ORIGINAL: dick Hanson
ORIGINAL: Sport_Pilot
On the big radial engines -this was a problem
That can be minimized with a good cowl design. A good radial cowl will allow the prop blast to go through the engine and out the back so that the prop will still provide good thrust, though slightly less than the outer blade.
The prop does not blast thu the cowl -
not how it works
but proper cowl and spinner does make a BIG difference.
Prop blast is a term that is not adequate. But it does go through the engine, enough to make a differance anyway, that is how it is cooled when sitting on the ground. The second part of that is that the air that does not go though must make its way over the curved outer ring, that is also important. The spinner is also important but the most efficient spinners tend to restrict cooling air on the ground.