Showing papers on "Propulsion published in 1983"

Resistance and propulsion of ships

Abstract: This book deals with the prediction of speed and power in ships - an important part of ship design - and describes the techniques used in ship model experiments as well as different types of experimental facilities. It considers different methods of estimating or determining speed and power. Questions regarding wake, thrust deduction, cavitation, and propeller design are covered. The book correlates the interaction between ship, machinery and propeller, and includes a thorough exposition of shipyards' and shipowners' needs for model testing.

Thrust augmenting ejectors, II

Abstract: : A discussion of the development of the compact jet-diffuser ejectors utilized for hovering and low speed flight propulsion has been presented This is followed by a description of ideal ejector performance as derived from a compressible flow theory, over the range of flight speeds from zero to supersonic speed These analyses introduced the concepts of ejector configuration optimization and the validity of the so-called 'second solution' to the mixing problem, wherein the flow after complete mixing is supersonic The ideal performance of thrust augmenting ejectors designed under this 'second solution' has been shown to be far superior to those designed by conventional methods The ability of properly designed ejectors to utilize the thermal energy of injected gas for the production of useful energy has also been described Finally, the influence of major losses has been discussed, including means for avoiding excessive performance degradation by proper optimization of the geometry of the ejector in view of these losses

Stored Chemical Energy Propulsion System for Underwater Applications

Abstract: An underwater propulsion system that couples a lithium fueled boiler with a standard Rankine cycle has been developed and demonstrated in an ocean environment. Although the demonstration vehicle was a small diameter axisymmetric body, other configurations have been subjected to study and experimentation. Various fuel-oxidizer combinations have been considered for use in the system, and these are examined along with the necessary supporting technologies for future development efforts. A brief history of the system development is included. It is concluded that the described system has been shown to be a viable candidate for numerous underwater applications.

Ship propulsion unit with a main and an auxiliary propeller

Abstract: 1. Ship's propulsion system which is driven from a main machine, preferably a Diesel engine or a gas or steam turbine, and consists of a main propeller and a fixedly installed tandem propeller between main propeller and rudder or of a main propeller and a rudder which is constructed as active rudder with or without jet or as a pivotable propeller with of without gear nacelle and which for improvement of the overall propulsion efficiency and the rudder effect permanently corotates as counterpropeller, characterized thereby, that a part of the total mechanical output is taken off by a synchronous generator (5) arranged at the end face of the main machine (2) or in the shafting (3) and conducted by way of an electrical shaft to a polyphase alternating current motor which drives the tandem propeller (6, 16), that the generator (5), during starting and reversing and in derivation from the travel command generator signal, receives shock excitation until the polyphase alternating current motor has started or reversed and the excitation is regulated towards U/f = constant.

Propulsion and Energetics Panel Working Group 14 on Suitable Averaging Techniques in Non-Uniform Internal Flows

Abstract: : In 1979 the Propulsion and Energetics Panel of AGARD established a Working Group named WG 14 whose terms of reference were to study the averaging techniques used for non-uniform internal flows. This problem is relevant to gas turbine systems, in which the actual flows are usually heterogeneous and three- dimensional. Nevertheless, the test analysis and performance prediction methods are presently based upon simple one-dimensional models. Members of WG 14 first reviewed current practices as employed by research and development teams in various research establishments and industry. The Group also undertook a theoretical analysis of the relations which may be correctly applied to steady flows. Consequently it was possible to discuss and classify known averaging methods. The theoretical study concludes by proposing refinements to known methods and a new approach to averaging for use with engine components and propulsion system analysis. A large variety of possible averaging techniques were identified. Some were based on theoretical considerations, others were without justification except in their simplicity or common usage. All the averaging procedures were tested and compared by preparing a number of sample calculations in ducted flows, turbojet components and a complete propulsion system.

Aircraft propulsion system arrangement

Abstract: In an aircraft arrangement comprising an aircraft fuselage provided with a wing on either side thereof and provided with a propeller propulsion system at the rear of the fuselage, the improvement comprising a propulsion system comprised of at least two independent propulsion units each mounted in its individual lateral fuselage section in a rear fuselage part formed by the central fuselage section originating from the outer contour of the main fuselage section and tapering toward the fuselage end, the lateral fuselage sections having an outer contour tapering in spindle form toward the fuselage rear to the diameter of the propeller spinner of each propulsion unit and propellers on each propulsion unit arranged behind the fuselage and the air frame.

