Download or read book Wind Tunnel Measurements of Dynamic Reefing Line Tension in Ribbon Parachutes written by D. F. Wolf and published by . This book was released on 1979 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the results of a series of wind tunnel tests conducted to measure the tension in ribbon parachute reefing lines. Three-foot diameter ribbon parachute models with porosities ranging from 10 to 25 percent were tested in the Vought Systems Low Speed Wind Tunnel. Simultaneous measurement of parachute axial force and reefing line tension allowed the reefing line tension to be expressed either as a percent of axial force or as a dimensionless tension coefficient. Maximum reefing line tensions for the 15, 20 and 25 percent porosity chutes ranged from 4 to 5 percent of axial force. Tensions for the 10 percent porosity chute were considerably higher. The 10 percent porosity chute also showed a significant dynamic effect in tension, with maximum values considerably higher than steady values.

Download or read book A Parametric Wind Tunnel Study of Ribbon Parachutes written by D. F. McVey and published by . This book was released on 1975 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the results of a series of wind tunnel tests conducted to define the effect of geometric porosity, reefing line length, and suspension line length on ribbon parachute drag. Twenty degree conical ribbon parachutes with nominal diameter of three feet, goemetric porosities from 15 to 30 percent and line lengths from 1.0 to 2.0 times the parachute nominal diameter were tested at dynamic pressures from 75 to 500 psf. Drag coefficients based on construction and average projected diameters are presented as a function of the independent variables. Data are also presented on parachute shape and inflated diameter. The wind tunnel drag coefficients are compared with data from free flight test of full scale parachutes and with othert wind tunnel data.

Download or read book Wind tunnel Investigation of Drag and Stabili Ty of Parachutes at Supersonic Speeds written by Nickolai Charczenko and published by . This book was released on 1964 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind tunnel Tests of Modified Cross Hemisflo and Disk gap band Parachutes with Emphasis in the Transonic Range written by James T. Foughner and published by . This book was released on 1974 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Parachute Recovery Systems written by Theo W. Knacke and published by . This book was released on 1992 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this manual is to provide recovery system engineers in government and industry with tools to evaluate, analyze, select, and design parachute recovery systems. These systems range from simple, one-parachute assemblies to multiple-parachute systems, and may include equipment for impact attenuation, flotation, location, retrieval, and disposition. All system aspects are discussed, including the need for parachute recovery, the selection of the most suitable recovery system concept, concept analysis, parachute performance, force and stress analysis, material selection, parachute assembly and component design, and manufacturing. Experienced recovery system engineers will find this publication useful as a technical reference book; recent college graduates will find it useful as a textbook for learning about parachutes and parachute recovery systems; and technicians with extensive practical experience will find it useful as an engineering textbook that includes a chapter on parachute- related aerodynamics. In this manual, emphasis is placed on aiding government employees in evaluating and supervising the design and application of parachute systems. The parachute recovery system uses aerodynamic drag to decelerate people and equipment moving in air from a higher velocity to a lower velocity and to a safe landing. This lower velocity is known as rate of descent, landing velocity, or impact velocity, and is determined by the following requirements: (1) landing personnel uninjured and ready for action, (2) landing equipment and air vehicles undamaged and ready for use or refurbishment, and (3) impacting ordnance at a preselected angle and velocity.

Download or read book Wind tunnel Investigation of Inflation of Disk gap band and Modified Ringsail Parachutes at Dynamic Pressures Between 0 24 and 7 07 Pounds Per Square Foot written by Charles H. Whitlock and published by . This book was released on 1969 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploratory wind-tunnel tests of the disk-gap-band and modified ringsail parachute configurations have been conducted at dynamic pressures between 0.24 and 7.07 lb/ft2 (11 and 339 N/m2). Both parachutes exhibited positive inflation characteristics over the range of the tests within technique limitations. The disk-gap-band configuration required less time and distance to inflate than the modified ringsail configuration did.

Download or read book Studies of Aerodynamics Dynamics and Stress Analysis of Ribbon Parachutes written by Sandia Corporation and published by . This book was released on 1976 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The following report describes the continuation of wind tunnel data evaluation as shown in Progress Reports 3 through 14 under Sandia Coropration Contract 63-2241 amd 02-4022, Ref 1 to 13. The data presented in this report are related to disreefing tests of a conical ribbon parachute with 140° included angle, concentric rings, and 25% geometric porosity. The data concerning the canopy profile and pressure distributions will be presented in chronological order starting at the time of disreefing and proceeding through inflation at various time intervals until steady state conditions for the fully inflated parachute are reached. The recorded and derived data recorded and derived data are used to obtain-force time histories which can be compared with a measured force-time recording. Also, so called radial force coefficients are derived which are based on the established canopy profiles and the related pressure data.

