Effect of airports elevation on the jet engine thrust ; (off-design operation)‎

الملخص EN

-It is well known that airport elevation with respect to sea level has a considerable effect on the jet engine thrust.

In this study an airplane type (Viper jet, Learjet) with jet engine type (J85- CJ610 ) was selected and tested at different elevations to show the effect of elevation on the engine thrust .

The study includes theoretical background about turbojet engines, thrust, atmosphere and the change of some parameters and the relation between the thrust and altitude.

According to the values of engine thrust in this study at different airports in the world for the selected engine mathematical calculation shows that the thrust decreases as altitude increases during maintaining the same speed, and as result of that the fuel consumption decreases also.

Mathematical calculations shows that at 11 km a jet engine develops 41% of the thrust at sea level .So the turbojet engine performance is more efficient at a higher altitude, but that requires a longer runway to attain the take-off speed.