Showing papers on "Propulsion published in 1978"

Hydrodynamic propulsion by large amplitude oscillation of an airfoil with chordwise flexibility

Abstract: The hydrodynamic forces due to the motion of a flexible foil in a large amplitude curved path in an inviscid incompressible flow are analysed. A parametric study of large amplitude oscillatory propulsion, with special emphasis on the effect of chordwise flexibility of the fin, is presented. This flexibility was found to increase the propulsive efficiency by up to 2% while causing small decreases in the overall thrust, compared with similar motion with rigid foils.

Prediction of steady and unsteady marine propeller performance by numerical lifting-surface theory

Abstract: The ability to predict steady and fluctuating distributions of forces acting on a marine propeller blade is of practical importance in the assessment of propulsive performance, the determination of propeller blade strength, the dynamic analysis of the hull and propulsion system, and the prediction of cavitation. This paper presents the results of a long-term effort carried out at Massachusetts Institute of Technology for the purpose of developing a numerical lifting-surface theory for marine propellers to be used as a practical tool in the solution of both steady and unsteady flow problems. The paper presents a review of the theory and a description of the numerical methods employed, followed by systematic tests establishing the numerical convergence of the procedure and a number of specific comparisons with published experimental and theoretical data.

Liquid Hydrogen as a Propulsion Fuel, 1945-1959. NASA SP-4404

Abstract: A historical review is presented on the research and development of liquid hydrogen for use as a propulsion fuel. The document is divided into three parts: Part 1 (1945-1950); Part 2 (1950-1957); and Part 3 (1957-1958), encompassing eleven topics. Two appendixes are included. Hydrogen Technology Through World War 2; and Propulsion Primer, Performance Parameters and Units.

Hybrid flywheel/compressed-fluid propulsion system for nonstationary applications

Abstract: The adaptation of a compressed-fluid (such as compressed-air) powered turbine in conjunction with the use of a flywheel as a hybrid propulsion system for nonstationary applications, such as vehicle drive, is shown and its practicality demonstrated This propulsion system requires a nonpolluting fluid, such as air, and a source of mechanical or electrical energy to compress said fluid and energize said flywheel, both of which act as energy storage media An expander/compressor unit, such as a turbine, is used for converting the stored energy of said compressed-fluid into shaft power by expanding said fluid, and recovering the braking energy during vehicle deceleration by compressing and storing the atmospheric air (if air is used) Said flywheel is used not only for providing peak powers necessary for vehicle acceleration but also for recovering the braking energy during vehicle deceleration and refilling said compressed-fluid in an emergency The propulsion system can use the unlimited supply of air as the primary energy-storage medium and said flywheel as the secondary energy-storage medium The propulsion system is not only regenerative but also quick-recharging; it, therefore, has high energy-efficiencies and broad applications

Pollution reducing aircraft propulsion

Abstract: Aircraft engine exhaust is mixed with air and fuel and recombusted. Air is drawn into the secondary combustion chamber from suction surfaces on wings. Exhaust of the secondary combustion chamber is blown over wing and fuselage surfaces.

Toward scramjet aircraft

Abstract: The possibility for civil, military, and remotely-piloted aviation above Mach 5 is discussed with reference to the scramjet. Actively cooled aircraft structures of low weight are described, together with jet nozzle design and combustion parameters. The scramjet is seen as operating alone or in tandem with ramjet propulsion, which would power an aircraft up to scramjet speeds. Attention is given to the specific impulse of the scramjet engine, with hydrogen as the primary fuel. Applications include: advanced reconnaissance and interceptor aircraft, strategic cruise (both aircraft and missiles), highly-maneuverable interceptor missiles, transports, aircraft-type launch vehicles, first stages for Space Shuttle launching craft, and single-stage-to-orbit vehicles. Research has focused on increasing the propulsion power of the scramjet engine, while reducing drag on the accompanying airframe.

Airship control system

Abstract: The invention is a system for providing propulsion, control, and stability to small airships (miniblimps) in free flight, especially lighter than air airships. Propulsion is provided by a single motor. Control is achieved by moving the propulsion motor up or down, or left or right. Stability is provided by a single fixed control surface.

