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The History and Future of the Centrifugal Compressor in Aviation Gas Turbines

Pratt & Whitney Canada, Inc.-David P. Kenny
Published 1984-10-15 by SAE International in United States
The relevance of the centrifugal compressor background for this award to the early developments and current business base of the Garrett Turbine Engine Company is noted.The development of turbo-machinery into the modern centrifugal compressor from Greek classic times to the demonstration of the first aviation gas turbines is traced.This is followed by a description of the evolution of the current high performance centrifugal compressors found in today's engines and some of the leading research demonstrations of the past decade.Recent developments in computer power indicate a massive increase in numerical analyses capability to full three-dimensional viscous solutions. The application of this to the future evolution of centrifugal compressor capability is discussed with projections for the improvement in performance over the next decade. The problems which limit the performance of centrifugal compressors are noted and arguments presented regarding their solutions.
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Injection Molding of 17-4 PH Stainless Steel

Hughes Aircraft Co., Canoga Park, CA-Thomas P. Marshall
Published 1984-10-01 by SAE International in United States
17-4 PH stainless steel has been successfully formed by powder metallurgy (P/M) injection molding. Injection molding is a relatively new P/M technique. In this process, metal powder is mixed with a plastic binder, and the part shape is injection molded as in plastics fabrication practice. The binder is extracted, and the part is sintered to 95-96% of full density.Sintering atmospheres and temperature profiles for optimized material properties were developed. Material mechanical properties were evaluated by tensile, impact, and fatigue tests. Five prototype fin bases for a missile were fabricated. The effect of Hot Isostatic Pressing was determined. The mechanical properties compare favorably to those of investment cast or wrought 17-4 PH steel.
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Winging It in the 1980's: Why Guidelines are Needed for Cockpit Automation

Air Line Pilots Association-M. R. Hoagland
Published 1984-10-01 by SAE International in United States
There have been many reasons for the introduction of automation into the cockpit of the modern airliner. In some cases the forces driving technology have caused the design of automated systems which compromise the ability of the pilot to fulfill his responsibilities for the safety of the airplane under his command. This paper will examine how these forces can lead to unnecessary cockpit automation, and will discuss what must be done to avoid the introduction of automated systems which have the effect of removing the human operator from the information and control processes.
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Discussion of Modal Test Techniques as Applied to a Spacecraft Structure

RCA Astro-Electronics, Princeton, NJ-Carl R. Voorhees, George A. Clark
Published 1984-10-01 by SAE International in United States
Several modal test techniques were employed in the recently completed modal test of a meteorological spacecraft. The primary technique, which was required by the customer, was the classical multiple-shaker sine-dwell method. Although this method is quite time-proven, it takes considerable time to perform the test. Very good results were obtained from this method. The results are used as a basis for comparison with the results of state-of-the-art, less proven but more time efficient test methods.The paper presents the results of the multiple-shaker sine-dwell test, and comparison is made with the results of both single-point random and multiple-point random tests. The paper concludes with a short discussion of the relative merits of each technique.
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Modern Technology Secondary Power Systems for Next Generation Military Aircraft

Garrett Turbine Engine Co., A Division of The Garrett Corp.-James A. Rhoden
Published 1984-10-01 by SAE International in United States
The next generation of military aircraft will require significantly increased internal power capability, with high density packaging and integration of secondary power system elements. These aircraft will be self-sufficient for autonomous operation free of ground support equipment. This paper reviews the concepts and capabilities of modern technology secondary power systems and the application to meet the requirements for these aircraft. The secondary power system elements include the gas turbine auxiliary power unit, aircraft mounted accessory gearboxes, emergency power units, pumps, and pneumatic drives. Mechanical, pneumatic, electric and hybrid techniques to integrate the subsystem will be reviewed and evaluated. In addition, a technology assessment is presented for future gas turbine auxiliary power units.
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Regulation, Deregulation and their Effects on Future Commuter Aircraft

