NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS CLEVELAND OH LEWIS FLIGHT PROPULSION LAB
Equations and charts are presented for computing the thurst, the power output, the fuel consumption, and other performance parameters of a turbine-propeller engine for any given set of operating conditions and component efficiencies. Included are the effects of the pressure losses in the inlet duct and the combustion chamber, the variation of the physical properties of the gas as it passes through the system, and the change in mass flow of the gas by the addition of fuel. In order to illustrate some of the turbine-propeller-system performance characteristics, the total thrust horsepower per unit mass rate of air flow and the specific fuel consumption are presented for a wide range of flight and engine-design operating conditions and a given set of design component efficiencies. The performance of a turbine-propeller engine containing a matched set of components is presented for a range of engine operating conditions. The influence of the characteristics of the individual components on off-design-point performance is shown. The flexibility of operation of two turbine-propeller engines is discussed one engine has a divided turbine system in which the first turbine drives only the compressor and the second turbine independently drives the propeller, and the other engine has a connected turbine system which drives both the compressor and the propeller.