Estimating aircraft true airspeed using temperatures from two different probes

Abstract

ENGINEERING NOTES 893 'R 0.99 0.98 0.02 0.01 -----NON MIXING • --MIXING 0 0.02 £ 0.04 0.06 Fig. 2 Effects of fan exit profiles on nozzle thrust and breakeven fan efficiency. ResultsSample results were calculated for the case where the compressure pressure ratio is 1.5, M 0 = 0.85, and M c = 0.5.The reduction in net thrust of the fanstream vs e is shown in Fig. 2. It can be seen that the mixing losses introduce a substantial penalty. It is also evident that substantial increases in compressor efficiency must be achieved to overcome the losses due to nonconstant enthalpy distribution if substantial mixing occurs. The quadratic nature of the losses due to nonconstant enthalpy make the concept of using slight variations in enthalpy quite attractive.Although these calculations are based on the simplified model of a perfect engine, it is expected that the predicted tendencies for the ratio of the net thrusts will remain quite accurate.