Originally Posted by Piltdown Man
We spell it "Auxiliary". I've also not heard of any that provide thrust that is used to power an aircraft. However, that does not mean to say that no thrust is generated - I'm sure it is, it's just that it's so relatively small it is of no consequence.
I believe its like a car's exhaust, any "propulsion" coming from the APU is just exhaust, the inlet of air is important to gain the power from the movement of the turbine.