Showing papers on "Propulsion published in 1984"

Aircraft configuration optimization including optimized flight profiles

Abstract: The Flight Optimization System (FLOPS) is an aircraft configuration optimization program developed for use in conceptual design of new aircraft and in the assessment of the impact of advanced technology. The modular makeup of the program is illustrated. It contains modules for preliminary weights estimation, preliminary aerodynamics, detailed mission performance, takeoff and landing, and execution control. An optimization module is used to drive the overall design and in defining optimized profiles in the mission performance. Propulsion data, usually received from engine manufacturers, are used in both the mission performance and the takeoff and landing analyses. Although executed as a single in-core program, the modules are stored separately so that the user may select the appropriate modules (e.g., fighter weights versus transport weights) or leave out modules that are not needed.

Energy Efficient Engine high pressure turbine component test performance report

Abstract: The high pressure turbine for the General Electric Energy Efficient Engine is a two stage design of moderate loading. Results of detailed system studies led to selection of this configuration as the most appropriate in meeting the efficiency goals of the component development program. To verify the design features of the high pressure turbine, a full scale warm air turbine test rig with cooling flows simulated was run. Prior to this testing, an annular cascade test was run to select vane unguided turn for the first stage nozzle. Results of this test showed that the base configuration exceeded the lower unguided turning configuration by 0.48 percent in vane kinetic energy efficiency. The air turbine test program, consisting of extensive mapping and cooling flow variation as well as design point evaluation, demonstrated a design point efficiency level of 90.0 percent based on the thermodynamic definition. In terms of General Electric cycle definition, this efficiency was 92.5 percent. Based on this test, it is concluded that efficiency goals for the Flight Propulsion System were met.

Concepts and status of laser-supported rocket propulsion

Abstract: Laser propulsion, a unique new system in which thrust is produced by the absorption of remote laser energy, has several distinct advantages over existing forms of propulsion. This article is intended as an overview of the status of laser propulsion based on a review of the scientific literature. Included in the discussion is an evaluation of the advantages and limitations of laser propulsion, as well as the types of missions for which it can best be used. The various types of proposed thrusters are also discussed, focusing on operation, current research, and unresolved problems. Also included is a thorough list of references documenting the research in this relatively young field.

The electromagnetic levitation and guidance technology of the 'transrapid' test facility Emsland

Abstract: A large scale test facility for the high speed ground transportation system TRANSRAPID has been built in Emsland. In the near future this test facility will show the economic feasibility of such a system. An essential component of this system is the magnetic levitation and guidance system of the vehicle. The requirements on this suspension system are: good ride comfort, high reliability and low operating costs. The elements of the suspension system are controlled cross field electromagnets with massive iron cores and rails for guidance and controlled longitudinal field magnets with a laminated iron core and rail for levitation. The reason for lamination is the combination of three operating tasks in the levitation magnets. These are: levitation, propulsion, and inductive power transfer to the vehicle. These magnets generate the exciting field of the synchronous linear motor. Due to these tasks the theoretical model for a levitation magnet has to be expanded in order to be able to describe these effects in dynamic simulations. The mechanical and the electrical structure of the suspension system must have several redundancies in order to get a high overall safety.

Design of Long-Endurance Unmanned Airplanes Incorporating Solar and Fuel Cell Propulsion

Abstract: Preliminary performance analysis and conceptual design are described for a class of unmanned airplanes possessing multi-day endurance capability. A mixed-mode electric power system incorporates solar cells for daytime energy production and a non-regenerative H2-O2 fuel cell to supply energy for night flight. The power system provides energy for all onboard systems, including propulsion, payload, and avionics. Excess solar energy is available during significant portions of the day, and may be used for climbing, maneuvering, or payload functions. By jettisoning fuel cell reactant product (water) during flight, vehicle endurance may be increased under certain conditions. Empirical structure sizing algorithms are combined with low-Reynolds number aerodynamics algorithms to estimate airplane size and geometry to meet prescribed mission requirements. Initial calculations for summertime, high-altitude flight (above 40,000 ft (12 km)) at moderate latitude (31 degrees N) indicate that mission endurance of several days may be possible for configurations having wing loadings on the order of 0.9 to 1.3 lb/ft squared. These aircraft tend to be somewhat smaller than solar-powered aircraft previously conceived for multi-month endurance utilizing regenerative fuel cell systems for night flight.

