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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.

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.

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.

The requirements of engine test cells and propulsion laboratories for propulsion education will be discussed. A typical versatile propulsion laboratory set-up for testing full-scale aircraft reciprocating engines, gas turbines, as well as small-scale rocket motors will also be presented. ...There are a variety of propulsion packages available for general aviation aircraft including reciprocating engines, small gas turbines, and rotary engines. ...In future, electrical propulsion will be a major contender in this market. The importance of general aviation propulsion education for aeronautical engineers will be addressed.

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.

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.

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.

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.

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.

A decentralized, multivariable controls methodology is being developed for the functional integration of a fighter's aerodynamic controls with those of its propulsion system (inlet, engine, and thrust vectoring/reversing nozzle). Integrated controls account for, and take advantage of the significant cross-coupling between these system elements.

The application of air breathing turbofan engines to a variable geometry, lifting, entry spacecraft provides a Cruise-spacecraft having increased operational flexibility. This spacecraft can accomplish a high performance, 3000 nautical mile lateral range mission, by combining the glide available from its medium hypersonic L/D (1. 7 to 2. 3) with subsonic cruise in the atmosphere. In this application, it excels low L/D spacecraft requiring orbit maneuvers to enhance lateral range. It is competitive with high L/D spacecraft while avoiding some of their advanced aerodynamic and thermal protection system technologies. For the reduced lateral range logistic mission, the spacecraft can utilize the “liquid L/D” principle to reduce cruise fuel and replace it with additional cargo. The Cruise-spacecraft is a medium L/D, slim, lifting body which uses an ablative lower surface and a radiative upper surface for protection during entry.

The design and performance characteristics of the aircraft and the propulsion system are fully integrated. The propulsion system that yields the lightest aircraft capable of satisfying the specified requirements is considered the superior system. ...A systematic method for selecting the superior propulsion system for a V/STOL aircraft is presented. A relatively well-defined set of aircraft requirements and a preselected group of candidate propulsion systems form the basis for the application of the methodology. ...A relatively well-defined set of aircraft requirements and a preselected group of candidate propulsion systems form the basis for the application of the methodology. The design and performance characteristics of the aircraft and the propulsion system are fully integrated.

The significant simultaneous improvement in these areas represents a formidable technical and economic challenge in airplane and propulsion system design, and it is important to identify those propulsion system and advanced technology areas which show a high potential payoff for the next generation supersonic transport. ...This paper will cover the promising propulsion systems including variable-cycle engine concepts for long-range supersonic commercial transport application. ...The benefits of applying advanced propulsion technology to solve the economic and environmental problems will be reviewed. The advanced propulsion technologies to be covered will be in the areas of structures, materials, cooling techniques, aerodynamics, variable engine geometry, jet noise suppressors, acoustic treatment, and low-emission burners.

Recent developments in sonic inlet technology are presented with particular emphasis on STOL propulsion systems. Inlet noise reduction requirements are discussed for an augmentor wing and an upper surface blowing type of propulsion system. ...Inlet noise reduction requirements are discussed for an augmentor wing and an upper surface blowing type of propulsion system. The current state of the art is discussed with respect to performance and noise potential of different sonic inlet concepts.

The paper provides an overview of the renewed interest in turboprop propulsion systems for future commercial transport designs. The potential operating cost advantage of advanced turboprop designs is shown relative to advanced turbofan designs. ...Critical technology items for the aerodynamic installation of turboprop propulsion systems are presented, along with experimental results addressing the main technology issue for wing-mounted turboprop installations.

The objective of this study is to determine if it is technically feasible to use airbreathing propulsion systems to provide an intercontinental vehicle which will bring virtually all major cities of the world within two hours flying time of each other. ...An extensive study of various propulsion and performance aspects of a single-stage long range Mach 7 delta wing trans port, Fig. 2, 30,000 lb payload (125 passengers and cargo), has been completed. ...The results of the study indicate that present state-of-the-art in propulsion, aerodynamics, insulation, cooling, and structures can provide a hypersonic airbreathing transport capability.

This paper describes the methods used for the performance modeling, which includes propulsion modeling methods and flight test procedures. The resulting flight test data are presented.

Requirements for advanced rocket propulsion systems are becoming increasingly more demanding. The use of high temperature capable materials in such systems, including applications in liquid rocket engines and solid rocket motors, offers potential benefits of increased performance and/or efficiency based on the engine operating cycle. ...This approach, when matured, offers the potential for fabrication of lightweight, durable, and cost-effective advanced rocket propulsion components.

Jet flaps, because of their propulsive lift characteristics, have the theoretical potential to improve fighter aircraft performance. Studies have shown that to achieve these improvements afterburning jet flaps are required. The benefits gained are primarily at high lift coefficients; consequently, there is a significant interaction between the jet flap effects and the wing aerodynamics. In order to integrate the jet flap into fighter designs, short afterburners are necessary. Titanium sandwich construction appears to be the best structural concept for a jet flap.

Within the next few years tighter restrictions on general aviation aircraft noise are expected. It is anticipated that these noise restrictions, like those imposed on larger transport aircraft now certified under Federal Aircraft Regulations, will be revised downward over a period of time. While it is expected that initial restrictions can be met by the current propeller technology, the larger lower tip speed propellers necessary to meet succeedingly more stringent restrictions may prove difficult to accept. In this paper an alternative to the propeller as a propulsor for general aviation aircraft is discussed. This is the subsonic tip speed low-pressure ratio fan which can be mated to turboshaft, rotary combustion, or reciprocating engines to provide a low noise propulsor in a small package. Information is presented which shows tradeoffs among noise, weight, size, cost, and performance.