| An Assessment of CFD Effectiveness for Vortex Flow Simulation to Meet Preliminary Design Needs |
MAR 2003 |
15 pages |
| Authors:
P. Raj; D. B. Finley; F. Ghaffari; LOCKHEED MARTIN AERONAUTICAL SYSTEMS MARIETTA GA
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 | The low-speed flight and transonic maneuvering characteristics of combat air vehicles designed for efficient supersonic flight are significantly affected by the presence of free vortices. At moderate-to-high angles of attack, the flow invariably separates from the leading edges of the swept slender wings, as well as from the forebodies of the air vehicles, and rolls up to form free vortices (see Figure 1). The design of military vehicles is heavily ... |
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| Flow Control of Vortical Structures and Vortex Breakdown over Slender Delta Wings |
MAR 2003 |
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| Authors:
Anthony Mitchell; Scott Morton; Pascal Molton; Yair Guy; AIR FORCE ACADEMY COLORADO SPRINGS CO DEPT OF AERONAUTICS
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 | An understanding of vortical structures and vortex breakdown is essential for the development of highly maneuverable and high-angle-of-attack flight. This is primarily due to the physical limits these phenomena impose on aircraft and missiles in extreme flight conditions. Demands for more maneuverable and stealthy air vehicles have encouraged the development of new control concepts for separated flows. The goal of this paper is to describe experimental flow control techniques used ... |
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| Pitfalls in the Interpretation of Delta Wing Flow Visualisation |
MAR 2003 |
17 pages |
| Authors:
Dr. D. I. Greenwell; DEFENCE EVALUATION AND RESEARCH AGENCY BEDFORD (UNITED KINGDOM)
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| This paper illustrates some pitfalls in the interpretation of flow visualisation images of delta wing leading-edge vortices. Numerical simulations of tracer particle trajectories in around straight and helical vortices are presented, representing unburst and burst delta wing vortices respectively. For straight vortices, the appearance of the 'smoke-ring' effect in wind tunnel testing is analysed, and shown to be unrelated to the size or presence of a viscous inner core in ... |
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| Virtual Development and Integration of Advanced Aerospace Systems: Alenia Aeronautics Experience |
MAR 2003 |
18 pages |
| Authors:
Marco Delpiano; Marco Fabbri; Claudia Garda; Elena Valfre; ALENIA AERONAUTICA SPA TORINO (ITALY)
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| Alenia Aeronautica has gained a solid and consolidated experience in this field within a number of past and ongoing programs. This paper will describe this experience, and will tackle the methods which are used and planned to be used, so to cross-transfer the above experience to other military as well as civilian programs. This document is organised as follows: a brief description of the Concurrent Engineering concept as used for ... |
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| Challenges of Aircraft Design Integration |
MAR 2003 |
11 pages |
| Authors:
F. Kafyeke; M. Abdo; F. Pepin; P. Piperni; E. Laurendeau; BOMBARDIER AEROSPACE DORVAL (QUEBEC) ADVANCED AERODYNAMICS
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| The design of a modern airplane brings together many disciplines: structures, aerodynamics, controls, systems, propulsion with complex interdependencies and many variables. Recent aircraft programs, such as Bombardier's Continental Jet program use participants located around the world and selected for their cost, quality and delivery capability. These participants share the risk on the program and must therefore be fully implicated in the design. A big challenge is to provide information on ... |
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| Preliminary Multi-Disciplinary Optimization in Turbomachinery Design |
MAR 2003 |
22 pages |
| Authors:
V. Panchenko; H. Moustapha; S. Mah; K. Patel; M. J. Dowhan; PRATT AND WHITNEY CANADA CORP LONGUEUIL(QUEBEC)
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| The gas turbine engine is a complex aerodynamic machine with performance, structural and manufacturability challenges. This paper gives an overview of a multidisciplinary optimization approach applied to the conceptual design of small aircraft engines. A description of major turbomachinery disciplines and the numerous interactions between disciplines is given followed by a discussion of the need for preliminary design optimization. The approach to development of such a system undertaken at Pratt ... |
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| Developpements numeriques recents realises en aeroelasticite chez Dassault Aviation pour la conception des avions de combat modernes et des avions d'affaires |
MAR 2003 |
12 pages |
| Authors:
E. Garrigues; Th. Percheron; DASSAULT AVIATION SAINT-CLOUD (FRANCE)
