What's the difference with motor housings?

[siberianhusky]

RC cars, planes and heli's are what is driving the electric rc market, makes sense to have the motors vented when the majority of them are going to be used in an aircooled application, we're probably only a few % of the total volume of motor sales, and the majority of that is going to a couple of brands.
I'm just getting into heli's and am amazed at the amount of aftermarket parts support, lol makes putting a new boat together easy as we only have a couple of choices for manufacturers. the majority of the stock at our LHS is car and heli related.