Patent ID: 6851303
Filing Date: 2005-02-08
Classification: F01D,F05D,G01L

Abstract:
1. A method for determining free field thrust of a gas turbine engine by use of an enclosed gas turbine engine test facility, wherein the enclosed gas turbine engine test facility comprises an enclosure having an air inlet and an exhaust outlet, there being located within the enclosure a thrust cradle having movable support means and thrust measurement means, the method comprising: attaching the gas turbine engine to the moveable support means; operating a gas turbine propulsion engine at at least one predetermined engine operating point; measuring thrust applied by the engine to the thrust cradle via the thrust measurement means; calculating gas turbine engine intake momentum drag generated by airflow into the gas turbine propulsion engine intake; calculating a thrust cradle drag force generated by airflow past the moveable support means of the thrust cradle; and adding the gas turbine engine intake momentum drag and the thrust cradle drag force to the measured thrust thereby determining the free field thrust at the at least one engine operating point.