Drag and Dynamics of Single and Clustered Parachutes in Freestream, and with Wake and Ground Effects PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Drag and Dynamics of Single and Clustered Parachutes in Freestream, and with Wake and Ground Effects PDF full book. Access full book title Drag and Dynamics of Single and Clustered Parachutes in Freestream, and with Wake and Ground Effects by Helmut G. Heinrich. Download full books in PDF and EPUB format.
Author: Helmut G. Heinrich Publisher: ISBN: Category : Drag (Aerodynamics) Languages : en Pages : 100
Book Description
Results of wind tunnel studies concerned with transient and steady state performance of single and clustered parachutes in cargo extraction systems are presented. In Part 1, circular flat and ringslot canopies singly suspended and in clusters of 2, 3, and 4, were deployed in freestream, in the wake of an aircraft, and near a simulated ground. As a further means of analysis, wake pressure surveys were performed on the DHC-4 Caribou and the C-130 Hercules aircraft and are presented in Part 2.
Author: Helmut G. Heinrich Publisher: ISBN: Category : Drag (Aerodynamics) Languages : en Pages : 100
Book Description
Results of wind tunnel studies concerned with transient and steady state performance of single and clustered parachutes in cargo extraction systems are presented. In Part 1, circular flat and ringslot canopies singly suspended and in clusters of 2, 3, and 4, were deployed in freestream, in the wake of an aircraft, and near a simulated ground. As a further means of analysis, wake pressure surveys were performed on the DHC-4 Caribou and the C-130 Hercules aircraft and are presented in Part 2.
Author: H. G. Heinrich Publisher: ISBN: Category : Parachutes Languages : en Pages : 108
Book Description
The drag and stability characteristics of single and clustered solid flat and ringslot parachutes as cargo extraction systems in the wake of a model of the Caribou airplane with windmilling and powered propellers are reported. The investigation also includes the effect of actuated wing trailing flaps, and the variation of the parachute performance parameters in midair and near the ground. It was found that in all cases the drag coefficient of the cluster decreases with the increased number of canopies in the cluster, and a single ringslot parachute is more stable than the most stable cluster of solid flat canopies. The effects of the powered propeller slipstream and flap actuation are noticeable but not dominating. Also, wake surveys of the airplane showed characteristic dynamic pressure defects or increases for power off or on flight conditions. The location of these pressure fields was noticeably influenced by flap actuation and ground effects.
Author: E. G. Ewing Publisher: ISBN: Category : Parachutes Languages : en Pages : 502
Book Description
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.
Author: Theo W. Knacke Publisher: ISBN: Category : Sports & Recreation Languages : en Pages : 524
Book Description
The purpose of this manual is to provide recovery system engineers in government and industry with tools to evaluate, analyze, select, and design parachute recovery systems. These systems range from simple, one-parachute assemblies to multiple-parachute systems, and may include equipment for impact attenuation, flotation, location, retrieval, and disposition. All system aspects are discussed, including the need for parachute recovery, the selection of the most suitable recovery system concept, concept analysis, parachute performance, force and stress analysis, material selection, parachute assembly and component design, and manufacturing. Experienced recovery system engineers will find this publication useful as a technical reference book; recent college graduates will find it useful as a textbook for learning about parachutes and parachute recovery systems; and technicians with extensive practical experience will find it useful as an engineering textbook that includes a chapter on parachute- related aerodynamics. In this manual, emphasis is placed on aiding government employees in evaluating and supervising the design and application of parachute systems. The parachute recovery system uses aerodynamic drag to decelerate people and equipment moving in air from a higher velocity to a lower velocity and to a safe landing. This lower velocity is known as rate of descent, landing velocity, or impact velocity, and is determined by the following requirements: (1) landing personnel uninjured and ready for action, (2) landing equipment and air vehicles undamaged and ready for use or refurbishment, and (3) impacting ordnance at a preselected angle and velocity.
