If you can get an accurate weight for the airframe as well, a measure of the wing area, and your performance expectations for the plane, we can be a lot more helpful in steering you toward some appropriate power systems. (IE, if you want glow-like performance, you're probably going to have to go brushless...)

Having said that, your speed controller will kill power to the motor when the battery gets low, but you still have power to the servos and can make a dead stick landing.

Matt