"John Mullen" wrote in message
...
"John Halliwell" wrote in message
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In article , John Keeney
writes
Curious, the "booms" (I note the plural form) were anticipated before
anyone flew Mach 1+?
While I suppose they would be predictable, I'ld be kind of surprised
that anyone had. Was there experience with unmanned missiles or
projectiles to showed it?

According to many reports from London and thereabouts during the latterly
months of the WWI Europe, the arrival of the V-2 was announced by its
exploding warhead, followed shortly thereafter by strange noises
(associated, presumably, with the missile's having passed through mach 1).
Assuming these reports were accurate, these would have given rise to an
expectation of an audible "boom" as an object of considerable mass (say, far
more so than a bullet) exceeded mach 1.

I had a friend, now late, who served in N Africa and in Sicily; he related
on a few occasions when I could get him to talk about his experiences that
when the Germans opened fire (but "over") on his formation with their 77mm
and 88mm cannon, he and his squad mates first heard the explosion of the
warhead, then a weird noise which sounded like something moving fast (like a
freight train, only far more frightening) through the air. I suggest this
phenomenon indicates that high-vel artillery rounds would routinely pass
through mach 1, and that their passage could be detected audibly by
survivors, and distinct from the warhead detonation. A 77mm or 88mm round is
far smaller than a V-2, so it seems probable that a V-2 would generate a
much louder "boom", which could be heard over a far larger radius (open to
correction on all of the above, of course).

Snip remainder.