#1 [url]

Oct 10 06 10:03 AM

Re: there is a solution

mvn_citizen wrote:

Most of the noise from a helicopter is produced from the blades, not the engine, so I don't think a muffler would solve anything serious.


You are correct. In an earlier posting of mine, I explained that the noise is actually the tips of the blades creating sonic booms. Not only that, but you have the Doppler effect working in conjunction with the sonic booms.

Nearly all helicopters are powered by "jet" engines. Those are very hard to put mufflers on. The fan jets are probably the least noise makers.

Our very quiet Special Operations helicopters use noise abatement methods on the engines and they have a large many-bladed prop that spins slower but has more lift. It is nearly silent, but this technology costs a bundle. Too much for our "life-flight" companies to buy.