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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.

A trade study comparing the overall benefits in placing large payloads to GEO with the nuclear electric propulsion option shows superiority of nuclear thermal propulsion. The resulting savings in orbital transfer time and the substantial reduction of overall lift requirement enables the use of low-cost launchers for several near-term military satellite missions. ...An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. ...An integral space power concept provides both the electrical power and propulsion from a common heat source and offers superior performance capabilities over conventional orbital insertion using chemical propulsion systems. This paper describes a hybrid (bimodal) system concept based on a proven, inherently safe solid fuel form for the high temperature reactor core operation and rugged planar thermionic energy converter for long-life steady state electric power production combined with NERVA-based rocket technology for propulsion.

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.

This paper comments upon the business considerations that depend upon technical predictions of reliability of the SST propulsion system. The necessary scope and timing of such predictions are delineated. Reasons for broadening the concept of reliability are offered.

It has been named the Propulsion Multiplexer (PMUX) System and has been specified for Pratt and Whitney Aircraft and General Electric engines for the Airbus Industrie A310 aircraft.

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.

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.

Multiengine vertical takeoff and landing (V/STOL) aircraft have a unique requirement to at least maintain aircraft trim after losing one engine during vertical landing. The most popular scheme by which this is accomplished involves using cross-shafted fans with variable inlet guide vanes. A significantly different approach is described herein whereby cross-ducted fan bleed air is used to obtain roll control and engine out roll trim. The installation of this cross-ducted system in a twin-engine V/STOL aircraft is described in detail along with different options for obtaining pitch control, pitch trim and yaw control. The optimum engine cycle for each configuration is defined based on mission performance results and vertical landing capabilities. The cross-ducted systems were found to offer significant advantages compared to the cross-shafted systems in terms of aircraft performance as well as design simplicity, versatility, reliability, vulnerability, survivability, and safety.

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.

Five requisites are categorized and examined in relation to the propulsion system. Specifically, the needs of reliability, maintainability, operational flexibility, salability, and profitability are discussed and the interplay and accumulative effects are described. ...Goals for the SST propulsion system are compared to the status of today’s operation and data showing historical trends are presented.

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.

Two decades of turboprop technology advances are discussed along with their application to a Prop-Fan propulsion system for modern high-speed commercial aircraft. The Prop-Fan propulsion system features a small diameter, multibladed propulsor geared to an advanced gas turbine engine. ...Several advanced technologies in the airframe and propulsion disciplines have been identified by NASA, with the turboprop being one of these. Two decades of turboprop technology advances are discussed along with their application to a Prop-Fan propulsion system for modern high-speed commercial aircraft.