joined wing, advanced aircraft configuration, energy efficient airplane, new generation aircraft, sweptback ing, sweptforward wing, rhombic planform wing, low speed wind tunnel test, aerodynamic characteristic, vertical fin, direct side force control, control surface effectiveness, side force generator, induced drag reduction, flow visualization
その他のタイトル(英)
Low-speed wind tunnel tests on a joined-wing aircraft model with various upper-fin
National Aerospace Laboratory Advanced Aircraft Research Group
National Aerospace Laboratory Advanced Aircraft Research Group
National Aerospace Laboratory Advanced Aircraft Research Group
Low-speed wind tunnel tests were conducted on a joined-wing aircraft model with various upper-fin (small wing-like surface fitted on the wing or the horizontal tail). The upper-fin was used to enhance direct side-force control capability. In this case, the upper-fin was equipped with a plain flap as a rudder. The effects of upper-fin on the aerodynamic characteristics of a joined-wing aircraft are described. The ratio of the rear to front wing span was selected 0.6 to be said best condition. Four different shaped upper-fins were installed at the three locations on the each wing at 0.6 half span, but four cases were not used. Reynolds number based on the mean aerodynamic chord was (from 6.5 to 6.7) x 10 (exp 5). the angle of attack was varied from zero deg to 25 deg, and the side-slip angle from zero deg to 15 deg. The results indicated that the upper-fin acts like a 'boundary layer fence' and protects wing tip stall when the upper-fin is installed on the wing. On the other hand, however, the upper-fin produced local flow separation over the wing, and this flow separation caused asymmetric lateral and directional characteristics with side-slip angle.