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Aerospace, IEEE Transactions on

Issue 2 • Date June 1965

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Displaying Results 1 - 25 of 101
  • [Front cover]

    Page(s): c1
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    Freely Available from IEEE
  • Supplement to IEEE Transactions on Aerospace

    Page(s): 1
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    Freely Available from IEEE
  • From the Editor ...

    Page(s): 2
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    Freely Available from IEEE
  • Index to the technical papers

    Page(s): 3 - 6
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    Freely Available from IEEE
  • Influence of Inverter Loads on the Airgap Flux of Aerospace Homopolar Alternators

    Page(s): 7 - 11
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    In this paper the effects of the time harmonics on the output voltage are investigated. Instead of a complete analysis, the waveshape of the line current is considered as recorded on an oscilloscope when the alternator supplies an inverter. The minimum airgap induction occurs when the magnetomotive forces of the fifth and seventh time harmonic oppose the field excitation. The reduction in the amplitude of the fundamental of the airgap induction caused by the time harmonics was found to be of the order of fifteen to twenty percent for a typical cyclo-inverter load. View full abstract»

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  • Optimization of Rotor Tooth Shape of Aerospace Homopolar Alternators

    Page(s): 12 - 17
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    In the first part of the optimization process, the width and depth of the rotor tooth are incrementally varied for two airgap radial lengths and two field excitations. In the second part the tooth shape that would yield a sinusoidal voltage is investigated. The numerical results are represented by curves for the no-load radial flux density in a 95 KVA, 120/208 v 3,400 cps alternator. The results show that the fundamental airgap flux density depends on the length of the airgap and on the rotor tooth width. It depends only slightly on the rotor tooth depth and excitation. A more sinusoidal output voltage can be obtained by flaring the tips of the rotor tooth and widening the rotor tooth. View full abstract»

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  • Aerospace Composite-Rotor Induction Motors

    Page(s): 18 - 23
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    The theoretical analysis based on electromagnetic field theory is given for high speed aerospace induction motors whose solid rotor is provided with layers of highly permeable and highly conductive materials. Numerical solutions indicate that the efficiency of the rotor as compared with a solid iron rotor is increased considerably. The torque-speed characteristic of the composite rotor motor rises steeply and is nearly flat between 20 and 100 percent slip. The design approaches the characteristic of a multiple cage motor. Operating temperatures are considerably reduced. View full abstract»

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  • Eddy Current Losses in the Rotor Teeth of Aerospace Homopolar Alternators

    Page(s): 24 - 31
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    The eddy current losses in rotor tooth-heads of homopolar alternators are generally high and a limiting factor of design. A method is established to calculate eddy current losses in rotor designs with titanium wedges in the intertooth space. A computer program solves numerically the boundary value problem that yields the electric field intensity in the conducting materials. Inverter loads on an experimental 95 KVA, 3,400 cps, three-phase homopolar alternator are calculated to be approximately five percent. View full abstract»

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  • Non-Linear Theory of Heteropolar Electrical Machines

    Page(s): 32 - 38
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    The partial differential equation for the vector-potential of heteropolar machines is established taking into account the non-linearities of the materials and the current distributions. The non-linear equation, similar to Poisson's equation, is transformed into a partial difference equation. The magnetic induction is found at discrete points in the cross section of the machine. A new relaxation procedure, accelerated greatly by the use of a new physical method of adjusting the vector potential between two successive iterations, is used. The method is shown for an aerospace synchronous generator. Calculated and test results of the no-load characteristic agree quite well. Pole tip saturation is fully considered. View full abstract»

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  • A Digital System for the Acquisition and Analysis of Random Data

    Page(s): 39 - 46
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    Statistical methods of analysis are used to obtain important physical properties of random signals. A description is given of the system which was designed for use in the Propulsion Wind Tunnel, Arnold Engineering Development Center, to provide the necessary signal conditioning and the analog-to-digital conversion at a rate high enough to prevent mixing of the spectral densities. The overall system transfer function is discussed, and the system limitations are defined. View full abstract»

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  • A Mach Number and Dynamic Pressure Computer for Analog Reduction of Wind Tunnel Data

    Page(s): 47 - 52
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    This paper describes the development of a special servo computer for wind tunnel applications to provide analog computations and indications of Mach number and dynamic pressure. Division of up to six aerodynamic variables by the dynamic pressure can also be performed. The computer uses simplified techniques as compared to usual analog computer practices which are allowable because of the special application. Multiple ranges of Mach number and dynamic pressure are used to obtain improved accuracy. The system can be used, with minor modifications, by most wind tunnel facilities. The basic techniques could also be used for an accurate air data computer for aircraft applications. View full abstract»

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  • Temperature Compensation of Transducers Using Semiconductor Strain Gages

    Page(s): 53 - 59
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    Temperature compensation of transducers using semiconductor strain gages involves an understanding of the interrelationships between basic sensor performance, transducer design and compensation techniques. This paper describes some of these interrelationships and gives specific information regarding conventional temperature compensation approaches used on production hardware. View full abstract»

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  • Solar Concentrator Surface Contour

    Page(s): 60 - 66
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    This paper describes an accurate and rapid non-contact surface analyzer for defining a three-dimensional solar concentrator surface contour using a digital computer. The data, representing the surface contour, can be recorded on computer tape and used for a number of final results. In addition to concentrator surface analysis, the analyzer is designed to have the capability for defining surfaces on numerous materials ranging in size from small machined parts to large airplane or missile skin contour. View full abstract»

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  • A Portable Equatorial Mount for Solar-Testing Large Solar Panels

    Page(s): 67 - 70
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    Testing in sunlight is an essential step in verifying the quality of large solar-cell panels, and in predicting space performance. Solar testing is usually done at high elevations to minimize absorption of sunlight by the atmosphere. A problem in such solar testing is the orientation of large panels toward the sun continuously, especially when wind gusts can occur. This paper describes a portable electric-motor driven equatorial mount for testing large solar panels. The equatorial mount is anchored by means of an automobile or truck. Design criteria such as geometrical relationships, structural loads, and gearbox details are provided. The pointing accuracy obtained is given. View full abstract»

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  • Infrared Reflecting Solar Cells

    Page(s): 71 - 75
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    The equilibrium temperature of a solar cell panel in space is a function of the ratio of solar absorptance to infrared emittance of the surface. This paper describes a method for reducing solar absorptance by constructing the solar cell so that it will be a reflector in the infrared part of the solar spectrum. Spectral transmittance, spectral reflectance, and spectral absorptance of silicon wafers and N/P and P/N solar cells are presented. A N/P cell equipped with a silver coating on the back surface and a 0.400 micron cutoff cover glass on the front was found to have solar absorptance of 0.66 which is 11 percent less than that of a standard N/P cell equipped with a similar cover glass. View full abstract»

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  • Packaging System for Extendable Solar Photovoltaic or Thermoelectric Arrays

    Page(s): 76 - 80
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    A packaging system usable for both oriented photovoltaic and flat plate thermoelectric solar arrays is presented which permits six circular disks to open out in an aerospace environment. For a base plate and disk radius of 50 cm, the system enables a maximum power of 435 watts to be delivered to a matched load by an oriented photovoltaic array of six disks plus base plate or 373 watts for 6 disks alone. The latter figure is to be compared with 150 watts (6 disks) for the oriented thermoelectric array. Several comparisons of the two systems in regard to weight, cost, and radiation resistance are discussed. Under certain circumstances, the thermoelectric array has potential cost and weight advantages on a per-watt basis in addition to radiation damage resistance advantages. View full abstract»

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  • Radiation Cooled Cryostat for Infrared Detectors

    Page(s): 81 - 85
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    Analysis and design of a cryostat which functions in space by radiative cooling alone are presented. Temperatures in the inner volume of the cryostat are predicted to reach cryogenic temperatures if the cryostat is placed in an earth orbit in the plane of the ecliptic. The advantages of the cryostat include (1) indefinitely long lifetime, (2) no cryogenic or heat pump plant as payload, and (3) the use of certain radio wave, millimeter wave, and infrared detectors. A parametric analysis of various cryostat configurations has been completed to allow solution of design parameters for various applications, earth orbital radii, and internal heat loads. View full abstract»

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  • Analytical Optimization of Magnetics for Static Power Conversion

    Page(s): 86 - 92
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    Since a prime objective of static power converter design is to minimize weight, optimizing magnetic components is particularly important. This paper derives the fundamental relationship between magnetic device weight and the basic design parameters. These include volt-ampere rating and frequency, characteristics of core and conductor materials, and ratios defining physical dimensions. Also, an expression for estimating heat rejection is obtained; thus, the practicality of a given design can easily be determined. View full abstract»

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  • Precisely Controlled 3-Phase Squirrel Cage Induction Motor Drives for Aerospace Applications

    Page(s): 93 - 97
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    The long sought means whereby complete control can be simply exercised over the speed and torque of a 3-phase squirrel cage induction motor has recently been reduced to practice and is currently in operation in full scale hardware. By means of an all solid-state cycloconverter type frequency changer power is supplied to the motor at a controlled frequency and voltage such that the motor is operated at controlled slip in a closed feedback system. In this loop the torque (and therefore, speed) can be instantaneously controlled. A low power level signal which varies the motor slip frequency is the controlling variable. The application of this concept to aerospace drives is discussed with particular attention given to servo-controlled antenna drive systems. View full abstract»

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  • Sub-Ripple Distortion Components in Practical Gycloconverters

    Page(s): 98 - 106
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    Continuing refinement of the cycloconverter design art has produced an all solid-state power converter which exhibits high efficiency, small size, light weight and high reliability. The controlability of the modern cycloconverter makes it particularly suitable for such applications as precise AC electric drive systems and light weight variable speed, constant frequency power generating systems. Due to the assumptions of infinite load inductance and infinite frequency ratio, the use of classical grid-controlled rectifier theory in the analysis of practical cycloconverters is not sufficiently accurate. According to classical theory, only ripple components of distortion appear in the cycloconverter output. This paper deals with the origin and nature of sub-ripple distortion components in the output. View full abstract»

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  • Dynamic System Analysis for Electrical Power Systems

    Page(s): 107 - 120
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    This paper analyzes the rotating rectifier type aircraft generator system so that a digital computer study of system transient response may be made. A detailed analysis of the generator is made using Park's equations. This analysis results in a mathematical model which is quite easily handled by a digital computer. A single time constant transfer function is used for the exciter-rectifier which has proved sufficiently accurate. The generator analysis could be extended to the exciter and rectifier equations derived in Reference 3 used to obtain better accuracy if sufficient exciter-rectifier data is available. The regulator transfer function is a ratio of polynomials with limits and constants furnished by the designer. The purpose of this paper is to present the detailed generator analysis and briefly discuss the methods of representing other system elements and the computer program used for problem solution. View full abstract»

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  • Mission Control Center - Houston Display and Control System

    Page(s): 121 - 125
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    Flight monitoring and control of manned spacecraft requires near-real-time assessment of large quantities of complex data. To provide centralized control, a Mission Control Center has been established at the Manned Spacecraft Center at Houston, Texas. This paper describes the design philosophy for the Display and Control System, with emphasis on modularity, versatility, and reliability. Technical and operational details are provided for the equipment designed and implemented to satisfy the flight control requirements. View full abstract»

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  • The Houston Mission Control Center

    Page(s): 126 - 131
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    The Mission Control Center, located near Houston, Texas, provides the capability for real-time control and direction of manned space-flight missions. The facility utilizes general-purpose digital computers and flexible, special-purpose systems to satisfy data routing, processing, display, control and communications functions. Systems are duplicated to provide simultaneous, but separate, mission control and mission simulation exercises. View full abstract»

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  • Digital Command - A Network for Manned Spaceflight

    Page(s): 132 - 138
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    Error-free radio command control of manned and unmanned spacecraft used in the manned spacecraft program is mandatory for mission success. This paper outlines the history, philosophies, and methods used in the development of the Digital Command Network implemented for this purpose. This network is designed to the concepts of error detection, versatility, and reliability. This paper will explain the basic concepts of design, the configuration of ground command sites involved, and the overall network which evolved to satisfy the command requirements of manned spaceflight control. View full abstract»

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  • Compatibility and Performance Testing of Communications Systems

    Page(s): 139 - 143
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    During the normal progress of design, fabrication, and integration of communications subsystems for spacecraft and for ground installations, every effort is made to assure that the equipment meets certain specifications relating to performance, environment, reliability, and interface capability. These specifications are based on the best available definition of requirements and interface characteristics of complementing subsystems. Frequently, in the field of manned spaceflight, the spacecraft subsystems, the launch vehicle subsystems, and the ground systems must be designed and constructed concurrently. This means that the operating and interface characteristics of one subsystem are not available for use by the engineers in the design of the other subsystems. Close technical liaison among the various engineering groups is essential in the accomplishment of overall systems' integrity. Component and subsystem testing has been developed to a high degree, but the results of these are necessarily limited. They cannot validate the overall systems' performance and compatibility. It is considered mandatory that the interfacing subsystems be mated to form a complete system in a controlled test environment as early as practicable in any program, especially in one involving communications systems as new and as complex as those for Apollo. This must be accomplished at such a phase in the program that corrective engineering details can be fed back to the cognizant design, fabrication, or integration groups involved in time for necessary modifications prior to the beginning of the flight phase. View full abstract»

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Aims & Scope

This Transactions ceased publication in 1965. The new retitled publication is IEEE Transactions on Aerospace and Electronic Systems.

Full Aims & Scope