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  • Chemistry  (11,435)
  • Inorganic Chemistry  (1,488)
  • AIRCRAFT PROPULSION AND POWER  (459)
  • 1995-1999
  • 1980-1984
  • 1975-1979  (11,894)
  • 1925-1929
  • 1978  (6,148)
  • 1975  (5,746)
Collection
Years
  • 1995-1999
  • 1980-1984
  • 1975-1979  (11,894)
  • 1925-1929
Year
  • 1
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1978-10-13
    Description: Picosecond spectroscopy is a relatively new field of science that utilizes ultrashort laser pulses to monitor events taking place in the 10(-12) second regime. The continuing development of picosecond spectroscopy has made possible the detection and measurement of the primary events in many physical and tiological processes. This article describes a currently used picosecond spectroscopy system that is capable of reliably recording picosecond events. Two areas of picosecond research are discussed; one concerns the interaction of electrons in fluids, and the second the primary events in vision.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rentzepis, P M -- New York, N.Y. -- Science. 1978 Oct 13;202(4364):174-82.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/694523" target="_blank"〉PubMed〈/a〉
    Keywords: Chemical Phenomena ; Chemistry ; Electrons ; *Kinetics ; Lasers ; Protons ; *Retinal Pigments ; *Rhodopsin ; Spectrum Analysis/*methods ; Temperature ; *Vision, Ocular
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1978-03-17
    Description: The history of U.S. foreign aid support of science and technology in Latin America is examined and an attempt is made to evaluate the scientific and economic growth of that area in relation to the total foreign aid effort.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Szmant, H H -- New York, N.Y. -- Science. 1978 Mar 17;199(4334):1173-82.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/415363" target="_blank"〉PubMed〈/a〉
    Keywords: Chemistry ; Cost-Benefit Analysis ; Education ; History, 20th Century ; International Educational Exchange ; Latin America ; *Research Support as Topic ; *Science/history ; United States
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1978-04-07
    Description: Glucose reacts nonenzymatically with the NH2-terminal amino acid of the beta chain of human hemoglobin by way of a ketoamine linkage, resulting in the formation of hemoglobin AIc. Other minor components appear to be adducts of glucose 6-phosphate and fructose 1,6-diphosphate. These hemoglobins are formed slowly and continuously throughout the 120-day life-span of the red cell. There is a two- to threefold increase in hemoglobin AIc in the red cells of patients with diabetes mellitus. By providing an integrated measurement of blood glucose, hemoglobin AIc is useful in assessing the degree of diabetic control. Furthermore, this hemoglobin is a useful model of nonenzymatic glycosylation of other proteins that may be involved in the long-term complications of the disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bunn, H F -- Gabbay, K H -- Gallop, P M -- New York, N.Y. -- Science. 1978 Apr 7;200(4337):21-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/635569" target="_blank"〉PubMed〈/a〉
    Keywords: Blood Glucose/metabolism ; Chemical Phenomena ; Chemistry ; Diabetes Complications ; Diabetes Mellitus/*blood/diagnosis ; Diphosphoglyceric Acids/blood ; Glycosides/blood ; Glycosuria/etiology ; Hemoglobin A/*metabolism ; Hemoglobins/*analysis/*metabolism ; Humans ; Kinetics ; Oxygen/blood ; Structure-Activity Relationship
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2006-03-02
    Description: A preliminary investigation into the use of modern control theory for the design of controls for a supersonic inlet is described. In particular, the task of controlling a mixed-compression supersonic inlet is formulated as a linear optimal stochastic control and estimation problem. An inlet can exhibit an undesirable instability due to excessive inlet normal shock motion. For the optimal control formulation of the inlet problem, a non quadratic performance index, which is equal to the expected frequency of inlet unstarts, is used. This physically meaningful performance index is minimized for a range of inlet disturbance and measurement noise covariances.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington Fourth Inter-Center Control Systems Conf.; p 323-335
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  • 5
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    In:  CASI
    Publication Date: 2006-01-11
    Description: Flight vehicles are characterized according to their manner of operation and type of propulsion system; and their associated sources of noise are identified. Available noise reduction technology as it relates to engine cycle design and to powerplant component design is summarized. Such components as exhaust jets, fans, propellers, rotors, blown flaps, and reciprocating-engine exhausts are discussed, along with their noise reduction potentials. Significant aircraft noise reductions are noted to have been accomplished by the application of available technology in support of noise certification rules. Further noise reductions to meet more stringent future noise regulations will require substantial additional technology developments. Improved analytical prediction methods, and well-controlled validation experiments supported by advanced-design aeroacoustic facilities, are required as a basis for an effective integrated systems approach to aircraft noise control.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA/Univ. Conf. on Aeron.; p 103-130
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  • 6
    Publication Date: 2006-02-28
    Description: Results of experimental investigations to control a supersonic mixed-compression inlet coupled to a turbojet engine are presented. Special instrumentation and servoactuators were developed to have sufficiently fast dynamic response so that basic propulsion system dynamics were the main limitation to controllability. In some cases servoactuator input signals were electronically limited to simulate moderate performance flight hardware.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA, Washington Fourth Inter-Center Control Systems Conf.; p 299-321
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  • 7
    Publication Date: 2011-08-16
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Acoustical Society of America; vol. 57
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  • 8
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    In:  CASI
    Publication Date: 2012-05-22
    Description: The problems created by fretting in turbine engines are discussed. The areas of greatest wear identified with the fan, compressor, and turbine blade mountings being the most critical items. Various methods for reducing or eliminating fretting in a turbine engine are described. Vacuum deposition of coatings by sputtering and ion plating are recommended as an economic method of applying thin films to inhibit fretting.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Specialists Meeting on Fretting in Aircraft Systems; 17 p
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  • 9
    Publication Date: 2012-05-22
    Description: Recently advanced simulation techniques have been developed for the digital computer and used as the basis for development of a generalized dynamic engine simulation computer program, called DYNGEN. This computer program can analyze the steady state and dynamic performance of many kinds of aircraft gas turbine engines. Without changes to the basic program, DYNGEN can analyze one- or two-spool turbofan engines. The user must supply appropriate component performance maps and design point information. Examples are presented to illustrate the capabilities of DYNGEN in the steady state and dynamic modes of operation. The analytical techniques used in DYNGEN are briefly discussed, and its accuracy is compared with a comparable simulation using the hybrid computer. The impact of DYNGEN and similar digital programs on future engine simulation philosophy is also discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Power Plant Controls for Aero-Gas Turbine Eng.; 23 p
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  • 10
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    Publication Date: 2011-08-17
    Description: The current status of the problem of gas turbine engine emissions is reviewed. Presently promulgated EPA standards and their implications for aircraft gas turbines are discussed. The progress and status of emissions reduction technology programs and other efforts which have emphasized advanced combustor technology are reviewed in detail. Also examined are those efforts underway to determine the emissions floor and incorporate those techniques into practical combustors of the future.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Progress in Energy and Combustion Science; 4; 2, 19; 1978
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  • 11
    Publication Date: 2011-08-17