Flywheel propulsion system for automotive vehicles or the like

Abstract: A propulsion system for use in automotive vehicles wherein the flywheel is connectable with the crankshaft of the internal combustion engine by a first clutch and with the input shaft of the change-speed transmission by a second clutch. When the engine would be idling (such as during stoppage of the vehicle at an intersection) or running unnecessarily for another reason (such as during coasting of the vehicle), the two clutches are disengaged and the flywheel rotates by inertia to restart the engine, when necessary, in response to engagement of the first clutch. If the RPM of the flywheel reaches a preselected lower threshold value, a starter-generator unit automatically accelerates the flywheel so that its RPM rises above the threshold value and is thus sufficient to ensure that the engine is restarted on engagement of the first clutch. The starter-generator unit has a rotor which is mounted directly on the flywheel and a stator which surrounds the rotor with minimal clearance and is connected directly to the housing of the engine. The generator of the starter-generator unit is a heteropolar Schmidt-Lorenz generator.

Marine propulsion device power steering system

Abstract: The marine propulsion device includes a propulsion unit mounted for tilting movement about a generally horizontal tilt axis and for pivotal steering movement about a vertical steering axis, and a power steering system adapted to operably connect an actuator to the propulsion for increasing the steering force applied to the propulsion unit by the actuator. The power steering system is wholly supported on the propulsion unit and includes a hydraulic cylinder-piston assembly having an axis extending in fixed parallel rotation to the tilt axis and including a cylinder, a piston mounted in the cylinder, and an extendable and retractable piston rod connected to the piston, and a control valve connected to a source of pressurized hydraulic fluid for selectively controlling the flow of hydraulic fluid to and from the opposite sides of the piston to extend and retract the piston rod. The control valve includes a valve member and valve housing rotatably and axially movable relative to each other. The valve member is connected to the actuator and the valve housing is connected to the piston rod for common movement and is connected to the propulsion unit to affect steering movement thereof in response to movement of the actuator.

Electric thruster performance for orbit raising and maneuvering

Abstract: Several electric thrusters are compared to chemical rockets for orbit raising and in-orbit maneuvering applications. For power-intensive payloads and satellites, electric propulsion can show substantial performance advantages over chemical propulsion. The arcjet is promising for near-future applications because of its low power requirements. The electrostatic thruster offers additional performance advantages over the arcjet, but with added power requirements. The performance of the electrostatic thruster can be enhanced considerably if the power processsing requirements can be reached. A performance gap exists between the specific impulse of an arcjet (-1000 s) and the minimum practical specific impulse of an electrostatic thruster (-2000 s). A highperformance thruster (thruster efficiency > 0.5) in this specific impulse range, with minimal power processing requirements, offers time-payload compromises intermediate of those possible with either the arcjet or the electrostatic thruster.

Continuously charged flywheel type power delivery system

Abstract: An improved control system and method for controlling the operation of a flywheel type power delivery system, such as used in an automotive vehicle. A predetermined maximum vehicle speed limit dictates the working displacement of a variable displacement engine to match efficient engine output to the power requirements of the system. Above a threshold vehicle speed of approximately 45 miles per hour, the flywheel is completely uncoupled from the system and vehicle propulsion is provided by direct coupling of the engine (at maximum displacement) through the continuously variable ratio transmission (CVT) to the vehicle driving wheels.

