I remember reading somewhere a long time ago (might have been a book) that, for convenience in giving the speed of aircraft as a Mach number, the speed of sound is taken as constant above a certain altitude. I also remember that that speed in mph was given with a resolution of 4 or 5 digits and looked quite authoritative. But I've never been able to find that kind of statement again. Does anyone here know?
- posted
6 years ago