Airframe/Propulsion Integration at Transonic Speeds

Abstract

A significant level of research is ongoing at NASA’s Langley Research center on integrating the propulsion system with the aircraft. This program has included nacelle/pylon/wing integration for turbofan transports, propeller/nacelle/wing integration for turboprop transports, and nozzle/afterbody/empennage integration for high-performance aircraft. The studies included in this paper focus more specifically on pylon shaping and nacelle bypass ratio studies for turbofan transports, nacelle and wing contouring, and propeller location effects for turboprop transports, empennage effects, and thrust vectoring for high-performance aircraft. The studies were primarily conducted in NASA Langley’s 16-Foot Transonic Tunnel at Mach numbers up to 1.20.

Key aerodynamic technologies for aircraft engine nacelles

“…Also affected is the wing spanwise loading, which will in turn cause an change in induced drag. There is no agreement as to the source of these degradations, with some authors concluding the pylon shape is to blame (95) and others concluding the channel effect of the nacelle, pylon and wing is to blame (96) .…”

Comparison of Conventional and Compression Pylon Designs for an Underwing Nacelle

“…The influence of pylon geometry can be gleaned from the experiments performed at NASA Langley Research Center [6][7][8] on propulsion integration. The investigations demonstrated the need for a careful contouring of the pylon/wing interface to reduce the adverse installation effects, such as lift loss due to the acceleration of airflow and subsequent shock caused by the presence of the pylon.…”