M.C.W. Davy
The de Havilland Aircraft of Canada, Limited-A.F. Toplis
Published 1984-10-01 by SAE International in United States
The traditional dividing line between small and large commercial transports has been based upon weight and passenger capacity. Airworthiness regulations have been matched to operating rules for each category in a way that permitted considerable economics to the smaller aircraft by comparison with the large.As technology and passenger demand both advance, this dividing line has become increasingly blurred, through extensions of both weight and passenger capacity as a means of preserving sensible public service, with the result that the development of a new family of commuter aircraft, larger than previously permitted though still smaller than existing jet equipment, has been encouraged.In spite of this equipment stimulus, growth in the commuter market remains unpredictable, accenting the need for flexibility of design to permit ready adaptation to each new need. It is suggested that the combination of new structural technologies coupled with wider application of systems design practices normally associated with larger aircraft, offers a means of economically providing such flexibility of design. The burgeoning range of smaller energy efficient turboprop engines appears to match this opportunity.…
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Presentation of Information on Multimode Displays: Abnormal and Emergency Aircraft Operations

Rockwell International Corp.-Gary R. Gershzohn
Published 1984-10-01 by SAE International in United States
The capability of a multimode display system to present data regarding malfunctioning aircraft systems is illustrated. The development of formats for abnormal operations is based on the correspondence between cognitive requirements of the pilot and displayed information. Three different stages of cognitive processing are identified and associated formats are developed. System architecture provides' for the display of required information tailored to pilot requirements in identifying, understanding, and solving malfunctions via a simple multimode display interface.
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Acquisition of Detailed Heat Transfer Behavior in Complex Internal Flow Passages

Mechanical and Aerospace Engr. Dept., Arizona State University-D. E. Metzger, R. S. Bunker, C. S. Fan
Published 1984-10-01 by SAE International in United States
Flow passages associated with internal cooling of high temperature engine components, especially those in gas turbine engines, frequently have very complex surface geometries. The flow channels usually are roughened to enhance heat transfer rates, and often incorporate sharp turns. The acquisition of detailed local heat transfer coefficient distributions over complex surface geometries is often extremely difficult or prohibitively expensive using conventional techniques. A relative new method of acquiring heat transfer coefficients through use of surface coatings that have precise melting points is described. As an example of the use of the technique, it is applied to the study of the effect of various rib roughness patterns on heat transfer through 90° turns in a rectangular cooling channel.
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Comparison of Voice Types for Helicopter Voice Warning Systems

Psycho-Linguistic Research Associates Menlo Park, CA-Carol A. Simpson, Kristine Marchionda-Frost, Teresa Navarro
Published 1984-10-01 by SAE International in United States
Three studies compared different computer generated voices for helicopter voice warnings. Study 1 compared three LPC-encoded voices (human female, human male, and phoneme synthesized) while pilots flew simulated nap-of-the earth missions. Flight performance and pilots' ratings via semantic differential scales were measured. Study 2 produced pilot preferences for direct synthesized speech compared to LPC-encoded human female speech and compared to LPC-encoded synthesized speech. Study 3 used phonetically balanced (PB) words heard in simulated helicopter noise to compare intelligibility of direct synthesized and LPC-encoded phoneme synthesized speech. There were no flight performance differences due to voice type (Study 1), but pilots preferred direct synthesized speech over both LPC-encoded human female speech and LPC-encoded synthesized speech (Study 2). PB word intelligibility was better for direct synthesized speech than for LPC-encoded synthesized speech; there were no differences associated with sex of listener or with being a pilot or not. A runs by speech type interaction suggests differential learnability of the two speech types. (Study 3). Implications of these findings for voice selection will be discussed.
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AN/APG-67 Multimode Radar Development Program

General Electric Co., Aerospace Electronic Systems Dept., Utica, NY-John S. Frichtel
Published 1984-10-01 by SAE International in United States
The AN/APG-67 Multimode Radar is the newest tactical fighter radar that is being designed and developed explicitly for Northrop's F-20 Tigershark. It is designed to support the six main missions of the F-20. In the air-to-air missions of supersonic intercept, combat air patrol, and air superiority, the radar modes include search and track for both look-up and look-down situations and automatic acquisition and track for air combat. Additional air-to-air capabilities include track-while-scan and provisions for AIM-7 continuous wave illumination. For the air-to-surface modes of interdiction, close air support, and sea detection, the radar's repertoire includes real beam ground map, high resolution doppler beam sharpening, coherent moving target indication, surface moving target track, and air-to-ground ranging.To meet the requirements of high performance and small size simultaneously, advanced technology was employed to the maximum extent possible. These hardware approaches were employed: an integrated low noise receiver, pulse compression, and digital Fast Fourier Transform processing. The small size was realized through extensive use of microwave integrated circuits, low peak power TWTA in the transmitter, and custom CMOS large…
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