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This paper reviews a recent internal study by Pratt & Whitney to define the optimum propulsion system characteristics for a commercial transport designed to fly at Mach 0.95. The impact on aircraft gross weight of propulsion cycle characteristics such as bypass ratio, overall pressure ratio, turbine temperature, nacelle weight, and drag as well as the important criteria of noise is reviewed. ...The impact on aircraft gross weight of propulsion cycle characteristics such as bypass ratio, overall pressure ratio, turbine temperature, nacelle weight, and drag as well as the important criteria of noise is reviewed.

The paper gives an overview of the propulsion content of the programs at the undergraduate and postgraduate levels, as offered to students in both Mechanical and Aerospace Engineering.

This paper will identify some of the primary propulsion integration problems for high performance aircraft at transonic speeds, and demonstrate several methods for reducing or eliminating the undesirable characteristics, while enhancing configuration effectiveness.

Measurements of the gas state properties in hypersonic propulsion system research present unique problems demanding unconventional diagnostic measurement system design solutions.

General aviation of the middle 1980's has been less than inspiring from a business viewpoint. Numerous aerodynamic innovations have matured, however, little progress has been made in powerplants. Although significant technology exists for powerplant design progress, low demand and product liability concerns have supressed implementation. The Merlyn design represents one of several present efforts to provide a particular technology to address specific needs in the aviation marketplace.

To achieve this goal, NASA has analyzed a hybrid body wing aircraft with a turboelectric distributed propulsion system. The propulsion system must be designed to operate at the highest possible efficiency in order to meet the reduced fuel burn goal. ...High density components are required to minimize the weight of the electric propulsion system while meeting the high power demand. Minimizing the electric propulsion system weight helps to reduce the amount of fuel required for propulsion. ...NASA's N3-X aircraft design under the Research and Technology for Aerospace Propulsion Systems (RTAPS) study is being designed to meet the N+3 goals, one of which is the reduction of aircraft fuel burn by 70% or better.

Wide scope systems studies of V/STOL propulsion were conducted by GE, encompassing the total air vehicle design and its operation in lift, transition, cruise, and STOL modes. ...To determine VTOL propulsion requirements, the author explains the necessity for incorporating the entire air vehicle into the analysis. ...It is felt that the performance indicated necessary by these studies is now attainable by the propulsion industry.

Propulsion system hardware has steadily increased in complexity which has placed even greater demands on the propulsion control hardware. ...Propulsion system hardware has steadily increased in complexity which has placed even greater demands on the propulsion control hardware. With the engine and inlet operating at higher levels of performance, the need for improvements in control system technology has become more evident. ...In addition to increased sensing and computation, it is required that the various inlet and engine control functions be integrated to achieve maximum propulsion system stability and performance during all flight conditions. This paper describes a three year exploratory research program for the design, development, and flight evaluation of an Integrated Propulsion Control System (IPCS).

Previous papers in this session described the historical aspects, tradeoffs, and requirements for powered lift propulsion systems, and it is shown that propulsion technology is more key to the success of this type of aircraft than for any previous fighter/attack aircraft. ...This paper discusses the NASA Lewis Research Center program activities which address required propulsion technology development. Several elements of this program have been initiated which address hot gas ingestion and ejector augmenter performance and some preliminary results are shown.

The general problem of applying propulsion systems to supersonic aircraft is discussed briefly and it is shown that neither turbojets nor ramjets are entirely satisfactory when used by themselves. ...In order to avoid the confusion resulting from the comparison of propulsion system performance using the special parameters associated with each type of engine, performance is compared along operating altitude-Mach number paths in terms of thrust and specific fuel consumption only. ...The combined propulsion system arrived at offers promise of good performance, light weight, low cost, and simple installation.

The goal of the propulsion community is to have the enabling propulsion technologies in place to permit a low risk decision regarding the initiation of a research STOVL supersonic attack/fighter aircraft in the mid-1990's. ...This program, the Supersonic STOVL Integrated Flight-Propulsion Controls Program, is part of the overall NASA Lewis Supersonic STOVL Propulsion Technology Program, it uses an integrated approach to an integrated program to achieve integrated flight-propulsion control technology.

