Drag and Stability Characteristics of a Variety of Reefed and Unreefed Parachute Configurations at Mach 1.80 with an Empirical Correlation for Supersonic Mach NumbersAn investigation was conducted at Mach 1.80 in the Langley 4-foot supersonic pressure tunnel to determine the effects of variation in reefing ratio and geometric porosity on the drag and stability characteristics of four basic canopy types deployed in the wake of a cone-cylinder forebody. The basic designs included cross, hemisflo, disk-gap-band, and extended-skirt canopies; however, modular cross and standard flat canopies and a ballute were also investigated. An empirical correlation was determined which provides a fair estimation of the drag coefficients in transonic and supersonic flow for parachutes of specific geometric porosity and reefing ratio. |
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Ai Ae area ratio Available from DDC ballute bow shock breathing frequency canopy asymmetry canopy inlet canopy shape Canopy type Porosity Confluence point conical shock wave coning frequency const Config constructed reefing ratio cross parachute D max Dacron decelerator deployment Disk-gap-band 125 Disk-gap-band Disk-gap-band canopies Disk-gap-band Disk-gap-band Disk-Gap-Band Parachutes downstream shock wave drag and stability drag coefficient increases EQUATION 11 exit area Extended skirt extended-skirt canopies extensive fabric flutter Figure 22 Figure 9 free-stream geometric porosity hemisflo canopies hemisflo parachute inflated disk inflated reefing ratio inlet diameter investigation kN/m² large coning angle leading edge Mach number Modular cross 086 Modular cross canopy Nylon oscillograph Parasonic photographic data Present data presented in figure reefing line schlieren Sinf slack suspension line spinning stable stagnation pressure standard flat canopy transonic tunnel U.S. Air Force underinflated unreefed Config unreefed parachutes upstream variation of drag varied from approximately Vent opening wind-tunnel