Showing papers on "Propulsion published in 1986"

Survey of supersonic combustion ramjet research at Langley

Abstract: The Hypersonic Propulsion Branch at NASA Langley Research Center has maintained an active research program in supersonic combustion ramjet (scramjet) and high speed ramjet propulsion since the 1960s. The focus for this research has centered on propulsion for manned reuseable vehicles with cryogenic hydrogen fuel. This paper presents some highlights of this research. The design philosophy of the Langley fixed-geometry airframe-integrated modular scramjet is discussed. The component development and research programs that have supported the successful demonstration of the engine concept using subscale engine module hardware is reviewed and a brief summary of the engine tests presented. An extensive bibliography of research supported by the Langley program is also included.

Propulsion control using longitudinal acceleration, steering angle, and speed to select slip threshold

Abstract: A propulsion control system for motor vehicles for preventing an undesirable spinning of the driven vehicle wheels when their slip exceeds a certain threshold value, having several slip thresholds that are connected or disconnected by a logic circuit as a function of the vehicle speed, the longitudinal acceleration, the steering angle and control signals of the propulsion control. The logic circuit may also be used for changing the rising and adjusting speeds of the control elements of the propulsion control.

Multiconfiguration reusable space transportation system

Abstract: A space transporation system comprises several different modular units usable in a plurality of different configurations for different payloads and space missions. The units include a first stage unit for providing primary propulsive force during launch, a payload carrying unit, which may be an orbital vehicle or simple payload canister, and an auxiliary propulsion unit for providing additional power either during launch or space flight. The units are all demountably securable together, and preferably all include aerodymanic devices such as fixed or swing wings for a controlled return to Earth. The first stage unit can act either as a single-stage-to-orbit vehicle carrying internal or external payload, or as the first stage of a multiple stage launch configuration including a payload unit and auxiliary propulsion units.

Propulsion control using steering angle and vehicle speed to determine tolerance range

Abstract: A propulsion control system for motor vehicles for maintaining stable driving conditions, having a computer unit for determining a desired value or a tolerance range for the rotational speed difference of the front wheels or of the lateral acceleration or of the yaw velocity, and having a comparator unit in which this desired value or tolerance range is compared with the measured actual value, in which case the difference between the actual value of the desired value or tolerance range is used as a control signal for the brakes of the wheels and/or for a power control element of the vehicle engine.

Polymer, metal, and ceramic matrix composites for advanced aircraft engine applications

Abstract: Advanced aircraft engine research within NASA Lewis focuses on propulsion systems for subsonic, supersonic, and hypersonic aircraft. Each of these flight regimes requires different types of engines, but all require advanced materials to meet their goals of performance, thrust-to-weight ratio, and fuel efficiency. The high strength/weight and stiffness/weight properties of resin, metal, and ceramic matrix composites will play an increasingly key role in meeting these performance requirements. At NASA Lewis, research is ongoing to apply graphite/polyimide composites to engine components and to develop polymer matrices with higher operating temperature capabilities. Metal matrix composites, using magnesium, aluminum, titanium, and superalloy matrices, are being developed for application to static and rotating engine components, as well as for space applications, over a broad temperature range. Ceramic matrix composites are also being examined to increase the toughness and reliability of ceramics for application to high-temperature engine structures and components.

Method and arrangement for propulsion regulation of an automobile

Abstract: The invention concerns a method for propulsion regulation of an automobile in the sense of prevention of undesirable spinning of the driven vehicle wheels whereby, as needed, only one of the wheel brakes is activated or the engine torque is reduced. Thereby is determined in the manner of an adaptive regulation in constant repetition from measured rotational speeds and stored vehicle and engine parameters for each driven wheel according to the relation M u =θ*.Δω, the excess moment causing the spinning of the wheel concerned and subsequently for each of the driven wheels in accordance with the relation M red =M u +k(Δω-s) the reduction moment required to eliminate the spinning/tendency to spin, which reduction moment is caused to be applied, depending on each driving situation, either in form of a brake torque in the correct magnitude and/or in form of a reduction of the engine torque in the correct magnitude.