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| North Carolina Agricultural and Technical State University Jet Propulsion Laboratory |
05 FEB 2003 |
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| Authors:
Frederick Ferguson; Mark Schulz; Mannur Sundaresan; NORTH CAROLINA AGRICULTURAL AND TECHNICAL STATE UNIV GREENSBORO DEPT OF MECHANICAL ENGINEERING
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| Active Jet Noise Control |
FEB 2003 |
77 pages |
| Authors:
Anjaneyulu Krothapalli; FLORIDA STATE UNIV TALLAHASSEE DEPT OFMECHANICAL ENGINEERING
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| A novel high-speed jet noise suppression technique using high- pressure gas microjet injection at the nozzle exit was developed with promising results using the laboratory scale jet. The main jet parameters, the nozzle pressure ratio and the temperature ratio are chosen to correspond with realistic engine operating conditions. Keeping in mind the applicability of the technique to full-scale engines, the microjet mass flow was kept at less than 2% of ... |
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| An Overview of the Utility of Stimulants as a Fatigue Countermeasure for Aviators |
FEB 2003 |
24 pages |
| Authors:
John Caldwell; AIR FORCE RESEARCH LAB BROOKS AFB TX HUMAN EFFECTIVENESS DIR/ BIODYNAMICS ANDPROTECTION DIV
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| Sleepiness and fatigue are common in the aviation environment even during peacetime, but during combat, fatigue can reach critical levels due to the necessity for sustained operations and the consequent requirement for lengthy duty schedules. Effective nonpharmacological countermeasures are often difficult to implement in these settings due to the situational demands and the unpredictable nature of war. Thus, during combat, pharmacological countermeasures (stimulants or Go Pills) may represent the only ... |
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| Kalman Filtering With Inequality Constraints for Turbofan Engine Health Estimation |
FEB 2003 |
36 pages |
| Authors:
Dan Simon; Donald L. Simon; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
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| Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This paper develops two analytic methods of incorporating state ... |
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| Effect of the "Long Term Solution" Seat Pack on Harvard II (CT156) Aircrew Accommodation |
FEB 2003 |
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| Authors:
Pierre Murphy; DEFENCE RESEARCH AND DEVELOPMENT CANADAOTTAWA (ONTARIO)
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| The requirement to include additional survival equipment as part of the seat survival kit of the Harvard II has caused a significant increase to the seat thickness (4 to 5 cm). A previous study determined that any increase in seat thickness would likely have repercussions on the ability of the taller individuals to see all of the information displayed by the Electronic Attitude Director Indicator (EADI), on control stick authority, ... |
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| Using the GPS to Improve Trajectory Position and Velocity Determination During Real-Time Ejection Seat Test and Evaluation |
FEB 2003 |
127 pages |
| Authors:
Christina G. Schutte; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| This document is a report of using the GPS to improve Trajectory Position and Velocity Determination during Real-Time Ejection Seat Test and Evaluation. |
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| Ageing Mechanisms and Control. Specialists' Meeting on Life Management Techniques for Ageing Air Vehicles (Les mecanismes vieillissants et le controle) (Reunions des specialistes des techniques de gestion du cycle de vie pour vehicules aeriens vieillissan |
FEB 2003 |
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| Authors:
NATO RESEARCH AND TECHNOLOGY ORGANIZATION NEUILLY-SUR-SEINE (FRANCE)
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| The costs of maintaining aging aircraft are draining the existing budgets. The Specialist Meeting provided guidance on strategies for the development and implementation of technologies and logistic management processes to reduce this economic burden. The emphasis was on military aircraft, but many of the principles could be applied to other defense systems. The papers covered the entire range of aging problems including structural integrity, collision, avionics, mechanical subsystems, structures and ... |
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| Spatial Disorientation - A Perspective |
FEB 2003 |
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| Authors:
Alan J. Benson; ROYAL AIR FORCE CENTRE OF AVIATION MEDICINE BEDFORDSHIRE (UNITED KINGDOM)
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| I am honored to have been invited to give the keynote address to this symposium on spatial disorientation. Spatial disorientation (S.D.) is not a new problem in aviation and over the last 50 years it has been addressed on numerous occasions within the NATO community. Yet despite the increased understanding of the varied aetiology of S.D. and improvement in the display of information to the pilot to facilitate correct spatial ... |