    Description: The noise-generating region of a suppressed turbojet exhaust is studied by cross-correlating static pressure fluctuations within the exhaust with far-field sound for Mach numbers up to 0.99, using a 31-tube nozzle having an area ratio of 3.1. Measurements made with an unsuppressed turbojet exhaust having an equivalent area ratio and operating under effectively equal thrust loads serve as the experimental control. Static pressure-level measurements, made with a calibrated high-temperature acoustically damped probe tube, show that noise suppression by multitube nozzles results from reduced turbulence levels. The maximum fluctuating static-pressure level in the unsuppressed turbojet exhaust is typically 5-6 dB higher than static-pressure levels in the suppressed exhaust under conditions of effectively equal static thrust. This suggests that the turbulence intensity in the multitube suppressor flow is reduced in excess of 20% compared with the unsuppressed jet exhaust.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Acoustical Society of America; vol. 63
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  • 12
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    In:  Other Sources
    Publication Date: 2011-08-17
    Description: NASA aims at developing propulsion technology to reduce the fuel consumption of present engines by 5%, that of new engines of the late 1980s by at least 12%, and that of an advanced early 1990s turboprop by an additional 15%. This paper reviews three separate NASA programs which take up these aims. They are, respectively, Engine Component Improvement, Energy Efficient Engine, and Advanced Turboprops.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Astronautics and Aeronautics; 16; July-Aug
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  • 13
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    Publication Date: 2011-08-17
    Description: The market place is examined for general aviation aircraft into the 1980's. The visible constraints that engine manufacturers must face regardless of the type of cycle are indicated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center The Rotary Combust. Engine; p 175-186
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  • 14
    Publication Date: 2011-08-17
    Description: The development of light aircraft with special emphasis on modern propulsion systems and production is discussed in terms of the application of rotary engines to aircraft. Emphasis is placed on the integrated ducted-fan propulsion system using rotary engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center The Rotary Combust. Engine; p 109-122
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  • 15
    Publication Date: 2011-08-17
    Description: Rotary engines with a chamber volume of 750 cc as a two rotor automotive powerplant, called KKM 871 are described. This engine is compared to a 3 liter or 183 cubic inch, six-cylinder reciprocating engine. Emphasis is placed on exhaust emission control and fuel economy.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center The Rotary Combust. Engine 85-107 (SEE N79-15961 07-07)
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  • 16
    Publication Date: 2011-08-17
    Description: The development of the rotary engine as a viable power plant capable of wide application is reviewed. Research results on the stratified charge engine with direct chamber injection are included. Emission control, reduced fuel consumption, and low noise level are among the factors discussed in terms of using the rotary engine in general aviation aircraft.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center The Rotary Combust. Engine; p 123-174
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  • 17
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    Publication Date: 2011-08-17
    Description: Progress in the development of rotary engines which use a thermal reactor as the primary part of the exhaust emission control system is reviewed. Possibilities of further improvements in fuel economy of future rotary engines are indicated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center The Rotary Combust. Engine; p 37-84
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  • 18
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    Publication Date: 2011-08-17
    Description: A review is presented of nonturbine general aviation engine programs underway at the NASA-Lewis Research Center. The program encompasses conventional, lightweight diesel, and rotary engines. Its three major thrusts are: (1) reduced SFC's; (2) improved fuels tolerance; and (3) reducing emissions. Current and planned future programs in such areas as lean operation, improved fuel management, advanced cooling techniques, and advanced engine concepts, are described. These are expected to lay the technology base, by the mid to latter 1980's, for engines whose total fuel costs are as much as 30% lower than today's conventional engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: The Rotary Combust. Engine; p 13-35
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  • 19
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    In:  Other Sources
    Publication Date: 2016-06-07
    Description: Engine sealing programs are discussed which are directed toward the two major classes of engine seals: engine shaft seals and primary gas path seals. In addition, some concepts and results from fundamental lubrication research, as it pertains to the lubrication of bearings, are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 305-327
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  • 20
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    Publication Date: 2016-06-07
    Description: The JT8D Refan Program for noise reduction is outlined, and the overall objectives and program status, test results, and current noise level predictions are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 81-97
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  • 21
    Publication Date: 2016-06-07
    Description: The progress in propulsion system noise reduction is reviewed. The noise technology areas discussed include: fan noise; advances in suppression including conventional acoustic treatment, high Mach number inlets, and wing shielding; engine core noise; flap noise from both under-the-wing and over-the-wing powered-lift systems; supersonic jet noise suppression; and the NASA program in noise prediction.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 1-63
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  • 22
    Publication Date: 2016-06-07
    Description: Some of the specific areas associated with straight jet and turboprop engine installations are outlined where drag reduction and, thus, improved aircraft system performance is obtained. Specific areas constitute air intake sizing for general aviation aircraft, exhaust duct geometries and cooling system arrangements for propeller powered aircraft.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Kansas Univ. Proc. of the NASA, Ind., Univ., Gen. Aviation Drag Reduction Workshop; p 245-256
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  • 23
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    Publication Date: 2016-06-07
    Description: The NASA research on scramjet technology for speeds above Mach 5 is reported. A brief overview of the NASA Hypersonic Research Engine (HRE) project is presented with emphasis on the most significant contributions on the HRE to scramjet technology. The work on high-performance airframe-integrated scramjet engines is described, and a new versatile research airplane is discussed with emphasis on propulsion.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 459-474
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  • 24
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    Publication Date: 2016-06-07
    Description: The recent developments and future potential of advanced materials for turbine components are described. The components discussed in detail are disks, blades, and vanes.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 209-288
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  • 25
    Publication Date: 2016-06-07
    Description: Aircraft fuel consumption is discussed in terms of its efficient use, and the conversion of energy from sources other than petroleum. Topics discussed include: fuel from coal and oil shale, hydrogen deficiency of alternate sources, alternate fuels evaluation program, and future engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 157-190
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  • 26
    Publication Date: 2016-06-07
    Description: The status of research efforts to apply low to intermediate temperature composite materials and advanced high temperature materials to engine components is reviewed. Emerging materials technologies and their potential benefits to aircraft gas turbines were emphasized. The problems were identified, and the general state of the technology for near term use was assessed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 187-204
