Aerodynamics of Battle-damaged Finite-Aspect-Ratio Wings

Wind-tunnel tests have been carried out on a battle-damaged NACA 641412 half-wing aspect ratio of 8.2. The simulated gunfire damage had a diameter of 0.2 wing chord and was located at midchord and at one of two spanwise locations. Tests were carried out at a Reynolds number of 5:5 105. Compared with an undamaged wing, the damage resulted in reduced lift, increased drag and a positive increase in pitching moment at zero lift. Moving the damage to near the tip reduced the magnitude of these effects. Using the static pressure difference between the upper and lower surfaces of the undamaged wing allowed the data from the present study to be successfully compared with previously published drag and lift data for a two-dimensional damaged airfoil. Tests on wings with aspect ratios of 6.2 and 10.3 produced similar trends in the aerodynamic characteristics and showed that the use of static pressure difference was equally effective in allowing comparisons with two-dimensional data.