Download or read book Analysis of Wind Tunnel Tests Concerning Disengagement Impulses of Parachute Suspension Lines and Risers written by Helmut G. Heinrich and published by . This book was released on 1972 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: A 28-ft solid flat parachute, United States Air Force Standard C-9 canopy was deployed from its deployment bag in a wind tunnel running at speeds of 115, 150, and 200 fps. By means of electronic instrumentation the impulses were recorded that developed when the risers and suspension lines are disengaged from their ties and stow loops. The disengagement impulses were repeatable, and their numerical value was established and confirmed. The influence of the impulses upon the velocity of the moving mass is significant.

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:

Download or read book Wind tunnel Tests of a Series of Parachutes Designed for Controllable Gliding Flight written by James A. Weiberg and published by . This book was released on 1967 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 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 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 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 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 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 AIAA Bulletin written by and published by . This book was released on 1973 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 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 The Effect of Line Disengagement Impulses Upon the Parachute Snatch Force written by Helmut G. Heinrich and published by . This book was released on 1966 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theory of parachute snatch force calculation incorporating the effect of the line disengagement impulses is developed and used to calculate snatch forces of the 28-ft solid flat circular parachute, C-9, for cases for which the results of numerous field tests are available. The calculated forces agree satisfactorily with the field test results. Further calculations with the same theory, however, without consideration of disengagement impulses showed consistently higher forces than the field tests results. This indicates that the disengagement impulses are significant contributions in the calculation of parachute snatch forces. Since the improved method of calculation provides the field tests fitting results, the benefits resulting from the disengagement impulses should be considered in the design of parachute deployment bags.

Download or read book Test Fixture and Data Acquisition System for Wind Tunnel Testing of Parachutes written by Charles J. Silcot and published by . This book was released on 1968 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: After the analysis of the means of measuring the force and stability characteristics of flexible, steerable, gliding parachutes in the AFFDL 12-foot open-throat vertical wind tunnel at Wright-Patterson Air Force Base, a system was designed, fabricated, installed, and tested for acceptance. This system consists of two major components: The first major component, a test fixture-balance assembly, provides the means of remotely operating model parachutes through various roll, pitch, and yaw angles. This assembly consists basically of a roll-traversing mechanism which supports a sting balance as it rolls and yaws along the inner perimeter of a semicircular trussed hoop. The hoop rests on a two-part structure designed for temporary installment above the tunnel lip. For the parachute attachment and positioning, the sting balance was selected in a preliminary study in preference to the wire or strut type of balance. The second major component, a data acquisition and readout system, displays and records in digital form the normal and axial forces and the moments at various canopy pitch, roll, and yaw attitudes. In the acceptance tests with a 9.375-foot steerable parachute canopy, lift, drag, and pitching moment were obtained at various angles of pitch and at air velocities ranging from 50 to 100 feet per second.

Download or read book Analysis of Parachute Opening Dynamics with Supporting Wind Tunnel Experiements written by Helmut G. Heinrich and published by . This book was released on 1968* with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study is concerned with identification of significant terms in the process of parachute inflation. For finite mass cases, the equations of motion for parachutes inflating in free air and in wind tunnel experiments are established and organized in view of the nonsteady terms of canopy size, systems velocity, included and apparent masses, and the time derivatives of these terms. Wind tunnel experiments are described, the results of which yield graphical and numerical time functions for the significant terms of the equation of motion and the force-time histories. The wind tunnel results are compared with full size test information and certain identities are shown. The significant terms are combined to functions unique for the test conditions and substituted in the equation of motion. Force-time functions so derived compare satisfactorily with measured force histories and the contributions of the individual terms to the instantaneous parachute force can be seen.