Originally Posted by
dead_pan
Slight aside, but talking of the engine blue note, there is a weird effect if you stand immediately below one on approach. A few seconds after the a/c passes overhead you get this odd sound effect, difficult to describe but like a threshing sound. No silly jokes please, and no, I wasn't imagining it.
Nothing new, as a youngster I used to go with my plane spotting older brother and stand by the approach lights to Ringway. Whenever a BEA Vanguard passed over you got a similar effect, a rushing sound several seconds after the aircraft had passed overhead. Another spotter who was in the ATC, and had been taught about such things, explained it was the 'vortexes off the wings and props'. At the age of seven I didn't have a clue what a vortex was but I knew I liked the noise they made.