Showing papers on "Propulsion published in 1979"

Quiet Clean Short-haul Experimental Engine (QCSEE)

Abstract: The design, fabrication, and testing of two experimental propulsion systems for powered lift transport aircraft are given. The under the wing (UTW) engine was intended for installation in an externally blown flap configuration and the over the wing (OTW) engine for use in an upper surface blowing aircraft. The UTW engine included variable pitch composite fan blades, main reduction gear, composite fan frame and nacelle, and a digital control system. The OTW engine included a fixed pitch fan, composite fan frame, boilerplate nacelle, and a full authority digital control. Many acoustic, pollution, performance, and weight goals were demonstrated.

Investigation of an Electromagnetic Damper for Vibration Control of a Transmission Shaft

Abstract: The paper reports work on a feasibility study of an electromagnetic damper for vibration control with specific reference to a simulation of a marine propulsion system with turbine shaft, flexible power transmission shaft and primary pinion shaft. Control of the vibrational behaviour was achieved by an electromagnetic damper at a point in the span, and the experiments confirm the possibility of controlling the behaviour of a simulated marine propulsion system by contactless electromagnetic damping.

Nuclear pulse propulsion - A historical review of an advanced propulsion concept

Abstract: Future space exploration, and in particular rapid manned exploration, requires propulsion systems that are much more advanced than present-day systems. The paper discusses the concept of the nuclear pulse rocket and reviews some of the history of the work carried out on this concept over the last 25 years. The external system (explosion outside the vehicle) and the internal system (explosion inside the vehicle) are compared. The capabilities of nuclear pulse systems are examined, demonstrating the striking advantage of this system over other concepts. Efforts should be concentrated on a program designed to develop nuclear pulse propulsion as a tool for exploiting the solar system. Ample bibliography is included.

Improvement of citybus fuel economy using a hydraulic hybrid propulsion system -- a theoretical and experimental study

Abstract: The paper describes the application of a hydraulic pump/motor and a hydro-pneumatic energy-storage as a supplement to the conventional internal combustion engine in a city bus. The resultant hybrid-system makes it possible to smooth out the combustion engine power output and to regenerate the braking-energy which in conventional busses dissipate as heat. Computer-simulation and supplementary experiments with a model-system have shown that, depending on the driving pattern of the bus, this type of hybrid-system would lead to a 10-30% fuel saving provided that an appropriate control strategy is used.

Interstellar Propulsion Using a Pellet Stream for Momentum Transfer

Abstract: A pellet-stream concept for interstellar propulsion is described. Small pellets are accelerated in the solar system and accurately guided to an interstellar probe where they are intercepted and transfer momentum. This propulsion system appears to offer orders-of-magnitude improvements in terms of engineering simplicity and power requirements over any other known feasible system for transport over interstellar distance in a time comparable to a human lifespan.

Ramjet Engine Testing and Simulation Techniques

Abstract: Simulation of flow conditions within the operating regime of ramjet engines requires unique ground test capabilities. The blowdown facility is an economical method of meeting the high air mass flow and pressure ratio requirements. Vitiated air heaters provide a flexible and cost-effective method of simulating trajectory temperature variation. Adequate simulation of the inlet flow conditions in freejet tests plays an important role in engine development. Ramjet engine ground test requirements are discussed. Methods of simulating the applicable parameters in direct-connect and freejet tests are reviewed. Techniques and devices that have proved beneficial in meeting aerodynamic simulation requirements are described.

Propulsion system for V/STOL aircraft

Abstract: A propulsion system for an aircraft having a fuselage and a wing with two nacelles disposed on opposite sides of the fuselage, each of the nacelles having a turbo fan therein with drive means connected thereto for air flow through the nacelle from a forward air inlet to air exit openings, the air flow within the nacelle divided into twi air streams, one of the air-streams being directed downwardly through a variable area forward chin nozzle provided with a cascade of vanes for directing the outflow in a desired direction with the other air stream exhausted through an aft nozzle of variable area at the aft outlet opening against a slotted flap system mounted aft of the aft nozzle against which the outflow from the aft nozzle is directed so that the two air streams provide pitch, roll and yaw control as well as balanced lift and propulsion utilizing controlled thrust modulation and vectoring for all regimes of flight from vertical takeoff and landing (VTOL) or short takeoff and landing (STOL) or a combination of these and conventional flight through a combination of nozzle area change and wing flap vectoring.

