Exhaust Ducting Effects on Takeoff Lift Loss of Two-Dimensional Hypersonic Configuration

Abstract

The National Aerospace Plane (NASP) configuration was designed to suit propulsion needs at hypersonic speeds. Like many hypersonic configurations, its lower fuselage surface was shaped to suit the propulsion system with an oblique shock compression ramp, scramjet combustion module, and a single expansion ramp nozzle. To minimize drag, the nose was very thin and the upper surface nearly flat. Previous work has shown this configuration produces poor low-speed and in-ground effect performance. This is characterized by significant power-on lift reduction that is intensified by ejector action while in-ground effect. The effects of exhaust ducting on the ground effect lift coefficients and surface pressure distributions of a two-dimensional model based on the NASP fuselage centerline geometry are demonstrated. A two-dimensional configuration was used in an attempt to separate the complex three-dimensional effects from the key problems with this configuration