I echo Wayne's reply! You can't have too much mechanical advantage. I try to keep mine at least 1:1 which (I though) was fine since I always use 'overkill' servos. However...I lost a GSP Katana earlier in the year due to what could have been flutter...impossible to tell. The servo was a HS 5925, 1 1/8" arm (center to last hole), CF rod, Nelson ball links, Robart 1" horn...with the thickness of the surface at the hingeline, the connection point of the horn was about 1 1/4" - 1 1/2" below the hingeline. I 'thought' that I had plenty of mechanical advantage, but I KNOW I didn't have as much as I could have. Really, I think in a panic I oversped the plane...but it's all water under the bridge...somewhere in that water is my OS 160 / VP30 pump / BCM Pitts muffler / Mejzlik prop / TruTurn spinner. Lesson learned. The radio gear survived and the aileron servos were not stripped.

Seems the current trend (at least on the last 3 ARFs and 3 kits I have built) is to have enormous ailerons. Typically I set up my radio and linkage to provide the maximum amount of travel allowable for rudder and elevators...but if I apply the same practice to the ailerons I ALWAYS have more aileron than I can use. Typically my third aileron rate is reserved for the guys that ask 'How fast will it roll?' (I'll click up to the third rate, show them, their response is usually 'Holy $h!t')...other than that I never use it. I could gain some serious mechanical advantage by having the throws in my second rate be the mechanical max.

Another consideration is servo resolution. It's wise to always adjust your endpoint adjustments to the max (providing maximum servo rotation) and go back from there to even out throws if needed. Also it would be wise to adjust your rates to be as high as possible on high rates...don't knock the highest rate down below 100%...if you do, you're cheating yourself out of servo travel. This allows you to use LONG horns on the surface but short arms on the servo, and provides the maximum amount of mechanical advantage.

All the recent flutter problems have made me take a serious second look at my setup methods. I'm glad you posted this Matt!

-Tom

Note: I edited the post...for some reason I was thinking the rates on my 10x could be adjusted higher than 100%...they can't. Kicking up the ATV values is good enough.