Electric propulsion system for aircraft

Abstract: An aircraft having a rotatively driven blade cooperating with an electrochemical power system for operating an electric drive system. The blade provides cooling heat transfer relative to the lithium/peroxide fuel system effecting desirable separation of the lithium-hydroxide monohydrate in a suitable filter/plenum provided as a portion of the power system. In one form, the cooling is effected by disposing a heat transfer portion of the power system in the path of air flow generated by the propulsion blade of the aircraft. In another form, the cooling is effected by flowing the electrolyte through the propulsion blade. Molarity of the electrolyte is maintained by separating the precipitated lithium-hydroxide monohydrate in solid form in the filter/plenum and addition of replacement hydrogen/peroxide solution from the reservoir thereof.

Spherical underwater vehicle

Abstract: A spherical vehicle for operation in a fluid medium utilizes an actuator disk or propeller of approximately half the diameter of the sphere for propulsion. In addition to providing the energy for driving the sphere, the actuator disk acts to draw the flow of fluid smoothly over the after part of the sphere, thus avoiding or minimizing the tendency of the flow to separate from the surface of the sphere and create turbulence. For aircraft launch, a heavy shroud protects the actuator disk propeller and assures that the vehicle will sink rapidly after impact. The shroud is jettisoned at a desired depth. Steering in pitch and yaw planes is effected through the use of a plurality of powered thrusters located at or just behind the circle of maximum diameter (with respect to the direction of motion) and selectively actuated by a guidance or control system. Alternatively a single reversible thruster may be used for steering in yaw combined with a movable internal weight for pitch control. A plurality of stub vortex generators are also located on the aft side of the sphere and are angled or controlled to oppose the torque created by the propeller or to effect other guidance functions. For stability, the center of gravity preferably is located substantially below the geometric center of the sphere. The particular embodiment shown is an electrically (battery) powered underwater vehicle, but the same general configuration also applies to a manned submarine vehicle having the usual propulsion means.

Propulsion control apparatus for passenger vehicles

Abstract: A cam controller for determining the operation of an electric motor is coupled with a stepping motor to provide predetermined positional movements of the cam controller in response to a desired electric motor operation control signal and in accordance with a programmed microprocessor determined comparison of the actual electric motor current with a requested current related to the desired operation control signal.

Propulsion installation characteristics for turbofan transports

Abstract: Several investigations have been conducted in the Langley 8-Foot Transonic Pressure Tunnel and the Langley 16-Foot Transonic Tunnel to investigate propulsion integration characteristics for turbofan transport aircraft. These studies have focused on reducing the interference drag for conventional underwing, overwing, upper surface and wing aft-mounted engine nacelle installations. The experimental data presented in this paper will illustrate the difficulties associated with properly integrating nacelles and pylons with advanced supercritical wings. In addition guidelines for integrating the nacelle/pylons to eliminate adverse interference effects and possibly achieve favorable interference are discussed.

Integrated Flight and Propulsion Operating Modes for Advanced Fighter Engines

Abstract: This paper presents the results of preliminary studies of advanced propulsion system requirements and capabilities for the next generation of fighter aircraft. It represents an examination of current and advanced concepts of internal variable engine geometry and advanced exhaust system concepts for use in expanding the role of the propulsion system in the flight process. Special engine operating modes are defined and their potential capabilities are described. In-flight thrust vectoring and reversing concepts are described and their use in providing propulsive pitch and yaw forces for flight control assist are discussed. Potential control concepts and requirements for implementing the advanced engine operating modes are also described.Copyright © 1983 by ASME

Non-Contact Suspension and Propulsion Technology

Abstract: SUMMARY As a result of extensive research and development in several countries, the technologies of magnetic suspension and linear electric drives are becoming available for transportation applications. The successful demonstration and operation of prototype vehicles has established the technical viability of these systems. Several urban transit or shuttle services, with magnetic suspension and/or linear motor propulsion are likely to be operational within 3-4 years. After the final stages ofdevelopment and rigorous testing, high speed systems are likely to be an option for intercity implementation by the end of the decade. This paper presents a report on the worldwide status of R&D and test programs of non-contact suspension and propulsion technology for guided ground transport.

