I have it on a flat foamie with a Rimfire-1000 and a Electrifly 640 li-po (20C) battery. I will be going about my flying and all of a sudden the motor stops, I can go through the arming procedure again and it will come back on but why? This usually happens about every flight, Maybe it's not the speed controller? Either the motor or speed control makes a high pitch sound when it's running, is this normal?

David

I run quite a few of the Electrifly SS ESC's and I've had the samething happen .. and its usually caused by the BEC being overloaded and resetting which causes the RX to loose power for a fraction of a second which causes the ESC to need to be rearmed .. check for a bound servo .. could also be that the ESC is overheating how many amps is the motor pulling? But it sounds more like the BEC is resetting what servos are you running? The SS-12 only has a 1.5amp BEC and that is going to be pushing the limit if your using 4 servos even if there the micro size..

The motor specs only call for a SS-8 controller, the servos are 4 Futaba 3110's. There are no binding in the servos or rods and the control surface hinges are floppy like a dish rag. I am running an 9X3.8 slow flyer prop, maybe it is to much prop?

If you are running 3S lipo with 4 servos, you have a problem[X(], 2S with 4 servos is marginal.
Sounds like you could use a Parkbec
http://www.dimensionengineering.com/ParkBEC.htm
A Watt meter would also tell you if you are drawing to much current from the pack, at least see if you can get a voltage reading of the battery when you apply full throttle. Don't be fooled by that 20C rating on the pack, if you are pulling about 12A continous, you are killing it.
Pete

I don't understand, why is a 3 cell pack a problem? A Rimfire 1000 is the smallest one they make. It only calls for a 8 amp controller.

David

Hi David,
The issue as to how many servos you can use on an ESC has nothing to do with the motor, the BEC in the ESC uses a linear voltage regulator to drop the battery voltage to the 5V that the receiver/servos use. in doing so it creates heat, the geater the voltage that the regulator has to drop, the more heat is produced, so as the voltage goes up (more cells), the less current you can safely pull thru the BEC circuit. Here's a simple bench test to see if the BEC is the problem, first remove the prop, then arm the ESC with a fully charged battery, then proceed to wiggle the sticks constantly, working all the servos, if the BEC is overheating, this will cause it to show up, better on the ground than in the air you should be able to feel if it's getting hot.
If you took the time to look at the Parkbec link in my last post you will see that it too is rated at 1.5A, the difference here is that it uses a switching type regulator, with this type it can provide the full current rating up to the max recommended cell count.
Good luck,
Pete