Download or read book Parachute Inflation A Problem in Aeroelasticity written by and published by . This book was released on 1994 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: In parachute research, canopy inflation is the least understood and most complex process to model. Unfortunately, it is during the opening process that the canopy experiences the largest deformations and loadings. The complexity of modeling the opening process stems from the coupling between the structural dynamics of the canopy, lines plus payload and the aerodynamics of the surrounding fluid medium. The addition of a computational capability to model the coupled opening behavior would greatly assist in understanding the canopy inflation process. Ongoing research at the U.S. Army Natick Research, Development and Engineering Center (Natick) focuses on this coupled problem. The solution to this problem will assist in the development of future U.S. Army airdrop systems, which include the capability of deploying at low altitudes and high speeds. This report describes research at Natick that currently involves coupling a computational fluid dynamics (CFD) code to a mass spring damper (MSD) parachute structural code. The model is described and results are presented.

Download or read book Parachute Inflation written by Keith R. Stein and published by . This book was released on 1994 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: In parachute research, canopy inflation is the least understood and most complex process to model. Unfortunately, it is during the opening process that the canopy experiences the largest deformations and loadings. The complexity of modeling the opening process stems from the coupling between the structural dynamics of the canopy, lines plus payload and the aerodynamics of the surrounding fluid medium. The addition of a computational capability to model the coupled opening behavior would greatly assist in understanding the canopy inflation process. Ongoing research at the U.S. Army Natick Research, Development and Engineering Center (Natick) focuses on this coupled problem. The solution to this problem will assist in the development of future U.S. Army airdrop systems, which include the capability of deploying at low altitudes and high speeds. This report describes research at Natick that currently involves coupling a computational fluid dynamics (CFD) code to a mass spring damper (MSD) parachute structural code. The model is described and results are presented.

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 A Discussion of Parachute Inflation Theories written by Bryan W. Roberts and published by . This book was released on 1975 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decades numerous attempts have been made to describe the inflation performance of aerodynamic decelerators. The most popular approaches of filling time and filling distance are based on two questionable assumptions. These assumptions relate to the form of a family of canopy profiles, and the volume flow into and from the canopy volume. More recently there has emerged new and important approaches to this basic problem. It will be shown how these newer methods can be used to predict the inflation shapes and the canopy pressure distribution as a function of time.

Download or read book Analysis of Deployment and Inflation of Large Ribbon Parachutes written by D. F. McVey and published by . This book was released on 1973 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method for predicting deployment and inflation of reefed ribbon parachutes is presented. The method is based on integration of axial and radial momentum equations developed in the paper. Axial and radial forces are assumed to be describable by drag and radial force coefficients. Computer solutions of the equations are compared to measured parachute loads and to parachute mouth and maximum diameters from tests of 23- and 76-ft diameter conical ribbon parachutes. Comparison of load histories indicated that snatch loads depend to a large extent on deployment bag design and packing influences. Computed loads and parachute size histories for the inflation process compared favorably with flight data. The concept of a radial force coefficient appears to have considerable merit as a means of computing inflation for most parachutes.

Download or read book Inflation of a Multi element Parachute Structure written by K. R. Reddy and published by . This book was released on 1975 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The time history of the inflation of a two-dimensional, multiple plate canopy is examined in detail. The canopy is idealised by a finite number of rigid plate elements hinged one to another. A finite wake flow past this structure is considered. It is postulated that there is a vortex sheet buried in and coincident with the physical location of the canopy. Finally, the total moment about each hinge is equated to zero to obtain a set of coupled, differential equations. Their solution gives the inflation history of the canopy.

Download or read book Parachute Stress Analysis During Inflation and at Steady State written by H. G. Heinrich and published by . This book was released on 1969 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the period from 1965 to 1969, two new methods for stress calculations have been proposed and general remarks primarily concerning the elasticity characteristics of a parachute cloth and pressure distribution have been made. The conservative way of performing a parachute stress snalysis consists of first establishing the geometry of the parachute canopy and then applying a certain pressure distribution. Subsequently, the pressure distribution has been linked to the instantaneous parachute force which can be obtained from an opening shock calculation. In this manner one can possibly obtain closed solutions with a minimum of empirical factors. An example of this approach is presented in detail in the following chapters.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Some Research Efforts Related to Problems of Aerodynamic Deceleration written by Helmut G. Heinrich and published by . This book was released on 1960 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The status of research efforts designed to explain physical phenomena associated with the operation of aerodynamic decelerators, in particular textile type parachutes, is presented. A theoretical approach to calculate the velocity and pressure distribution in the turbulent wake of basic bodies of revolution is outlined and compared to actual test results. The concept of the effective porosity of textile materials is developed, and its influence upon the aerodynamic and opening characteristics of conventional textile parachute canopies is discussed. The results of research efforts to reduce parachute inflation time with a minor increase of opening force are presented.

Download or read book Aerodynamic Characteristics of Parachutes at Mach Numbers from 1 6 to 3 written by Julian D. Maynard and published by . This book was released on 1961 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Parachute Stress Analysis During Inflation and at Steady State written by H. G. Heinrich and published by . This book was released on 1964 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stresses occurring in the cloth of a parachute during the period of inflation and under steady state are calculated for a number of instantaneous shapes which are characteristic of the opening process and the steady state. The method is general and may be applied to any type of parachute built out of solid cloth, concentric rings or ribbons. The presented analysis is related to canopies consisting of triangular gores but can be extended to other gore patterns. A numerical calculation is made for a solid flat circular parachute during the period of opening and at steady state.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1985 with total page 1156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Parachute Stress Analysis During Inflation and at Steady State written by Helmut G. Heinrich and published by . This book was released on 1966 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: The stresses occurring in the cloth of a parachute during the period of inflation and at a steady state are calculated for a number of instantaneous shapes that are characteristic of the opening process and the steady state. The method is general and may be applied to any type of parachute built out of solid cloth, concentric rings, or ribbons. The presented analysis is related to canopies consisting of triangular gores but can be extended to other gore patterns. A numerical calculation is made for a solid flat circular parachute during the period of opening and at steady state.

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 Aerodynamic Inflation and Oscillation of Wedges with Particular Reference to Parachutes written by Kada Rami Reddy and published by . This book was released on 1976 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Suspension Line Length on Viking Parachute Inflation Loads written by Theodore A. Talay and published by BiblioGov. This book was released on 2013-07 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA Technical Reports Server (NTRS) houses half a million publications that are a valuable means of information to researchers, teachers, students, and the general public. These documents are all aerospace related with much scientific and technical information created or funded by NASA. Some types of documents include conference papers, research reports, meeting papers, journal articles and more. This is one of those documents.

Download or read book Aeronautical Engineering written by and published by . This book was released on 1971 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)