The aerodynamic design of the F-12 engine air inlet is discussed following development from its inception to the present configuration. A description of the various tests related to the inlet is presented, along with some of the tests results. The importance of engine, inlet, and ejector matching is discussed. Close coordination between the airframe and engine manufacturer allowed the selection of an airframe-mounted ejector with inherent performance advantages. The nozzle requirements affected the final selection of the inlet bleed system. Early testing of inlet distortion on the engine compressor rig helped provide adequate engine stall margins. Comparison of early one-eighth scale model data with recent NASA test and flight data is included.