On the detectability of antimatter propulsion spacecraft

Abstract: It is shown that the NASA Gamma-Ray Observatory will be able to detect large interstellar spacecraft at distances up to ∼ 300 pc by the γ-ray emission from the propulsion system alone. The distance limit is set by the possibility of recognizing such objects by their proper motions.

Propulsion system for integral trains

Abstract: A rail vehicle propulsion system having an engine (52) whose speed is a function of a selected vehicle speed, an alternator (54) connected to the engine (52) for generating an electrical signal to drive on electric motor (58) connected to the axle by a variable automatic mechanical transmission (60). The electric motor (58) reflects the load on the axle to the engine (52) through the alternator (54). The alternator drives a plurality of electric motor transmission combinations. For ease of servicing, the engine and alternator are mounted on a removable pallet (2l7).

Marine propulsion device air intake system

Abstract: A marine propulsion device comprising a propulsion unit including a rotatably mounted propeller, and an engine drivingly connected to the propeller and including an air intake, a cowl assembly surrounding the engine and including a front located adjacent the air intake and a rear including an air inlet, and a baffle for isolating air from the engine and for conducting the air around the engine from the air inlet to the air intake.

Detachable thrust vector mechanism for an aeronautical vehicle

Abstract: A relatively inexpensive, high efficiency, detachable thrust vector mechanism is provided for addressing the current shortcomings in the art In the illustrative embodiment, the invention is used in conjunction with a nautical or aeronautical vehicle having primary propulsion means and at least one fin movable, to provide maneuverability, in response to a conventional control system The invention is a detachable thrust vector mechanism comprising auxiliary propulsion means pivotally attached to the missile through connecting means Contact means are provided for transferring bi-directional motion of the fin to the auxiliary propulsion means The mechanism is operable to provide auxiliary thrust for the missile along a thrust vector determined by the control system The invention is effective to provide missile steerage at low speeds, particularly during initial launch and pitchover The mechanism of the present invention falls away during flight to fully exploit the original optimized aerodynamic or hydrodynamic design of the missile The thrust vector mechanism of the present invention conserves the main motor fuel, reduces the initial missile launch signature and effectively increases its range The invention also provides a low cost, disposable mechanism for converting a missile designed for high speed (air-to-air) launches to one adapted for low speed (surface) launches That is, under the teachings of the present invention, existing missiles may be inexpensively retrofit to provide thrust vector control

Gas turbine jet engine of multi-shaft double-flow construction

Abstract: A gas turbine jet propulsion unit of multi-shaft-double-flow construction in which a front compressor or fan supplies compressed air into a secondary channel arranged coaxially to the propulsion unit axis and formed between outer and inner wall structures, from which a secondary air component is taken and blown out against the turbine housing structures for purposes of turbine component cooling; the secondary air channel extends essentially over the entire propulsion unit length or at least up to the area near the turbine housing structure while the secondary air component is taken off from the secondary flow by way of openings in the inner wall structure which are arranged in direct proximity of the respective turbine housing structure.

Diesel Electric Locomotive Propulsion Systems-A Look into the Future

Abstract: The demand for increased productivity in train operation has been the driving force in creating today's energy-efficient high-horsepower diesel electric locomotives. A key in obtaining this productivity improvement has been the evolution of the electric transmission that has allowed the locomotive's effective tractive effort to increase along with its diesel engine horsepower. A means of correlating the relative efficiency, reliability, performance, size, and weight of the available propulsion technologies and control strategies is developed, along with trade-offs in applying these technologies and strategies to locomotives now and in the future. Both dc and the various types of ac propulsion technologies are included. How the basic strategy of individual axle control or total locomotive control (for both dc and ac technologies) relates to locomotive productivity is covered along with variations such as power equipment staging in the overall optimization process.

