Originally Posted by Malte
Hello,
aircraft like the A320, A319 etc. produce a metallic "rrrrrrrrrrrrrrrrrr"-sound
when the engines are running at full thrust. B757 and B767 (depends on engine type) also have this sound sometimes, and if you listen carefully, you will also hear it in a 737 or 747, but not that loud as in the airbus family.
I have a few questions concerning the "rrrrrrrrrrrrrrrrr"-sound:
1) Why does it exist, what are the technical reasons for it? This is most interesting for me.
2) Why is it only at high thrust levels?
3) Why is it stronger in some aircraft (i.e. A320) und weaker in other aircraft (i.e. B767)
4) Does an ordinary airline pilot
know why the engine produces such a sound?
Thanks!
Malte
EDDH
the rrrrrrrrrrrr sound varies with the number of blades in the front end, the spinning speed of the engine and the echo effect of the long or short tube in the front of the engine. Variations in these features between aircraft and engines affects the sound that you hear out of each ear depending on what side of the aircraft is your closest ear window
I have never met an ordinary airline pilot so I have no idea what he knows.