Considering the new engine sounds thingy:
Wouldnt it make more sence to have a seperate sound for the prop blades so that the power settings on your throttle make that really nice growling sound
And then of course...RPM settings would only effect the actual engine sound (ya know...the thing with the pistons and pipes).
As it stands now the two are kind of lumped together and while its ok....if I had my way......