Servo trim tab

[Maxray]

My son just asked me why I don't put a servo trim tab on my Eagle.
Good question... He said he could easily make up an Arduino nano set up to drive a high torque 1/4 scale R/C servo with
a Potentiometer very cheaply. Since I have an Arduino set up to run my strobes and power to my GPS, I can't think of any reason not to.
Should be a pretty easy mod. Would eliminate extra cables and pulleys. He said he could put in a fail safe mode to center it in case of power loss.
Whatcha' guys think?

[ParQld]

I would be interested to follow this project. keep posting your thoughts. I think being able to able and centre the trim if there is an issue is critical.

[Maxray]

10-4, Will do ParQ!

[Sweet B]

The late great Brian Austein incorporated the same principles you are talking about. I 'm  looking to do the same thing as well. Use a three axis R/C autopilot attached to trim tabs to auto-level, hold altitude and maybe a little yaw control. Providing the inputs are gradual and you are able to maintain control at max defection of tabs you should be OK. My disclaimer:I'm not an engineer but I do all my own stunts. Check it out. 

[Maxray]

Excellent! Thank you!

[Sweet B]

More than happy to work collaborate with you if you'd like to go down this path.   

[sideband]

I had kicked this idea around in my head when I bought my CE plans. I'm looking forward to seeing this project. I'm more than happy to help where I can!

[Maxray]

That's great guys! I have ordered all of the parts necessary for this project. I will draw up a trim tab attachment in CAD
and make a prototype. I will post the videos on YouTube. 

[okdonn]

While I love the use of modern electronics to simply do things that used to be hard to do, I don't feel that the electronically controlled trim tabs are in the spirit of Leonard's designs. Perhaps a spring system as used by Steve Wittman in the Tailwind would be more in the spirit of the Eagles?
Of course, it's your aircraft, build it like you want ...

[Maxray]

A tried and true method for sure Don. Steve was a great designer. Thank you. However, that is the complexity and weight I want to get away from on my Eagle. I'm going for a simpler and lighter arrangement.
I drew up a sort of basic concept for how I will attach my trim tab/servo arrangement. Of course it will change as I go. I will use springs in the linkage.
Thanks guys!

[Kamcoman77]

I like your idea of a trim tab that can be added to the rear of the elevator. If the tab is not much bigger than 4" x 8" there may be no need for springs, unless that is for some sort of failsafe. Suggest the servo be inside the elevator (weather) and the trim tab horn be more in line with the hinge axis.

[Dan_]

I'm a big fan of Steve Wittman, also of John Monnett who was very close to Wittman. 

Monnett's first design was a formula vee racer (Sonerai I) (1968?) that I'm sure Steve had a lot of input on.  Since they both lived in Oshkosh and Steve invented formula vee.

The sonex trim system is very light, stone cold simple and takes away the complexity and expense of building a trim tab that can flutter and fail.  They even use it on the Sub Sonex jet...

[Maxray]

I like that mod Kam!

[Maxray]

Dan, the Sonex system has me re thinking everything! I have everything to make a clone of it. I like the
idea of a simple leadscrew and anti backlash nut controlled by a simple knob to adjust the stick position...
I may limit the Arduino to the strobes and GPS power....

[ParQld]

Here is a link to the Install of the Sonex Trim system