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| Technical Evaluation Report |
FEB 2003 |
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| Authors:
Gunter Kagerbauer; EUROPEAN AERONAUTIC DEFENCE AND SPACE DEUTSCHLAND GMBH MUNCHEN (GERMANY)
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| The programme for the Specialists' Meeting was structured into ten sessions covering the wide topic of aging air vehicle problems and in total thirty-one comprehensive papers were presented. Due to the non-availability of some authors and withdrawal of some papers on short notice the programme had to be continuously rearranged, but thanks to the effort by the Chairmen of the Specialists' Meeting Dr. J. W. Lincoln and Dr. M. Winstone ... |
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| Managing the Aging Aircraft Problem |
FEB 2003 |
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| Authors:
John W. Lincoln; AERONAUTICAL SYSTEMS CENTER WRIGHT-PATTERSON AFB OH
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| Aging aircraft face many challenges. Certainly, one of the most costly is corrosion. The United States Air Force (USAF) spends approximately $800 million dollars a year for corrosion detection, prevention, and repair. Another major challenge is structural fatigue cracking. This problem has significant safety implications as well as economic. Aging mechanical subsystems constitute a challenge in that they can have such a severe impact on aircraft availability. Aging wiring is ... |
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| Setting up a Strategic Architecture for the Life Cycle Management of USAF Aging Aircraft |
FEB 2003 |
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| Authors:
M. Carpenter; J. White; AERONAUTICAL SYSTEMS CENTER WRIGHT-PATTERSON AFB OH AGING AIRCRAFT SYSTEM PROGRAM OFFICE
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| The average age of United States Air Force (USAF) aircraft is over 22 years and increasing. The USAF is buying only a fraction of the new aircraft necessary to simply stop the declining age trend. The real effects of aging are seen in increased costs of ownership, and decreasing availability of aircraft to accomplish their mission. With thousands of aircraft in the USAF fleet, managed by numerous agencies, the job ... |
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| USAF Strategy for Aging Aircraft Structures Research and Development |
FEB 2003 |
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| Authors:
Frank M. Grimsley; John W. Lincoln; Michael L. Zeigler; AERONAUTICAL SYSTEMS CENTER WRIGHT-PATTERSON AFB OH
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| Many nations are now keeping aircraft in their inventories longer than ever before. In many cases, aircraft are left in the inventory longer because they are still operationally effective; however, in most cases, they remain in the inventory because the money is not available to replace them. Aircraft, which are seeing the effects of aging through corrosion and fatigue cracking, are causing their operators to bear a significant economic burden ... |
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| USAF Strategy for Aging Aircraft Subsystem Research and Development |
FEB 2003 |
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| Authors:
William C. Kinzig; AERONAUTICAL SYSTEMS CENTER WRIGHT-PATTERSON AFB OH AEROSPACE ENGINEERING DIR
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| Like many other nations today, the United States Air Force (USAF) is retaining their existing aircraft longer than planned. It is estimated that the current average age of aircraft in the USAF inventory today is 22 years old. By 2003, 75% of the USAF inventory will be over 20 years old. As the age of our fleet continues to rise, aircraft mission capable rates degrade and there is a potential ... |
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| Common Understanding of Life Management Techniques for Ageing Air Vehicles |
FEB 2003 |
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| Authors:
Thomas Vogelfaenger; EUROPEAN AERONAUTIC DEFENCE AND SPACE DEUTSCHLAND GMBH MUNCHEN (GERMANY)
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| Aging aircraft are a growing problem in both military and commercial aviation. With the economic constraints of keeping current military and civilian aircraft in service, and the growing demand for air travel worldwide, the problems of aging aircraft will continue to worsen. The service life extension of equipment or a system over the initial design period is indeed a question of safety however, as the subsequent explanations show, this a ... |
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| Management of Corrosion in Aging Military Systems |
FEB 2003 |
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| Authors:
