Handling Qualities Assessment of a Blended Wing Body Configuration Under Uncertainty Considerations

Abstract

The unconventional shape of the blended wing body configuration affects its flight dynamics significantly. Therefore, a handling qualities assessment of blended wing body configurations requires particular attention, optimally at an early stage of the development process in order to enter design changes already during the preliminary design phase. However, flight dynamic investigations at such an early stage are subject to considerable uncertainty, originating from simplifying model assumptions, unknown external conditions, lack of empirical data and more. The topic of this paper is to analyse the handling qualities of the blended wing body configuration designed within the project FrEACs (Future Enhanced Aircraft Configurations) of the DLR (German Aerospace Center) under uncertainty considerations. The first part of this paper investigates influences of single parameter variations on different handling quality criteria for longitudinal and lateral-directional motion. The position of the centre of gravity is found to have significant impact on the considered longitudinal criteria. The lateral-directional motion is also influenced by the position of the centre of gravity. In addition, aerodynamic damping derivatives and moments of inertia also affect the lateral-directional criteria significantly, having an about equally dominant impact. The second part of this work investigates the probability that uncertainties, occurring in the design process, lead to different handling qualities than intended. Therefor various parameters are varied simultaneously assuming a random normal distribution.