Jim Wilson wrote: > Yeah but look at the values again...we're getting close to tropopause > value at 23000ft. Mach should be well over 600knots at 23000ft, > unless it's _really_ warm.
Mach 1 at the tropopause and above is just about exactly 295 m/s, which is 573 knots *true* airspeed. The numbers you quote are "indicated" airspeed (that's the "I" in KIAS). That means that they are corrected for density (basically by the square root of the density ratio at subsonic speeds) and are much lower than true speeds at low densities. At 23000 feet MSL, the correction is about 1.5, which agrees very closely with the numbers you cite. Andy -- Andrew J. Ross NextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
