Aerodynamical Study of a UAV Launch from a Military Transport Aircraft

Abstract

In this study unsteady Reynolds-Averaged Navier-Stokes simulations (URANS) have been carried out with the DLR TAU-code for a controlled airdrop of one full scale-UAV from the loading platform of an airborne transport aircraft. The URANS simulations have been tightly coupled with a flight mechanic (FM) tool in each time step to capture the dynamics of the UAV during the airdrop. The general procedure of the investigated airdrop is to accelerate the UAV on the loading platform and release it backwards in downstream direction. The influence of the orientation of the acceleration vector determined by the launch mechanism and the release velocities will be investigated in detail in this study. In addition, the influence of the initial alignment of the UAV with respect to the loading platform is analyzed in terms of a safe separation and aerodynamic stability. In general, the study was performed for angles of attack of the transport aircraft of α = 0°, α = 2°, α = 4° at an altitude of FL030 and an indicated airspeed of 130 kts, which corresponds to a Mach number of about 0.208.