The design and operating characteristics of a 30-kW thermal arcjet engine for space propulsion

Abstract: Attention is given to the design features of a radiation-cooled, 30-kW thermal arcjet thruster, whose laboratory tests have yielded specific impulses of up to 935 sec at 36-44 percent thrust efficiency, together with a cumulative lifetime of over 400 hours. All materials used, including seals, can sustain operation at temperatures sufficiently elevated to require the radiation of all waste heat. This electric propulsion system is ideally suited to missions such as the Space-Based Radar. A detailed consideration is conducted for the thruster's seals, which are the most critical element of the design.

Train control having a supervisory monitor providing improved operating safety and better maintenance support

Abstract: A train control and monitoring system detects operating errors in controlled devices in each car and disables a car propulsion system if an error is detected. Operator reset is employed to reactivate a car, but operator reset control is disabled if a limit error count is reached and in that event only a supervisor reset can reactivate the car. When a car performs with good behavior through a power/brake cycle, the error count is decremented by one count.

Marine installation including fuel/oil mixing device

Abstract: A marine installation comprising a marine propulsion device including a propulsion unit having a lower unit supporting a propeller and a powerhead including a two-stroke internal combustion engine having an apparatus for feeding a fuel/oil mixture to the engine and including a fuel/oil mixture pump having an inlet and being operable to create suction at the inlet, a flexible hose releasably connected to and communicating with the inlet of the fuel/oil mixture pump, and a remote tank having an interior providing a fuel reservoir, having a fitting releasably connected to the flexible hose, having a top wall including a first opening which is adapted to afford filling of fuel into the interior of the tank and which is adapted to removably receive a cap covering the first opening, and a second opening spaced from the first opening, and having an oil storing, oil pumping and fuel/oil mixing device located in the tank and including an upper wall closing the second opening and being secured to the top wall of the tank, and having therein an opening which is adapted to afford filling of oil into the oil storing, oil pumping, and fuel/oil mixing device and which is adapted to removably receive a cap covering the opening in the upper wall, an endless wall depending into the tank from the upper wall to partially define an oil reservoir communicating with the upper wall opening, and an oil pumping and fuel/oil mixing apparatus secured to the depending wall to form the bottom of the oil reservoir and including a first inlet communicating with the oil reservoir, a second inlet communicating with the fuel reservoir, and an outlet communicating with the fitting.

Propulsion control using lateral acceleration and propulsion control signals to select slip thresholds

Abstract: A propulsion control system for motor vehicles for preventing an undesirable spinning of the driven vehicle wheels when their slip exceeds a certain threshold value, having several slip thresholds that are connected or disconnected by a logic circuit as a function of vehicle speed, the lateral acceleration and control signals of the propulsion control. The logic circuit may also be used for changing the increase and adjusting speeds of the control elements of the propulsion control, and for connecting the drive of the wheels of an additional axle and disconnecting it again directly or under certain conditions, in a delayed way.

Multimegawatt nuclear electric propulsion - First order system design and performance evaluation

Abstract: The development of space nuclear power supplies capable of delivering high levels of power (1 to 10 MWe) for long life (5 to 10 years) is being considered. An important potential application of these systems will be to provide power for advanced electric propulsion devices such as ion thrusters or Magneto-Plasma-Dynamic (MPD) thrusters. High-powered Nuclear Electric Propulsion (NEP) concepts based on both ion and MPD thrusters are reviewed. To allow for mission performance evaluation, power supply, power processing, and thruster subsystems are characterized for both ion and MPD propulsion systems designed for operation in the 1 to 10 MWe power range. Several proposed missions which are significantly enhanced by the performance potential of these devices are investigated. Studied missions include near-earth orbit raising, cis-lunar cargo transportation, and planetary exploration. If developed, these 1 to 10 MWe NEP systems may provide a technological base for the development of even larger propulsion systems with power levels of up to hundreds of megawatts. The potential performance and technologies associated with such ultra-high-powered NEP systems is explored.

