This document has been declared "Stabilized" and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist.
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,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.
The overall objectives and approach described in this document were intended to provide guidance and benchmarking. Readers may refer to this approach and practice guidance for application, comparison, or extension to their specific related tasks, using the appropriate technical data, requirements and the most current applicable references. The general approach and guidance are considered stable in regards to the above stated intent.