FOREBODY INFLUENCE ON ROTATING PARACHUTE AERODYNAMIC PROPERTIES

For certain requirements of trajectory night conditions, some parachut e-payload systems are mechanically closely coupled systems and have a small diameter ratio of the canopy to the payload. The effect of decre asing diameter ratio on the aerodynamic performance of the system has been experimentally investigated on cross-type rotating parachutes. Th e results show a significant decrease in the drag coefficient with dec reasing diameter ratios, as the forebody wake interferes with the flow around the parachute. Similarly, with an increase of the forebody's d iameter, a decrease in the spin was observed. The diameter ratio also affects the static stability. This effect varies between improved stab ility for short cord configurations, commonly used for submunitions, t o a reduction in stability when the cords are longer, The investigatio n also included the effects of the canopy aspect ratio, different supp ort systems, and the attachment diameter of the cords to the payload.