Posted: 19 May 2006, 17:47
I think that's what I said...The only variables being T and c, which will both change for a given Flight Level on a day to day basis...But not enough to worry about when planning...Your scanned table above is based on ISA.TobyVickers wrote:Speed of sound is given by:
C=SQR(gamma*R*T)
Where gamma is the ratio of specific heats (which is about 1.4 for air), R is the gas constant (0.286 kJ/kg/K for air) and T is the absolute temperature in Kelvin.
Mach number is of course:
Ma = v/c where v is the velocity of the gas or object we are concerned with and c is the local speed of sound.