Motor "turns"?
 

What is meant when one says a motor is a "5 turn, 7.5 turn, 3 turn, etc."?

RE: Motor
 

That refers to the number of wire turns per stator tooth in a motor to complete a winding. More wire turns will result in a lower motor Kv.

RE: Motor
 

To put it another way, if two motors are otherwise identical, the one with more turns will spin slower than the one with fewer turns.

On the other hand, the one with more turns will be able to spin a larger prop than the one with fewer turns.

So in general terms, if you want to spin a large prop at relatively low RPM, suitable for a slow flyer or a 3D type plane, you would want a motor with more turns (low kV).

But if you want to spin a small prop at relatively high RPM for a fast-flying plane, you would want a motor with fewer turns (high kV). Low turn (high kV) motors are also used in gearbox applications, including helis.

- Jeff

RE: Motor
 

I had good luck moving to 3S in one model by using a lower-Kv version of the original motor on 2S (a HiModel series in a scratch-built). By dropping motor Kv from 1600 to 1000Kv, I was able to continue using a 9x5 on 3S without overdrawing. Thrust and duration improved dramatically.

RE: Motor
 

You rarely hear the discussion of "turns" in aircraft.   That typically is more around RC cars.

In aircraft we focus on kV which is a constant that tells you what RPM the motor will try to turn per volt applied.

You can ignore turns.