Advanced beamed-energy and field propulsion concepts

Abstract: Specific phenomena which might lead to major advances in payload, range and terminal velocity of very advanced vehicle propulsion are studied. The effort focuses heavily on advanced propulsion spinoffs enabled by current government-funded investigations in directed-energy technology: i.e., laser, microwave, and relativistic charged particle beams. Futuristic (post-year 2000) beamed-energy propulsion concepts which indicate exceptional promise are identified and analytically investigated. The concepts must be sufficiently developed to permit technical understanding of the physical processes involved, assessment of the enabling technologies, and evaluation of their merits over conventional systems. Propulsion concepts that can be used for manned and/or unmanned missions for purposes of solar system exploration, planetary landing, suborbital flight, transport to orbit, and escape are presented. Speculations are made on the chronology of milestones in beamed-energy propulsion development, such as in systems applications of defense, satellite orbit-raising, global aerospace transportation, and manned interplanetary carriers.

Power management process

Abstract: A power management system is disclosed for an advanced helicoptor having h 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 power use gage connected to the lift propulsion unit which has an output that varies according to the amount of power used by that propulsion unit and a circuit which is connected to the power use gage 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 an indicator which indicates to the pilot the amount of power remaining for the thrust propulsion unit, or can be connected directly to a limit actuator for limiting the amount of power the pilot can apply to the thrust propulsion unit.

Alternate Propulsion Energy Sources.

Abstract: : This report contains a summary of the non-proprietary technical results of the referenced contract. The objective of the contract was to survey the entire field of advanced propulsion to uncover and carry out a technical assessment of any concept that showed promise of leading to a major advance in available energy sources for space power and propulsion in the next century. In general, any concept that might derive energy from the space environment was to be considered, as well as any unconventional methods of storing energy in a compact form that may have applicability to space power and propulsion. In Phase I, 64 concepts were uncovered and preliminary technical assessments were carried out on 28 of the more promising concepts. For Phase 2, it was recommended that further studies be carried out on solid metastable helium, solar heated plasmas, perforated solar sails, and antiproton annihilation propulsion. Of these, the Air Force selected two concepts to receive the major portion of the Phase 2 effort, solar heated plasmas and antiproton annihilation.

An analysis of propulsion options for transport of lunar materials to earth orbit

Abstract: This paper describes the results of analyses of space-based transportation systems for the transport of extraterrestrial materials from their point of origin on the lunar surface to final delivery point in earth orbit and transport of equipment and supplies for extraterrestrial processing to the operational site. The emphasis has been on the use of near-term (pre-year 2000) propulsion systems, such as advanced chemical (H2, O2) and nuclear-electric systems. More exotic systems (mass drivers, nuclear-thermal rockets, etc.) were also considered to evaluate the potential to be gained by use of post-year 2000 technologies. Finally, the effects of using extraterrestrial propellants (e.g., H2 from lunar polar water-ice for chemical systems) were compared to those of propulsion systems deriving all or part of their propellants from the earth.

Measuring method of ship propulsion

Abstract: PURPOSE:To easily and promptly measure propulsive force of a ship, by arranging a fixed part on a quay at a face-to-face position to the propulsive direction, connecting the ship to the fixed part with a mooring tool of ropes and the like, driving a propeller of the ship and measuring tension of the mooring tool. CONSTITUTION:A ship 8 is stopped to a fixed part 7, protrusively provided on a quay 6, through mooring tools 4, 5 of ropes or the like arranged with a propulsion tester 1. An internal combustion engine in the ship 8 is driven at a prescribed speed, if a propeller 10 is rotated, the ropes 4, 5 are pulled to the direction of propulsion, and an applied load is measured by the tester 1. If the mooring tools 4, 5 are extensibly provided parallelly to the propulsive direction of the ship 8, the measured load itself reads propulsion of the ship, thus easy and correct measurement can be performed.

Helicopter auxiliary energy system

Abstract: Autorotation in helicopters at low altitudes can be achieved even when the inherent design of the helicopter would prohibit successful entry into the autorotation mode Angular kinetic energy from the main propulsion engine is stored in a flywheel which automatically transfers this energy to the main drive shaft in the event of engine failure During normal operation, the flywheel is driven through the main drive shaft by coupling to a secondary drive shaft The main drive shaft in turn is driven by the engine through an overrunning clutch assembly The flywheel is maintained within an evacuated housing whereby air drag is substantially eliminated In the event of engine failure, the overrunning clutch disengages the engine from the main drive shaft and flywheel will continue to apply energy to the main drive shaft through the secondary drive shaft to permit autorotation and a no-damage landing even at low altitude flight levels