System for stable running of marine propulsions

Abstract: A number of embodiments of arrangements for stabilizing the running of a marine propulsion unit by slowing the speed of the propulsion unit when an underwater obstacle is struck. In some embodiments, the slowing is accomplished by misfiring of the engine and in other embodiments, the speed is reduced by throttling the fuel supply to the engine. The embodiments illustrate the application of the principle to an outboard drive of an inboard/outboard drive arrangement or for an outboard motor. The striking of the underwater obstacle is sensed by either an impact sensor, by sensing the angular position of the outboard drive, or by sensing the rise in pressure in a shock absorber that resists the popping up action.

Solar thermal propulsion unit

Abstract: This invention relates to a space vehicle 10 in which solar radiation is utilized to generate thrust by virtue of a solar thermal propulsion unit 12. The propulsion unit comprises basically reaction engines 14 including a DeLaval nozzle 22, heating chamber 26, solar window 28 and inflatable paraboloid solar collector 34.

Composite shafting for naval propulsion systems

Abstract: The use of advanced composite materials for propulsion shafting would enable corrosion, galvanic effects, weight, life-cycle costs, bearing loads, magnetic signature, alignment problems, and the use of strategic materials to be reduced while increasing allowable fatigue stress, flexibility, and vibration damping characteristics. The US Navy is investigating the possibility of adopting a standardised family of composite shafts manufactured by a highly-automated filament-winding process incorporating continuous graphite and glass filaments in a thermosetting epoxy resin mix. A trial of a small-diameter shaft of this type on a dockyard craft has given encouraging results, and work is now in hand on a number of points that require further development, in particular the joint between the shaft and a metal flange or propeller.

A model propulsion simulator for evaluating counter rotating blade characteristics

Abstract: Three Model Propulsion Simulators (MPS) were designed and built to evaluate candidate counterrotation Ultra bypass fan model blade designs of nominally 2-ft (0.61 m) tip diameter for an advanced 'pusher-type' aircraft engine. These propulsion simulators (nominally 1/5 engine size) are capable of operation over a wide range of subsonic conditions and can deliver up to 750 shaft horsepower per rotor at rotor speeds of 10,000 rpm. The rotor thrust and torque, dynamic blade stresses, and system temperature data are transmitted through an integral telemetry system to facilitate data acquisition. Salient features of the design, instrumentation, and operation of these simulators are described in this paper.

Propulsion control using longitudinal acceleration to determine slip thresholds

Abstract: A propulsion control system for preventing an undesirable spinning of the vehicle wheels to be controlled, particularly of motor vehicles equipped with a multi-axle drive. The reference speed required for the slip threshold formation is formed from the speed of the uncontrolled driving wheels by an integration with a time constant derived from the longitudinal acceleration of the vehicle, by which a falsification of the reference speed signal is kept within limits in the case of a spinning of the uncontrolled wheels.

Water propulsion unit of water jet propulsion craft

Abstract: Several embodiments of water propulsion units for water jet propulsion crafts wherein an improved bearing support is provided for supporting an elongated drive shaft to permit the engine to be positioned well forwardly in the hull. In accordance with each embodiment, the bearing support member is elongated and is affixed rigidly to the jet propulsion unit in a radial direction for facilitating alignment.

Propulsion for boats consisting of jets of air drawn into a pair of longitudinal channels under the hull.

Abstract: Propulsion for boats (10) by jets of compressed air inside a pair of parallel longitudinal channels (11) open underneath, placed below the hull, substantially horizontal, one on each side of a third wider axial channels (13) suitable for formation, as a consequence of the movement of said boat, of a cushion of air that sustains the hull when sliding over the water.