Self-refueling space propulsion system and operating method

Abstract: A propulsion system for reusable space-based vehicles is presented wherein the propulsive working fluid is atmospheric gas. Acceleration or deceleration propulsion is obtained by expelling or ingesting atmospheric gas respectively. Consequently, propulsive working fluid expelled during accelerating forward propulsive maneuvers is automatically replenished during decelerating retro propulsive maneuvers. The refueling retro thrust is generated by a large diameter hypervelocity has inlet diffuser mounted at the front of the vehicle which scoops up atmospheric gas while traversing through the tenuous upper regions of a planet's atmosphere. The vehicle thereby transfers a portion of its momentum to the collected gas which was initially at rest in the atmosphere. This transfer of momentum generates a decelerating retro thrust by a reverse application of the theory of classical rocket propulsion. The collected gas is condensed, stored on-board the vehicle, and utilized as propulsive working fluid for generating forward propulsive accelerating thrust by expelling the gas at high velocity. The vehicle could operate either as a self-refueling interorbital transfer vehicle or as an interplanetary transfer vehicle moving from planet to planet utilizing each planetary atmosphere as propulsive working fluid.

Jet propelled boat

Abstract: A jet propelled boat (10) whose propulsion unit is very compact vertically and in which entrance of the water into the exhaust system is effectively prevented. The jet propulsion unit includes an engine (42) having a vertical output shaft (83), an impeller housing (44) secured to the engine beneath the same and housing an impeller (76) driven by the engine and an exhaust gas housing (43) surrounding the impeller housing having the walls thereof spaced from the impeller housing (44) sufficiently to form a gas chamber, this exhaust gas housing being connected to the exhaust gas discharge (34) below the normal water line and also to the exhaust manifold. The propulsion unit may be used either in connection with an inboard engine or with an outboard engine. In either case, provision is made for changing the direction of the boat and for reversing the same. In the case of the outboard engine, I provide a novel arrangement for combining in one housing below the propulsion unit, an inlet (104) for admitting water to the impeller, a chamber (43) for exhausting the exhaust gas quietly and an elbow (135) for reversing the flow of water issuing from the jet nozzle when it is desired to reverse the boat. In the inboard form of the invention, a swival connection (352) is provided for reversing the discharge nozzle (351) to reverse the direction of the boat, this arrangement discharges the water immediately below the boat without the nozzle extending below the boat.

Marine propulsion steering assist device

Abstract: A marine propulsion device comprising a propulsion unit pivotable about a first steering axis to steer a marine vehicle, a trim tab mounted on the propulsion unit and pivotable about a second steering axis for assisting in steering the vehicle, and a hydraulic sensing arrangement for sensing torque on the propulsion unit relative to the first steering axis to pivot the trim tab in response to the torque. The device also includes steering mechanism for pivoting the propulsion unit about the first steering axis to steer the vehicle. The steering mechanism includes a steering member connected to the propulsion unit, and operable to move the steering member to pivot the propulsion unit. The steering mechanism operable to move the steering member includes a push-pull cable with a core and a flexible housing. The hydraulic sensing arrangement permits lost motion between the flexible housing and the steering member and the hydraulic sensing arrangement senses torque on the propulsion unit relative to the first steering axis by movement of the flexible housing relative to the steering member.

Brushless DC Motor Propulsion Using Synchronous Motors for Transit Systems

Abstract: In this paper, a brushless dc motor propulsion system using synchronous motors is described which is suitable for transit applications. The propulsion system consists of two-quadrant transistorized front-end chopper and a three-phase transistorized inverter (forming the electronic commutator for the synchronous machine phase currents) to provide both controlled propulsion and regenerative braking. The control scheme makes the system operate stably at all speeds and avoids loss of synchronization. Performance characteristics of the drive are derived and compared with those of a dc motor propulsion drive. Improved low-speed performance and reduced torque pulsation are achieved by proper switching of the electronic commutators. A prototype model using a 5-hp synchronous motor is built and tested.

Vehicle propulsion plant

Abstract: An internal combustion engine for vehicle propulsion has a number of cylinders arranged in two parallel planes and connected to two crank shafts within a common engine block. A selectively operable clutch is fitted at at least one of the crank shafts, and a gearing coordinates the output from the two crank shafts. A coupling is provided between the gearing and the output shaft of the engine plant.

