Ah yes, the noise! Living in Cornwall, we rarely saw them but frequently heard them - unmistakeable!! ... from memory, (pretty ropey source, nowadays) it was a bit like a swarm of motorbikes
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Sometime in the 50s, one, inbound from the States, lost an engine and (rumour has it) SAC required total abandonment for such condition! Crew baled out and the beast continued on its own for about 45 minutes before crashing on three county boundaries, near Lechlade. My brother was sent out from Colerne on guard duty on the wreckage.