Author: Carl W. Peterson Publisher: ISBN: Category : Drag (Aerodynamics) Languages : en Pages : 47
Book Description
An experiment was conducted to evaluate approximate analytical methods for predicting the reduction in parachute drag caused by forebody wake effects. The drag of a 20° conical ribbon parachute was measured at several axial stations behind an ogive cylinder forebody with and without fins. The same parachute was tested in "undisturbed" flow (where wake effects were neligible) so that the effects of suspension line length on parachute drag could be separated from the drag losses caused by the turbulent wake. Total head pressure surveys were made across the forebody wake and integrated scross the canopy skirt area to determine the effective dynamic pressure acting on the parachute. Experimental results confirmed the validity of the underlying physical model of the parachute/wake interaction: the ratio of parachute drag behind a forebody divided by wake-free parachute drag is equal to the ratio of effective dynamic pressure acting on the parachute divided by free-stream dynamic pressure. However, the inability of existing turbulent wake theoretical models to make accurate predictions of wake velocity distributions for arbitrary forebody shapes is a fundamental limitation of the drag-loss analysis. If wake velocity profiles are known, the empirical constants in the turbulent wake theoretical models can be adjusted and accurate estimates of wake-induced parachute drag loss can be obtained from existing theory.
Author: C. W. Peterson Publisher: ISBN: Category : Parachutes Languages : en Pages : 10
Book Description
An experiment was conducted to evaluate approximate analytical methods for predicting the reduction in parachute drag due to forebody wake effects. The drag of a 20° conical ribbon parachute was measured at several axial stations behind an ogive-cylinder forebody with and without fins. The same parachute was tested in "undisturbed" flow (where wake effects were negligible) so that the effects of suspension line length on parachute drag could be separated from the drag losses caused by the turbulent wake. Total head pressure surveys were made across the forebody wake and integrated across the canopy skirt area to determine the effective dynamic pressure acting on the parachute. Experimental results confirmed the validity of the underlying physical model of the parachute/wake interaction: the ratio of parachute drag behind a forebody divided by wake-free parachute drag is equal to the ratio of effective dynamic pressure acting on the parachute divided by freestream dynamic pressure. However, the inability of existing turbulent wake theoretical models to make accurate predictions of wake velocity distributions for arbitrary forebody shapes is a fundamental limitation of the drag loss analysis. If wake velocity profiles are known, the empirical constants in trhe turbulent wake theoretical models can be adjusted and accurate estimates of wake-induced parachute drag loss can be obtained from existing theory.
Author: D. E. Waye Publisher: ISBN: Category : Aerodynamic load Languages : en Pages : 14
Book Description
A study was performed to evaluate the performance of equivalent drag area single parachute systems and cluster parachute systems during the early inflation and initial deceleration phase. Analytical work showed that the cluster system could exhibit better performance during this unsteady aerodynamic phase due to a significant decrease in the apparent mass of air influenced by the parachutes. Two test programs have been performed in support of these assumptions. The first compared systems with parachute effective drag areas of approximately 750 ft2 and a payload of 2400 lbs. The cluster system performed better and exhibited less susceptibility to parachute collapse due to wake recontact. The second series comapred systems with parachute effictive drag areas of approximately 260 ft2 with a payload of 800 lbs. The advantagees of the cluster system in this case were less apparent but performance was moderately improved.
Author: Sanger M. Burk Publisher: ISBN: Category : Aerodynamics, aircraft Languages : en Pages : 24
Book Description
A drop-test investigation has been conducted to determine the stability and drag characteristics of radially vented (duplex) parachutes. Parachutes of two different designs were tested: a large parachute with high geometric porosity and a small parachute with low geometric porosity designed for the same descent velocity with the same load. The results of the tests show that the large high-porosity duplex parachute was very stable in descent, oscillations averaging about [plus-or-minus]3.40; and the average drag coefficient based on the total canopy area and based on the fabric area alone were approximately 0.38 and 0.55, respectively. The small, low-porosity duplex parachute was also very stable in descent, oscillations averaging about [plus-or-minus]4.50; and the average drag coefficients based on the total canopy area and based on the fabric area alone were approximately 0.62 and 0.79, respectively. The oscillations for the cluster of three solid flat circular parachutes, tested for comparison purposes, were [plus-or-minus]7.10. The average drag coefficients based on the total canopy area and the fabric area alone were approximately 0.64 and 0.65, respectively.
Author: Helmut G. Heinrich
Author: Helmut G. Heinrich
Author: H. G. Heinrich
Author: Defense Documentation Center (U.S.)
Author: Kenneth Bruce Buchanan
Author: E. G. Ewing
Author: Theo W. Knacke
Author: Carl W. Peterson
Author: C. W. Peterson
Author: D. E. Waye
Author: Sanger M. Burk