Improved Inlets for T-38 Airplane

A change in the design of the engine inlets of the T-38 airplane significantly reduces takeoff distances while increasing safety margins. Although the newer inlet design (see Figure 1) is based on well-known engineering principles, it is unique and will prove invaluable to the NASA fleet and to other T-38 fleets; e.g., the fleets flown by the United States Air Force (USAF) and by foreign governments. The change in design was needed because in an inlet of the older design, separation of flow in the lower third of the inlet degraded efficiency, even under normal takeoff conditions. Johnson Space Center (JSC) engineers compensated for this deficiency in formulating the newer design by adopting an inlet shaped according to aerodynamical considerations; the shape was chosen to minimize separation of flow to produce greater engine thrust as the T-38 accelerates to takeoff speed.