Abstract:

ESDU PERF RP 2/0 provides a method for the incremental correction of flight-measured data to standard conditions at constant pressure height. Unlike the method in the group ESDU PERF RP 1/0 to 1/3, it takes into account compressibility and applies to engines that are turbo-blown, compounded or have charged temperature control. The general performance equation for the aircraft is differentiated at constant pressure height to obtain expressions for the correction of level speed and rate of climb for changes in weight and temperature. These expressions include factors for the behaviour of the aircraft drag with Mach number, propeller efficiency with advance ratio, compression ratio and tip Mach number, and engine power with temperature. Guidance is given on methods to derive appropriate values for those factors, and it is noted that for the propeller great accuracy is unnecessary. A method for treating uncompounded engines is suggested and is used to provide boost and fuel flow corrections for temperature changes.