Orbit-raising and maneuvering propulsion : research status and needs

Abstract: Orbit-raising and maneuvering propulsion: research status and needs , Orbit-raising and maneuvering propulsion: research status and needs , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Wind propulsion for all types of vehicles and stationary machines

Abstract: There is provided a wind propulsion device for driving a transmission shaft connected through intermediate members with devices for force transmission. The wind propulsion device comprises a wind impeller having a plurality of wind wings which are concavely curved against the air stream. The wind wings are axially connected to a semisphere convexly curved against the air stream which is axially disposed with respect to said impeller. The semisphere guides the air stream impinging on the center of the impeller to the tips of the wings for efficient wind utilization.

Wheelchair anti-rollback mechanism

Abstract: The customary side hand propulsion ring adjacent to each main wheel of a manual wheelchair is mounted through a lost motion connection between the propulsion ring and main wheel so that the propulsion ring can have limited rotational movement relative to the main wheel. A friction brake drum or partial drum fixed to the wheelchair frame inside of the main wheel is engaged by at least one of a plurality of circumferentially spaced over center friction locking devices pivotally held on the main wheel. Each over center friction locking device is moved by a release element to a non-locking position relative to the drum or partial drum in response to reverse movement of the propulsion ring by a chair occupant. Economy and ease of operation are provided for. The wheelchair occupant need not remove his or her hand from the propulsion ring when operating the anti-rollback mechanism.

Power management system

Abstract: A power management system is disclosed for an advanced helicopter having both lift and thrust propulsion units and at least one power plant which comprises, a signal generator for generating a first signal which is proportional to the power available from the power plant, a circuit connected to the lift propulsion unit which has an output that varies according to the amount of power used by that propulsion unit and which receives the first signal for generating a second signal which is proportional to the amount of power remaining The circuit is either used to power a limit actuator for limiting the amount of power the pilot can apply to the thrust propulsion unit or drive an indicator which indicates to the pilot the amount of power remaining for the thrust propulsion unit, or perform both functions

Driveline for a track-laying vehicle with continuously variable steering and propulsion transmissions

Abstract: A driveline for a track-laying vehicle such as a tank includes a propulsion transmission (200) and a steer transmission (100), both driven from the engine crankshaft (1), and both of the toroidal race-rolling traction type continuously-variable ratio transmissions. An arrangement of epicyclic gears (12, 13) and clutches (H, C1, C2) transmits drive from the propulsion variator (200) in four regimes to summing epicyclic gears (6, 7) associated with left-hand and right-hand tracks. Steering of the tracks is achieved by summing the drive, in the summing epicyclic gears (6, 7), from the steer variator (100).

Method and system for improved V/STOL aircraft performance

Abstract: A method and system for improved performance of a V/STOL aircraft characterized by directing a major portion of exhaust gas flow from a propulsion system through a closed conduit means to exit through a thrust producing primary nozzle that includes turning apparatus for forming a bend for the exhaust flow downstream of the propulsion source; turning the exhaust flow while simultaneously bleeding-off through at least one secondary nozzle a second and minor portion of the exhaust flow from an outer portion of the bend downstream of the bend leasing edge to reduce the vortex formation in the bend and directing the bleed-off and exhaust flows adjacent each other and oriented in the same direction in all flight modes for recovery of the maximum thrust potential. Also disclosed are preferred embodiments of the respective source of propulsion, primary and secondary thrust nozzles, flaps and orientation of the secondary thrust nozzles adjacent the flaps for improved performance because of preventing of the formation of the thrust inhibiting vortices in the turn and the improved lift and prevention of boundary layer separation of the flow over the flap surfaces providing lift.

A Microcomputer-Based Propulsion Control System of a Hybrid Electric Vehicle

Abstract: This paper describes a hybrid electric vehicle drive control system under microcomputer control where the propulsion power is shared between a gasoline engine and a dc motor. The control functions have been developed, analyzed, and implemented with highlevel language in a dual Intel 8086 microcomputer system. The drive system has been integrated and tested, and shows excellent results.

