Free-Drop Testing on Internal Store Separation by the Fast-Response Pressure Sensitive Paint

The kinetic and aerodynamic characteristics of a store-model releasing from a cavity of the flying-wing aircraft-model are obtained by freedrop testing based on dynamic similarity. The pressure distribution measurement on the surface of the dynamic model is explored by using the fast-response pressure sensitive paint (PSP) technique. The mass-inertia parameters of the dynamic store-model are obtained by the heavy-model method based on Mach number similarity. The ratio of length-to-depth of the cavity-model is 6.0 and the Mach number of the wind tunnel testing is 0.8. The effects of different angle-of-attack of the aircraft-model and different positions of the store-model in the cavity-model are studied. The results show that the position of the store-model in the cavity has the greatest influence on the separation characteristics of the store-model releasing from the cavity-model. When the distance is L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>= 25mm, the pressure on the head-area of the store-model is obviously higher than that in the rear-area resulting in a nose-up pitching moment, which make the pitch-angle of the store-model increase all the time and finally collides with the cavity of the aircraft-model. Reducing the angle-of-attack of the aircraft-model does not change the effect of the store-model colliding with the cavity region. When the distance is L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>= 39mm, the store-model can be safely separated from the aircraft-model at a given angle-of-attack.