WorldCat Identities

United States Army Aviation Research and Technology Activity

Overview
Works: 182 works in 221 publications in 1 language and 12,787 library holdings
Genres: Conference proceedings 
Classifications: TL521.3.T4, 621.833
Publication Timeline
Key
Publications about United States Publications about United States
Publications by United States Publications by United States
Most widely held works by United States
Five year ground exposure of composite materials used on the Bell model 206L flight service evaluation by Donald J Baker ( )
3 editions published in 1989 in English and held by 267 WorldCat member libraries worldwide
During the past ten years, NASA has sponsored programs to build a data base and establish confidence in the long-term durability of advanced composite materials. Flight service experience is being obtained on primary and secondary structural components installed on commercial aircraft and from material specimens exposed at different locations. Although commercial aircraft and helicopters may fly in the same environment the behavior of composite materials on each vehicle may differ substantially. Most of the projected usage for composites in helicopter fuselage is Kevlar-49/epoxy with selective reinforcement of graphite/epoxy using 250 F curing epoxies. Most commercial aircraft are using 350 F cure graphite/epoxy systems with very little use of Kevlar/epoxy. Considering only the effects of moisture, materials in the minimum gage structure in most helicopter fuselage would reach equilibrium moisture content in a short time whereas the heavier gage structure on a commercial aircraft could take months to reach an equilibrium condition
Stability of a rigid rotor supported on oil-film journal bearings under dynamic load by Bankim C Majumdar ( )
3 editions published in 1987 in English and held by 265 WorldCat member libraries worldwide
Acoustic measurements from a rotor blade-vortex interaction noise experiment in the German-Dutch wind tunnel (DNW) by R. M Martin ( )
3 editions published in 1988 in English and held by 258 WorldCat member libraries worldwide
Correlation of puma airloads evaluation of CFD prediction methods ( )
3 editions published in 1989 in English and held by 236 WorldCat member libraries worldwide
Scaling effects in the static large defelction [i.e. deflection] response of graphite-epoxy composite beams by Karen E Jackson ( )
3 editions published in 1989 in English and held by 236 WorldCat member libraries worldwide
Reduction of blade-vortex interaction noise using higher harmonic pitch control ( )
3 editions published in 1989 in English and held by 235 WorldCat member libraries worldwide
The effects of structural flap-lag and pitch-lag coupling on soft inplane hingeless rotor stability in hover by William G Bousman ( Book )
3 editions published in 1990 in English and held by 159 WorldCat member libraries worldwide
Performance data from a wind-tunnel test of two main-rotor blade designs for a utility-class helicopter by Jeffrey D Singleton ( Book )
1 edition published in 1990 in English and held by 153 WorldCat member libraries worldwide
Matrix density effects on the mechanical properties of SiC/RBSN composites by Ramakrishna T Bhatt ( Book )
1 edition published in 1990 in English and held by 152 WorldCat member libraries worldwide
The room temperature mechanical properties were measured for SiC fiber-reinforced reaction-bonded silicon nitride composites (SiC/RBSN) of different densities. The composites consisted of approx. 30 vol % uniaxially aligned 142 um diameter SiC fibers (Textron SCS-6) in a reaction-bonded Si3N4 matrix. The composite density was varied by changing the consolidation pressure during RBSN processing and by hot isostatically pressing the SiC/RBSN composites. Results indicate that as the consolidation pressure during RBSN processing and by hot isostatically pressing the SiC/RBSN composites. Results indicate that as the consolidation pressure was increased from 27 to 138 MPa, the average pore size of the nitrided composites decreased from 0.04 to 0.02 um and the composite density increased from 2.07 to 2.45 gm/cc. Nonetheless, these improvements resulted in only small increases in the first matrix cracking stress, primary elastic modulus, and ultimate tensile strength values of the composites. In contrast, HIP consolidation of SiC/RBSN resulted in a fully dense material whose first matrix cracking stress and elastic modulus values were approx. 15 and approx. 50 percent higher, respectively, the ultimate tensile strength values were approx. 40 percent lower than those for unHIPed SiC/RBSN composites. The modulus behavior for all specimens can be explained by simple rule-of-mixture theory. Also, the loss in ultimate strength for the HIP temperature. (SDW)
