|Quoting AeroWeanie (reply 5):|
Jet engines dump their exhaust at a speed higher than the flight speed. This difference causes shear, which is a major noise source. This is particularly bad when the airspeed is low (take off or landing) and the thrust is high.
So if I am not mistaken then, does this mean that as the aircraft gains speed during the takeoff roll, the difference in speed between the exhaust and the ambient air becomes less, and the exhaust actually gets quieter?
Of course, I'm assuming this loss in exhaust noise is probably negligable, though, since airframe turbulence and similar noises get louder as the plane accelerates, and as a result the whole plane doesn't make any less noise.
B-52s don't take off. They scare the ground away.