A WIND-TUNNEL INVESTIGATION OF FORCES ON CONES AT LOW MACH NUMBERS.

Abstract : The investigation was conducted to obtain subsonic aerodynamic forces on cones. Nine aluminum cones varying in apex angel from 10 degrees to 90 degrees were tested. Lift, drag and pitching moment were measured at angles of attack varying from -5 deg. to 180 deg. in 10 degree increments and at a dynamic pressure of up to 200 lb./sq. ft. The measured data was first corrected for tare and interference effects; three-dimensional wind-tunnel-boundary-corrections were then applied to correct the data to free-air conditions. This data is presented in graphical form as lift, drag and pitching moment coefficient versus angle of attack for each cone. A plot of drag coefficient versus Reynolds Number at each angle of attack for the 30 degree cone and the 60 degree cone showed the drag almost constant for each angle of attack over the small range of Reynolds Numbers tested (Re = 15,000 to Re = 57,000). The maximum lift to drag ratio for the three smallest cones (10 deg. to 30 deg. cone apex angle) occurred at an angle of attack between 30 deg. to 40 deg.; for every other cone (40 deg. to 90 deg. cone apex angle) the maximum L/D was at an angle of attack between 120 deg. and 130 deg. (Author)