Gas turbine engine power plant

Abstract: A V.S.T.O.L. gas turbine power plant includes a main gas turbine engine having an exhaust gas propulsion nozzle and a fan arranged within a fan duct, which duct terminates in two nozzles such that a portion of the fan air may be directed vertically downwards or horizontally, the remaining portion of the fan air acts as a working fluid in one or more further auxiliary gas turbine engines each engine including a vectorable exhaust nozzle.

Mechanical transmission arrangement

Abstract: A modified hypocycloid gear arrangement is incorporated as a transmission converting rotary motion into linear motion or vice versa in any form of prime mover, such as a gas engine, internal combustion engine, or any form of pump or other energy converter, in place of a conventional crank-connecting rod transmission element; specific embodiments are disclosed, relating to single, twin, flat-four, vee-8 and other single and multi-cylinder piston engines and motors and their adaptions, e.g. to vibration-free surgical power saws and torpedo propulsion units, due to the improved mechanical efficiency and precise engine balancing allowed by transmission arrangemenets according to the invention disclosed.

Method for determining spinning or slipping of the wheels in propulsion vehicles without dead axles

Abstract: A method for determining the spinning or slipping of the wheels in propulsion vehicles without dead axles, particularly railroad vehicles in which: the highest and the lowest wheel velocity of the measured wheel velocities of all axles is determined; the highest wheel velocity is selected in the presence of a braking command, and otherwise, the lowest wheel velocity is selected; a simulated car velocity is determined from the selected wheel velocity taking accelerating or decelerating influence variables into consideration; and the simulated car velocity is compared with the measured wheel velocities and the differences that result are converted into signals for influencing the drive or the braking device of the respective axle.

Prop-fan propulsion - Its status and potential

Abstract: Studies have established that advanced turboprop (prop-fan) equipped aircraft will reduce fuel consumption by 15 to 30 percent compared to aircraft equipped with high-bypass turbofan engines of equivalent technology. A reduction in direct operating costs of approximately 10 percent has been identified for commercial aircraft as well as approximately 20 percent lower gross weight airplane for long endurance military missions. The prop-fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficiency program which includes both analytical studies and experimental tests. The experimental work encompasses performance and acoustic wind tunnel tests on several prop-fan models. The prop-fan technology status is reviewed in the major areas of performance, installed effects, cabin noise, blade structure and maintenance cost. Also, further activities required to complete the technical validation of prop-fans are described.

Aerodynamic design and performance testing of an advanced 30 deg swept, eight bladed propeller at Mach numbers from 0.2 to 0.85

Abstract: The increased emphasis on fuel conservation in the world has stimulated a series of studies of both conventional and unconventional propulsion systems for commercial aircraft. Preliminary results from these studies indicate that a fuel saving of from 15 to 28 percent may be realized by the use of an advanced high speed turboprop. The turboprop must be capable of high efficiency at Mach 0.8 above 10.68 km (35,000 ft) altitude if it is to compete with turbofan powered commercial aircraft. An advanced turboprop concept was wind tunnel tested. The model included such concepts as an aerodynamically integrated propeller/nacelle, blade sweep and power (disk) loadings approximately three times higher than conventional propeller designs. The aerodynamic design for the model is discussed. Test results are presented which indicate propeller net efficiencies near 80 percent were obtained at high disk loadings at Mach 0.8.

Electric drive propulsion system for vehicles

Abstract: A combination of a combustion engine connected to operate intermittently at its point of peak efficiency for effecting recharge of an electric power drive system provides a vehicle drive system capable of 100 miles per gallon.

Planned flight test of a mercury ion auxiliary propulsion system. 1: Objectives, systems descriptions, and mission operations

Abstract: A planned flight test of an 8 cm diameter, electron-bombardment mercury ion thruster system is described. The primary objective of the test is to flight qualify the 5 mN (1 mlb.) thruster system for auxiliary propulsion applications. A seven year north-south stationkeeping mission was selected as the basis for the flight test operating profile. The flight test, which will employ two thruster systems, will also generate thruster system space performance data, measure thruster-spacecraft interactions, and demonstrate thruster operation in a number of operating modes. The flight test is designated as SAMSO-601 and will be flown aboard the shuttle-launched Air Force space test program P80-1 satellite in 1981. The spacecraft will be 3- axis stabilized in its final 740 km circular orbit, which will have an inclination of approximately greater than 73 degrees. The spacecraft design lifetime is three years.

