Wind-tunnel Investigation of the Opinion Characteristics, Drag, and Stability of Several Hemispherical Parachutes PDF Download

Author: Stanley H. Scher
Publisher:
ISBN:
Category :
Languages : en
Pages : 27

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Author: Stanley H. Scher
Publisher:
ISBN:
Category : Drag (Aerodynamics)
Languages : en
Pages : 34

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Book Description
An investigation has been conducted to determine the opening characteristics of several hemispherical parachutes and to study the influence of the parachute design variables on these opening characteristics. The effects of design variables on the drag and stability characteristics of the parachutes were also evaluated.

Author: George M. Ware
Publisher:
ISBN:
Category : Parachutes
Languages : en
Pages : 26

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Author: Nickolai Charczenko
Publisher:
ISBN:
Category : Drag (Aerodynamics)
Languages : en
Pages : 30

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Author: James Matthew Cunnington
Publisher:
ISBN:
Category : Parachutes
Languages : en
Pages : 152

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Author: Sanger M. Burk
Publisher:
ISBN:
Category : Aerodynamics, aircraft
Languages : en
Pages : 24

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A drop-test investigation has been conducted to determine the stability and drag characteristics of radially vented (duplex) parachutes. Parachutes of two different designs were tested: a large parachute with high geometric porosity and a small parachute with low geometric porosity designed for the same descent velocity with the same load. The results of the tests show that the large high-porosity duplex parachute was very stable in descent, oscillations averaging about [plus-or-minus]3.40; and the average drag coefficient based on the total canopy area and based on the fabric area alone were approximately 0.38 and 0.55, respectively. The small, low-porosity duplex parachute was also very stable in descent, oscillations averaging about [plus-or-minus]4.50; and the average drag coefficients based on the total canopy area and based on the fabric area alone were approximately 0.62 and 0.79, respectively. The oscillations for the cluster of three solid flat circular parachutes, tested for comparison purposes, were [plus-or-minus]7.10. The average drag coefficients based on the total canopy area and the fabric area alone were approximately 0.64 and 0.65, respectively.

Author: James T. Foughner
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 44

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Transonic wind-tunnel studies were conducted with modified cross, hemisflo, and disk-gap-band parachute models in the wake of a cone-cylinder shape forebody. The basic cross design was modified with the addition of a circumferential constraining band at the lower edge of the canopy panels. The tests covered a Mach number range of 0.3 to 1.2 and a dynamic pressure range from 479 Newtons per square meter to 5746 Newtons per square meter. The parachute models were flexible textile-type structures and were tethered to a rigid forebody with a single flexible riser. Different size models of the modified cross and disk-gap-band canopies were tested to evaluate scale effects. Model reference diameters were 0.30, 0.61, and 1.07 meters (1.0, 2.0, and 3.5 ft) for the modified cross; and nominal diameters of 0.25 and 0.52 meter (0.83 and 1.7 ft) for the disk-gap-band; and 0.55 meter (1.8 ft) for the hemisflo. Reefing information is presented for the 0.61-meter-diameter cross and the 0.52-meter-diameter disk-gap-band. Results are presented in the form of the variation of steady-state average drag coefficient with Mach number. General stability characteristics of each parachute are discussed. Included are comments on canopy coning, spinning, and fluttering motions.

Author: J. S. Deitering
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

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Tests were conducted in the 40-inch supersonic wind tunnel of the von Karman Gas Dynamics Facility to investigate the drag and stability characteristics of a series of fabric parachute models. The models were tested at Mach numbers from 1.5 to 5 at dynamic pressures corresponding to altitudes of 65,000 to 135,000 ft, respectively. Three basic configurations were examined: conventional ribbon parachutes with varied amounts of reefing, flat-roofed parachutes (hyperflo canopy designs) without reefing, and tandem-canopy parachutes composed of reefed ribbon parachutes with hyperflo canopies sewn in the suspension lines. Drag and motion data for each configuration were recorded by oscillograph drag traces and high-speed schlieren and regular movies. The performance of the various chutes is discussed, and drag data are presented. (Author).

Author: Lana M. Couch
Publisher:
ISBN:
Category : Aerodynamics, Supersonic
Languages : en
Pages : 116

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An 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.

Author: Sanger M. Burk
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 22

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