Passive control of pitch-break of a BWB UCAV model using vortex generator

To examine the effect of vortex generator on pitch-break control for a BWB model having lambda wing configuration, wind tunnel experiments were conducted. Tests were carried out at two freestream velocities of 30 m/s and 60 m/s. Experimental results of the BWB model, which was modified slightly from UCAV 1303, at various angles of attack are presented. Aerodynamic force and moment coefficients and chordwise pressure distributions at several spanwise stations are included. Spanwise location of a vortex generator was selected based on pressure distributions of the BWB model at several angles of attack and through a preliminary test. Well known pitch-break or pitch-up phenomenon was identified to occur at a specific angle of attack for the case without vortex generator. When the vortex generator was installed, this pitch-break was found to be delayed to a much larger angle of attack, which might well be adopted for efficient flight control.