Download or read book Parachute Filling Time and Opening Force Estimates written by R.G. Hume and published by . This book was released on 1973 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Calculation of Filling Time and Transient Loads for a Parachute Canopy During Deployment and Opening written by Bruce Wilcox and published by . This book was released on 1958 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical relations are developed for use in predicting the filling time and transient shock forces during the deployment and opening of a parachute canopy. These relations are used to calculate filling times and loads which are compared with measured values obtained from fullscale parachute research flight tests. The comparison is shown to be good.

Download or read book Recovery System Design Guide written by E. G. Ewing and published by . This book was released on 1979 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document serves as the third revision of the USAF Parachute Handbook which was first published in 1951. The data and information represent the current state of the art relative to recovery system design and development. The initial chapters describe representative recovery applications, components, subsystems, material, manufacture and testing. The final chapters provide empirical data and analytical methods useful for predicting performance and presenting a definitive design of selected components into a reliable recovery system.

Download or read book Theory and Experiment on Parachute Opening Shock and Filling Time written by Helmut G. Heinrich and published by . This book was released on 1971 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method of parachute opening force and filling time calculation is presented which is based on the time functions of aerodynamic drag, included air mass, apparent mass, and effective porosity. Using the momentum and continuity equations, an idealized canopy shape development and a linear drag area-time relationship, expressions are obtained for the canopy volume and velocity. The calculated peak forces agree well with at least mean square averages of field test results of 28-ft solid flat parachutes deployed at speeds from 175 to 450 fps at altitudes of 6,000, 13,000, and 21,000 ft and with suspended weights between 200 and 820 lb.

Download or read book A Method for the Calculation of Parachute Opening Forces for High Altitude Balloon Payloads written by Peter L. Miller and published by . This book was released on 1975 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the questions most frequently asked by scientists/experimenters who design balloon payloads concerns the magnitude of the opening forces of the parachute recovery system. Existing theory and an analytical method recently developed for horizontal deployment are adapted to balloon systems requirements. Engineering methods are used to develop expressions which allow the assessment of the parachute opening forces.

Download or read book Elementary Estimates of Parachute Opening Forces written by M. H. L. Waters (B.Sc.(Eng)) and published by . This book was released on 1957 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simple assumptions of the rate of parachute inflation are used to construct data sheets for parachute maximum loads and other quantities. The aim is to present an elementary analysis in detail as a basis for future comparison with experiment. Appendices treat non-horizontal motion of the parachute and store, and estimate the effect on the opening load, of the virtual air mass associated with the canopy. The 'shock factor' as measured in wind tunnel tests is also discussed, and the last Appendix extends the method of calculation to reefed parachutes.

Download or read book The Opening Time of Parachutes Under Infinite Mass Conditions written by Helmut G. Heinrich and published by . This book was released on 1968 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the infinite mass case, equations have been developed which provide the canopy filling time for solid cloth as well as for ribbon and ringslot parachutes. The results obtained by this method agree satisfactorily with empirical information given in the United States Air Force Parachute Handbook.

Download or read book Dynamics of the Opening Parachute written by J. R. Foote and published by . This book was released on 1952 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A model of the opening parachute is proposed and the equations of continuity and of motion are written. The two main parameters are: a coefficient to account for cloth porosity, and a coefficient to provide some choking of the mouth due to looseness of the cloth. The equations are solved under certain assumptions and the results are used to predict both how the force on the suspended load and how the opening rate vary with time. Experimental data is used to select values of the porosity coefficient for various altitudes. In each case the predicted shock force maximum is of the proper order of magnitude, as shown by experiment. A drag term is used which is the sum of the usual type of viscous drag term and a set of inertial drag terms calculated by F.S. Weinig for an expanding sphere. The viscous drag term is of leading importance. The drag coefficient is varied with the porosity coefficient by means of a type of formula indicated by experiment. This gives a greater drag coefficient at higher altitudes and helps to cause a greater shock force at higher altitudes and helps to cause a greater shock force by giving a greater opening rate and less parachute filling time.

Download or read book Study of Parachute Opening written by J. R. Foote and published by . This book was released on 1958 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: A model of the opening parachute is considered which permits extensive mathematical analysis. Included are the effects of nine physical parameters, governing drag, initial speed and diameter, parachute dimensions and load, altitude, cloth permeability, and a choking factor representing a difference between the model geometry and observed parachute geometry. The governing equations are developed to a point permitting calculations of system speed, opening rate, and shock force as functions of time. Numerous calculations were made in which the choking factor was varied to yield experimentally-known forces, the variation of this factor having been guided by means of analysis of motion pictures of parachute openings. Other theory was developed for calculation of the individual effects of all the parameters upon the shock force. The nature of current measured data and an insufficient number of calculations have not permitted a verification of this theory for calculation of the individual effects of all the parameters.

Download or read book Inflation and Performance of Three Parachute Configurations from Supersonic Flight Tests in a Low density Environment written by Charles H. Whitlock and published by . This book was released on 1969 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ten flight tests of modified-ringsail, disk-gap-band, and cross parachute configurations with deployment at Mach numbers and dynamic pressures corresponding to conditions expected during entry into a Martian atmosphere have been completed. Comparison of flight results indicates that theoretical snatch force values were never exceeded when the deployment techniques of these tests were used. Opening loads showed no definite trend with Mach number. Values for filling times compared favorably with generally accepted empirical curves based on 15-percent geometric porosity. Canopy stability was good when Mach numbers were below 1.4 for the modified-ringsail and disk-gap-band configurations.

