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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,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.

Propulsion measurements and thrust methods presented in the current published versions of AIR1703 and AIR5450 place a primary focus on the engine reactionary force (thrust) acting to propel an aircraft in the forward direction. In contrast, this document addresses the use of the engine reactionary force in the opposite direction (reverse thrust) to supplement aircraft deceleration. This document’s application spans commercial and military transport turbofan engine applications for various engine and reverse thrust configurations. The discussion and examples primarily focus on separate flow exhaust turbofan engines. Piston and turboprop variable-pitch propeller blade applications are not covered. Although reverse thrust has been utilized for in-flight deceleration, primarily for short takeoff and landing aircraft and military fighter applications, this application of reverse thrust is only covered in a cursory manner.

This report covers engine tests performed in Altitude Test Facilities (ATFs) with the primary purpose of determining steady state thrust at simulated altitude flight conditions as part of the in-flight thrust determination process. As such it is complementary to AIR1703 and AIR5450, published by the SAE E-33 Technical Committee. The gross thrust determined using such tests may be used to generate other thrust-related parameters that are frequently applied in the assessment of propulsion system performance. For example: net thrust, specific thrust, and exhaust nozzle coefficients. The report provides a general description of ATFs including all the major features. These are: Test cell air supply system. This controls the inlet pressure and includes flow straightening, humidity and temperature conditioning. Air inlet duct and slip joint. Note that the report only covers the case where the inlet duct is connected to the engine, not free jet testing.

This report covers engine tests performed in Altitude Test Facilities (ATFs) with the primary purpose of determining steady state thrust at simulated altitude flight conditions as part of the in-flight thrust determination process. As such it is complementary to AIR1703 and AIR5450, published by the SAE E-33 Technical Committee. The gross thrust determined using such tests may be used to generate other thrust-related parameters that are frequently applied in the assessment of propulsion system performance. For example: net thrust, specific thrust, and exhaust nozzle coefficients. The report provides a general description of ATFs including all the major features. These are: Test cell air supply system. This controls the inlet pressure and includes flow straightening, humidity and temperature conditioning. Air inlet duct and slip joint. Note that the report only covers the case where the inlet duct is connected to the engine, not free jet testing.

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.