Airplane engines play the key role on all aircraft. Propulsion engineers are all involved in making better engines by improving their performance. One of the usual problems on jet engines is the base drag. Base drag is maximum when an engine is having cold subsonic air flow around and high supersonic hot jet flows from the center of it which is more than 95% of the flight time. This drag on a 2D model was calculated by using Subsonic panel modeling as the outer body of the engine and the flow and also using supersonic paneling as the inner jet flow. At first an estimated model is given to the program and after some time a final model with some drag is obtained. Then by using this model some cold air (Same flow as free stream) at one time and hot air (Same flow as Jet) at another time is injected into the base between the solid body and the outer cold airflow and the inner hot jet flow. It was seen that this injection reduces the base area and also the length of the base wake consequently decreases the base drag. The injection of hot air reduces the drag more than when the injection is done by cold air.

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