Experimental Investigation of Wing Rock of Slender Wings and Aircraft Configurations

Abstract

Experimental investigations of the wing rock characteristics of a slender delta wing with 80° sweep, and a 2.5% model of an F-18 are summarized. The studies were conducted in order to identify physical mechanisms responsible for wing rock of slender wings and aircraft configurations. Results obtained on the slender delta wing indicate that wing rock is sustained by a time lag in vortex position, and limited in amplitude by the unsteady behavior of vortex strength. Vortex breakdown has been shown not to be a primary mechanism in wing rock, however its appearance was shown to reduce the steady state amplitude of the motion. The results obtained on the F-18 subscale model agree with those obtained on the full scale flight vehicle. Flow and motion characteristics observed on the F-18 model are consistent with those seen on the slender wing.