Download or read book Force Distribution in the Suspension Lines of Cross Parachutes written by William P. Ludke and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The force distribution in the several suspension lines attached to an arm of a Cross-type parachute is nonuniform. rhe outer suspension lines carry the minimum force. The forces increase in each suspension line as the line attachment approaches the center of the arm with the maximum force carried by the most central lines. This report describes a series of wind tunnel tests to measure the force in individual selected suspension lines of Cross-type parachutes with 8, 16, and 24 suspension lines. The test results show that . lengthening the inner suspension lines tend Lo equalize the suspension line forces. The static pressure distribution adjacent to the parachute center line was measured for each parachute model. Positive pressures were found to exist ahead of the canopy skirt hem as well as inside the canopy. The magnitude of the pressures is influenced by the canopy cloth permeability.

Download or read book Force Distribution in the Suspension Lines of Cross Parachutes written by William P. Ludtke and published by . This book was released on 1989 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The force distribution in the several suspension lines attached to an arm of a Cross-type parachute is nonuniform. The outer suspension lines carry the minimum force. The forces increase in each suspension line as the line attachment approaches the center of the arm with the maximum force carried by the most central lines. This report describes a series of wind tunnel tests to measure the forces in individual selected suspension lines of Cross type parachutes with 8, 16, and 24 suspension lines. The test results show that lengthening the inner suspension lines tends to equalize the suspension line forces. The static pressure distribution adjacent to the parachute center line was measured for each parachute model. Positive pressures were found to exist ahead of the canopy skirt hem as well as inside of the canopy. The magnitude of the pressures is influenced by the canopy cloth permeability.

Download or read book Evaluation of a Parachute Load Distribution Measuring System During Low Altitude Drop Tests written by I. S. Hoffman and published by . This book was released on 1969 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: In conjunction with the low-altitude preflight drop test phase of the NASA Supersonic High-Altitude Parachute Experiments (SHAPE) program, canopy-load-distributed measurements were made on each of three types of parachute during deployment (by means of a mortar) from an aircraft-dropped payload. Loads were measured with miniature load cells at various locations on the canopies and in the suspension lines of 30- and 40-foot-diameter (9.14 and 12.19 meters) parachutes, with a total of seven measurements of this type being made on each of seven instrumented parachute drops. Out of a total of 49 such individuual measurement attempts, there were six individual load-cell problems, which included one of lead-wire breakage during parachute deployment. Total parachute load measurements were also made during each test by means of a tensionmeter in the main riser line. In addition, for the total parachute instrumentation program, data from approximately 40 percent of the channels were not obtained due apparently to onboard telemetry malfunction.

Download or read book Evaluation of Massless spring Modeling of Suspension line Elasticity During the Parachute Unfurling Process written by Lamont R. Poole and published by . This book was released on 1972 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A general theory on mathematical modeling of elastic parachute suspension lines during the unfurling process was developed. Massless-spring modeling of suspension-line elasticity was evaluated in detail. For this simple model, equations which govern the motion were developed and numerically integrated. The results were compared with flight test data. In most regions, agreement was satisfactory. However, poor agreement was obtained during periods of rapid fluctuations in line tension.

Download or read book Flight Tests of Cross Modified Ringsail and Disk gap band Parachutes from a Deployment Altitude of 3 05 Km 10 000 Ft written by and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pressure Distribution Measurements of Conventional Ribbon Parachutes in Supersonic Flow written by Eugene L. Haak and published by . This book was released on 1962 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventionally shaped Ribbon parachutes do not function satisfactorily as aerodynamic decelerators in supersonic flow. Particularly objectionable is their unstable behavior. In order to determine the cause of this structural and dynamic instability, a series of pressure distribution measurements were made on ribbon parachutes at Mach numbers of 0.8, 1.2, 3.0, and 4.5. This report presents the results of measurements and attempts to indicate the effect of suspension lines and forebodies on the pressure distribution of the parachute canopy.

