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The purpose of this document is to provide guidance on in-flight thrust determination of engines that are impacted by intentional or unintentional thrust vectoring. However, as indicated in the Foreword, the field of aircraft thrust vectoring is varied and complex. For simplicity and coherence of purpose, this document will be limited in scope to multi-axis thrust vectoring nozzles or vanes attached to the rear of the engine or airfame; single-axis thrust vectoring and unintentional thrust vectoring (fixed shelf or deck configuration) are special cases of this discussion. Specifically excluded from this scope are thrust vectoring created primarily by airframe components such as wing flaps, etc.; lift engines, propulsive fans and thrust augmenting ejectors; and powerplants that rotate or otherwise move with respect to the airframe.

AIR 4065, "Propeller/Propfan In-Flight Thrust Determination" addresses steady state propeller thrust as applied to aircraft which are usually powered by gas turbine engines. It includes theory, examples, and methods which have been used. Specifically two methods are discussed, the "J" or traditional J,C p ,C t ,ν method including the SBAC variation and a new method we call the "Theta" method which is dependent on knowing blade angle, power/torque and flight Mach number. Implementation guidelines are offered as well as overall approaches to flight testing. Appendices include expansions on theory and testing as well as examples.

AIR 4065, "Propeller/Propfan In-Flight Thrust Determination" addresses steady state propeller thrust as applied to aircraft which are usually powered by gas turbine engines. It includes theory, examples and methods which have been used. Specifically two methods are discussed, the "J" or traditional J,Cp,Ct, η method including the SBAC variation and a new method we call the "Theta" method which is dependent on knowing blade angle, power/torque and flight Mach number. Implementation guidelines are offered as well as overall approaches to flight testing. Appendices include expansions on theory and testing as well as examples.

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 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 emerging ultra high bypass ratio ADP engines, with nozzle pressure ratios significantly lower, and bypass ratios significantly higher, than those of the current turbofan engines, may present new in-flight thrust determination challenges that are not specifically covered in AIR1703. This document addresses candidate methods and the additional challenges to the thrust determination for these ADP engines. These novel challenges result in part from the fact that some large ADP engines exceed present altitude test facility capabilities. The traditional methods of nozzle coefficient extrapolation may not be most satisfactory because of the increased error due to the ADP higher ratio of gross to net thrust, and because of the increased sensitivity of in-flight thrust uncertainty at the lower fan nozzle pressure ratio.

In-Flight Thrust Determination, SAE AIR1703 reviews the major aspects of processes that may be used for the determination of in-flight thrust (IFT). It includes discussions of basic definitions, analytical and ground test methods to predict installed thrust of a given propulsion system, and methods to gather data and calculate thrust of the propulsion system during the flight development program of the aircraft. Much of the treatment is necessarily brief due to space limitations. This document and the British Ministry/Industry Drag Analysis Panel (MIDAP) Guide (Reference 1.11), which SAE Committee E-33 used as a starting point, can be used to understand the processes and limitations involved in the determination of in-flight thrust. Application to a specific in-flight thrust determination program will require the use of many important assumptions not fully developed in this document, and these assumptions must be evaluated during the conduct of the program.

In-Flight Thrust Determination, SAE AIR1703 reviews the major aspects of processes that may be used for the determination of in-flight thrust (IFT). It includes discussions of basic definitions, analytical and ground test methods to predict installed thrust of a given propulsion system, and methods to gather data and calculate thrust of the propulsion system during the flight development program of the aircraft. Much of the treatment is necessarily brief due to space limitations. This document and the British Ministry/Industry Drag Analysis Panel (MIDAP) Guide (Reference 1.11), which SAE Committee E-33 used as a starting point, can be used to understand the processes and limitations involved in the determination of in-flight thrust. Application to a specific in-flight thrust determination program will require the use of many important assumptions not fully developed in this document, and these assumptions must be evaluated during the conduct of the program.