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  • Aircraft Design, Testing and Performance
  • Chemistry
  • 2010-2014  (5)
  • 1975-1979
  • 1965-1969
  • 1950-1954
  • 1940-1944
  • 2011  (5)
  • 1
    Publication Date: 2019-07-13
    Description: Application of high speed, advanced turboprops, or propfans, to subsonic transport aircraft received significant attention and research in the 1970s and 1980s when fuel efficiency was the driving focus of aeronautical research. Recent volatility in fuel prices and concern for aviation s environmental impact have renewed interest in unducted, open rotor propulsion, and revived research by NASA and a number of engine manufacturers. Unfortunately, in the two decades that have passed since open rotor concepts were thoroughly investigated, NASA has lost experience and expertise in this technology area. This paper describes initial efforts to re-establish NASA s capability to assess aircraft designs with open rotor propulsion. Specifically, methodologies for aircraft-level sizing, performance analysis, and system-level noise analysis are described. Propulsion modeling techniques have been described in a previous paper. Initial results from application of these methods to an advanced single-aisle aircraft using open rotor engines based on historical blade designs are presented. These results indicate open rotor engines have the potential to provide large reductions in fuel consumption and emissions. Initial noise analysis indicates that current noise regulations can be met with old blade designs and modern, noiseoptimized blade designs are expected to result in even lower noise levels. Although an initial capability has been established and initial results obtained, additional development work is necessary to make NASA s open rotor system analysis capability on par with existing turbofan analysis capabilities.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-12112 , 11th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference; Sep 20, 2011 - Sep 22, 2011; Virginia Beach, VA; United States
    Format: application/pdf
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  • 2
    Publication Date: 2019-07-13
    Description: Two full scale crash tests were conducted on a small MD-500 helicopter at NASA Langley Research Center fs Landing and Impact Research Facility. One of the objectives of this test series was to compare airframe impact response and occupant injury data between a test which outfitted the airframe with an external composite passive energy absorbing honeycomb and a test which had no energy absorbing features. In both tests, the nominal impact velocity conditions were 7.92 m/sec (26 ft/sec) vertical and 12.2 m/sec (40 ft/sec) horizontal, and the test article weighed approximately 1315 kg (2900 lbs). Airframe instrumentation included accelerometers and strain gages. Four Anthropomorphic Test Devices were also onboard; three of which were standard Hybrid II and III, while the fourth was a specialized torso. The test which contained the energy absorbing honeycomb showed vertical impact acceleration loads of approximately 15 g, low risk for occupant injury probability, and minimal airframe damage. These results were contrasted with the test conducted without the energy absorbing honeycomb. The test results showed airframe accelerations of approximately 40 g in the vertical direction, high risk for injury probability in the occupants, and substantial airframe damage.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-11537 , SEM Annual Conference and Exposition on Experimental and Applied Mechanics; Jun 13, 2011 - Jun 15, 2011; Uncasville, CT; United States
    Format: application/pdf
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  • 3
    Publication Date: 2019-07-13
    Description: This is an overview presentation of research being performed in the Advanced Materials Task within the NASA Subsonic Rotary Wing Project. This research is focused on technology areas that address both national goals and project goals for advanced rotorcraft. Specific technology areas discussed are: (1) high temperature materials for advanced turbines in turboshaft engines; (2) polymer matrix composites for lightweight drive system components; (3) lightweight structure approaches for noise and vibration control; and (4) an advanced metal alloy for lighter weight bearings and more reliable mechanical components. An overview of the technology in each area is discussed, and recent accomplishments are presented.
    Keywords: Aircraft Design, Testing and Performance
    Type: E-17741 , NASA Fundamental Aeronautics 2011 Technical Conference; Mar 15, 2011 - Mar 17, 2011; Cleveland, OH; United States
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  • 4
    Publication Date: 2019-07-12
    Description: Aircraft fuel efficiency is a function of many different parameters, including characteristics of the engines, characteristics of the airframe, and the conditions under which the aircraft is operated. For a given vehicle, the airframe and engine characteristics are for the most part fixed quantities and efficiency is primarily a function of operational conditions. One important influence on cruise efficiency is cruise altitude. Various future scenarios have been postulated for cruise altitude, from the freedom to fly at optimum altitudes to altitude restrictions imposed for environmental reasons. This report provides background on the fundamental relationships determining aircraft cruise efficiency and examines the sensitivity of efficiency to cruise altitude. Analytical models of two current aircraft designs are used to derive quantitative results. Efficiency penalties are found to be generally less than 1% when within roughly 2000 ft of the optimum cruise altitude. Even the restrictive scenario of constant altitude cruise is found to result in a modest fuel consumption penalty if the fixed altitude is in an appropriate range.
    Keywords: Aircraft Design, Testing and Performance
    Type: NASA/TM-2011-217173 , L-20048 , NF1676L-13123
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  • 5
    Publication Date: 2019-07-13
    Description: The objective of this paper was to provide an update on NASA s current tools for design and analysis of hybrid wing body (HWB) aircraft with an emphasis on Vehicle Sketch Pad (VSP). NASA started HWB analysis using the Flight Optimization System (FLOPS). That capability is enhanced using Phoenix Integration's ModelCenter(Registered TradeMark). Model Center enables multifidelity analysis tools to be linked as an integrated structure. Two major components are linked to FLOPS as an example; a planform discretization tool and VSP. The planform discretization tool ensures the planform is smooth and continuous. VSP is used to display the output geometry. This example shows that a smooth & continuous HWB planform can be displayed as a three-dimensional model and rapidly sized and analyzed.
    Keywords: Aircraft Design, Testing and Performance
    Type: AIAA Paper 2011-0360 , NF1676L-10850 , 49th AIAA Aerospace Scienes Meeting; Jan 04, 2011 - Jan 07, 2011; Orlando, FL; United States
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