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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 127 records · Page 7

Materials for Advanced Turbine Engines: Power Metallurgy Rene 95 Rotating Turbine Engine Parts - Volume 1

An attempt was made to improve methods for producing powder metallurgy aircraft gas turbine engine parts from the nickel base superalloy known as Rene 95. The parts produced were the high pressure turbine aft shaft for the CF6-50 engine and the stages 5 through 9 compressor disk forgings for the CFM56/F101 engines. A 50% cost reduction was achieved as compared to conventional cast and wrought processing practices. An integrated effort involving several powder producers and a major forging source were included.

Pfouts, W. R.↗

Effect of propeller slipstream on the drag and performance of the engine cooling system for a general aviation twin-engine aircraft

The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was investigated experimentally. The semispan model was mounted vertically in the 40- by 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-flow configuration. It was found that the propeller slipstream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slipstream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack, that is, climb condition. For the cruise condition those improvements were more moderate.

Katz, J.↗

Orbit Transfer Vehicle Engine Study. Phase A, extension 1: Advanced expander cycle engine optimization

The performance optimization of expander cycle engines at vacuum thrust levels of 10K, 15K, and 20K lb is discussed. The optimization is conducted for a maximum engine length with an extendible nozzle in the retracted position of 60 inches and an engine mixture ratio of 6.0:1. The thrust chamber geometry and cycle analyses are documented. In addition, the sensitivity of a recommended baseline expander cycle to component performance variations is determined and chilldown/start propellant consumptions are estimated.

Mellish, J. A.↗

Conventional engine technology. Volume 1: Status of OTTO cycle engine technology

Federally-mandated emissions standards have led to major changes in automotive technology during the last decade. Efforts to satisfy the new standards were directed more toward the use of add-on devices, such as catalytic converters, turbochargers, and improved fuel metering, than toward complete engine redesign. The resulting changes are described and the improvement brought about by them in fuel economy and emissions levels are fully documented. Four specific categories of gasoline-powered internal combustion engines are covered, including subsystem and total engine development. Also included are the results of fuel economy and exhaust emissions tests performed on representative vehicles from each category.

Dowdy, M. W.↗

Activities of the Aeronautics and Space Engineering Board Commission on Engineering and Technical Systems

The agenda of the Aeronautics and Space Engineering Board meeting is reviewed. Items discussed included; engineering and technical requirements of the space station, NASA's altitude wind tunnel, rocket engine casings, advanced flight vehicle technology, the space shuttle, and on-orbit space maintenance. Board members along with their institutional affiliation are listed.

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Effect of control logic modifications on airstart performance of F100 engine model derivative engines in an F-15 airplane

A series of airstarts were conducted in an F-15 airplane with two prototype Pratt and Whitney F100 Engine Model Derivative engines equipped with Digital Electronic Engine Control (DEEC) systems. The airstart envelope and the time required for airstarts were defined. Comparisons were made between the original airstart logic, and modified logic which was designed to improve the airstart capability. Spooldown airstarts with the modified logic were more successful at lower altitudes than were those with the original logic. Spooldown airstart times ranged from 33 seconds at 250 knots to 83 seconds at 175 knots. The modified logic improved the airstart time from 31% to 53%, with the most improved times at slower airspeeds. Jet fuel starter (JFS)-assisted airstarts were conducted at 7000 m and airstart times were significantly faster than unassisted airstarts. The effect of altitude on airstart times was small.

Crawford, D. B.↗

Space Station Engineering and Technology Development: Proceedings of the Panel on In-Space Engineering Research and Technology Development

In 1984 the ad hoc committee on Space Station Engineering and Technology Development of the Aeronautics and Space Engineering Board (ASEB) conducted a review of the National Aeronautics and Space Administration's (NASA's) space station program planning. The review addressed the initial operating configuration (IOC) of the station. The ASEB has reconstituted the ad hoc committee which then established panels to address each specific related subject. The participants of the panels come from the committee, industry, and universities. The proceedings of the Panel on In Space Engineering Research and Technology Development are presented in this report. Activities, and plans for identifying and developing R&T programs to be conducted by the space station and related in space support needs including module requirements are addressed. Consideration is given to use of the station for R&T for other government agencies, universities, and industry.

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Airstart performance of a digital electronic engine control system on an F100 engine

The digital electronic engine control (DEEC) system installed on an F100 engine in an F-15 aircraft was tested. The DEEC system incorporates a closed-loop air start feature in which the fuel flow is modulated to achieve the desired rate of compressor acceleration. With this logic the DEEC equipped F100 engine can achieve air starts over a larger envelope. The DEEC air start logic, the test program conducted on the F-15, and its results are described.

