comment by Kevin Powell on January 31, 2020 at 12:06am
Jason: interesting! Would you tell me more... why an Arduino to control elevator trim ?

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