Passing planes and other whoosh sounds

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shmeeed ◴[17 Apr 25 07:40 UTC] No.43714083[source]▶

I'm just armchair musing here, and I'm definitely no expert on sound waves, but I wonder if they considered the fact that most airliners have more than one engine. Could the effect also be the superposition of multiple engine sounds?

Those have a fixed spatial distance, too, and the effect would (I suppose) change with the lateral angle to the listener during the fly-by. This theory should be pretty easy to falsify, because then the effect would not occur if the plane's path went exactly overhead.

replies(2): >>43714179 #>>43723238 #

nicemountain ◴[17 Apr 25 07:57 UTC] No.43714179[source]▶

>>43714083 #

For that, the pressure waves (sound) coming from the engines would have to be somewhat coherent, or correlated in phase. Since what we're hearing is essentially turbulence, that's not going to be the case.

replies(1): >>43716945 #

jeffbee ◴[17 Apr 25 13:57 UTC] No.43716945[source]▶

>>43714179 #

Engines in modern aircraft are phase-locked, though.

replies(2): >>43717177 #>>43718598 #

Toutouxc ◴[17 Apr 25 15:49 UTC] No.43718598[source]▶

>>43716945 #

Do you have a source for that? I’ve heard about something that some twin-props have, but definitely not jets. The engines don’t even run at the same RPM.

replies(1): >>43718812 #

jeffbee ◴[17 Apr 25 16:07 UTC] No.43718812[source]▶

>>43718598 #

https://www.osti.gov/biblio/6356085

It is what the "Sync" switch on the panel does.

replies(1): >>43719824 #

Toutouxc ◴[17 Apr 25 17:27 UTC] No.43719824[source]▶

>>43718812 #

Yes, but it seems like no turbofan synchrophaser systems have been implemented yet. Only on turboprops.

https://aviation.stackexchange.com/questions/71738/is-engine...

replies(1): >>43720229 #