Basic Study of Superconducting Electromagnetic Thrust Device for Propulsion in Seawater

Abstract: Electromagnetic ship propulsion has been the object of several investigations [1–5]. In fact, one of the studies [5] provided calculations which showed that with electromagnetic propulsion approximately 90% of the thrust could be available for a 100,000-ton submarine tanker. However, because of the problems of applying an electrical current to seawater and the insignificant thrust realized for a small model ship, the practical application of this device has not been realized.

VTOL aircraft with steerable electric motor - has airscrews driven by electric motors powered from ground through cables

Abstract: The vertical takeoff or landing aircraft is driven by an electric motor, moved for steering purposes. Power is supplied to the aircraft from a cable to the ground, by a stationary or mobile source. The electric motors (A2, A7) drive the airscrews (A1). The motors and air screws are pivoted on their mounting axis. These axes can be moved independently of each other for steering purposes. This aircraft can also carry i.c. engines for propulsion purposes. The electric motor can also be powered by batteries on board.

Aerodynamic characteristics of a counter-rotating, coaxial, hingeless rotor helicopter model with auxiliary propulsion

Abstract: A wind-tunnel model test at advance ratios from 0 to 0.3 with and without auxiliary jet engine thrust is reported. At each advance ratio and engine thrust, both the control power and the aircraft stability were measured. The results indicate that there is a cross-coupling for collective pitch and longitudinal cyclic pitch inputs. The control power for these inputs increased with advance ratio. There was also cross-coupling for differential collective pitch inputs. The airframe was longitudinally unstable, but the instability was less at the highest advance ratio tested. The airframe showed both positive effective dihedral and positive directional stability.

Simulated propeller slipstream effects on a supercritical wing

Abstract: To quantify the installed performance of high speed (M = 0.8) turboprop propulsion systems, an experimental program designed to assess the magnitude of the aerodynamic interference of a propeller slipstream on a supercritical wing has been conducted. The test was conducted in the NASA Ames 14-foot wind tunnel. An ejector-nacelle propeller slipstream simulator was used to produce a slipstream with characteristics typical of advanced propellers presently being investigated. A supercritical wing-body configuration was used to evaluate the interference effects. A traversing total pressure rake was used to make flow field measurements behind the wing and to calibrate the slipstream simulator. The force results indicated that the interference drag amounted to an increase of ten counts or about 3% of the wing-body drag for a two engine configuration at the nominal propeller operating conditions. However, at the higher swirl angles (11 deg vs. 7 deg nominally) the interference drag was favorable by about the same magnitude.

Stowable nozzle plug and method for air breathing missile

Abstract: A missile with an air breathing gas turbine propulsion engine configured with a translating exhaust plug nozzle to minimize longitudinal length of the engine section.

Aircraft with circular wing

Abstract: An aircraft is provided with a circular wing member which is rotatably mounted to a fuselage member. The circular wing member provides lift for horizontal flight and also provides gyroscopic stabilization of aircraft attitude. The circular wing member is substantially free of aerodynamically active flight control or propulsion members and, in a preferred embodiment, has a concentration of mass at its outer rim. The fuselage is provided with propulsion means for effecting and controlling vertical and horizontal flight. The propulsion means provides horizontal or vertical thrust along vectors which pass through the aircraft center of mass.

Electric propulsion system for wheeled vehicles

Abstract: An electric propulsion system for a wheeled vehicle has a generator and motor connected to a drive shaft and an electrical system for charging a battery during all conditions of power transfer from the wheels of the vehicle to the generator to minimize energy required for propulsion. A variable speed power coupling unit connecting the motor to the drive shaft has sprockets revolving about a belt connected sun sprocket with speed control effected by varying the rate of satellite sprocket rotation.