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  • 27
    Publication Date: 2016-06-07
    Description: Progress in the development of combustor technology to meet the standards for the allowable pollutant emission levels of aircraft gas turbine engines is reported. The high-bypass-ratio turbofan engines which power the large commercial aircraft were emphasized along with efforts to reduce emission for near term applications. Recommendations for continuing research to reduce emissions to meet far term needs are given.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 205-216
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  • 28
    Publication Date: 2016-06-07
    Description: Research is reviewed in the following areas: turboprop powered transport aircraft; wind tunnel aerodynamic and acoustics tests of model propellers; turboprop maintenance; and wind tunnel tests on airframe-turboprop interactions. Continued development of the technology for advanced turboprop transport was emphasized.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 139-166
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  • 29
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Turbofan engine noise research relevant to conventional aircraft is discussed. In the area of fan noise, static to flight noise differences were discussed and data were presented for two different ways of simulating flight behavior. Experimental results from a swept rotor fan design are presented which show that this concept has potential for reducing the multiple-pure-tone or buzz-saw noise related to the shock waves on a fan operating at supersonic tip speeds. Acoustic suppressor research objectives centered around the effect of the wave system generated by the fan stage that is the input to the treatment. A simplifying and unifying parameter, mode cutoff ratio was described. Results are presented which show that suppressor performance can be improved if the input wave is more precisely described. In jet noise, calculated results showing the potential noise reduction from the use of internal mixer nozzles rather than separate flow nozzles are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 167-185
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  • 30
    Publication Date: 2016-06-07
    Description: The characteristics and systems benefits of an energy efficient engine (E3) suitable for use on advanced subsonic transport aircraft were determined. Relative to a current CF6-50C engine, the following benefits were estimated: 14.4% reduction in installed cruise specific fuel consumption, and a reduction in direct operating cost of more than 5%. The advanced technology E3 system would also permit: compliance with FAR 36 (1977) noise limits, and compliance with 1981 EPA emission standards.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 111-138
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  • 31
    Publication Date: 2016-06-07
    Description: A mixed exhaust, direct drive fan turbofan configuration was selected from four candidates. This choice was based on its ability to exceed study goals of 12% lower thrust specific fuel consumption and 5% lower direct operating cost by the 1990's with commercially acceptable technical risk and relative mechanical simplicity. The evaluation leading to configuration selection is discussed. Necessary technology advancements are identified and related to the goals.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 89-110
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  • 32
    Publication Date: 2016-06-07
    Description: A feasibility analysis screening method for predicting the airline acceptance of a proposed engine performance improvement modification was developed. Technical information derived from available test data and analytical models is used along with conceptual/preliminary designs to establish the predicted performance improvement, weight and installation characteristics, the cost for new production and retrofit, maintenance cost and qualitative characteristics of the performance improvement concepts being evaluated. These results are used to arrive at the payback period, which is the time required for an airline to recover the investment cost of concept implementation, and to predict the amount of fuel saved by a performance improvement concept. The assumptions used to calculate the payback period and fuel saved are discussed. A summary of the results when the screening method is applied is presented for several representative JT8D and JT9D performance improvement concepts. An example of the input information used to develop the summary results is shown.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 79-80
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  • 33
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Potential CF6 engine performance improvements directed at reduced fuel consumption were identified and screened relative to airline acceptability and are reviewed. The screening process developed to provide evaluations of fuel savings and economic factors including return on investment and direct operating cost is described. In addition, assessments of development risk and production potential are made. Several promising concepts selected for full-scale development based on a ranking involving these factors are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 59-78
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  • 34
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    Publication Date: 2016-06-07
    Description: Technology for fuel-efficient subsonic CTOL transport aircraft is discussed. The engine component improvement project, the energy efficient engine project, and the advanced turboprop project are included. The overall goals and objectives of each project are reviewed and the approach and schedule for accomplishing these project goals and objectives are given.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center CTOL Transport Technol., 1978; p 9-23
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  • 35
    Publication Date: 2016-06-07
    Description: The fundamental vortex theory for a single rotation propeller with a finite number of blades is reviewed. The theory leads to the specification of a radial distribution of bound circulation on each blade for minimum induced loss, analogous to the elliptic spanwise distribution of bound circulation on a wing for minimum induced drag. A propeller designed in accord with this theory has been tested in a water tunnel where it exhibited high efficiency in spite of localized cavitating flow. A knowledge of the flow field for an optimum propeller is of value to the airframe designer seeking to maximize the performance of the airplane-propeller combination.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Kansas Univ. Proc. of the NASA, Ind., Univ., Gen. Aviation Drag Reduction Workshop; p 273-293
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  • 36
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    Publication Date: 2016-06-07
    Description: The Supersonic Cruise Airplane Research (SCAR) technology program is reported. Mission requirements, cycle considerations, engine evaluation, and SCAR test results are discussed. It is concluded that improved aerodynamics and structures, greater use of composites, and more-refined active controls are needed in the airframe area for designing an economically viable, environmental acceptable supersonic aircraft.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 441-457
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  • 37
    Publication Date: 2016-06-07
    Description: Current full-scale engine development programs are discussed, and efforts to improve the available technology base are presented. The Lewis full-scale engine test facilities are described. Several typical engine programs and plans for research in aeromechanical instability or flutter are summarized. An overview of Lewis studies of flow distortion and its effects on engine stability is presented. The origins and nature of the distortion problem are summarized, and some of the results and methods for both steady and time-varying distortions are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 329-385
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  • 38
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    Publication Date: 2016-06-07
    Description: The composites research being conducted at Lewis for the application of composite materials to fan and compressor blades, is reviewed. The major areas discussed include the development of improved materials and fabrication methods, recent progress in providing composite fan and compressor blades with improved resistance to foreign object damage, and the development of advanced design and analysis procedures for composite blades.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 191-208
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  • 39
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    Publication Date: 2016-06-07
    Description: The objectives, scope, and status of the NASA Quiet, Clean, Short-Haul Experimental Engine program are reviewed. The progress reported is concerned with engine design concepts for short-haul aircraft where part of the engine thrust is used to help lift the aircraft. Both under-the-wing, and over-the-wing configurations are discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 65-80
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  • 40
    Publication Date: 2016-06-07
    Description: The environmental effects are discussed of engine effluents of future large fleets of aircraft operating in the stratosphere. Topics discussed include: atmospheric properties, aircraft engine effluents, upper atmospheric measurements, global air sampling, and data reduction and analysis
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 139-156
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  • 41
    Publication Date: 2016-06-07
    Description: The selection of components, control design, simulation, and tests are examined for designing supersonic propulsion systems. Inlet-engine combination under electronic control are shown. Design and test results from the integrated control for afterburning turbofan and supersonic cruise inlet are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 387-440
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  • 42
    Publication Date: 2016-06-07
    Description: The improved technology is discussed of engine main-shaft ball bearings, and spur gears in power transmission drive trains. Much of the technology can be applied to other ball and roller bearings, and to other spur and bevel gears throughout the engine, drive train, and accessory systems.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 289-303
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  • 43
    Publication Date: 2016-06-07
    Description: Combustor development is discussed as it relates to emissions reduction. The nature of the aircraft pollution problem is examined along with the aircraft pollution standards that have been established by the Environmental Protection Agency. The effect of engine operating conditions on pollutant formation levels is shown, as well as how close present-day engines are to meeting the established standards. The magnitude of the emissions reductions required to meet these standards is indicated. The progress that has been made in evolving the needed emissions reduction technology is the main topic.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aeron. Propulsion; p 99-137
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  • 44
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2017-10-02
    Description: Gas path seals are discussed with emphasis on sealing clearance effects on engine component efficiency, compressor pressure ratio, and stall margin. Various case-rotor relative displacements, which affect gas path seal clearances, are identified. Forces produced by nonuniform sealing clearances and their effect on rotor stability are examined qualitatively, and recent work on turbine-blade-tip sealing for high temperatures is described. The need for active clearance control and for engine structural analysis is discussed. The functions of the internal-flow system and its seals are reviewed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Seal Technol. in Gas Turbine Eng.; 41 p
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  • 45
    Publication Date: 2016-06-07
    Description: Jet engine components are considered that influence propulsion system integration on the airframe and related aircraft drag areas. Emphasis is placed on high Mach number inlet geometries, boattailed nozzle configurations, propulsive wing installation, wing surface blowing lift, fuselage mounted nacelles, and thrust reversal.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Kansas Univ. Proc. of the NASA, Ind., Univ., Gen. Aviation Drag Reduction Workshop; p 365-385
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  • 46
    Publication Date: 2017-10-02
    Description: Advanced materials, coatings, and cooling technology is assessed in terms of improved aircraft turbine engine performance. High cycle operating temperatures, lighter structural components, and adequate resistance to the various environmental factors associated with aircraft gas turbine engines are among the factors considered. Emphasis is placed on progress in development of high temperature materials for coating protection against oxidation, hot corrosion and erosion, and in turbine cooling technology. Specific topics discussed include metal matrix composites, superalloys, directionally solidified eutectics, and ceramics.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD High Temp. Probl. in Gas Turbine Eng.; 31 p
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  • 47
    Publication Date: 2019-06-28
    Description: This report describes the design configuration and method used to design the forced engine exhaust to bypass air mixing system for Lycoming's QCGAT engine. This mixer is an integral part of the total engine and nacelle system and was configured to reduce the propulsion system noise and fuel consumption levels.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-159426 , LYC-78-36
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  • 48
    Publication Date: 2019-06-28
    Description: A mixer exhaust system was designed to meet the proposed performance and exhaust jet noise goals for the AiResearch QCGAT engine. Some 0.35 scale models of the various nozzles were fabricated and aerodynamically and acoustically tested. Preliminary optimization, engine cycle matching, model test data and analysis are presented. A final mixer exhaust system is selected for optimum performance for the overall flight regime.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135386 , AIRESEARCH-21-2861
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  • 49
    Publication Date: 2019-06-28
    Description: Two basic inlet concepts, a high throat Mach number (0.79) design and a low throat Mach number (0.60) design, were tested with four diffuser acoustical treatment designs that had face sheet porosity ranging from 0 to 24 percent for the high Mach number inlet and 0 to 28 percent for the low Mach number inlet. The tests were conducted in a low speed wind tunnel at free stream velocities of 0, 41, and 62 m/sec and angles of attack to 50 deg. Inlet throat Mach number was varied about the design value. Increasing the inlet diffuser face sheet porosity resulted in an increase in total pressure loss in the boundary layer for both the high and low Mach number inlet designs, however, the overall effect on inlet total pressure recovery of 0.991 at the design throat Mach number, a free stream velocity of 41 m/sec, and an angle of attack of 50 deg; Inlet flow separation at an angle of attack of 50 deg was encountered with only one inlet configuration the high Mach number design with the highest diffuser face sheet porosity (24 percent).
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1178 , E-9542
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  • 50
    Publication Date: 2019-06-28
    Description: The preliminary design of an engine which satisfies the requirements of a quiet, clean, general aviation turbofan (QCGAT) engine is described. Also an experimental program to demonstrate performance is suggested. The T700 QCGAT engine preliminary design indicates that it will radiate noise at the same level as an aircraft without engine noise, have exhaust emissions within the EPA 1981 Standards, have lower fuel consumption than is available in comparable size engines, and have sufficient life for five years between overhauls.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-164222 , R75AEG026-VOL-1
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  • 51
    Publication Date: 2019-06-27
    Description: Results of tests conducted on preliminary design polymeric-composite fan blade for the under the wing (UTW) OCSEE engine are presented. During this phase of the program a total of 17preliminary OCSEE UTW composite fan blades were manufactured for various component tests including frequency characteristics, strain distribution, bench fatigue, dovetail pull, whirligig overspeed and whirligig impact. All tests were successfully completed with the exception of whirligig impact tests. Improvements in local impact capability are being evaluated for the OCSEE blade under other NASA and related programs.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134846 , R75AEG411
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  • 52
    Publication Date: 2019-06-27
    Description: The component testing of a ball spline variable pitch mechanism is described including a whirligig test. The variable pitch actuator successfully completed all planned whirligig tests including a fifty cycle endurance test at actuation rates up to 125 deg per second at up to 102 percent fan speed (3400 rpm).
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135354 , R77AEG394
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  • 53
    Publication Date: 2019-06-27
    Description: Aft fan noise reduction techniques were investigated. The 1/3 octave band sound data were plotted with the following plots included: perceived noise level vs acoustic angle at 2 fan speeds; PWL vs frequency at 2 fan speeds; and sound pressure level vs frequency at 2 aft angles and 2 fan speeds. The source noise plots included: band pass filter sound pressure level vs acoustic angle at 2 fan speeds; and 2nd harmonic SPL acoustic angle at 2 fan speeds.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134850 , R75AEG252-VOL-2
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  • 54
    Publication Date: 2019-06-27
    Description: Six filament-wound, composite spar-shell fan blades were impact tested in a whirligig relative to foreign object damage resulting from ingestion of birds into the fan blades of a QCSEE-type engine. Four of the blades were tested by injecting a simulated two pound bird into the path of the rotating blade and two were tested by injecting a starling into the path of the blade.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135393 , R78AEG444
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  • 55
    Publication Date: 2019-06-27
    Description: A hybrid-computer simulation of the over the wing turbofan engine was constructed to develop the dynamic design of the control. This engine and control system includes a full authority digital electronic control using compressor stator reset to achieve fast thrust response and a modified Kalman filter to correct for sensor failures. Fast thrust response for powered-lift operations and accurate, fast responding, steady state control of the engine is provided. Simulation results for throttle bursts from 62 to 100 percent takeoff thrust predict that the engine will accelerate from 62 to 95 percent takeoff thrust in one second.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135049 , R76AEG218
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  • 56
    Publication Date: 2019-06-27
    Description: High bypass geared turbofan engines and propulsion systems designed for short-haul passenger aircraft are described. The propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing is emphasized. The aerodynamic and mechanical preliminary design of the QCSEE under the wing 1.34 pressure ratio fan with variable blade pitch is presented. Design information is given for two pitch change actuation systems which will provide reverse thrust.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134842 , R75AEG213
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  • 57
    Publication Date: 2019-06-27
    Description: The viability of proposed bearing designs to operate at application conditions is described. Heat rejection variables were defined for the test conditions. Results indicate that there is potential for satisfactory operation of spherical roller bearing in the QCSEE main reduction gear application.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134890
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  • 58
    Publication Date: 2019-06-27
    Description: A component pressure test was conducted on a F101 PFRT combustor to evaluate the emissions levels of this combustor design at selected under the wing and over the wing operating conditions for the quiet clean short haul experimental engine (QCSEE). Emissions reduction techniques were evaluated which included compressor discharge bleed and sector burning in the combustor. The results of this test were utilized to compare the expected QCSEE emissions levels with the emission goals of the QCSEE engine program.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134916 , R75AEG449
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  • 59
    Publication Date: 2019-06-27
    Description: A digital electronic control was combined with conventional hydromechanical components to operate the four controlled variables on the under-the-wing engine: fuel flow, fan blade pitch, fan exhaust area, and core compressor stator angles. The engine and control combination offers improvements in noise, pollution, thrust response, operational monitoring, and pilot workload relative to current engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134920 , R75AEG483
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  • 60
    Publication Date: 2019-06-27
    Description: The mechanical performance of the over-the-wing engine is described with emphasis on the advanced technology components. The overall dynamic response of the engine was excellent.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135325 , R77AEG475-VOL-3
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  • 61
    Publication Date: 2019-06-27
    Description: Sea level, static, ground testing of the over-the-wing engine and boilerplate nacelle components was performed. The equipment tested and the test facility are described. Summaries of the instrumentations, the chronological history of the tests, and the test results are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135323 , R77AEG473-VOL-1
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  • 62
    Publication Date: 2019-06-27
    Description: The detail design of the under the wing experimental composite nacelle components is summarized. Analysis of an inlet, fan bypass duct doors, core cowl doors, and variable fan nozzle are given. The required technology to meet propulsion system performance, weight, and operational characteristics is discussed. The materials, design, and fabrication technology for quiet propulsion systems which will yield installed thrust to weight ratios greater than 3.5 to 1 are described.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135352 , R77AEG588
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  • 63
    Publication Date: 2019-06-27
    Description: The design and analysis of a composite fan blade for the under the wing (UTW) QCSEE is presented. The blade is designed for a variable pitch, 18 bladed rotor and is constructed from a hybrid composite combination of materials consisting of Kevlar-49, type AS graphite, boron, and S-glass fibers in a PR288 epoxy resin matrix. The blade has an attached platform which is constructed of AS-graphite, PR288 epoxy resin matrix and aluminum honeycomb. The blade is designed to satisfy aerostability and cyclic life and strength requirements with a light weight construction. The attached platform is designed for a fail-safe condition in that it is retainable by the blade, under centrifugal force loading, even in the event of blade to platform bond separation. Details of the blade design and the results of stress, vibration, and impact analysis are included.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134840 , R75AEG278
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  • 64
    Publication Date: 2019-06-27
    Description: The aerodynamic and mechanical preliminary design of the QCSEE over the wing 1.36 pressure ratio fan is presented. Design information is given for both the experimental and flight designs.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134841 , R75AEG381
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  • 65
    Publication Date: 2019-06-27
    Description: An advanced composite frame which is flight-weight and integrates the functions of several structures was developed for the over the wing (OTW) engine and for the under the wing (UTW) engine. The composite material system selected as the basic material for the frame is Type AS graphite fiber in a Hercules 3501 epoxy resin matrix. The frame was analyzed using a finite element digital computer program. This program was used in an iterative fashion to arrive at practical thicknesses and ply orientations to achieve a final design that met all strength and stiffness requirements for critical conditions. Using this information, the detail design of each of the individual parts of the frame was completed and released. On the basis of these designs, the required tooling was designed to fabricate the various component parts of the frame. To verify the structural integrity of the critical joint areas, a full-scale test was conducted on the frame before engine testing. The testing of the frame established critical spring constants and subjected the frame to three critical load cases. The successful static load test was followed by 153 and 58 hours respectively of successful running on the UTW and OTW engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135278 , R77AEG439
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  • 66
    Publication Date: 2019-06-27
    Description: Detailed design parameters are presented for a variable-pitch change mechanism. The mechanism is a mechanical system containing a ball screw/spline driving two counteracting master bevel gears meshing pinion gears attached to each of 18 fan blades.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134873 , R77AEG327
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  • 67
    Publication Date: 2019-06-27
    Description: Tests of a twenty inch diameter, low tip speed, low pressure ratio fan which investigated aft fan noise reduction techniques are reported. The 1/3 octave band sound data are presented for all the configurations tested. The model data are presented on 17 foot arc and extrapolated to 200 foot sideline.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134851 , R75AEG252-VOL-3
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  • 68
    Publication Date: 2019-06-27
    Description: Tests of a 20 inch diameter, low tip speed, low pressure ratio fan which investigated aft fan noise reduction techniques are reported. These techniques included source noise reduction features of selection of vane-blade ratio to reduce second harmonic noise, spacing effects, and lowering the Mach number through a vane row. Aft suppression features investigated included porosity effects, variable depth treatment, and treatment regenerated flow noise. Initial results and selected comparisons are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134849 , R75AEG252-VOL-1
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  • 69
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: The overall reliability and maintenance costs (R&MC's) of past and current turboprop systems were examined. Maintenance cost drivers were found to be scheduled overhaul (40%), lack of modularity particularly in the propeller and reduction gearbox, and lack of inherent durability (reliability) of some parts. Comparisons were made between the 501-D13/54H60 turboprop system and the widely used JT8D turbofan. It was found that the total maintenance cost per flight hour of the turboprop was 75% higher than that of the JT8D turbofan. Part of this difference was due to propeller and gearbox costs being higher than those of the fan and reverser, but most of the difference was in the engine core where the older technology turboprop core maintenance costs were nearly 70 percent higher than for the turbofan. The estimated maintenance cost of both the advanced turboprop and advanced turbofan were less than the JT8D. The conclusion was that an advanced turboprop and an advanced turbofan, using similar cores, will have very competitive maintenance costs per flight hour.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135192 , EDR-9132
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  • 70
    Publication Date: 2019-06-27
    Description: The design and testing of the over the wing engine, a high bypass, geared turbofan engine, are discussed. The propulsion system performance is examined for uninstalled performance and installed performance. The fan aerodynamic performance and the D nozzle and reverser thrust performance are evaluated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135324 , R77AEG474-VOL-2
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  • 71
    Publication Date: 2019-06-27
    Description: The PMR process development, tooling concepts, testing conducted to generate materials properties data, and the fabrication of a subscale model of the inner cowl are presented. It was concluded that the materials, processes, and tooling concepts were satisfactory for making an inner cowl with adequate structural integrity.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135279 , R78AEG206
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  • 72
    Publication Date: 2019-06-27
    Description: The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the over-the-wing (OTW) nacelle acoustic treatment design are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the OTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135268 , R76AEG228
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  • 73
    Publication Date: 2019-06-27
    Description: The acoustic considerations involved in the low source noise basic engine design and the design procedures followed in the development of the under-the-wing (UTW) engine boilerplate and composite nacelle acoustic treatment designs are presented. Laboratory experiments, component tests, and scale model and engine tests supporting the UTW engine acoustic design are referenced. Acoustic design features include a near-sonic inlet, low fan and core pressure ratios, low fan tip speed, high and low frequency stacked core treatment, multiple thickness treatment, and fan frame and stator vane treatment.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135267 , R76AEG195
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  • 74
    Publication Date: 2019-06-27
    Description: An acoustic and aerodynamic test program was conducted on a 1/6.25 scale model of the Quiet, Clean, Short-Haul Experimental Engine (QCSEE) forward thrust over-the-wing (OTW) nozzle and OTW thrust reverser. In reverse thrust, the effect of reverser geometry was studied by parametric variations in blocker spacing, blocker height, lip angle, and lip length. Forward thrust nozzle tests determined the jet noise levels of the cruise and takeoff nozzles, the effect of opening side doors to achieve takeoff thrust, and scrubbing noise of the cruise and takeoff jet on a simulated wing surface. Velocity profiles are presented for both forward and reverse thrust nozzles. An estimate of the reverse thrust was made utilizing the measured centerline turning angle.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135254 , R75AEG504
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  • 75
    Publication Date: 2019-06-28
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AD-A066464 , FTD-ID(RS)T-0860-78
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  • 76
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: A rotatable disc is described that consists of parallel plates tightly joined together for rotation about a hub. Each plate is provided with several angularly projecting spaced lands. The lands of each plate are interposed in alternating relationship between the lands of the next adjacent plate. In this manner, circumferential displacement of adjacent sectors in any one plate is prevented in the event that a crack develops. Each plate is redundantly sized so that, in event of structural failure of one plate, the remaining plates support a proportionate share of the load of the failed plate. The plates are prevented from separating laterally through the inclusion of generally radially extending splines which are inserted to interlock cooperating, circumferentially adjacent lands.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 77
    Publication Date: 2019-06-27
    Description: The results of dynamic digital blade row compressor model studies of a J85-13 engine are reported. The initial portion of the study was concerned with the calculation of the circumferential redistribution effects in the blade-free volumes forward and aft of the compression component. Although blade-free redistribution effects were estimated, no significant improvement over the parallel-compressor type solution in the prediction of total-pressure inlet distortion stability limit was obtained for the J85-13 engine. Further analysis was directed to identifying the rotor dynamic response to spatial circumferential distortions. Inclusion of the rotor dynamic response led to a considerable gain in the ability of the model to match the test data. The impact of variable stator loss on the prediction of the stability limit was evaluated. An assessment of measurement error on the derivation of the stage characteristics and predicted stability limit of the compressor was also performed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134953 , R76AEG484-VOL-2
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  • 78
    Publication Date: 2019-06-27
    Description: A series of iterative combustor pressure rig tests were conducted on two combustor concepts applied to the AiResearch TFE731-2 turbofan engine combustion system for the purpose of optimizing combustor performance and operating characteristics consistant with low emissions. The two concepts were an axial air-assisted airblast fuel injection configuration with variable-geometry air swirlers and a staged premix/prevaporization configuration. The iterative rig testing and modification sequence on both concepts was intended to provide operational compatibility with the engine and determine one concept for further evaluation in a TFE731-2 engine.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-159415 , AIRESEARCH-21-2817
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  • 79
    Publication Date: 2019-06-27
    Description: The concept of a combined V/STOL propulsion and aircraft attitude control system was subjected to large scale engine tests. The tilt nacelle/attitude control vane package consisted of the T55 powered Hamilton Standard Q-Fan demonstrator. Vane forces, moments, thermal and acoustic characteristics as well as the effects on propulsion system performance were measured under conditions simulating hover in and out of ground effect.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-152181 , PDR-698-8
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  • 80
    Publication Date: 2019-06-27
    Description: Advanced aircraft turbine engine combustor technology was used to reduce low-power emissions of carbon monoxide and unburned hydrocarbons to levels significantly lower than those which were achieved with current technology. Three combustor design concepts, which were designated as the hot-wall liner concept, the recuperative-cooled liner concept, and the catalyst converter concept, were evaluated in a series of CF6-50 engine size 40 degree-sector combustor rig tests. Twenty-one configurations were tested at operating conditions spanning the design condition which was an inlet temperature and pressure of 422 K and 304 kPa, a reference velocity of 23 m/s and a fuel-air-ration of 10.5 g/kg. At the design condition typical of aircraft turbine engine ground idle operation, the best configurations of all three concepts met the stringent emission goals which were 10, 1, and 4 g/kg for CO, HC, and Nox, respectively.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135434 , DOC-R78AEG408
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  • 81
    Publication Date: 2019-06-27
    Description: The potential benefits of combining full-coverage film cooling with a thermal-barrier coating were investigated analytically for sections on the suction and pressure sides a high-temperature, high-pressure turbine vane. Metal and ceramic coating temperatures were calculated as a function of coating thickness and coolant flow. With a thermal-barrier coating, the coolant flows required for the chosen sections were half those of an uncoated design, and the metal outer temperatures were simultaneously reduced by over 111 K (200 F). For comparison, transpiration cooling was also investigated. Full-coverage film cooling of a coated vane required more coolant flow than did transpiration cooling.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1310 , AVRADCOM-TR-78-20
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  • 82
    Publication Date: 2019-06-27
    Description: An advanced electro-optical system was developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in an operating gas turbine engine. This system is applicable to fan, compressor, and turbine blade tip clearance measurement requirements, and the system probe is particularly suitable for operation in the extreme turbine environment. A study of optical properties of blade tips was conducted to establish measurement system application limitations. A series of laboratory tests was conducted to determine the measurement system's operational performance characteristics and to demonstrate system capability under simulated operating gas turbine environmental conditions. Operational and environmental performance test data are presented.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-159402 , FR-10200A
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  • 83
    Publication Date: 2019-06-27
    Description: Stability audit plots were used to determine if peak distortion data taken from a subscale inlet model can be used to predict peak distortion levels for a full scale flight test vehicle.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-144874
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  • 84
    Publication Date: 2019-06-27
    Description: The effect of filter cutoff frequency on turbulence plots were used to determine if peak distortion data taken from a subscale inlet model can be used to predict peak distortion levels for a full scale flight test vehicle.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-144870
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  • 85
    Publication Date: 2019-06-27
    Description: The selection procedure is described which was used to arrive at the configurations tested, and the performance characteristics of the test nozzles are given.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135239-VOL-2
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  • 86
    Publication Date: 2019-06-27
    Description: Experiments were conducted in which a stream of premixed propane and air was burned under conditions representative of gas turbine operation. Emissions of NOx, CO, and unburned hydrocarbons (UHC) were measured over a range of combustor inlet temperature, pressure, and residence time at equivalence ratios from 0.7 down to the lean stability limit. At an inlet temperature of 600 K, observed NOx levels dropped markedly with decreasing pressure for pressures below 20 atm. The NOx levels are proportional to combustor residence time and formation rates were principally a function of adiabatic flame temperature. For adiabatic flame temperatures of 2050 K and higher, CO reached chemical equilibrium within 2 msec. Unburned hydrocarbon species dropped to a negligible level within 2 msec regardless of inlet temperature, pressure, or equivalence ratio. For a combustor residence time of 2.5 msec, combustion inefficiency became less than 0.01% at an adiabatic flame temperature of 2050 K. The maximum combustion inefficiency observed was on the order of 1% and corresponded to conditions near the lean stability limit. Using a perforated plate flameholder, this limit is well represented by the condition of 1800 K adiabatic flame temperature.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-3032 , GASL-TR-248
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  • 87
    Publication Date: 2019-06-27
    Description: Acoustic data are presented scaled to a full size engine by a factor of 8 on a 96.9 m (320 ft) arc and a 731.5 m (2400 ft) sideline.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135239-VOL-1-SECT-2
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  • 88
    Publication Date: 2019-06-27
    Description: A computer program that calculates the coolant flow and the metal temperatures of a full-coverage-film-cooled vane or blade was developed. The analysis was based on compressible, one-dimensional fluid flow and on one-dimensional heat transfer and treats the vane or blade shell as a porous wall. The calculated temperatures are average values for the shell outer-surface area associated with each film-cooling hole row. A thermal-barrier coating may be specified on the shell outer surface, and centrifugal effects can be included for blade calculations. The program is written in FORTRAN 4 and is operational on a UNIVAC 1100/42 computer. The method of analysis, the program input, the program output, and two sample problems are provided.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1259 , E-9491 , AVRADCOM-TR-78-19(PL)
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  • 89
    Publication Date: 2019-06-27
    Description: Acoustic data plots are presented which were obtained in the tests on scale nozzles for use on duct-burning turbofan engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135239-VOL-1-SECT-3
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  • 90
    Publication Date: 2019-06-27
    Description: Model scale data on a 12.2 m (40 ft) arc are presented which were obtained in the hot, static acoustic tests on eleven nozzle designs suitable for use on duct-burning turbofan engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135239-VOL-1-SECT-1
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  • 91
    Publication Date: 2019-06-27
    Description: A short, annular dump diffuser was designed to use suction to establish stabilized vortices on both walls for improved flow expansion in the region of an abrupt area change. The diffuser was tested at near ambient inlet pressure and temperature. The overall diffuser area ratio was 4.0. The inlet height was 2.54 cm and the exit pitot-static rakes were located at a distance from the vortex fence equal to two or six times the inlet height. Performance data were taken at near ambient temperature and pressure for nominal inlet Mach numbers of 0.18 to 0.41 with suction rates of 0 to 18 percent of the total inlet airflow. The exit velocity profile could be shifted toward either wall by adjusting the inner- or outer-wall suction rate. Symmetrical exit velocity profiles were unstable, with a tendency to shift back to hub- or tip-weighted profile. Diffuser effectiveness was increased from about 47 percent without suction to over 85 percent at a total suction rate of about 14 percent. The diffuser total pressure losses at inlet Mach numbers of 0.18 and 0.41 decreased from 1.1 and 5.6 percent without suction to 0.48 and 5.2 percent at total suction rates of 14.4 and 5.6 percent, respectively.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1194 , E-9332
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  • 92
    Publication Date: 2019-06-27
    Description: A type of noncontacting electro-optical extensometer was used to measure the displacement between parallel targets mounted on the leading edge of a simulated turbine blade throughout a complete heating and cooling cycle. The blade was cyclically heated and cooled by moving it into and out of a Mach 1 hot gas stream. The principle of operation and measurement procedure of the electro-optics extensometer are described.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-73886 , E-9500
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  • 93
    Publication Date: 2019-06-27
    Description: Tests were conducted in a 20 inch diameter single stage air cooled turbine designed to evaluate the effects of film cooling air on turbine aerodynamic performance. A comparison was made of the experimental results and an analytical method of evaluating film injection effects on turbine performance. The results are used to determine the effects of film cooling on overall engine performance for selected cycle conditions. The engine performance studies are used to show the cycle benefits of increased gas temperature at various coolant flow rates.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD High Temp. Probl. in Gas Turbine Eng.; 11 p
    Format: text
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  • 94
    Publication Date: 2019-06-27
    Description: The use of leaning vanes for tone noise reduction was examined in terms of their application in a typical two-stage high pressure ratio fan. In particular for stages designed with outlet guide vanes and zero swirl between stages, leaning the vanes of the first stage stator was studied, since increasing the number of vanes and the gap between stages do not provide the desired advantage. It was shown that noise reduction at higher harmonics of blade passing frequency can be obtained by leaning the vanes.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-152134
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  • 95
    Publication Date: 2019-06-27
    Description: A modified Zeldovich kinetic scheme was used to predict nitric oxide formation in the burned gases. Nonuniformities in fuel-air ratio in the primary zone were accounted for by a distribution of fuel-air ratios. This was followed by one or more dilution zones in which a Monte Carlo calculation was employed to follow the mixing and dilution processes. Predictions of NOX emissions were compared with various available experimental data, and satisfactory agreement was achieved. In particular, the model is applied to the NASA swirl-can modular combustor. The operating characteristics of this combustor which can be inferred from the modeling predictions are described. Parametric studies are presented which examine the influence of the modeling parameters on the NOX emission level. A series of flow visualization experiments demonstrates the fuel droplet breakup and turbulent recirculation processes. A tracer experiment quantitatively follows the jets from the swirler as they move downstream and entrain surrounding gases. Techniques were developed for calculating both fuel-air ratio and degree of nonuniformity from measurements of CO2, CO, O2, and hydrocarbons. A burning experiment made use of these techniques to map out the flow field in terms of local equivalence ratio and mixture nonuniformity.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-2977
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  • 96
    Publication Date: 2019-06-27
    Description: The results of a theoretical investigation of geometric variables for lift-cruise-fan, tilting nacelle inlets operating at high incidence angles are presented. These geometric variables are investigated for their effects on surface static to free stream pressure ratio, and the separation parameters of maximum to diffuser exit surface velocity ratio and maximum surface Mach number for low speed operating conditions. The geometric parameters varied were the internal lip contraction ratio, external forebody to diffuser exit diameter ratio external forebody length to diameter ratio and internal lip major to minor axis ratio.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1205 , E-9387
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  • 97
    Publication Date: 2019-06-27
    Description: Film injection from discrete holes in a smooth, flat plate was studied for two configurations: (1) spanwise injection through a four hole staggered array; and (2) compound angle injection through a 49 hole staggered array. The ratio of boundary layer thicknesses to hole diameter and the Reynolds number were typical of gas turbine film cooling applications. Streaklines showing the motion of the injected air were obtained by photographing small, neutrally buoyant, helium-filled soap bubbles that followed the flow field.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1195 , E-9340
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  • 98
    Publication Date: 2019-06-27
    Description: An airflow and thrust calibration of an F100 engine, S/N P680059, was conducted to study airframe propulsion system integration losses in turbofan-powered high-performance aircraft. The tests were conducted with and without thrust augmentation for a variety of simulated flight conditions with emphasis on the transonic regime. The resulting corrected airflow data generalized into one curve with corrected fan speed while corrected gross thrust increased as simulated flight conditions increased. Overall agreement between measured data and computed results was 1 percent for corrected airflow and -1 1/2 percent for gross thrust. The results of an uncertainty analysis are presented for both parameters at each simulated flight condition.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TP-1069 , E-9257
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  • 99
    Publication Date: 2019-06-27
    Description: Acoustics data obtained in experiments with two low pressure ratio 50.8 cm (20 in.) diameter model fans differing in design tip speed were compared. Determination of the average throat Mach number used to compare high Mach inlet noise reduction characteristics was based on a correlation of inlet wall static pressure measurements with a flow field calculation. The largest noise reductions were generally obtained with the higher tip speed fan. At a throat Mach number of 0.79, the difference in noise reduction was about 3.5 db with static test conditions. Although the noise reduction increased for the lower tip speed fan with a simulated flight velocity of 41 m/sec (80 knots), it was still about 2 db less than that of the high tip speed fan which was only tested at the static condition. However, variations in acoustic performance could not be absolutely attributed to the different fan designs because of differences in inlet lip contours which resulted in small variations of peak wall Mach number and axial extend of supersonic and near-sonic flow.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-73880 , E-9489
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  • 100
    Publication Date: 2019-06-27
    Description: A new concept for a scramjet engine design was presented. The inlet transformed a rectangular shaped capture stream into a cross section which was almost circular in shape at the inlet throat or combustor entrance. The inlet inner surface was designed by the method of streamline tracing. The high pressure and temperature regions of the combustor were almost circular in shape and thus the benefits of hoop stresses in relation to structural weight could be utilized to reduce combustor and engine weights. The engine had a center body consisting of a 20 deg included angle cone, followed by a constant diameter cylinder. Fuel injection struts were arranged in a radial array and were swept 54 deg from the center body to the inlet inner surface and had values of length to maximum average thickness between 5.6and 6.6 which were felt to be structurally reasonable. Combustor wetted areas were shown to be less than those of the present fully rectangular engine concept.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-78657
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