Design Studies of Low-Noise Propulsive-Lift Airplanes 730378

A review is presented of low-noise airplanes designed for operation in the 1980 time period. Aircraft with parametric engines covering a range of fan pressure ratios and noise levels were developed conceptually under contract with NASA Advanced Concepts and Missions Division, supported by the NASA Lewis Research Center contracts for the Quiet Clean STOL Experimental Engine (QCSEE) Study Program. Powered-lift concepts included externally blown flap, augmentor wing, internally blown flap, and over-the-wing upper surface blowing. Performance, sizing, and costs are described for 148 passenger airplanes with design field length varying from 2000-4000 ft. Techniques for reducing noise are evaluated in terms of aircraft performance, weight, and cost; experimental data on decayer nozzles are presented and assessed with respect to effectiveness in exhaust noise reduction and aircraft performance penalties.

Noise footprints for aircraft with different lift concepts and different field length capabilities are discussed from the standpoint of community acceptance of STOL short-haul service at existing carrier airports, general aviation airports, or dedicated new STOLports.

Recommendations are made for further work in development of rational criteria for short-haul noise levels and for areas that hold promise of further noise reduction.