Top-mounted inlet system feasibility for transonic-subsonic fighter aircraft applications

To inlet flow field and engine inlet performance data for an advanced fighter aircraft configuration were obtained over the Mach 0.6 to 2.0 range. The studies not only provided extensive data for the baseline arrangement, but also evaluated the effects of key aircraft configuration variables (inlet location, canopy-dorsal integration, wing leading-edge extension planform area, and variable incidence canards) on top inlet performance. In order to set these data in the context of practical aircraft systems top inlet performance is compared with that of more conventional inlet/airframe integrations. The results of these evaluations show that, for the top inlet configuration tested, relatively good inlet performance and compatibility characteristics are maintained during subsonic and transonic maneuver. However, at supersonic speeds, flow expansion over the forebody and wings causes an increase in local inlet Mach number subsequently reduces inlet performance levels. These characteristics infer that although top inlets many not pose a viable design option for aircraft requiring a high degree of supersonic maneuverability, they have distinct promise for vehicles with subsonic and transonic maneuver capabilities.