Aileron Servos in the Wing

[Kurt Bozarth]

For those who have had success with outboard ailerons servos holding up in the wing, what servos are you using?

Kurt

[GaryS]

Jim Allen and I have both been using Futaba S3174SV's without issue in our Stregas. We also didn't have issues with our Caudrons, but neither of us got a lot of flights on them. I wouldn't suggest doing outboard servos with plug-in wings like the Dara's, as I did have aileron servo issues in mine.

[Hanknsd]

Hey, Kurt.
This was right under your nose.
Hank D

[DHG]

Kurt,

I use the KST DS135MG, same as Chuck Andraka recommends, or the Turnigy equivalent (somethingsomething 177, if I recall correctly). This is a metal-case, metal-gear digital servo with 3 mounting tabs.

Some mods are necessary. Open the case and dab E-6000 on all the wires wherever they come close to something, so they're more or less glued in & can't vibrate. There's already some kind of white gummy stuff on the solder joints, which is good, but adding E-6000 in more places is better. Then open up the holes in the mounting tabs to 5/32" using a titanium drill bit, and use a reinforced Dremel cutting wheel to make a 3/32" slot between the hole and the outside so you can squeeze a grommet through the slot & into the hole. Then mount the servo to your plywood mounting plate using normal servo screws and brass eyelets, taking care to ensure that nothing except the grommets are touching the case.

For some reason there's more vibration outboard on the wing than there is at the center section, closer to the engine. Maybe a physicist can explain that. I had to quit flying my new Estrellita at the Nats because I lost aileron authority; after some troubleshooting I found several blobs of glue and one plywood rail touching the servo case(s). After I got home I relentlessly scoured & sanded the bays and remounted the servos with new, fresh grommets and eyelets that were matched to the thickness of the grommets. The servos checked out so I didn't swap them out but just reinstalled them. I flew the airplane 3 times yesterday and all's well so far.

I really like the lightweight, direct linkages you can use with wing-mounted servos plus the ability to mix for differential, snap flap and landing flap functions. But the cost of that seems to be extra attention to mounting.

Maybe TMI here but I thought I'd share a little knowledge as well as the servo recommendation. Good luck!

Cheers,
Duane

[ceandra]

Duane:

The KST-135 is not suitable for LiFe voltages. It works fine on 5-cell NmHi. The X10-mini replaces it and is a wide voltage servo.

Chuck

[Kurt Bozarth]

Thanks guys for all of the great information!

[fizzwater2]

Hey, Kurt.
This was right under your nose.
Hank D

Hank - where did those nifty mounts come from?

[Hanknsd]

http://www.soaringusa.com/Servo-Frame-S3150.html