Very loud noise, 4 Oct 21

[Brian]

I've just thought of a better example to describe the noise.
Back when the Harrier jump-jet was a regular display feature at UK air shows, one of its tricks was to fly parallel to the audience line, slow down then stop and hover. It would then rotate so it was nose-on to the crowd, before lifting the nose until it was pointing vertically and accelerating skywards.
It was incredibly loud, and maintained its pitch and direction - much like today's noise!