Ratio of the Cruise Thrust (or Power) to that at Take-off at Standard Sea Level Conditions.

Jet Aircraft:

..\Images\INFO0893_wmf.gif

Propeller Aircraft:

..\Images\INFO0894_wmf.gif

Note: ..\Images\INFO1558_shg.gif should be taken at Mach 0 and sea level conditions.

..\Images\INFO1557_shg.gif should be taken at the cruise Mach number and cruise altitude.

For example values see Reference: Roskam, J: Airplane Design Part III : pp. 306-324; 1989