Modal analysis of multistage gear systems coupled with gearbox vibrations ( Book )
2 editions published between 1990 and 1991 in English and held by 150 WorldCat member libraries worldwide
Identification of XV-15 aeroelastic modes using frequency-domain methods by C. W Acree ( Book )
1 edition published in 1989 in English and held by 139 WorldCat member libraries worldwide
A flight-dynamic helicopter mathematical model with a single flap-lag-torsion main rotor by Marc D Takahashi ( Book )
1 edition published in 1990 in English and held by 137 WorldCat member libraries worldwide
Correlation of Puma airloads lifting-line and wake calculation ( Book )
1 edition published in 1989 in English and held by 135 WorldCat member libraries worldwide
A cooperative program, undertaken by organizations in the United States, England, France, and Australia, assessed the strengths and weaknesses of four lifting-line/wake methods and three CFD methods by comparing their predictions with the data obtained in flight trials of a research Puma. The Puma has been tested in two configurations: a mixed-bladed rotor with instrumented rectangular-tip and swept-tip blades, and a configuration with four identical swept-tip blades. The present paper examines the results of the lifting-line predictions. The better lifting-line methods show good agreement with lift at the blade tip for the configuration with four swept tips; the moment is well- predicted at 0.92 R, but deteriorates outboard. The predictions for the mixed- bladed rotor configuration range from fair to good. The lift prediction is better for the swept-tip blade than for rectangular-tip blade, but the reasons for this cannot be determined because of the unmodeled effects of the mixed- bladed rotor. Keywords: Helicopter flight test; Computational fluid dynamics; Helicopter airloads correlation; Helicopter rotors; Rotor blades rotary wings. (edc)
Applications of flight control system methods to an advanced combat rotorcraft ( Book )
1 edition published in 1989 in English and held by 129 WorldCat member libraries worldwide
Review and analysis of the DNW/model 360 rotor acoustic data base by R. A Zinner ( Book )
1 edition published in 1989 in English and held by 129 WorldCat member libraries worldwide
Theory of gearing by F. L Litvin ( Book )
1 edition published in 1989 in English and held by 91 WorldCat member libraries worldwide
The author has significantly contributed to the goals of the NASA/ army transmission program by his accomplishments in the science of gearing and his authorship of this book. His work has provided a mathematical basis which improves our understanding of bevel gear geometry and the manufacturing procedure. His work has provided solutions to reduce gear noise and to enable a smoother transfer of power in helicopters. In summary, he has directly contributed to advance the state of the art in helicopter power transmission technology, and has made a significant contribution to NASA's research projects and to the public good. This book explains the most general problems of the theory of gearing, but it represents only a part of Dr. Litvins's accomplishments. His research contributions have improved (1) almost all types of gearing including spur, helical, hypoid, bevel, worm, and noncircular gears; (2) tools for gear manufacture; and (3) computer programs for simulation of meshing and contact. His theorems, methods for gear synthesis, and methods for gear generation represent a very significant contribution to the science of gearing
Integrated Technology Rotor Methodology Assessment Workshop proceedings of a workshop by Integrated Technology Rotor Methodology Assessment Workshop ( Book )
1 edition published in 1988 in English and held by 91 WorldCat member libraries worldwide
Efficient fault diagnosis of helicopter gearboxes by H Chin ( Book )
3 editions published in 1993 in English and held by 83 WorldCat member libraries worldwide
Distributed simulation using a real-time shared memory network ( Book )
2 editions published in 1993 in English and held by 82 WorldCat member libraries worldwide
Fault detection of helicopter gearboxes using the multi-valued influence matrix method by Hsinyung Chin ( Book )
3 editions published in 1993 in English and held by 82 WorldCat member libraries worldwide
 
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Alternative Names

controlled identity United States. Army Aviation Research and Development Command

United States. Army Aviation Research & Technology Activity
United States. Army Aviation Systems Command. Aviation Research and Technology Activity
US Army Aviation Research and Technology Activity
Languages
English (40)