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Technical Paper

10 KWe Dual-Mode Space Nuclear Power System for Military and Scientific Applications

A 10 KWe dual-mode space power system concept has been identified which is based on INEL's Small Externally-fueled Heat Pipe Thermionic Reactor (SEHPTR) concept. This power system will enhance user capabilities by providing reliable electric power and by providing two propulsion systems; electric power for an arc-jet electric propulsion system and direct thrust by heating hydrogen propellant inside the reactor. The low thrust electric thrusters allow efficient station keeping and long-term maneuvering. The direct thrust capability can provide tens of pounds of thrust at a specific impulse of around 730 seconds for maneuvers that must be performed more rapidly. The direct thrust allows the nuclear power system to move a payload from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO) in less than one month using approximately half the propellant of a cryogenic chemical stage.
Technical Paper

3-D Numerical Analysis Investigating Distribution of Contact Pressures for a Number of Cylindrical Bearing Axial Profiles When Placed Under Radial Load Conditions

Increased torque values passing from engine to transmission have, increasingly become a problem regarding shaft misalignment. Engineers are restricted with regard to applying ISO standards when investigating bearing life cycles as they tend only to cover normal [radial thrust] load conditions. Depending on the application, the need has arisen for numerical models to determine reduction in normal life cycles due to abnormal running conditions. The Simulia Finite Element package Abaqus v6.7 provides trends in the deformations, contact pressures and their respective distribution. It was found the most efficient profile, with regards to a uniform contact pressure, under both radial and misaligned conditions is the toroidal profile.
Technical Paper

A Communications Architecture Concept for ATIS

Three recent developments suggest cost-beneficial approaches to communications for Advanced Traveler Information Systems (ATIS) : 1) the use of FM subcarrier for efficient paging-type (digital) one-way broadcast, along with the upcoming introduction of Radio Data System (RDS) vehicle receivers, 2) the rapidly growing use of RF “tags” for automatic tolling, which have recently been upgraded for discrete zone two-way communication, and 3) the “signal processing gain” and “demand access” capability of spread-spectrum-type coding, which together make event-driven communications more feasible and cost-beneficial. An architecture concept exploiting these thrusts is outlined in terms of a “baseline” and a higher level ATIS. The baseline emphasizes basic traffic exception and safety messages and supports higher level (optional) services such as navigators and invehicle route guidance computers.
Journal Article

A Comparison between Regular and Vibration-Assisted Drilling in CFRP/Ti6Al4V Stack

As aircraft programs currently ramp up, productivity of assembly processes needs to be improved while keeping quality, reliability and manufacturing cost requirements. Efficiency of the drilling process still remains an issue particularly in the case of CFRP/metal stacks: hot and long metallic chips are difficult to remove and often damage the surface of CFRP holes. Low frequency axial vibration drilling has been proposed to solve this issue. This innovative drilling process allows breaking up the metallic chips in such a way that jamming is avoided. This paper presents a case of CFRP/Ti6Al4V drilling on a CNC machine where productivity must be increased. A comparison is made between the current regular process and the MITIS drilling process. First the analysis and comparison method is presented. The current process is analyzed and its limits are highlighted. Then the vibration process is implemented and its performances are studied.
Technical Paper

A Comparison of Propulsion Systems for V/STOL Supersonic Combat Aircraft

Three lift/propulsion concepts for a V/STOL supersonic combat aircraft have been compared. The intention was to show the effect of the propulsion system on aircraft weight and size, performance, and life cycle costs for: 1 Vectored thrust with Plenum Chamber Burning (bypass air augmentation) 2 Lift engines and a lift/cruise reheated turbofan 3 A reheated lift/cruise turbofan with a remote augmented lift system (RALS) For a postulated deck-launched intercept mission, the vectored thrust propulsion system with Plenum Chamber Burning gives the smallest and cheapest aircraft having the required performance. In addition, for a given take-off ground run the vectored thrust powered aircraft has the longest fighter escort mission radius.
Technical Paper

A Comprehensive Model of Piston Skirt Lubrication

This paper describes a comprehensive model of piston skirt lubrication, developed for use in conjunction with piston secondary dynamic analysis, to accurately characterize the effects of the skirt-cylinder oil film on piston motions. The model represents both hydrodynamic and boundary lubrication modes and applies an asperity contact pressure when surfaces are in close proximity with each other. In addition to skirt dimensions and surface roughness properties, the circumferential extent of lubrication, an arbitrary skirt profile and bore distortion are specifiable inputs to the model. The model is also extended to represent the oil starvation at the cylinder end of the skirt by allowing the axial extent of lubrication on the skirt surface to vary circumferentially and with time to satisfy continuity of oil.
Technical Paper