Download or read book WInd tunnel Investigation of the Opening Characteristics Drag and Stability of Several Hemispherical Parachutes written by Stanley H. Scher and published by . This book was released on 1949 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Parametric Study of Parachute Pressure Distribution by Wind Tunnel Testing written by William B. Pepper and published by . This book was released on 1975 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure distribution data for solid and ribbon parachutes are presented. Three-foot diameter model parachutes of 0, 10, 15, 20, 25, 30, and 40 percent geometric porosity were tested. Suspension line lengths of 1.0, 1.5, and 2.0 constructed diameters were used. Reefing line lengths of 19, 38, and 57-in. were tested. Two 7 x 10-ft, wind tunnels were used to test over a range of dynamic pressure from 35 to 600 lb/ft2. Integration of the measured pressures over the inflated canopy profiles generally resulted in drag force values which agree within 10 percent of force balance drag data.

Download or read book Wind Tunnel Investigation of Flexible Parachute Model Characteristics at Mach Numbers 1 5 to 5 written by J. S. Deitering and published by . This book was released on 1964 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).

Download or read book Pressure and Profile Data of 20 Conical Ribbon Parachutes written by Helumt G. Heinrich and published by . This book was released on 1977 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sandia Laboratories, Albuquerque, N.M., established wind tunnel data of 3 ft ribbon parachute models concerning canopy profiles, drag forces and pressure distribution. The data were analyzed at the University of Minnesota and resulted in presentations of drag coefficients, projected diameters and drag areas of reefed and unreefed and parachutes versus geometric porosity and suspension line length as well as in tables and graphs of canopy coordinates and related pressure distributions. Presssure integration about the canopy surfaces as given by the established coordinates provided drag forces which agreed satisfactorily with measured forces. Also, radial force coefficients of the various configurations were established. The results of this study are intended to serve as background information for related investigations such as studies concerning parachute dynamics, stress analysis, etc.

Download or read book Development and Experimental Verification of a Single degree of freedom Inflation Model for Ribbon and Ringslot Parachutes written by John Michael Macha and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple, approximate model of parachute inflation is described. The model is based on the traditional, practical treatment of the fluid resistance of rigid bodies in non-steady flow, with appropriate extensions to accommodate change in canopy inflated shape. Correlations for the steady drag and steady radial force as functions of the inflated radius are required as input to the dynamic model. In a novel approach, the radical force is expressed in terms of easily obtainable drag and reefing line tension measurements. A series of wind tunnel experiments provides the needed correlations. Coefficients associated with the added mass of fluid are evaluated by calibrating the model against an extensive reliable set of flight data. A parameter is introduced which appears to universally govern the strong dependence of the axial added mass coefficient on motion history. Thought comparisons with flight data, the model is shown to realistically predict inflation forces for ribbon and ringslot canopies over a wide range of sizes and deployment conditions.

Download or read book Ribbon and Gliding Type Parachutes Evaluated in the 7 by 10 Foot Transonic Wind Tunnel written by Jonah Ottensoser and published by . This book was released on 1975 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment has been conducted in the NSRDC 7- x10-foot transonic tunnel for the Sandia Corporation to evaluate various parachute parameters. The experiment consisted of three main parts: the first phase evaluated the disreefing characteristics of the various parachutes as well as the drag forces before, during and after disreefing; the second phase measured the pressure distribution around the chute as well as the grag forces; and the fingal phase evaluated the disreefing and drag characteristics of gliding type parachutes. The free stream dynamic pressure varied from 65 to 500 psf.

Download or read book Ribbon and Gliding Type Parachutes Evaluated in the 7 by 10 Foot Transonic Wind Tunnel written by Jonah Ottensoser and published by . This book was released on 1975 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment has been conducted in the NSRDC 7- x10-foot transonic tunnel for the Sandia Corporation to evaluate various parachute parameters. The experiment consisted of three main parts: the first phase evaluated the disreefing characteristics of the various parachutes as well as the drag forces before, during and after disreefing; the second phase measured the pressure distribution around the chute as well as the grag forces; and the fingal phase evaluated the disreefing and drag characteristics of gliding type parachutes. The free stream dynamic pressure varied from 65 to 500 psf.

Download or read book Wind tunnel Investigation of the Static Aerodynamic Characteristics of a Multilobe Gliding Parachute written by George M. Ware and published by . This book was released on 1968 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transonic Wind tunnel Tests of a Lifting Parachute Model written by and published by . This book was released on 1976 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wind tunnel Tests of a Series of 18 foot diameter Parachutes with Extendable Flaps written by Berl Gamse and published by . This book was released on 1962 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: