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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Advanced composites wing study program, volume 2

The study on utilization of advanced composites in commercial aircraft wing structures was conducted as a part of the NASA Aircraft Energy Efficiency Program to establish, by the mid-1980s, the technology for the design of a subsonic commercial transport aircraft leading to a 40% fuel savings. The study objective was to develop a plan to define the effort needed to support a production commitment for the extensive use of composite materials in wings of new generation aircraft that will enter service in the 1985-1990 time period. Identification and analysis of what was needed to meet the above plan requirements resulted in a program plan consisting of three key development areas: (1) technology development; (2) production capability development; and (3) integration and validation by designing, building, and testing major development hardware.

Harvey, S. T.↗
NASA NTRS1976

Potential improvements in turbofan engine fuel economy

The method developed for initial evaluation of possible performance improvements in the NASA Aircraft Energy Efficiency Program, directed toward improving the fuel economy of turbofan engines, is outlined, and results of the evaluation of 100 candidate engine modifications are presented. The study indicates that fuel consumption improvements of as much as 5% may be possible in current JT3D, JT8D, and JT9D turbofan engines. Aerodynamic, thermodynamic, material, and structural advances are expected to yield fuel consumption improvements on the order of 10 to 15% in advanced turbofan engines, with the greatest improvement stemming from significantly higher cycle pressure ratios. Higher turbine temperature and fan bypass ratios are also expected to contribute to fuel conservation.

Hines, R. W.↗
NASA NTRS1976

Airframe technology for energy efficient transport aircraft

NASA has initiated a comprehensive Aircraft Energy Efficiency Program which is concerned with the development of approaches for reducing fuel consumption in new aircraft of the 1980-2000 time period. A review is presented of the airframe technologies selected for emphasis in the NASA program, taking into account an evaluation of their potential for reducing transport direct operating costs through fuel efficiency. Attention is given to the importance of fuel efficiency, the impact of advanced technology, advanced composite structures, the NASA composite primary structures program, advanced aerodynamics and active controls, supercritical wing geometry, active load and flutter control, and aspects of laminar flow control.

Leonard, R. W.↗
NASA NTRS1978

Prop-fan propulsion - Its status and potential

Studies have established that advanced turboprop (prop-fan) equipped aircraft will reduce fuel consumption by 15 to 30 percent compared to aircraft equipped with high-bypass turbofan engines of equivalent technology. A reduction in direct operating costs of approximately 10 percent has been identified for commercial aircraft as well as approximately 20 percent lower gross weight airplane for long endurance military missions. The prop-fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficiency program which includes both analytical studies and experimental tests. The experimental work encompasses performance and acoustic wind tunnel tests on several prop-fan models. The prop-fan technology status is reviewed in the major areas of performance, installed effects, cabin noise, blade structure and maintenance cost. Also, further activities required to complete the technical validation of prop-fans are described.

Dugan, J. F., Jr.↗
NASA NTRS1980

Investigation of performance deterioration of the CF6/JT9D, high-bypass ratio turbofan engines

The aircraft energy efficiency program within NASA is developing technology required to improve the fuel efficiency of commercial subsonic transport aricraft. One segment of this program includes engine diagnostics which is directed toward determining the sources and causes of performance deterioration in the Pratt and Whitney Aircraft JT9D and General Electric CF6 high-bypass ratio turbofan engines and developing technology for minimizing the performance losses. Results of engine performance deterioration investigations based on historical data, special engine tests, and specific tests to define the influence of flight loads and component clearances on performance are presented. The results of analysis of several damage mechanisms that contribute to performance deterioration such as blade tip rubs, airfoil surface roughness and erosion, and thermal distortion are also included. The significance of these damage mechanisms on component and overall engine performance is discussed.

Ziemianski, J. A.↗
NASA NTRS1980

Advanced transport aircraft technology

Various elements of the NASA aircraft energy efficiency program are described. Regarding composite structures, the development of three secondary and three medium-primary components to validate structural and fabrication technology is discussed. In laminar flow control, the design of advanced airfoils having large regions of supercritical flow with features which simplify laminarization are considered. Emphasis is placed on engine performance improvement, directed at developing advanced components to reduce fuel consumption in current production engines, and engine diagnostics aimed at identifying the sources and causes of performance deterioration in high-bypass turbofan engines. In addition, the results of propeller aerodynamic and acoustic tests have substantiated the feasibility of achieving the propeller efficiency goal of 80% and confirmed that the effect of blade sweep on reducing propeller source noise was 5-6 dB.

Winblade, R. L.↗
NASA NTRS1980

Boundary layer stability analysis of a natural laminar flow glove on the F-111 TACT airplane

A natural laminar flow airfoil has been developed as a part of the aircraft energy efficiency program. A NASA flight program incorporating this airfoil into partial wing gloves on the F-111 TACT airplane was scheduled to start in May, 1980. In support of this research effort, an extensive boundary layer stability analysis of the partial glove has been conducted. The results of that analysis show the expected effects of wing leading-edge sweep angle, Reynolds number, and compressibility on boundary layer stability and transition. These results indicate that it should be possible to attain on the order of 60% laminar flow on the upper surface and 50% laminar flow on the lower surface for sweep angles of at least 20 deg, chord Reynolds numbers of 25 x 10 to the 6th and Mach numbers from 0.81 to 0.85.

Runyan, L. J.↗
NASA NTRS1982

Evaluation of wind tunnel performance testings of an advanced 45 deg swept 8-bladed propeller at Mach numbers from 0.45 to 0.85

The increased emphasis of fuel conservation in the world and the rapid increase in the cost of jet fuel has stimulated a series of studies of both conventional and unconventional propulsion systems for commercial aircraft. The results of these studies indicate that a fuel saving of 15 to 30 percent may be realized by the use of an advanced high-speed turboprop (Prop-Fan) compared to aircraft equipped with high bypass turbofan engines of equivalent technology. The Prop-Fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficient Program. This effort includes the wind tunnel testing of a series of 8 and 10-blade Prop-Fan models incorporate swept blades. Test results indicate efficiency levels near the goal of 80 percent at Mach 0.8 cruise and an altitude of 10.67 km (35,000 ft). Each successive swept model has shown improved efficiency relative to the straight blade model. The fourth model, with 45 deg swept blades reported herein, shows a net efficiency of 78.2 at the design point with a power loading of 301 kW/sq meter and a tip speed of 243.8 m/sec (800 ft/sec.).

Rohrbach, C.↗
NASA NTRS1981

Materials and structures/ACEE

Light weight composites made from graphite fibers, glass, or man made materials held in an epoxy matrix, and their application to airframe design are reviewed. The Aircraft Energy Efficiency program is discussed. Characteristics of composites, acceptable risks, building parts and confidence, and aeroelastic tailoring are considered.

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NASA NTRS1981

Propulsion/ACEE

The research objectives of the NASA aircraft energy efficiency program are summarized. Engine component improvements for turbofan engines, diagnostics, the development of advanced turboprop engines, and propeller noise analysis are discussed.

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NASA NTRS1984

Airframe technology for aircraft energy efficiency

The economic factors that resulted in the implementation of the aircraft energy efficiency program (ACEE) are reviewed and airframe technology elements including content, progress, applications, and future direction are discussed. The program includes the development of laminar flow systems, advanced aerodynamics, active controls, and composite structures.

James, R. L., Jr.↗
NASA NTRS1981

Acoustic flight testing of advanced design propellers on a JetStar aircraft

Advanced turboprop-powered aircraft have the potential to reduce fuel consumption by 15 to 30 percent as compared with an equivalent technology turbofan-powered aircraft. An important obstacle to the use of advanced design propellers is the cabin noise generated at Mach numbers up to .8 and at altitudes up to 35,000 feet. As part of the NASA Aircraft Energy Efficiency Program, the near-field acoustic characteristics on a series of advanced design propellers are investigated. Currently, Dryden Flight Research Center is flight testing a series of propellers on a JetStar airplane. The propellers used in the flight test were previously tested in wind tunnels at the Lewis Research Center. Data are presented showing the narrow band spectra, acoustic wave form, and acoustic contours on the fuselage surface. Additional flights with the SR-3 propeller and other advanced propellers are planned in the future.

Lasagna, P.↗
NASA NTRS1984

Synthesis and toughness properties of resins and composites

Tensile and shear moduli of four ACEE (Aircraft Energy Efficiency Program) resins are presented along with ACEE composite material modulus predictions based on micromechanics. Compressive strength and fracture toughness of the resins and composites were discussed. In addition, several resin synthesis techniques are reviewed.

Johnston, N. J.↗
NASA NTRS1982

Fuel efficiency through new airframe technology

In its Aircraft Energy Efficiency Program, NASA has expended approximately 200 million dollars toward development and application of advanced airframe technologies to United States's commercial transports. United States manufacturers have already been given a significant boost toward early application of advanced composite materials to control surface and empennage structures and toward selected applications of active controls and advanced aerodynamic concepts. In addition, significant progress in definition and development of innovative, but realistic systems for laminar flow control over the wings of future transports has already been made.

Leonard, R. W.↗
NASA NTRS1988

The winning edge

Aeronautics research at NASA is reviewed, stressing NASA's leading role in the development of technological advances. The Aircraft Energy Efficiency program for improving transport aircraft and the Natioanl Aerospace Plane program are examined. NASA research facilities and wind tunnels, and research in materials and structures and aviation safety and automation are discussed.

Rosen, Cecil C., III↗
NASA NTRS1994

Winglets for the Airlines

Originally developed as part of the Aircraft Energy Efficiency Program in the 1970's, winglets are now used by long-ranging aircraft as well as business jets and smaller planes. The winglet is an upturned wingtip, a lifting surface designed to operate in the wingtip "vortex," a whirlpool of air at an airplane's wingtips. It takes advantage of the turbulent vortex flow by producing forward thrust. This reduces drag and improves fuel efficiency. After McDonnell Douglas conducted wind tunnel tests of winglets in 1978-79, the technology was incorporated into the MD-11, their large payload, long range airplane. There are now more than 100 MD-11s in service.

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NASA NTRS1980

Longhorn Business Jets

Developed in NASA's Aircraft Energy Efficiency program and manufactured by Gates Learjet Corporation, the winglet is an aerodynamic innovation designed to reduce fuel consumption and improve airplane performance. Winglets are lifting surfaces designed to operate in the "vortex" or air whirlpool which occurs at an airplane's wingtip. Complex flow of air around wingtip creates drag which retards the plane's progress. Winglet reduces strength of vortex and thereby reduces strength of drag. Additionally, winglet generates its own lift, producing forward thrust in the manner of a boat's sail. Combination of reduced drag and additional thrust adds up to significant improvement in fuel efficiency.

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NASA NTRS1981

Energy efficient engine component development and integration program

Accomplishments in the Energy Efficient Engine Component Development and Integration program during the period of April 1, 1981 through September 30, 1981 are discussed. The major topics considered are: (1) propulsion system analysis, design, and integration; (2) engine component analysis, design, and development; (3) core engine tests; and (4) integrated core/low spool testing.

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