Determination of the propulsion performance characteristics of air-breathing jet engine
V.I. Zvegintsev
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: air-breathing jet engine, aerodynamic drag, “real thrust”, flight tests, bench tests, trajectory calculation
Abstract
The traditional approach to measuring the thrust of air-breathing jet engines (ABJEs) was proposed by B.S. Stechkin in 1929. In this approach, the thrust is determined as the difference between the momenta of the gas flows at the engine inlet and outlet. The approach involves some methodological and terminological problems. Based on a critical analysis of available concepts, the present article proposes a new approach to determining the ABJE thrust in the form of the decrease of the initial drag of the aircraft + ABJE system when the power plant operates with fuel supply and energy release. For the thrust thus obtained, we propose using the term “real thrust”. It is shown that the proposed approach eliminates terminological problems and simplifies the technique for measuring the thrust characteristics of the ABJE. The paper considers various options for applying the proposed approach to the determination of the “real thrust” for different cases of using and modeling ABJEs, including the calculation of flight trajectories of the aircraft with ABJE.
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