THE AERODYNAMIC CHARACTERISTICS OF NON-AERODYNAMIC SHAPES
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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A wind tunnel investigation of three basic shapes cubes, rectangles, and cylinders was conducted to determine the aerodynamic characteristics of similar shaped cargos carried externally by helicopters or VSTOL aircraft. The ratio of side area to frontal area was used as a parameter to plot the lift, drag, and pitching moment versus angle of attack for the three shapes. The lift, drag, and pitching moment coefficients were plotted for angles of attack from 5 degrees to -90 degrees. The change in slopes of the pitching moment of both rectangles and cylinders was smooth and gradual indicating no rapid changes in static stability. By using a very flat nose fairing, it was possible to reduce the drag by 30 at 0 degrees angle of attack without increasing the forces at the larger angles of attack.