Graham Clark; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AERONAUTICAL AND MARITIME RESEARCH LAB
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| This paper discusses research in Australia into the impact of corrosion on structural integrity, and reviews the steps being taken to improve the capability of the Australian Defence Force to manage corrosion in aircraft. The aim of the research discussed is to develop useful methodologies which are similar to those already in place for fatigue management and which can therefore be introduced relatively easily, and the paper discusses some of ... |
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| Corrosion Management of the Italian Air Force Fleet |
FEB 2003 |
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| Authors:
Mario Colavita; Fabrizio De Paolis; ITALIAN AIR FORCE ROME CSV DEPT OF CHEMISTRY
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| Economic, safety and logistic issues are strongly affected by military aircraft corrosion, more when it regards an aging fleet. Italian Air Force manages this matter by a Corrosion Control Register Program (CCR), a flexible and integrated support for making decisions both on prevention and operational measures. |
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| Corrosion Management - A Statistical Approach |
FEB 2003 |
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| Authors:
Robert Bell; Don Shelton; Mike Falugi; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
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| One of the major cost drivers for any aging aircraft is the mitigation of corrosion damage. This problem has been exacerbated as aircraft are being kept in service beyond their original design service life in terms of both flight hours and calendar years. As this trend continues, the need to understand the impact corrosion has on reliability, maintainability, and the cost to maintain an aircraft becomes increasingly important. This paper ... |
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| Improved Corrosion Maintenance Practices |
FEB 2003 |
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| Authors:
R. Kinzie; AIR FORCE CORRISION PREVENTION AND CONTROL OFFICE ROBINS AFB GA
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| The USAF, and much of the aerospace industry, currently manage corrosion by providing clear engineering direction that it will be found and fixed prior to becoming a structural or safety concern. New procurements have been reduced and current fleets are now at, or projected to be beyond, their original design lives. While there is significant fatigue life left, corrosion maintenance costs are escalating rapidly. Initial protection systems have broken down ... |
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| Life and Damage Monitoring-Using NDI Data Interpretation for Corrosion Damage and Remaining Life Assessments |
FEB 2003 |
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| Authors:
Jerzy P. Komorowski; David S. Forsyth; Nicholas C. Bellinger; David W. Hoeppner; NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) INST FOR AEROSPACE RESEARCH
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| The progress achieved in the understanding and modelling of fatigue and fracture in aircraft structures has led to the development of Damage Tolerance as the framework for ensuring continued airworthiness. Success of Damage Tolerance and Fail-Safe concepts combined with general economic conditions led to the current situation where an increasing number of aircraft are operated beyond their original design goal. |
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| Life Extension Methodologies and Risk-Based Inspection in the Management of Fracture Critical Aeroengine Components |
FEB 2003 |
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| Authors:
A. D. Boyd-Lee; D. Painter; G. F. Harrison; QUINTEQ LTD FARNBOROUGH (UNITED KINGDOM) STRUCTURES AND MATERIALS CENTRE
|
| This paper briefly describes the main methodologies used in the assessment of fracture critical parts. The development of a procedure for the quantitative assessment of non-finite results is discussed and typical life extension levels are illustrated. Risk assessment is considered within the context of the safe life methodology. It is used to quantify the potential risks associated with the short-term continued operation of life-expired parts and to allow their managed ... |
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| Life Cycle Management Strategies for Aging Engines |
FEB 2003 |
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| Authors:
J-P. Immarigeon; W. Beres; P. Au; A. Fahr; W. Wallace; NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) INST FOR AEROSPACE RESEARCH