Download or read book UNITED STATES AIR FORCE PARACHUTE HANDBOOK written by United States. Army Air Forces. Materiel Command and published by . This book was released on 1947 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Techniques for Selection and Analysis of Parachute Deployment Systems written by Earle K. Huckins and published by . This book was released on 1970 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Parachute Scale Effects written by William B. Walcott and published by . This book was released on 1963 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to determine the effects of changing scale upon drag coefficients, filling time, peak opening force, and stability for single, unreefed textile parachute canopies. The investigation was confined to Flat Circular, Extended Skirt, Ringslot, Ribless Guide Surface, Circular Flat Ribbon, and Conical Ribbon parachutes operating in the subsonic flow regime at altitudes below 20,000 feet. As an integral part of the study, a survey of the existing literature and test data, a compilation of all pertinent data, and recommendations for future experimental investigations were made. Scaling equations with associated 95-percent confidence intervals were developed for the drag coefficient of the Flat Circular and Extended Skirt parachutes through the use of multiple regression analysis which the indicates the significant variables and their functional forms. Because the available data was poorly distributed, the equations will have to be used circumspectly to avoid misleading conclusions.

Download or read book WADC Technical Report written by United States. Wright Air Development Division and published by . This book was released on 1953 with total page 1278 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of Parachute System Mass and Suspension Line Elastic Properties on the Ladt 3 Viking Parachute Inflation Load written by Theodore A. Talay and published by BiblioGov. This book was released on 2013-07 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analytical calculations have considered the effects of 1) varying parachute system mass, 2) suspension-line damping, and 3) alternate suspension-line force-elongation data on the canopy force history. Results indicate the canopy force on the LADT #3 parachute did not substantially exceed the recorded vehicle force reading and that the above factors can have significant effects on the canopy force history. Analytical calculations have considered the effects of i) varying parachute system mass, 2) suspension line damping, and 3) different suspension-line force-elongation data on the canopy force history. Based on the results of this study the following conclusions are drawn: Specifically, 1. At the LADT #3 failure time of 1.70 seconds, the canopy force ranged anywhere from 15.7% below to 2.4% above the vehicle force depending upon the model and data used. Therefore, the canopy force did not substantially exceed the recorded vehicle force reading. 2. At a predicted full inflation time of 1.80 seconds the canopy force would be greater than the vehicle force by from 1.1% to 10.6%, again depending upon the model and data used. Generally, 3. At low altitudes, enclosed and apparent air mass can significantly effect the canopy force calculated and should, therefore, not be neglected. 4. The canopy force calculations are sensitive to decelerator physical properties. In this case changes in the damping and/or force-elongation characteristics produced significant changes in the canopy force histories. Accurate prediction of canopy force histories requires accurate inputs in these areas.

Download or read book Textile Technology Digest written by and published by . This book was released on 1993 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993-07 with total page 1484 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Snatch Force During Lines first Parachute Deployment written by Earle K. Huckins (III.) and published by . This book was released on 1971 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Snatch force is generally considered to be the maximum suspension-line tension at the vehicle during the deployment process prior to canopy inflation. For a canopy-first type of deployment, the maximum tension is generated immediately after the decelerator is completely extended. However, for a lines-first deployment, the maximum tension gnerally occurs as the canopy skirt emerges form the deployment bag.

Download or read book Reefing of Parachutes written by Theodore W. Knacke and published by . This book was released on 1981 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents data on the forces in reefing lines. The force data were obtained from wind tunnel tests, from aerial free-flight tests and through the analysis of known reefing line failures. It was found that forces in reefing lines vary with the type of parachute used, with the reefing ratio, with the length of the suspension lines and with single or multiple stage reefing. The report discusses the difference in the reefing line forces of first stage drogue chutes, ordnance type retardation parachutes and large final descent main parachutes. Recommendations are made for stressing the reefing lines for various types of application.

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 Effects of Canopy Geometry and Cloth Permeability on the Drag Coefficient of a Cross Parachute in the Fully Open and Reefed Conditions for a W L Ratio of 0 3 written by W. P. Ludtke and published by . This book was released on 1982 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes a series of wind-tunnel tests on the cross-type parachute to investigate the effects of cloth permeability, number of suspension lines, and suspension line length in the fully opened and reefed conditions. Forty-inch-diameter models with a canopy arm width-to-length ratio (W/L) of 0.3 were tested at various velocities from 50 fps to 293 fps in the fully inflated state. Results of these tests demonstrate that the parachute geometry and cloth permeability do have an effect on the drag capability of the cross parachute. Additional tests of reefed configurations for several reefing line lengths-to- canopy-diameter ratios from 0.6 to 1.6 at a constant velocity of 203 fps established the reefed characteristics of this parachute. The steady state forces in the reefing line were measured by use of strain gage links. Data are presented in tabular and graphical format. Photographs of representative canopy shapes are included for illustration.