I have had the pleasure(?) of living with Fast Jet, Multi engine and Rotary wing aircraft and I can say that Rotary aircraft have to be the least offensive to the ears. OK, so jets scream by and then thier gone but MY GOD what a racket! Rotary aircraft can be noisy but are great to watch, safe to fly and are the ONLY vehicle to have saved more lives then they have claimed. Helicopter are truely brilliant machines (except the Osprey, thats just weird!)
AD