A Computer Model of a Pulsejet Engine

This paper deals with the performance prediction of one member of a family of thrust producing intermittent combustion engines, namely the pulsejet. The first part is concerned with formulating basic concepts of how pulsejets work. It describes the different methods of providing intake valving action and derives theory to demonstrate the operation of the aerodynamic tuned valve in particular. The second part is concerned with devising a computer program to simulate and predict the performance of valveless pulsejets. The program is based on the method of characteristics for calculating unsteady gas flow. Theories and techniques are given to handle the major problems associated with this application. These problems include the large range of discontinuous temperature and entropy, flow through an area discontinuity and the calculation of mean thrust.
Technical Paper

A Corporate Product Quality Assurance Program

This paper outlines what a large company is doing on a corporate staff basis to help combat Product Liability problems. Eaton Corporation is multi-national and serves a variety of markets. The extensive and complex line of products dictates the need for a well organized, corporate Product Assurance Program. The program is made up of five thrusts: 1) Corporate Policy, 2) Guidelines, 3) Divisional Committees, 4) Surveys and 5) Training. Utilizing a product development project, the implementation of several elements of Product Quality Assurance are explained. The program was designed for flexibility and emphasizes the chairman's motto to “DO IT RIGHT THE FIRST TIME, EVERY TIME.”
Technical Paper

A Design Approach to Integrated Flight and Propulsion Control

A decentralized, multivariable controls methodology is being developed for the functional integration of a fighter's aerodynamic controls with those of its propulsion system (inlet, engine, and thrust vectoring/reversing nozzle). Integrated controls account for, and take advantage of the significant cross-coupling between these system elements. A high-fidelity, six-degrees-of-freedom (6 DOF) aircraft simulation has been developed, incorporating advanced tactical fighter features such as variable cycle engines, variable geometry inlets, 2D-CD TV/TR nozzles, canards and a propulsive lift concept. A comprehensive evaluation test plan, including a piloted simulation, has been developed to validate this integrated-controls design methodology. Preliminary results show significant benefits of integrated control in terms of enhanced aircraft maneuverability, precise flight path control, reduced pilot workload, and fault tolerant system design.
Technical Paper

A General Three-Dimensional Potential-Flow Method Applied to V/STOL Aerodynamics

This paper describes a numerical method for solving three-dimensional incompressible flow problems and its use in predicting the aerodynamic characteristics of V/STOL aircraft. Arbitrary configuration and inlet geometry, fan inflow distributions, thrust vectoring, jet entrainment, angles of yaw, and flight speeds from hover through transition can be treated. Potential-flow solutions are obtained with the method of influence coefficients, using source and doublet panels distributed on the boundary surfaces. The results include pressure distributions, lift, induced drag and side force, and moments. Theoretical solutions are presented for clean lifting wings and for a NASA fan-in-wing model. Comparisons with the experimental NASA data demonstrate the validity of the approach and uncover the importance of viscous effects, fan inflow distribution, and jet entrainment.
Technical Paper

A Ground Test Program to Support Condition Monitoring of a Spacecraft Attitude Control Propulsion System

The Comet Rendezvous Asteroid Flyby (CRAF) mission involves seven years of flight from 0.6 to 4.57 Astronomical Units (AU), followed by about 915 days of maneuvering around a comet. Ground testing will characterize the very critical attitude control system thrusters' fuel consumption and performance for all anticipated fuel temperatures over thruster life. The ground test program characterization will support flight condition monitoring. A commercial software application hosted on a commercial microcomputer will control ground test operations and data acquisition using a newly designed thrust stand. The data acquisition and control system uses a graphics-based language and features a visual interface to integrate data acquisition and control.
Technical Paper

A High-Speed Fuel Lubricated Hybrid Thrust Bearing for Limited-Life Turbine Engines

The feasibility of operating a mainshaft thrust bearing at high speeds with jet fuel mist as the coolant and lubricant has been demonstrated in both rig and engine testing. A split-inner ring hybrid thrust bearing ( silicon nitride balls ) was successfully operated to 1.67 x 106 DN at maximum Hertzian contact stresses up to 322,000 psi. The bearing configuration also included BG-42 inner and outer rings and a Dupont polyimide Vespel separator. The incorporation of a fuel lubrication system for limited-life turbine engines has many advantages, including; Lower cost ( elimination of oil system related hardware ). Enhanced long-term storage reliability Increased cold start reliability.
Technical Paper


