A compact form of thrust deflector: System considerations and model tests

Abstract

A compact form of thrust deflector, of possible application to existing turbofans, is described. The use of the deflector in various roles is discussed. The basic design allows, in principle, continuous variation of deflection from zero to design maximum with no effect on upstream flow conditions. In addition no upstream flow distortion should result from deflector installation. These expectations were confirmed by model tests on the balances of the NRC V jSTOL propulsion tunnel. Two model versions (TDS 60 and TDS 130) with design maximum deflections of 60° and 130° were operated over a range of pressure ratio from 1.1 to 1.6 at various deflection settings from zero to maximum. In each case, test results indicated upstream flow conditions and deflector performance coefficients to be independent of deflection setting. Achieved maximum deflections were slightly (2°) in excess of design. Measured performance coefficients indicate that the thrust deflection system can be matched straightforwardly to appropriate existing engines with relatively small thrust losses (2 - 3% for TDS 60, 4% for TDS 130).