Wheelchair having anti-rollback mechanism

Abstract: The propulsion wheels of a manually propelled wheelchair are equipped with one-way engaging and one-way freewheeling clutch devices which cooperate with races fixed to the wheelchair frame, whereby unwanted backward movement of the wheelchair is prevented and forward movement at all times is enabled. An override mechanism including a spider attached to each hand propulsion ring disables the one-way engaging clutch devices when the wheelchair occupant intentionally moves the propulsion wheels in a backward mode. No controls separate from the manual propulsion wheels are present, assuring the chair occupant constant control of the chair through the hand propulsion rings at all times.

Marine propeller with main propeller and additional propeller

Abstract: The invention deals with a ship propulsion plant which has a main propeller driven by a main engine and a tandem propeller. The overall propulsion efficiency and the rudder action are thereby improved. A portion of the total mechanical power of the main engine or a shaft-driven generator is fed via an electric wave to the three-phase motor of the tandem propeller so that, during starting or reversing as a function of the signal from the cruise control-signal generator, the shaft-driven generator is given a shock excitation until the three-phase motor is started or reversed and the excitation is regulated to U/f = constant.

Marine propulsion device with tilt and trim means with fluid filtering

Abstract: A marine propulsion device including a member adapted to be connected to a boat hull, and a propulsion assembly pivotally connected to the member for vertical swinging movement when the member is attached to the boat hull. The device also includes a plurality of hydraulic assemblies, each of the hydraulic cylinder assemblies including a hydraulic cylinder and a piston rod slideably received in the cylinder. The hydraulic cylinder assemblies are mounted between the member and the propulsion assembly to effect the vertical swinging movement of the propulsion assembly in response to movement of the piston rods in one direction relative to the cylinders and in the opposite direction relative to the cylinders. The marine propulsion device further includes a reversible pump including a first port and a second port. The marine propulsion device further includes a hydraulic conduit system communicating between the first and second ports and the cylinder assemblies for moving the piston rods in one direction relative to the cylinders in response to pressurization of the first port, and for moving the piston rods in the opposite direction relative to the cylinders in response to pressurization of the second port. The conduit system also includes a filter and a control arrangement communicating with the filter for requiring substantially all of the fluid flowing from the hydraulic cylinder assemblies to the pump to pass through the filter.

River towboat hull and propulsion

Abstract: This paper was presented in Jan. 1982 at a S.N.A.M.E. meeting. The Authors discuss the design of river- towboat hull forms and propulsion arrangements, and review recent European research to illustrate the influence, on towboat propulsive performance, of limited water-depth, barge-train wake, nozzle propellers, and the arrangement of the barges. A design- procedure example is included for the propellers of a 5600-hp twin- screw towboat pushing a 15-barge tow in deep and shallow water. Conclusions are drawn concerning: reasons for the towboat's propulsive coefficient being lower than that of merchant ships; comparison, in model tests, between conventional and catamaran towboats; recommendations on tunnel stern design; published formulae which, for a 15-barge train, under-estimate tow- resistance and over-estimate towboat performance; and a design philosophy for selecting the propeller operating point.

Water pump location for marine propulsion device

Abstract: A marine propulsion device comprising a propulsion unit, a horizontal drive shaft rotatably supported in the propulsion unit, a second drive shaft rotatably supported in the propulsion unit, and water pump means. The horizontal drive shaft has an aft end, and is adapted to be rotationally driven by an engine. The second drive shaft has upper and lower ends, and extends transversely to the horizontal drive shaft. The second drive shaft is connected to the horizontal drive shaft for rotationally driving the second drive shaft, and is adapted to drive a propeller. The water pump means communicates with the cooling jacket of the engine for circulating water through the cooling jacket, and is drivingly connected to one of the upper end of the second drive shaft and the aft end of the horizontal drive shaft.

Advanced propulsion concepts for orbital transfer vehicles

Abstract: Studies of the United States Space Transportation System show that in the mid-to-late 1990s expanded capabilities for Orbital Transfer Vehicles (OTV) will be needed to meet increased payload requirements for transporting materials and possible men to geosynchronous orbit. NASA is conducting a technology program in support of an advanced propulsion system for future OTVs. This program is briefly described with results to date of the first program element, the Conceptual Design and Technology Definition studies.