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| Diminishing budgets for new weapon systems are creating% pressure within NATO nations to keep legacy aero engines in operation well beyond their service life expectancy. Techniques for safely extracting maximum usage out of aging components in these engines, to reduce maintenance costs, are discussed. The mechanisms responsible for the aging of components are described. The different strategies that fleet managers may adopt for extending component lives economically and safely are ... |
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| Assessment of the Efficacy of Polish Air Force Engines for Life Extension vis-a-vis Technology and Practices Prevalent in other NATO Countries |
FEB 2003 |
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| Authors:
Ryszard Szezepanik; M. Witos; AIR FORCE INST OF TECHNOLOGY WARSAW (POLAND)
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| The goal of the paper is to share PAF former and present experiences about dealing with aging engine structures and strategies for their repair versus technology and practices prevalent in other NATO countries. Some issues of safe operation of aging aeronautical products have been presented on the grounds of the engine-operation model. Special emphasis has been put on some aspects of both: initial tolerances in components engineering and stochastic loads ... |
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| Engine Life Extension through the Use of Structural Assessment, Non-Destructive Inspection, and Material Characterization |
FEB 2003 |
|
| Authors:
Sharon Vukelich; AERONAUTICAL SYSTEMS CENTER WRIGHT-PATTERSON AFB OH PROPULSION DEVELOPMENT SYSTEM OFFICE
|
| For over twenty years, the USAF has had a life extension program for major rotating hardware, such as rotors, seals, and shafts. This program was called Retirement-For-Cause (RFC). Damage tolerance philosophies are essential to this lifting technique. Damage tolerance has been applied to all new engine programs as part of the Engine structural Integrity Program (ENSIP) within the USAF since 1984. An essential element of ENSIP and RFC is non- ... |
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| Wire Integrity Field Survey of USAF Legacy Aircraft |
FEB 2003 |
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| Authors:
Joseph S. Kuzniar; George A. Slenski; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS MANUFACTURING DIR/SYSTEMS SUPPORT DIV
|
| Wiring is so fundamental to current aerospace equipment that we often forget it is a system unto itself The aging of a wire system can result in loss of critical functions in equipment powered by the system or in loss of critical information regarding the operation of certain parts of the equipment. Either result can lead to catastrophic equipment failure or to smoke and fire. Consequently, the safety of aerospace ... |
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| Wiring System Diagnostic Techniques for Legacy Aircraft |
FEB 2003 |
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| Authors:
David H. Johnson; Edward L. White; Joseph J. D'Angelo Jr.; Dwayne Dicks; Adam L. Decker; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS MANUFACTURING DIR/SYSTEMS SUPPORT DIV
|
| As aircraft continue to age, managing the overall wiring system is becoming an important issue. Over time, the accumulation of stresses from the operational environment, installation, and maintenance can induce wiring failures. In both design and maintenance, wiring is usually treated more as a commodity than a subsystem. A systematic process for managing wiring is only now just emerging. A major challenge is the development of wiring diagnostic equipment. The ... |
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| Requirements for Risk Assessment Tools for Aircraft Electrical Interconnection Subsystems |
FEB 2003 |
|
| Authors:
Christopher Smith; Robert Pappas; WILLIAM J HUGHES TECHNICAL CENTER ATLANTIC CITY NJ
|
| The continued safe operation of aircraft well into their expected service life depends on the safe and effective transfer of electrical power and signals between aircraft electrical devices. This in turn requires the enduring physical integrity of the electrical interconnect subsystem (EIS), which is comprised predominately by wire, connectors, switching devices (including relays and solid state switches) and protective devices such as circuit breakers. Recently there has been speculation that, ... |
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| The Pivotal Role and Current Status of Nondestructive Inspection Systems in the Maintenance of Aging Aircraft |
FEB 2003 |
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| Authors:
J. P. Gallagher; W. C. Hoppe; Alan Berens; David Stubbs; Charles Buynak; DAYTON UNIV OH RESEARCH INST
|
| This paper discusses the pivotal role that Nondestructive Inspection (NDI) plays not only for maintaining safety through early crack detection in airframes and engines, but also for minimizing corrosion maintenance costs. The paper is based on multiple projects that have supported developing and validating NDI systems for crack detection in airframe and engine components and for corrosion detection in airframe structures. These projects have led to a new understanding of ... |