Motor vehicle propulsion system

Abstract: Small constant power engine drives liquid filled flywheel to store large amounts of kinetic energy. When motor vehicle acceleration is desired, the flywheel liquid is coupled to a turbine which is connected through a drive train to drive the rear wheels. The transfer of liquid from the flywheel kinetic energy storage to the turbine controls vehicle acceleration.

Electric vs Chemical Propulsion for a Large-Cargo Orbit Transfer Vehicle

Abstract: Techniques for sizing electrically or chemically propelled orbit transfer vehicles and analyzing fleet requirements are used in a comparative analysis of the two concepts for various levels of traffic to geosynchronous orbit. The vehicle masses, fuel requirements, and fleet sizes are determined and translated into launch vehicle payload requirements. Technology projections beyond normal growth are made and their effect on the comparative advantages of the concepts is determined. A preliminary cost analysis indicates that electric propulsion greatly reduces launch vehicle requirements and would be competitive with chemical propulsion if the technology of power generation systems advances to where reusability can be achieved at low cost.

Ship propulsion transmission having a torque converter for driving a fixed pitch propeller in reverse

Abstract: A propulsion transmission for driving a fixed pitch propeller of a ship, the transmission including a prime mover, that is a power source, such as a gas turbine engine, or a diesel engine for example, and also having a disengageable clutch between the prime mover and the propeller and for transmitting power to the propeller for driving it in a forward direction. The transmission also includes a hydraulic torque converter of the single stage, fixed housing type and which is connected between the prime mover and the propeller for driving the propeller in the reverse direction when the disengageable clutch is inoperative.

Hydrazine Monopropellant Reciprocating Engine Development

Abstract: A hydrazine fueled piston engine for providing 11.2 kW was developed to satisfy the need for an efficient power supply in the range from 3.7 to 74.6 kW where existing nonair-breathing power supplies such as fuel cells or turbines are inappropriate. The engine was developed for an aircraft to fly to 21.3 km and above and cruise for extended periods. A remotely piloted aircraft and the associated flight control techniques for this application were designed. The engine is geared down internally (2:1) to accommodate a 1.8 m diameter propeller. An alternator is included to provide electrical power. The pusher-type engine is mounted onto the aft closure of the fuel tank, which also provides mounting for all other propulsion equipment. About 20 hrs of run time demonstrated good efficiency and adequate life. One flight test to 6.1 km was made using the engine with a small fixed-pitch four-bladed propeller. The test was successful in demonstrating operational characteristics and future potential.

Marine propulsion system

Abstract: A marine propulsion system for a cruising boat or the like which utilizes two engines, one of the engines having substantially more power than the other. The propulsion system provides for twin propellers and propeller shafts and either engine (but not both) can be made to drive the twin shafts. The engines are positioned in line with one another on the fore and aft center line of the boat and the drive shafts of the two engines extend into a common transmission assembly. Clutches in the transmission assembly permit either one of the engine drive shafts to be drivingly connected to an athwartships shaft the ends of which are respectively connected through transmission gear case units to the propeller shafts. The propeller shafts are laterally spaced from one another and are parallel to the center line of the boat. With this arrangement, the more powerful engine can be used for high speed cruising or when severe weather conditions dictate and the less powerful engine can be used for slow speeds and economical long distance cruising.

A review of hybrid rockets: present status and future potential

Abstract: This paper discusses the potential of the hybrid rocket engine as a viable and attractive mode of propulsion for both space vehicles and missiles. Research and development work on this engine in other countries is presented and evaluated. The various advantages of a hybrid engine over solid and liquid engines and its problems are highlighted. It has been argued that because of the low technology needed in the development of the hybrid system, it constitutes a cost-and-time-effective propulsion system for several applications in space programmes as well as weapon systems. In support of this conclusion, experience on the developmental studies of a variable thrust 100 kg engine is presented. Some future possibilities for hybrid propulsion systems are cited.

Starting circuit for a trackbound electric propulsion vehicle having a synchronous linear motor

Abstract: A circuit arrangement for starting a trackbound electric propulsion vehicle having a synchronous linear motor without iron in which the motor's stator is a traveling-field winding installed along the track. The exciter of the motor is a translator arranged on the propulsion vehicle, preferably as a superconducting magnet coil. The traveling-field winding is powered, section by section, from stationary, controlled, static converters at voltages and frequencies which can be varied by a control device. The relative position of the exciter with respect to the traveling-field winding and the travel velocity are determined by a computing circuit from the phase currents and voltages at the feed point. In starting, the control circuits of the control device are opened and a starting circuit is added instead. The starting circuit determines the required thrust, the travel velocity, and the exciter position relative to the traveling-field winding from a velocity reference value controlled by a start-up generator. A signal for damping the control component determining the thrust is derived from a measured value of thrust. In this manner, the starting of the propulsion vehicle is made possible without the motor falling out of step or the occurrence of undesirable hunting.

