Originally Posted by
HuggyU2
Lots of good discussions and arguing on various sites over this. But, oddly, not much good, distilled data/info.
Scenario: two single-engine prop planes. Engine quit and seizes in one. Engines quits but prop rotates in the other. Everything else equal. Which has more drag?
Without generating more argument and opinion (yeah... like that will happen), can you post a link to a definitive source for an answer? And that will explain it without formulas that take up 7 pages. I'd like something that can be understood by a History major.
I believe the correct answer is it depends, if both aircraft have fixed pitch cruising props say set at 18 degrees, like something like a 172, I'd say the correct answer is there ain't much difference...
if both aircraft are constant speed singles a wind milling prop set to low rpm, resulting in blade angle angle of 30 degrees the wind milling prop, would probably glide a little further than other aircraft with a stuck prop which has moved to flat pitch.
A propeller being dragged through the air at high rpm that results in flat pitch will result in far more drag by far.
I think the pitch that makes the difference is about 15 degrees.
This tallies with what I have observed in flight. The resistance movement of engine/gearbox is a bit of a red herring, and doesn't stand up to scrutiny.
I can't find anything that explains this in simple terms however there a some papers on this, but they are not easy reads.