A review of electric propulsion systems and mission applications

Abstract: The satisfaction of growing demands for access to space resources will require new developments related to advanced propulsion and power technologies A key technology in this context is concerned with the utilization of electric propulsion A brief review of the current state of development of electric propulsion systems on an international basis is provided, taking into account advances in the USSR, the US, Japan, West Germany, China and Brazil The present investigation, however, is mainly concerned with the US program The three basic types of electric thrusters are considered along with the intrinsic differences between chemical and electric propulsion, the resistojet, the augmented hydrazine thruster, the arcjet, the ion auxiliary propulsion system flight test, the pulsed plasma thruster, magnetoplasmadynamic propulsion, a pulsed inductive thruster, and rail accelerators Attention is also given to the applications of electric propulsion

Boat and propulsion system including a transom platform

Abstract: A boat and propulsion system especially useful for shallow water operation. A boat, such as a flat bottom fishing boat, is provided with a lowered transom and a platform attached to the transom which extends upwardly at an angle along the sides of the boat to define a well area which receives and drains any backwash. An air cooled internal combustion engine is provided with a straight propeller shaft and propeller attached thereto. A motor plate rigidly attached to the engine may be removably mounted on a swivel-hinge assembly mounted on the platform to allow double axis movement of the engine and propeller in relation to the platform. This provides for a thrusting position with the propeller in the water and a neutral position with the propeller held above the water. A control handle may be removably connected to the motor plate to provide one handed steering and throttle control by the operator. The motor plate is detached from the swivel-hinge assembly to allow removal and transportation of the engine and propeller shaft combination in a trunk of an automobile with the control handle removed. The propeller is approximately 95% weedless as it runs at a water level above that from the bottom of the boat during operation and thus needs no skegs or deflector plates. A propeller shaft housing and coupling guard are mounted on the engine and enclose the propeller shaft and coupling of the propeller shaft to the engine drive shaft.

Accelerator control for a vehicular propulsion system having a continuously variable ratio transmission

Abstract: A control system and method for a vehicular propulsion system which includes a continuously variable ratio transmission (CVT) and an engine having a relatively steep torque-speed characteristic. Attenuation of the accelerator pedal output--which directly controls the transmission ratio--when the engine is operating in the highly sensitive "critical speed range" spanning the steep portion of its torque-speed characteristic, serves to smooth vehicle responsiveness and driveability, and improve control.

Rendezvous with Saturn's rings

Abstract: The science rationale and instrumentation and engineering feasibility and design of a mission to rendezvous with the rings of Saturn are studied. In situ exploration of the rings requires spacecraft systems with enormous propulsive capability. Nuclear Electric Propulsion (NEP) can effectively provide the required total impulse. The power source must be nuclear because the solar energy reaching Saturn in only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers. The NEP system assumed for this mission employs a nuclear reactor heat source, a thermal-to-electric conversion system, and a mercury ion engine electric propulsion system.

Space station propulsion analysis study

Abstract: This paper summarizes the impacts on the weight, volume and power usage of a manned space station and its 90-day resupply for three integrated, auxiliary propulsion subsystems. The study was performed in coordination with activities of the Space Staton Concept Development Group (CDG). The study focused on three space station propulsion high-low thrust options that make use of fluids that will be available on the manned space station. Specific uses of carbon dioxide, water and cryogen boiloff were considered. For each of the options the increase in station hardware mass and volume to accommodate the dual thrust option is offset by the resupply savings, relative to the reference hydrazine system, after one to several resupplies. Over the life of the station the savings in cost of logistics could be substantial. The three options are examples of alternative technology paths that, because of the opportunity they provide for integration with the environmental control life support system (ECLSS) and OTV propellant storage systems, may reduce the scarring which is required on the early station to meet the increasing propulsion requirements of the growth station.