A lot of people don't fully understand the math/geometry of surface setup. Becuase the Cessna isn't going to need 50* throws like a 3D plane, you can get away with a lot less. Where the math and geometry come in is that you can really amplify a servo's torque mechanically VERY easily. A lot of people don't realize this.

For example:

Servo X has 200oz of torque. Manufacturers come up with this value on a 1 inch servo arm at either 4.8 or 6V depending.

Now consider this. What happens when you reduce the servo arm to 0.5" in length?? YOU'VE JUST UPPED THE SERVO'S OUTPUT POWER BY 50%!!! Thus your 200oz servo is now putting out 300oz! That's a massive increase. Now what happens if you also increase your ATV to the max (like 125 or 150% depending on radio)? Now you have 50% more resolution as well because 1024 steps (common for servos) * 50% = 1548 steps of resolution. Now, also consider running 6.6V a123 RX packs and you've just added another 10% of power and speed to the servo. In the end you can have your 200oz servo putting out 330+ oz of torque all due to setup!!! Not to mention, because you have a shorter servo arm, you will GREATLY reduce servo gear wear/slop and your servos are going to last a lot longer.

I see a lot of guys that have their massive 1.5" arms on 100cc planes and are trying to run them for IMAC. They lose a TON of resolution being that they have to run the throws at 30-40% of ATV thus affecting their precision, accuracy, snap exits are poor (due to blow-back from lack of servo power due to setup), etc.

Anyway, just wanted to make you aware that you'll be abl to get away with a lot less servo if you plan out your setup properly!

Eganwp