Experimental Research of Tandem-Scheme UAV Model Aerodynamic Characteristics

Tandem-wing aerodynamic scheme became widespread for tube launch UAV due to possibility of required flight performance realization under tight dimension constraints. In this work results of wind tunnel weight and visual tests of UAV model with wingspans about 1 m are presented. Model aerodynamic characteristics were defined by six-component wind tunnel balance at Mach number 0.075 and Reynolds number 187 000 calculated for one wing chord of 0.11 m. Model stagger (390, 490, 590 mm), rear wing dihedral angle (0°, -5°, -9°), forward-to-rear wingspan ratio (0.67; 0.9; 0.92; 1.24) were variable. It was determined that model is longitudinal and directional static stable, has high maximal lift-drag ratio (in range from 10.6 to 13.7) and acceptable maximal lift coefficient without flaps (from 1.05 to 1.09) and critical angle of attack (from 15.1 to 16.4°). Stagger increasing leads to zero or positive maximal lift-drag ratio increasing. If forward wing span is larger than rear wing span than stagger increasing is more effective with zero dihedral angle. If rear wing span is larger than forward wing span than stagger increasing is more effective with negative dihedral angle.