Experimental determination of improved aerodynamic characteristics utilizing biplane wing configurations

Improving the aerodynamic characteristics of an airplane with respect to a higher lift coefficient, a lower drag coefficient and a higher lift over drag ratio as a function of angle of attack will make it more efficient, thus conserving energy or improving performance. Investigations were carried out to determine if the aerodynamic characteristics of biplane wing systems could be made more efficient, for low subsonic speeds, than a monoplane of comparable area and aspect ratio. A variable position three-dimensional biplane wing system, and a fuselage that could be fitted with a monoplane wing or the variable position biplane wing system were tested in the University of Missouri-Rolla subsonic wind tunnel at a Reynolds number of 8.7 x 105 per foot. Lift, drag, and pitching moment characteristics of each configuration were investigated to determine the effect of changing the position of the biplane wings relative to each other and how the characteristics compared to those of the monoplane. All the biplane wings tested were shown to have a significant decrease in drag coefficient over the monoplane at a cruise condition. The maximum lift over drag ratios of the biplane wings tested were shown to be significantly higher than that of the monoplane. General trends of drag coefficient and maximum lift over drag ratio and how they vary with the relative position of the biplane wings to one another are presented and compared with the characteristics of the monoplane --Abstract, page ii