Question for the Motor Heads

[DK-nme]

Originally Posted by kimosabi

Propeller tips are known to reach the speed of sound but not the whole blade. Ever wondered what the "flapping" sounds from helicopters are?

Ahem, this is a quote from the following link, just to confirm my earlier statement about prop tip speed, not exceeding the speed of sound:

"You will not see prop tips moving much faster than 600 knots, as this is getting too close to the speed of sound, and all sorts of nasty aerodynamic things start to happen in the vicinity of the prop tips. The noise alone is bad enough!"

http://www.avweb.com/news/pelican/182082-1.html