Study of External Dynamic Flap Loads on a 6 Percent B-1B Model

The origin of dynamic pressure loads on external divergent engine nozzle flaps of the B-1B aircraft was investigated in the NASA/LaRC 16-ft transonic tunnel using a 6 percent full-span model with powered engine nacelles. External flap dynamic loads and afterbody drag associated with flap removal were measured using this model. Both dry and maximum A/B power nozzles were evaluated in this study. As a result of this study, the principle mechanisms responsible for high dynamic external flap loads were determined along with performance penalty associated with flap removal.