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| Advances in Structural Integrity Analysis Methods for Aging Metallic Airframe Structures with Local Damage |
FEB 2003 |
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| Authors:
James H. Starnes Jr.; James C. Newman Jr.; Charles E. Harris; Robert S. Piascik; Richard D. Young; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER
|
| Analysis methodologies for predicting fatigue-crack growth from rivet holes in panels subjected to cyclic loads and for predicting the residual strength of aluminum fuselage structures with cracks and subjected to combined internal pressure and mechanical loads are described. The fatigue-crack growth analysis methodology is based on small-crack theory and a plasticity induced crack-closure model, and the effect of a corrosive environment on crack-growth rate is included. The residual strength analysis ... |
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| Widespread Fatigue Damage Assessment Approach |
FEB 2003 |
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| Authors:
Paul W. Tan; Catherine A. Bigelow; John G. Bakuckas Jr; WILLIAM J HUGHES TECHNICAL CENTER ATLANTIC CITY NJ
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| A methodology to assess the development of widespread fatigue damage (WFD) and its effect on the residual strength of aircraft structure has been developed. The three major components of the methodology are crack initiation, crack growth and linkup, and residual strength. The crack initiation methodology uses experimentally generated equivalent initial flaw size (EIFS) data and an analytical closure model to determine initial flaw sizes and distribution for multiple-site cracking. The ... |
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| Programme for Life Extension and Widespread Fatigue Damage Evaluation to Ensure Continued Structural Integrity of Airbus Large Transport Category Airplanes |
FEB 2003 |
|
| Authors:
Hans Trey; Hans-Juergen Schmidt; EADS AIRBUS GMBH HAMBURG (GERMANY) FATIQUE AND FRACTURE MECHANICS DEPT
|
| The Airworthiness Assurance Working Group (AAWG) has been charted by FAA to enhance and develop rules for continued structural integrity of large transport category airplanes. The subgroup AAWG - RWG(3 (Rule Writing Group) has completed a draft proposal for enhancement of AC91-56 and the introduction of operational rules of aircraft operated under 14 CFR Parts 91, 121, 125, 129 and 135. |
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| Bonded Repair Technology for Aging Aircraft |
FEB 2003 |
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| Authors:
Alan Baker; Richard Chester; James Mazza; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS MANUFACTURING DIR/SYSTEMS SUPPORT DIV
|
| NATO weapons systems are being extended well beyond their design lives due to decreases in defense budgets and the rising costs associated with procuring new hardware. This situation makes it increasingly important that methods for extending the lives of these weapon systems in a cost-effective manner be developed and implemented to the greatest extent possible. Adhesive bonding technology, particularly bonded composite repairs/enhancements, has been successfully applied by several nations to ... |
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| Sustaining an Aging Aircraft Fleet with Practical Life Enhancement Methods |
FEB 2003 |
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| Authors:
Len Reid; FATIGUE TECHNOLOGY INC SEATTLE WA
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| Extension of aircraft beyond their original design service life or operation in expanded or different roles pose challenges in continuing to operate these aircraft economically or safely. Management of the fleet generally entails increased structural inspection and maintenance, repair of inevitable fatigue damage or possible structural replacement. In a large number of cases structural elements become life limiting or require major rework due to fatigue cracks and damage originating at ... |
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| The Need for a Systems Engineering Approach for Measuring and Predicting the Degradation of Aging Systems and How It Can Be Achieved |
FEB 2003 |
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| Authors:
William Robinson; Gisele Welch; Gary O'Neill; GEORGIA TECH RESEARCH INST ATLANTA LOGISTICS AND MAINTENANCE RESEARCH CENTER
|
| This paper will explore the need for a comprehensive approach to measuring, and predicting, degradations in aging NATO aircraft and use of these predictions in a systems approach' to solving the challenges faced in supporting these aircraft. Various groups within the NATO countries have already accomplished significant progress in this area, so this paper is an attempt to refine a more global process that will provide the most useful results ... |
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| Life Cycle Cost Modeling and Simulation to Determine the Economic Service Life of Aging Aircraft |
FEB 2003 |
