[renormalised (Carl)]

Originally Posted by Peter Ward

Guys...I think a major point is being lost here... "groundspeed" is a little irrelevant.....you will not produce a sonic boom doing M0.86 in a jetstream adding another M0.15 to your progress over terra firma....your speed through the air is still "just" M0.86.


Sure, some ground-speeds can get up to quite a clip (or just the opposite if you happen to be flying the opposite direction), but the airspeed (ie speed through the airmass) is the same...hence no sonic boom even if your ground speed is Mach 1.01

Quite correct.