Wing Elasticity Effects on Store Separation

Abstract

The study explores wing elasticity effects on the store-separation process. The nominal test case is that of an unmanned aerial vehicle that carries two identical stores on two wing stations. The stores are ejected during straight and level flight at , 2500 m. Simultaneous, time-accurate analysis of the dynamic aeroelastic wing response and the store’s trajectory reveals that the most significant aeroelastic effect is a roll motion developed by the store. This roll motion is due to misalignment of the ejection force vector and the store’s center of gravity, due to the wing’s static and dynamic elastic deformations. The second part of the paper presents a parametric study of the effects of various structural and configurational parameters on the wing’s response and consequently on the store’s rolling motion. A more flexible wing, a heavier store, a larger ejection force, or a shorter ejection period all result in increased store rolling. Store ejection from an asymmetric configuration (of a single store) yielded a very similar store roll compared to the symmetric ejection. The dynamic wing response plays a major role in generating the store roll, in different conditions of friction between the store body and ejection piston. A practical observation is that the store roll is dependent on the relation between the ejection period and the low structural frequencies of the wing. This can be used to plan an optimal ejection profile.