[quote=Starman] 500 feet in 15 seconds is a relatively slow "drop", isn't it?
Not really, that's 2000 fpm. That will kill you. A carrier landing for example, executed at a 3.5 deg glide slope, will run about 650-700 FPM and you hit pretty hard.
Helicopters don't necessarily have to maintain a constant glide path during stable powered flight, even in autorotation, so the forward airspeed can vary during the descent.
"All that the South has ever desired was that the Union, as established by our forefathers, should be preserved, and that the government, as originally organized, should be administered in purity and truth." – Robert E. Lee
