Turbine Fan for BL Motors

[Dafni]

Folks, you know about these integrated fans on the Plettenberg motors.
Can somebody please try to explain how they work/look on the inside. Or maybe even post a pic.

I got the idea of making something like this myself.

What do you think? A selfmade part (lathe) on the endbell of the motor, whit a fan (possibly attached to the shaft) and air directed along the can.

Might be a silly idea...