Abstract:

ESDU PERF RP 1/3 gives formulae derived using the method of ESDU PERF RP 1/0 for the incremental correction of flight measured fuel consumption data to standard conditions. Tests may be made over a complete range of engine speeds, boosts and heights or by taking readings on the 'envelope' which is defined by the conditions for maximum distance per unit of fuel at a given speed. In the former case corrections are made at constant engine speed and boost, and speed is first corrected for weight and temperature changes using the formulae in ESDU PERF RP 1/1, after which fuel flow is corrected for temperature change using a formula provided that applies at constant boost. When results obtained on the 'envelope' are corrected speed, fuel flow and boost must be corrected because results have been obtained partly throttled and partly full throttle. Again speed is corrected using the formulae of ESDU PERF RP 1/1 for weight and temperature changes and then, for data obtained at full throttle, boost and fuel flow are corrected using formulae provided while, for part throttle results, fuel flow is corrected at constant boost. A worked example illustrates the use of the method.