Burcham, F. W., Jr.↗

Augmentor transient capability of an F100 engine equipped with a digital electronic engine control

An F100 augmented turbofan engine equipped with digital electronic engine control (DEEC) system was evaluated. The engine was equipped with a specially modified augmentor to provide improved steady state and transient augmentor capability. The combination of the DEEC and the modified augmentor was evaluated in sea level and altitude facility tests and then in four different flight phases in an F-15 aircraft. The augmentor configuration, logic, and test results are presented.

Burcham, F. W., Jr.↗

Real-time in-flight thrust calculation on a digital electronic engine control-equipped F100 engine in an F-15 airplane

Computer algorithms which calculate in-flight engine and aircraft performance real-time are discussed. The first step was completed with the implementation of a real-time thrust calculation program on a digital electronic engine control (DEEC) equiped F100 engine in an F-15 aircraft. The in-flight thrust modifications that allow calculations to be performed in real-time, to compare results to predictions, are presented.

Ray, R. J.↗

Performance studies on the application of four-engine and two-engine USB propulsive lift to the E-2C aircraft

A study has been completed of the performance benefits to be derived from applying advanced upper-surface blowing (USB) propulsive-lift technology to the E-2C aircraft. The results of comparing four-engine with two-engine USB configurations are discussed, and engine sizing and aerodynamic/structural considerations pertaining to the E-2C/USB modification are examined. The effects of the modification on performance are described in detail with regard to takeoff distance and landing distance estimation in free-deck operations, operations using catapult and arresting gear, ceiling and radar surveillance missions, and range and endurance capability.

Riddle, D. W.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 20: Engineers as information processors: A survey of US aerospace engineering faculty and students

U.S. aerospace engineering faculty and students were surveyed as part of the NASA/DoD Aerospace Knowledge Research Project. Faculty and students were viewed as information processors within a conceptual framework of information seeking behavior. Questionnaires were received from 275 faculty members and 640 students, which were used to determine: (1) use and importance of information sources; (2) use of specific print sources and electronic data bases; (3) use of information technology; and (4) the influence of instruction on the use of information sources and the products of faculty and students. Little evidence was found to support the belief that instruction in library or engineering information use has significant impact either on broadening the frequency or range of information products and sources used by U.S. aerospace engineering students.

Holland, Maurita Peterson↗

An RL10A-3-3A rocket engine model using the Rocket Engine Transient Simulator (ROCETS) software

The RL10 engine is a critical component of past, present, and future space missions. The paper discusses the RL10A-3-3A engine system and its model created using the ROCETS computer code. The simulation model will give NASA an in-house capability to simulate the performance of the engine under various operating conditions and mission profiles. A comparison of steady-state model predictions with test-stand data is presented together with a comparison of predicted start transient behavior with flight data.

Binder, Michael↗

Preliminary Report on Experimental Investigation of Engine Dynamics and Controls for a 48-inch Ram-jet Engine

Engine dynamics and controls data are presented for a ram-jet engine which was operated in a free-jet facility at a Mach number of 2.76 and altitudes from 68,000 to 82,000 feet. The predominant engine dynamic characteristics was dead time, with values ranging from 0.018 to 0.053 sec. The control systems were designed to hold a constant ratio of a diffuser static pressure to an inlet-cone reference static pressure. Response times and percent overshoot to fuel-flow disturbances that would have caused subcritical operation without control are included for a wide range of control settings. For all settings, the control response was fast enough (0.08 to 0.5 sec) to prevent subcritical operation.

Vasu, George↗

Software engineering as an engineering discipline

The purpose of this panel is to explore the emerging field of software engineering from a variety of perspectives: university programs; industry training and definition; government development; and technology transfer. In doing this, the panel will address the issues of distinctions among software engineering, computer science, and computer hardware engineering as they relate to the challenges of large, complex systems.

Freedman, Glenn B.↗

A minimum cost tolerance allocation method for rocket engines and robust rocket engine design

Rocket engine design follows three phases: systems design, parameter design, and tolerance design. Systems design and parameter design are most effectively conducted in a concurrent engineering (CE) environment that utilize methods such as Quality Function Deployment and Taguchi methods. However, tolerance allocation remains an art driven by experience, handbooks, and rules of thumb. It was desirable to develop and optimization approach to tolerancing. The case study engine was the STME gas generator cycle. The design of the major components had been completed and the functional relationship between the component tolerances and system performance had been computed using the Generic Power Balance model. The system performance nominals (thrust, MR, and Isp) and tolerances were already specified, as were an initial set of component tolerances. However, the question was whether there existed an optimal combination of tolerances that would result in the minimum cost without any degradation in system performance.

Gerth, Richard J.↗