I suppose I should add that gamma varies with temp. For dry air g=1.401 @0 deg C. g=1.405 @ -80 deg C.
Also note TAT and SAT are expressed in deg K (ie deg C+273.16).
The value of gamma is an experimentally derived number. The theoretical value for a diatomic gas is 7/5 ie 1.4 . Air is of course only about 99% diatomic O2 and N2. The other 1% being other gases (mainly Ar).
Last edited by Re-entry; 14th Sep 2006 at 02:00.