Hydraulically driven railway car

Abstract: A motorized track car with a wheeled lower portion for rolling along a railroad track, and a platform carried by the wheeled lower portion. The platform has seating accommodation for one or more persons with the propulsion means for the vehicle disposed below the platform. The propulsion means consists of an internal combustion engine drivingly connected to hydraulic pump means providing fluid pressure for hydraulic motors drivingly associated with wheels of the car. There is control valve means operable by a person seated on the platform to control flow of hydraulic fluid for the pump and motor to vary the speed of travel of the vehicle from zero to maximum in each of forward and backward directions of travel. There is brake means operatively associated with at least one wheel of the track car and operable from the platform and, preferably, by a single lever control which also operates the control valve means. The arrangement of the propulsion means and seating accommodation is such as to provide a compact vehicle with maximum accommodation for a pay load and a vehicle weight such that it can be manually removed from and placed on the track by no more than two persons.

Linear synchronous motor development for urban and rapid transit systems

Abstract: The following paper presents and discusses technical variants in magnetic suspension-repelling permanent magnets, electrodynamic and electromagnetic suspension methods, controlled lift magnets. In addition, propulsion methods for magnetically suspended vehicles are also shown. The synchronous long stator linear motor has achieved particular importance since it makes possible an efficient energy conversion. The load-carrying capacity is not reduced by the weight of the drive and the layout enables a very good integration of the lift and thrust functions. A further reduction of the on-board power requirements can be achieved by using permanent magnets to generate the rated induction in the air gap. Several magnetic suspension systems constructed or under construction with the long stator method are also mentioned.

The Accelerometer Methods of Obtaining Aircraft Performance from Flight Test Data (Dynamic Performance Testing)

Abstract: : There are, in general, two basic methods of obtaining aircraft performance from flight test data. The first of these methods, the Direct method, is to fly a particular maneuver of interest and mathematically correct this maneuver to a given set of standard conditions. Several similar maneuvers at different flight conditions are then combined in a composite map representing one aspect of the aircraft performance. The Indirect method is more subtle and has its basis deeper in theory. By this method, a group of aerodynamic and propulsion parameters are developed which in themselves are only numbers and do not represent performance. These parameters are not tied to a specific maneuver or maneuver type, but in general relate the physical forces required to achieve a certain flight condition. Such parameters for an aircraft would be the drag coefficient, lift coefficient, thrust available, fuel flow requirements, etc. However, these parameters can be combined with known facts about the airframe and propulsion system in such a fashion as to compute airplane performance. With the advent of highly accurate accelerometers, the dynamic maneuvers have become attractive for development of aerodynamic data when obtaining aircraft performance using the Indirect Method.

Iceberg propulsion system

Abstract: A tabular iceberg is used as an energy source for a propulsion system which propels the iceberg across vast distances of the ocean with minimal fuel consumption. The iceberg thus becomes, in effect, a self-propelled vessel in which potential energy associated with the iceberg is converted to kinetic energy to power the propulsion system. Two propulsion mechanisms can be used, preferably in conjunction. The first mechanism uses the gravity flow of melting ice to provide propulsive thrust, while the second mechanism utilizes the temperature differential between the iceberg and the surrounding water to power a heat cycle engine, which, in turn, drives a generator to provide electricity which runs propeller drive motors.

Energy efficient engine: Propulsion system-aircraft integration evaluation

Abstract: Flight performance and operating economics of future commercial transports utilizing the energy efficient engine were assessed as well as the probability of meeting NASA's goals for TSFC, DOC, noise, and emissions. Results of the initial propulsion systems aircraft integration evaluation presented include estimates of engine performance, predictions of fuel burns, operating costs of the flight propulsion system installed in seven selected advanced study commercial transports, estimates of noise and emissions, considerations of thrust growth, and the achievement-probability analysis.

Turbine engine thrust booster

Abstract: Trim signals are removed from the fuel control computers of aircraft propulsion engines to increase thrust upon detection of a predetermined difference between engine speeds.

Cost Comparisons of Dual-Fuel Propulsion in Advanced Shuttles

Abstract: Econometric analyses of advanced Earth-to-orbit vehicles indicate that there are economic benefits from the development of new vehicles beyond the space shuttle as traffic increases. Vehicle studies indicate the advantage of the dual-fuel propulsion in single-stage vehicles. This paper shows the economic effect of incorporating dualfuel propulsion in advanced vehicles. Several dual-fuel propulsion systems are compared to a baseline hydrogen and oxygen system.

