Gust Load Prediction on Supersonic Fighter Aircraft using Aerodynamic Panel Methods

Kurzfassung

Military supersonic fighter configurations, due to their high maneuverability requirements, are usually sized through maneuver loads. This work investigates if gusts can exert higher loads on the main structure and outer wing areas as well, possibly exceeding the maneuver loads. In order to determine whether gust loads need to be considered as a design criterion for supersonic combat aircraft, this work presents a comprehensive gust load analysis at different flight conditions within the sub- and supersonic regime. For this, mission profiles, certification requirements, and current research outcomes are assessed and gust load computations using aerodynamic panel methods are executed at the example of the DLR Future Fighter Demonstrator configuration. As the aircraft is naturally unstable within the subsonic regime, a simplified pitch controller is implemented to allow for feasible closed-loop time domain simulations. The results of the gust load campaign suggest that the quasi-steady method is not able to accurately predict the gust loads acting on a supersonic combat aircraft, significantly falling short of the dynamic gust loads. Although the maneuver loads envelope is generally larger for positive loads, negative peak bending moments exceed the maneuver loads and may thus be a sizing factor for the aircrafts lower skin. High accelerations due to short gust impacts can be observed on the wing tips, possibly sizing payload and attachment points.