This paper presents the overall scope of the NASA Lewis High Performance Aircraft Propulsion Research Program. High performance fighter aircraft of interest include supersonic fighters with such capabilities as short takeoff and vertical landing (STOVL) and/or high maneuverability. ...The NASA Lewis effort involving STOVL propulsion systems is focused primarily on component-level experimental and analytical research. ...The overall objective of the NASA Inlet Experiments portion of the HATP, which NASA Lewis leads, is to develop and enhance inlet technology that will ensure high performance and stability of the propulsion system during aircraft maneuvers at high angles of attack. To accomplish this objective, both wind-tunnel and flight experiments are used to obtain steady-state and dynamic data, and computational fluid dynamics (CFD) codes are used for analyses.

Investigation into electric propulsion continues to be an area of hopeful research since the pioneering age of aviation. However, more recent global awareness of carbon emissions on the planet and the desire to create more efficient systems has reinvigorated new life into the field. ...Experimental studies on electric propulsion by virtue of asymmetrical electrodes, on a micro scale, have yielded potentially superior efficiency ratings when compared to currently adopted methods. ...This method of propulsion is unique and possesses several features that differentiate it from conventional methods of propulsion.

This paper presents (1) a chronology of Air Force technical activity on future propulsion concepts, (2) a status report on NASA research on scramjet technology for future systems which may require speeds above Mach 5, and (3) a description of a research vehicle by which advanced propulsion technology and other technologies related to high speed can be demonstrated. ...This paper presents (1) a chronology of Air Force technical activity on future propulsion concepts, (2) a status report on NASA research on scramjet technology for future systems which may require speeds above Mach 5, and (3) a description of a research vehicle by which advanced propulsion technology and other technologies related to high speed can be demonstrated.

Two propulsion related drag correlation parameters have been developed. Existing or planned parametric jet aftbody drag data can therefore be reduced into a simple prediction technique for aircraft preliminary design studies. ...The drag due to the external nozzle geometry correlates with the average slope of the aftbody's area distribution (Integral Mean Slope), and the drag influence of the internal nozzle geometry/exhaust plume correlates with an effective plume inclination angle (Plume Correlation Parameter). The propulsion related drags of single, twin, and two-dimensional jet installations, and convergent, convergent-divergent, and plug nozzles are shown to correlate with the two parameters.

During the 1970's, our hypersonic effort dwindled to a few dedicated research efforts which refined propulsion, aerodynamics, and computational fluid dynamics principles. To make real progress in the 1980's, and beyond, a focus and a rekindled effort was needed. ...The primary emphasis of the paper is National Aero-Space Plane propulsion technology. Key technical challenges are noted and a discussion of progress relative to those challenges associated with propulsion is presented. ...Key technical challenges are noted and a discussion of progress relative to those challenges associated with propulsion is presented.

The Waste Management/Rocket Propulsion System appears capable of satisfying many propulsion requirements; for example, orbit change maneuvers, aerodynamic drag makeup, midcourse correction, terminal braking, and auxiliary and emergency propulsion. ...To date, spacecraft designers have considered life support systems and rocket propulsion systems as independent subsystems of a manned spacecraft. The Integrated Waste Management/Rocket Propulsion System concept developed by Rocket Research Corp. under NASA Contract NAS 1–6750, has demonstrated that human waste products can form a useful propellant ingredient and provide propulsion, as well as be an effective means of removing and sterilizing spacecraft waste. ...The Integrated Waste Management/Rocket Propulsion System concept developed by Rocket Research Corp. under NASA Contract NAS 1–6750, has demonstrated that human waste products can form a useful propellant ingredient and provide propulsion, as well as be an effective means of removing and sterilizing spacecraft waste.

A multimode propulsion control system concept has been developed for the remotely piloted research vehicle of the NASA Highly Maneuverable Aircraft Technology program.

The purpose of this paper is to identify some of the constraints imposed on an airplane propulsion system by transonic cruise speeds and to explore some ways to satisfy them. As the design Mach number of an airplane is increased above the 0.85 level toward 1.0, good airplane performance depends increasingly on careful tailoring of the propulsion installation and its integration into the overall configuration to establish a good compromise between drag, internal nacelle performance, and the practical considerations that produce an excellent airplane. ...As the design Mach number of an airplane is increased above the 0.85 level toward 1.0, good airplane performance depends increasingly on careful tailoring of the propulsion installation and its integration into the overall configuration to establish a good compromise between drag, internal nacelle performance, and the practical considerations that produce an excellent airplane.

We analyse 635 set-years of service experience of 147 merchant-marine steam-turbine-gear propulsion sets, finding an MTBF of 23.5 set-years. The sets of one good-sized fleet have 3 times as large an MTBF as the rest of the sample, a fine return on the more conservative attention paid them.