Download or read book Parachute Inflation Process Wind tunnel Study written by Edwin Pounder and published by . This book was released on 1956 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents results of an experimental study of the parachute inflation process. The investigation was carried out in a low speed wind tunnel using small cloth models, and an analysis is presented which gives a basis for extrapolation of the data recorded to any reasonably low Mach number case. The drag of the parachutes and the shapes of the canopies during the inflation process are studied in considerable detail, and some qualitative studies of the flow fields are conducted. The principle variables studied are parachute type, velocity (dynamic pressure), and canopy porosity. The theoretical analysis develops a procedure by which full scale characteristics can be predicted from wind tunnel data, and several examples are computed to illustrate the technique.

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 Dynamics of Parachute Inflation written by H. G. Heinrich and published by . This book was released on 1969 with total page 28 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 sigificant 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.

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.

Download or read book A Method to Reduce Parachute Inflation Time with a Minor Increase of Opening Force written by Helmut G. Heinrich and published by . This book was released on 1960 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: A short opening time and a moderate opening force are desirable characteristics in practically all parachute applications. However, the relationship between opening time and force is one of the most intricate functions in the dynamics of the parachute inflation. In particular, parachutes with a characteristically fast inflation develop in general a high opening force. In the following study, a method has been devised for which, in wind tunnel tests, the duration of the initial phase of the inflation has been reduced, whereas the final phase, during which the maximum force occurs, remains basically unchanged.

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 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 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 Feasibility Study of Aerodynamic Reefing of Subsonic Parachutes written by Helmut G. Heinrich and published by . This book was released on 1973 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inflation characteristics of solid flat circular model parachutes with stiffness indices in the order of 1.17 and various annular slots were studied in a wind tunnel at velocities up to 265 fps. The amount of the geometric porosity was varied as well as the location of the annular slots. It was found that at a speed of 250 fps models with geometric porosities up to 18% inflated immediately, with porosities between 18% and 28% the models showed random inflation and collapsing, and at porosities of 28% and higher squidding or aerodynamic reefing was observed. The location of the slots did not influence the inflation characteristics significantly. The critical speed was established for a number of models; however, the conclusion was reached that more efforts have to be made in order to understand the mechanics of squidding to be able to take advantage of the principle of aerodynamic reefing for full scale design. (Author).

Download or read book Opening Dynamics of a T 10 Parachute with Inflation Aids written by Helmut G. Heinrich and published by . This book was released on 1970 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: The characteristic times and opening forces were studied for various inflation aid configurations of a model T-10 parachute. Finite mass wind tunnel tests were conducted in the horizontal return wind tunnel at a snatch velocity of 70 fps with a suspended load of 1.1 lbs. Relative to results of the standard T-10 parachute, the percentage decrease in the characteristic time and the corresponding percentage increase in the peak force were presented for five centerline, three internal parachutes and two centerline-internal combinations.

Download or read book U S Government Research Reports written by and published by . This book was released on 1958 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Flow Field During the Inflation of Clustered Parachutes written by R. J. Niccum and published by . This book was released on 1966 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clustered parachutes during the period of inflation were simulated by elliptical cylinders in potential flow and so-called O'Hara shape parachutes in water flow and wind tunnel experiments. The results are presented in the form of streamline and pressure distribution plots around the respective bodies. Results show that when geometric symmetry is disturbed, the flow field becomes unsymmetrical and strong attractive or repulsive forces are developed. This allows a variety of inflation modes to occur and, hence, poor cluster opening performance.

Download or read book Study of Parachute Forces and Canopy Pressure Distribution Measured in a Subsonic Wind Tunnel Under Infinite Mass Conditions written by Helmut G. Heinrich and published by . This book was released on 1972 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the purpose of parachute canopy stress analysis during the period of inflation, the pressure distribution measured on a ring-slot parachute model is related to the instantaneous parachute force. The correlation of pressure and force data is based on test results established at the Deutsche Forschungsanstalt fuer Luft-und Raumfahrt (DFLR), Braunschweig, Germany. The final pressure-force-time relationship incorporate individual as well as averaged test data. A fair agreement could be shown between measured forces and those obtained from numerical integration of differential pressure over the canopy surface.

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 An Experimental Study of the Performance of Clustered Parachutes in a Low speed Wind Tunnel written by B. Kurt Baca and published by . This book was released on 1985 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent interest in clusters of parachutes prompted a review of cluster drag data and inflation characteristics. This examination indicated that very little well-documented data exist that are suitable for broad applications. A low-speed wind-tunnel test program was devised to measure the effects of variations in four important parameters on the terminal drag and stability of clusters of parachutes. The parameters studied were canopy number, canopy type, riser length, and reefing. Efforts were made to account for effects stemming from the experiment's design, especially wind-tunnel blockage. Many of the results of the wind-tunnel tests were validated by a series of drop tests. Terminal drag and stability data are presented here along with proposed explanations for observed phenomena.

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.