Nacelle Integration Study on a Mach-2.2 Supersonic Cruise Aircraft

Abstract

Results of a propulsion system integration study performed on a Mach-2.2 advanced supersonic cruise aircraft are discussed. A study configuration developed in a joint NASA-Douglas supersonic technology program was used as the baseline airframe to study the detailed problems of inlet-nacelle -airframe integration at Mach 2.2. Numerous inlet-nacelle combinations were examined in a preliminary screening study. Promising configurations were evaluated in a nacelle installation study in which structural weight and installed wave drag were traded leading to the selection of an axisymmetric single-engine pod installation as the most promising configuration. A detailed nacelle shape study was conducted, and a wing reflex was designed. A cooperative NASA-Douglas wind-tunnel test of the refined nacelle with both mixed and external compression inlets was conducted with the nacelles installed on both a refined baseline wing and a reflexed wing. An installation drag penalty equal to 4.3% of the baseline wing-body drag was observed for the external compression inlet over the mixed compression inlet. Wing reflexing improved the trimmed wing-body-nacelle drag by 3.0% of the wing-body drag. Good agreement was observed between calculated and experimental increments in induced drag due to nacelle installation.