The purpose and intent of Subcommittee E-33E's effort, the reporting objectives, and the limitations inherent in the reported findings and recommendations are reviewed since these factors are the basis of the information contained in this document.
SAE E-33E Subcommittee was formed to assess the level of industry experience that exists in the area of thrust determination during aircraft time-variant operating conditions. A prime objective was to provide a center for gathering expertise and to be a forum for the exchange of ideas and viewpoints. The committee recognized that a practice for the rigorous treatment of time-dependent thrust did not exist and that several critical aspects of its accounting would need to be investigated.
The specific objectives of this document are:
a. To examine aircraft and engine operating conditions under which the quasi-steady thrust assumption is valid.
b. To determine the extent to which time-dependent (nonstationary) force accounting for engine net thrust and propulsion system throttle-dependent terms is required, consistent with existing and developing thrust-minus-drag techniques.
c. To report time-dependent thrust methodologies and measurement techniques used for flight and ground testing.
d. To present the results of a data review of state-of-the-art methodology appropriate to the determination of aircraft-installed thrust during quasi-steady and dynamic maneuvers.
e. To provide guidelines for validating and improving time-dependent thrust determination as appropriate to a specific program.
This document addresses definitions of thrust, force, and drag from test principles (when possible) based on steady practices as defined in AIR1703. It is limited to fixed-wing and variable swept wing aircraft employing turbojet or turbofan engines with nonvectoring or fixed vectored nozzle position but not with time-variant vectoring terms. It is not the purpose of this document to detail onboard high-response data systems or develop new in-flight thrust methodologies. Conclusions and recommendations are valid only where criteria and data for a specific program or application have been identified and measurement uncertainty aspects of the data understood. It is anticipated that this document will be updated periodically as new developments in ground and flight testing occur.