R.M. Deslandes, A. Eberle, S. Donauer, A. Baeten, R. Gleissl

Within the last decades, the prediction of store separation have performed great improvements. Since the very first numerical steps based on linear Panel Methods, we may find today a huge variety of highly sophisticated applications up to almost complex Navier Stokes solutions on time dependent and dynamically breathing meshes. Several powerful CFD strategies are now well installed all over the world as useful tool inside of store separation clearance processes. The target of this paper is to highlight that beside all these improvements, there is still a bunch of remaining areas which are still not addressed but could considerably affect the predictive accuracy of a store separation prediction. Therefore the paper deals with the identification of sources for steady state and unsteady deformations which affect the separation behaviour of external stores such as fuel tanks, cruise missiles and rockets. Experimental data will show how aeroelastic deformation can sensitively affect the effective local orientation of a 2000Lbs class missile on the hooks and contribute to a considerable mismatch of the nominal case. A similar case is presented for a fuel tank installed on a wing pylon of a variable sweep fighter aircraft. It will be shown how structural response during ejection can completely change the nominal wind-off tuning of ejector performance based on a rigid body pit drop test. The resulting accelerations not only affect all interfacing systems such as ejector gas system, structural integrity of the rail launcher but could also have an impact on sensitive parts of the store itself. Without the knowledge of such effects, if dominant, clearance work and associated recommendations remain uncertain and unsafe or too restricted if conservative. Therefore the paper also addresses the necessity of using accurate methods enabling at least the identification of such effects which remain undetected using the standard high speed movie for flight test analysis.

International Forum on Aeroelasticity and Structural Dynamics, 2005, München

Conference Paper

englisch

21,0 x 29,7 cm, 12 Seiten

DGLR-Bericht, 2005, 2005-04, International Forum on Aeroelasticity and Structural Dynamics 2005; S.1-12; 2005; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

in getr. Zählung;

structures, external stores, separation

Bibliothek

2005