Design and optimization of propulsion systems employing scarfed nozzles

Abstract: A methodology for the design and optimization of tactical solid propellant propulsion systems employing scarfed nozzles is presented. A performance prediction computer code based on an axisymmetric flowfield model and utilizing the method-of-characteristics solution technique is employed as the primary analysis tool. This performance code is used through a series of parametric studies to obtain a performance map for lengthconstrained scarfed nozzles. The results of these parametric studies are curve-fitted to relationships that express scarf-nozzle performance as a function of nozzle geometric parameters. The relationships are differentiated to obtain the set of geometric parameters for a given nozzle projected length, which maximizes the motor axial performance. The set of optimum geometric parameters for each given nozzle projected length is employed in additional curve fits. These curve fits are used to express the optimum values of the geometric parameters and the corresponding optimum performance as a function of nozzle projected length. The curve fits for the optimum quantities are used to develop a series of relationships that expresses the length of a tactical propulsion system as a function of projected nozzle length. These system relationships are employed to obtain the nozzle geometry, which minimizes the propulsion system length for a specific delivered impulse requirement. The results of this study provide the propulsion system designer with a methodology for selecting the optimum nozzle design for length-constrained applications.

Energy efficient solid propellant attitude control system

Abstract: An energy efficient solid propellant attitude control system for use on post boost vehicles equipped with post boost control systems, post boost propulsion systems, and velocity control systems utilizes gas from a gas generator to drive a gas turbine which drives an alternator to produce electrical power. The turbine effluent gas is selectively directed to highly vectorable hinged nozzles to provide attitude control for the post boost vehicle. Power from the alternator is used to drive electromechanical actuators which orient the highly vectorable hinged nozzles. The turbine effluent gas is also selectively directed to fixed thrusters and twin axial thrust motors.

Semi-venturi airfoil aircraft

Abstract: A VTOL/STOL aircraft of simple design and construction The aircraft has a central semi-venturi shaped airfoil surface defining a channel integral to the fuselage, a canard system and a horizontal stabilizer system at the respective ends of the channel, and a propulsion unit for accelerating airflow through the channel to achieve stable and easily maneuverable flight

Low-thrust rocket trajectories

Abstract: The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

Propulsion Evaluation for Orbit-on-Demand Vehicles

Abstract: Future earth-to-orbit vehicles may be required to reach orbit within hours or even minutes of a decision. A study has been conducted to consider vehicles with such a capability. In Phase I of the study, 11 vehicles were designed to deploy 5000 lb to a polar orbit. Changes in the designs were examined parametrically for increased on-orbit maneuvers, increased payload, and other mission variations. Based on the results, two concepts were selected for Phase II design work: a vertical-takeoff, two-stage system and a horizontal-takeoff, two-stage system with an airbreathing subsonic first stage. The results of several propulsion evaluations are presented, including liftoff thrust-to-weight effects, dual-fuel propulsion for a horizontal-takeoff concept, and the effect of using fluorine.

A method of power generation and it's use in a propulsion device

Abstract: The method uses a compressed primary fluid (eg gas) to heat and vaporize under pressure a liquid secondary fluid and the use of the resultant vapour/gas/steam or mixed said compressed primary medium and said vapor/gas steam for power generation purposes in for example an expansion device. Various methods of compressing the medium and various uses of the method (eg in gas turbine, i.c. oil, two stroke, four stroke engines) are contemplated. In a propulsion device application, ambient air compressed in cowling 6 transfers heat to a chamber 2 via fins 4 whereby liquid CO2 supplied by injector 1 at an atomiser 3, is vapourised and ejected through jet-pipe 7 via a nozzle 5, thus assisting, by induction, the air flow through the cowling 6. A pump 10 is used during starting, thereafter the injector 1 is stated to be driven by fluid bled through line 9. A three-way valve 8 enables transfer from a liquid CO2 supply to a liquid air supply at high altitudes. The fluids leaving the pipe 7 may be used to drive a turbine driving a fan or an airscrew.