Optimizing Exhaust — Nozzle/Airframe Thrust Minus Drag

This paper discusses exhaust nozzle performance, the interaction of exhaust nozzle and airframe, and the need for considering the effect of interactions when estimating overall performance. New performance parameters such as interference drag and equivalent thrust are introduced to account for these interactions. These parameters can be used to provide a consistent semi-empirical approach to optimizing exhaust nozzle/airframe performance and to measure achievements during the optimization process. Emphirical correlations based on the new parameters are displayed for several exhaust nozzle/aircraft combinations.