Airbreathing propulsion system for supersonic vehicles

Abstract: A propulsion system for airbreathing vehicles having a ducted inlet for a supersonic powerplant and incorporating means in the vehicle for momentarily changing the normal flight attitude of the vehicle for obtaining high inlet pressure recovery for the propulsion powerplant and thereafter returning the vehicle to a normal flight attitude.

Performance Potential and Research Needs of a Hypersonic, Airbreathing, Lifting Missile Concept

Abstract: This paper reports the results of a conceptual study to define the performance potential, scaling relationships, and research needs of a hypersonic missile concept formulated about an airframe-integrated propulsion system. A baseline missile design is developed and the rationale for selecting a heat-sink structural approach is described. Modifications to a NASA-Langley-developed fixed-geometry, modular scramjet are presented that may be required to achieve the dual-mode, "hydrocarbon-fueled" engine operational characteristics utilized in predicting missile performance potential. A heat-sink structure is shown to be a viable concept for Mach 6 missiles for ranges of up to 200 n.mi. A heat-sink structure protected by multiwall heat shields is suggested as a potentially attractive system for long-range cruise missiles. Airframe-integrated propulsion systems are shown to offer potentially large benefits for missiles that require high maneuverability. The use of the missile forebody for generating inlet precompression as well as lift and use of the afterbody as a high-expansion ratio, low-drag nozzle also offer improved missile cruise performance. It is concluded that technologies being developed for hypersonic aircraft, with appropriate modifications, also can be useful for hypersonic, airbreathing, lifting missiles.

HESCOMP. The Helicopter Sizing and Performance Computer Program. User's Manual. Revision 2.

Abstract: : The purpose of the HESCOMP computer program is to provide the means for a rapidly developing helicopter sizing and mission performance data. The program can be used to define design requirements, such as weight breakdown, required propulsive power, and physical dimensions of aircraft which are designed to meet specified mission requirements. It is also useful in sensitivity studies involving both design trade-offs and performance trade-offs. HESCOMP may be used for sizing helicopters for which the type of aircraft and the mission profile are specified. Alternatively, it may be used for mission calculations for aircraft for which sizing details (gross weight, fuel available, engine power and fuel consumption, etc.) are known. As a combination of these two capabilities, it may be used first to size a helicopter for a given mission and then calculate the off-design point performance for other missions. It contains size trends equations which reflect the variation of helicopter dimensions with gross weight, detailed statistical weight trends equations, a routine for sizing of engines to match airframe requirements, a comprehensive library of engine cycle data, a library of rotor cycle data, and a variety of optional procedures for calculating rotor and propeller (cruise only) performance. The program can be used to study any single, tandem, or coaxial pure winged, compound, or auxiliary propulsion helicopter.

Semi-submerged sail ship

Abstract: A cargo carrying vessel which is provided with an elongated bulbous pressure hull designed to operate in a semi-submerged state. The vessel is provided with one or more rigid wing sails to aid propulsion and solar cell arrays are mounted on each wing sail to generate electrical energy. The electrical energy is used to power an electric motor which drives the vessel in conventional manner. Excess energy may be stored in banks of storage batteries which form part of the internal ballasting of the vessel.

Aerodynamic propeller-driven land vehicle

Abstract: A land motor vehicle having aerodynamic propellers at the anterior and posterior ends for providing aerodynamic propulsion. The propellers are attached for rotation with a drive shaft which extends longitudinally of the vehicle and which is powered by an engine through a clutch and transmission.

The superconducting paddlewheel as an integrated propulsion levitation machine for high speed ground transportation

Abstract: The rotary superconducting motor, RSM, is shown to provide economical propulsion as well as levitation on a thinner aluminum track than “conventional” repulsion magnetic suspension. With the RSM, thrust and braking are provided by controlling the relative speed of rotation of the motor essentially independent of lift at all forward speeds. Using thin-plate theory, the lift and drag forces on the rotary superconducting motor are evaluated as a function of the forward speed of the vehicle as well as the relative speed of rotation of the motor. Although significant power is dissipated in the track through eddy current losses, evaluation of the energy consumption of the RSM over a route profile of 750 km with 5 intermediate stops shows this propulsion levitation system to have an energy consumption of 0.76 MJ/seat-km - significantly lower than other means of propelling and levitating high speed ground transportation.