Drag and Stability of Guide Surface, Ribbon, and Ringslot Parachutes at High Subsonic Speeds

Four conventional type parachutes; namely, a ribbed and a ribless guide surface parachute and a ribbon and ringslot parachute were tested at Mach numbers of 0.5 and 0.8 to establish their drag and stability characteristics and to evaluate their general performance in this Mach number range. In all cases the parachute models were stable and their drag coefficient increased slightly with increasing Mach number. It was found that both the drag and the stability of the guide surface type parachutes change with cloth porosity. Tests also indicate that for both the ribbed and ribless guide surface parachutes, the tangent force coefficient increases with increasing stagnation pressure at a constant Mach number, and while the stability of the ribless guide surface parachute increases, that of the ribbed type is essentially unchanged. (Author).