Airframe-integrated propulsion system for hypersonic cruise vehicles

Abstract: Research on a new, hydrogen burning, airbreathing engine concept which offers good potential for efficient hypersonic cruise vehicles is considered. Features of the engine which lead to good performance include; extensive engine-airframe integration, fixed geometry, low cooling, and the control of heat release in the supersonic combustor by mixed-modes of fuel injection from the combustor entrance. The engine concept is described along with results from inlet tests, direct-connect combustor tests, and tests of two subscale boiler-plate research engines presently underway at conditions which simulate flight at Mach 4 and 7.

Multi storey floating hotel - has ring shaped superstructure supported on pontoon with lifts, stairs and ventilation shafts

Abstract: A floating structure particularly intended for uses as a floating hotel, is built onto a pontoon which may be circular in plan, with a number of storeys for accommodation arranged one above the other These can be ring shaped of decreasing diameter towards the top, leaving a central well Staircases and lifts can be incorporated The base of the pontoon is flat, and can incorporate underwater windows The central well can be fitted with a suitable roof, or can be adapted as a helicopter landing deck Propulsion units can be fitted around the periphery for rotating the vessel about its axis

Vibration absorbed engine exhaust means for motor propelled boats

Abstract: A motor-propelled boat comprising a boat hull, an internal combustion engine mounted on the boat hull through a resilient mounting and adpated to drive a propulsion unit, the engine including a body and exhaust unit connected with the body, the exhaust including a first pipe rigidly connected with the body and a second pipe connected with the first pipe through a resilient connecting unit, the second pipe being further supported through a resilient support by the body of the engine.

Propulsion system for a marine vessel

Abstract: A propulsion system including a steerable propeller which can be vertically lowered out of and raised into a vertical protecting sleeve is disclosed. The propeller is driven from a motor lying above deck of a ship driven by the propeller and a shaft connects the propeller with the motor. The drive shaft includes an upper part which fits in a telescopic manner into a lower hollow shaft connected to vertical displacement apparatus.

By-pass gas turbine engines

Abstract: In a by-pass gas turbine engine, the by-pass exhaust flow is mixed with the core engine exhaust flow internally of the engine before passage through the final exhaust (propulsion) nozzle. The exhaust flow mixer comprises alternate inwardly and outwardly inclined substantially planar "fingers", which are arrayed around and attached to the circumference of the aft end of the core engine and extend generally downstream thereof. The fingers are effective to deflect the exhaust flows by virtue of the Coanda effect.

Propulsion apparatus for electric driven car

Abstract: PURPOSE:To decrease battery weight and to improve fuel efficiency of prime mover, electric driven car is started by supplying current from to DC motor from battery, the exciting current is supplied to electromagnetic coupling to start prime mover.

Application of advanced high speed turboprop technology to future civil short-haul transport aircraft design

Abstract: With an overall goal of defining the needs and requirements for short-haul transport aircraft research and development, the objective of this paper is to determine the performance and noise impact of short-haul transport aircraft designed with an advanced turboprop propulsion system. This propulsion system features high-speed propellers that have more blades and reduced diameters. Aircraft are designed for short and medium field lengths; mission block fuel and direct operating costs (DOC) are used as performance measures. The propeller diameter was optimized to minimize DOC. Two methods are employed to estimate the weight of the acoustic treatment needed to reduce interior noise to an acceptable level. Results show decreasing gross weight, block fuel, DOC, engine size, and optimum propfan diameter with increasing field length. The choice of acoustic treatment method has a significant effect on the aircraft design.

Pontoon built up of standard container units - having vertical key-hole section recesses which receive dumb=bell shaped coupling elements and propulsion unit mountings

Abstract: The pontoon is built up of standard container size units (1218 x 243 cm in plan) for transportation in broken down form and building up in situ to the required size. Near the ends of its longest sides, each unit has full (or substantially full) depth vertical recesses of keyhole section. By lowering suitably sized dumb-bell section coupling pieces into these recesses, the units can be firmly locked together. The tops of the coupling pieces carry bollards. Recesses not in use for couplings can serve as mounting bases for outboard motors etc.