The heavily loaded thrust bearing in aircraft turbines must be 100% reliable, which requires a different philosophy from that on which catalog ratings are based, namely, 10% of failures. Principal problems are: 1) to raise the minimum life of bearings regardless of the wide spread between minimum and maximum, and 2) to raise the permissible operating temperature. Metallurgical improvements offer the best possibilities for gain in 1 and 2 above. Other factors such as geometry, finish, and dimensional accuracy are helpful in category 1 but do not promise large gains.
Journal Article

A Method for the Evaluation of the Effectiveness of Turboelectric Distributed Propulsion Power System Architectures

Radical new electrically propelled aircraft are being considered to meet strict future performance goals. One concept design proposed is a Turboelectric Distributed Propulsion (TeDP) aircraft that utilises a number of electrically driven propulsors. Such concepts place a new and significant reliance on an aircraft's electrical system for safe and efficient flight. Accordingly, in addition to providing certainty that supply reliability targets are being met, a contingency analysis, evaluating the probability of component failure within the electrical network and the impact of that failure upon the available thrust must also be undertaken for architecture designs. Solutions that meet specified thrust requirements at a minimum associated weight are desired as these will likely achieve the greatest performance against the proposed emissions targets.
Technical Paper

A Method of Predicting and Improving NVH and Stress in Operating Crankshaft Using Nonlinear Vibration Analysis

Vibration behavior of a crankshaft in operation is complicated and difficult to simulate because of oil effects on journals, coupled vibration of crankshaft system parts, combustion and inertia acting on the crankshaft. Particularly, the stiffness and damping of oil film vary with crank angles and thus the numerical analysis must deal with nonlinear vibration. This oil film effects also diversify the vibration modes of the crankshat; the vibration modes in an actual operation differs from that in statically experiment modal analysis. This paper describes a new method developed by the author to analyses, predict, and reduce noise and vibration using several techniques including numerical simulation, finite element method, Sommerfeld concept on oil film effects, and modal frequency response.
Technical Paper

A New Ford 3-Speed Automatic Transmission

Article outlines the design objectives of the 1966 Ford high capacity automatic transmission and discusses the effect of these objectives on various transmission components. Major features described are a new 1 - 2 shift control and band cooling system, sintered iron applications, method of reducing thrust loads on engine crankshaft, and drivetrain resonance. Appendix gives general information on the transmission.
Technical Paper

A New Reaction Control Approach for Sounding Rockets

This paper concerns a new technique designed to provide high performance reaction control systems for sounding rockets. Proportional control of differential thrust and simple adaptive control of thrust magnitude (based on the level of demanded thrust) is utilized. The control is being implemented with a combination of electronic and fluidic components for an Aerobee 150 sounding rocket payload whose goal is a pointing stability of 0.1 arc second.
Technical Paper

A New Type of Bearing for Passenger Car Flanged Axles

This paper includes a brief description of present day rear axle designs and their bearings. It also includes a complete discussion of the design objectives of a new concept in single row tapered roller bearings and of the design features of this new bearing. The new bearing is preadjusted and carries thrust loads in either direction, as well as radial loads in any combination. A detailed discussion of its development and testing, both laboratory and field, is presented.
Technical Paper


The concept of using the air cushion ground effect principle to aid an aircraft's take-off and landing is relatively new. This allows the airplane to hover and accelerate to flying speed at a definite height, i. e., free of the ground. This study was initiated to determine whether such a procedure is feasible for the take-off of an airplane, and in so doing, to examine some dominating parameters. This study is limited in scope: the take-off consists of a constant height acceleration to flying speed, then a pull-up to clear an obstacle; a low aspect ratio wing is assumed, furthermore, all thrust is obtained from the lifting fan during take-off. In addition, stability considerations were neglected, augmentation is assumed unaffected by forward speed, the lift fans are operated at constant power and at only one pressure ratio, and the total ram drag was used.
Technical Paper

A Parametric Evaluation of Supersonic STOVL

This paper describes the results of a study to evaluate parametric variations to a single engine short-takeoff vertical-landing fighter/attack aircraft design. The variables considered involved thrust vectoring, thrust degradation, maximum lift, and other changes to determine the impact on short-takeoff performance, but subject to a vertical-landing capability. The results indicate that there are certain parameters that have a significant effect on short-field performance. Also, the optimal control strategies for transitions from a short-takeoff to forward flight and from forward flight to hover are determined. The results have applicability beyond the configuration evaluated.