Download or read book Notes on a Theoretical Parachute Opening Force Analysis Applied to a General Trajectory written by William P. Ludtke and published by . This book was released on 1988 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents a method for calculating the inflation reference time and opening shock forces of the solid-cloth family of parachutes when deployed at an arbitrary trajectory angle to the horizontal. The method is extended to other types of parachutes, but it is limited in that the inflation reference times are not calculated as part of the deployment process. Particular inflation times must be provided as input data to the furnished computer program. The variation of opening shock force versus inflation reference time may be surveyed by providing several values or using actual field test data. Examples are used to demonstrate the effects of canopy cloth rate of airflow, altitude, and trajectory deployment angle for constant velocity and constant dynamic pressure altitude profiles. Keywords: Variable deployment angle, Inflation time, Parachute technology, Opening shock, Calculation methods, Altitude effects.

Download or read book Opening Force and Filling Time of 35 Foot Diameter 10 Flat Extended Skirt Canopies written by Lawrence L. Watson and published by . This book was released on 1974 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: An in-house test program was accomplished with thirty-five foot diameter canopies of the type T-10 and of heavier construction incorporating 2.25 ounce nylon cloth and 1500 pound tensile strength suspension lines. The test canopies were deployed behind cylindrically shaped test vehicles of weights ranging between 174 and 865 pounds. Parachute deployments were programmed to occur at altitudes between 600 and 37,000 feet, at speeds between 200 and 475 ft/sec, and along horizontal and vertical trajectories. Force-time histories, space positioning data, and on-board photographic recordings of the parachute opening process were obtained for each of the forty-six deployment tests conducted. The results of the data analysis show that two distinct force peaks are generated during canopy inflation.

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 A Linearised Theory of Parachute Opening Dynamics written by Helmut G. Heinrich and published by . This book was released on 1972 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inflation of a parachute encompasses problems of aerodynamics, dynamics, and elasticity. The most noticeable effects of the interaction of the events are the opening force and the filling time. Attempts to analyse the opening process and to predict the opening force date back to 1927. Since then a considerable number of methods have been published. Some of them are primarily analytical, others more empirical, and several deal with isolated problems. The earliest and most analytically oriented studies are by Scheubel and O'Hara.

Download or read book Aerodynamic Deployable Decelerator Performance Evaluation Program written by E. Bloetscher and published by . This book was released on 1967 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Aerodynamic Deployable Decelerator Performance-Evaluation Program (ADDPEP) aims to advance the state of the art by developing the most effective analytical and empirical techniques for designing aerodynamic deployable decelerators and for evaluating these engineering techniques through wind-tunnel and free-flight tests. During ADDPEP Phase 2, two types of decelerators were investigated: large reefed supersonic parachutes and raminflated balloon-type BALLUTEs. The areas investigated included analytical and engineering design, material capabilities, fabrication techniques, and wind-tunnel and free-flight tests. Free-flight tests were performed on a hemisflo parachute having a nominal 16-ft-diameter canopy, a 10-percent extended skirt, and a 14-percent porosity. This design was tested for 200,000-lb opening loads, deployment Mach numbers were 1.50, 1.63, and 1.84 at altitudes of 13,700, 15,500, and 10,500 ft, respectively. The results confirmed that this parachute has excellent aerodynamic characteristics and adequate strength. Five-foot-diameter BALLUTEs, both textile and metal, were fabricated. These were designed for a broad spectrum of deployment conditions ranging from Mach 2.7 at 73,000 ft to Mach 10 at 225,000 ft. The textile BALLUTEs were wind-tunnel and free-flight tested; the metal BALLUTEs were wind-tunnel tested only. Flight tests were limited to Mach 9.7, and wind-tunnel tests to Mach 3. The flight test data supported wind-tunnel data, which indicated that excellent stability and structurally adequate designs can be attained with five-foot-diameter BALLUTEs.

Download or read book Experimental Determination of Parameters for the Calculation of Parachute Filling Times written by Rudi J. Berndt and published by . This book was released on 1964 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: The filling or inflation process of a flat circular, solid cloth type parachute canopy operating under finite mass conditions is analyzed in detail. Experimental test results acquired during model tests in wind tunnels and during full scale tests on personnel and air drop type parachute canopies at altitudes between sea level and 21,000 feet form the basis for the analysis. Parameters and relationships acquired as a result of the experimental test programs or derived analytically are expressed in mathematical terms so that they may be used directly for the solution of the mass balance and instantaneous velocity equations upon which the calculations of parachute filling time is based. The parameters and relationships concern the shape of the inflating canopy, the growth of the drag area of the canopy, the canopy flow velocities and growth of the air volume enclosed by the drag producing surface, and the instantaneous velocity of the load-parachute configuration.

Download or read book Notes on a Parachute Opening Force Analysis Applied to a Vertical Toward the Earth Trajectory written by William P. Ludtke and published by . This book was released on 1987 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recovery of payloads from high altitude often requires the deployment of parachutes on trajectories that are essentially vertical and toward the earth. The parachute opening shock force developed by a parachute deployed in this manner exceeds the opening shock force of the same parachute system deployed horizontally at the same altitude and velocity. As the deployment trajectory angle varies from horizontal to vertical, the opening shock force increased to a maximum. Hence, the vertical trajectory has special significance. This report develops an analysis to permit the calculation of opening shock forces in vertical deployment. The validity of the rule of thumb that 'the vertical deployment opening shock force exceeds the horizontal shock force by one 'g' is tested, and criteria are developed. Examples are used to demonstrate applications of the approach, and a method of calculating the inflation time of Solid Cloth parachutes in vertical fall developed. Keywords: Vertical inflation time; Limiting ballistic mass ratio.