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| Authors:
K. R. Sperry; K. E. Burns; BOEING CO OKLAHOMA CITY OK
|
| Estimating the point at which the advantages of a modem aircraft alternative exceed the economic burden of maintaining aging aircraft is very complex. This paper presents a cost estimating methodology to forecast costs associated with * maintaining an aging aircraft fleet, by combining traditional Operation and Support (O&S) cost elements from a USAF AFI 65-503 CORE model, with expert analysis to quantify maintenance cost growth due to aging. The result ... |
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| Extending Aircraft Engine Lives |
FEB 2003 |
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| Authors:
Otha B. Davenport; AERONAUTICAL SYSTEMS CENTER WRIGHT-PATTERSON AFB OH PROPULSION DEVELOPMENT SYSTEM OFFICE
|
| It gives me great pleasure to appear before you today. I am honored to be the keynote speaker and the topic of extended engine life is extremely important to many of our military and civilian aircraft today. I have been fortunate to have a career where I have found myself working both beginning of new high technology developments of aircraft and aircraft engines to the older or even ancient "Keep ... |
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| Technical Evaluation Report |
FEB 2003 |
8 pages |
| Authors:
C. J. Eady; BRITISH AIRWAYS HEATHROW (UNITED KINGDOM)
|
| The goal of the NATO-RTO is to conduct and promote cooperative research and information exchange within NATO and with its Partners. To achieve this goal, the RTO has set out three key objectives: * To support the development and effective use of national defense R&T and thus maintain a technological lead within the alliance. * To meet the military needs of the alliance. To provide advice to NATO and national ... |
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| Long-Term Operation and Maintenance of Engine Monitoring Systems - Recommendations Derived from 15 Years of OLMOS Use by the GAF |
FEB 2003 |
15 pages |
| Authors:
Hugo Pfoertner; MTU AERO ENGINES GMBH MUNICH (GERMANY)
|
| Some aspects of the operation of a monitoring system over a time of several decades are discussed. It is shown, that the classical system design approach with well-defined definition, development, introduction and operation phases has to be replaced by a network of parallel activities. These activities are driven by the requirements to maintain fleet readiness and safe operation under the constraints of shrinking budgets and personnel reduction. Other factors driving ... |
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| Coupled Multi-Disciplinary Optimization for Structural Reliability and Affordability |
FEB 2003 |
10 pages |
| Authors:
Galib H. Abumeri; Christos C. Chamis; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| A computational simulation method is presented for Non-Deterministic Multidisciplinary Optimization of engine composite materials and structures. A hypothetical engine duct made with ceramic matrix composites (CMC) is evaluated probabilistically in the presence of combined thermo-mechanical loading. The structure is tailored by quantifying the uncertainties in all relevant design variables such as fabrication, material, and loading parameters. The probabilistic sensitivities are used to select critical design variables for optimization. In this ... |
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| Cost Reduction and Engine Life Extension Through Engine Life Monitoring at SNECMA |
FEB 2003 |
8 pages |
| Authors:
Frederic Genot; SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION MOISSY-CRAMAYEL (FRANCE)
|
| The current market of the military Aircraft Gas Turbine Engines imposes reductions in the support costs. It has now become necessary to adapt our maintenance policy to comply with the new requirements. The present tendency focuses on a better knowledge of the real engine operation conditions to better relate damage to mission types. Our former maintenance policies for military engines were too expensive. SNECMA adopted the damage tracking on the ... |
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| Fatigue Crack Growth Predictions for Simplified Spectrum Loading: Influence of Major Cycles on Minor-Cycle Damage Rates |
FEB 2003 |
14 pages |
| Authors:
Stephan M. Russ; Andrew H. Rosenberger; James M. Larsen; W. S. Johnson; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE
|
| As part of the Engine Structural Integrity Program, USAF turbine-engine components are subject to a damage tolerance or crack-growth assessment. This assessment involves the prediction of crack-growth lifetimes from an initial flaw size under simulated mission loading. The accuracy of the prediction is dependent upon numerous assumptions and inputs: how well the actual mission is simulated by the simpler load spectrum, the accuracy of the component temperature and stress analysis, ... |
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| The Inadequacy of Safe-Life Prediction: Aero-Engine Fan and Compressor Disk Cracking |
FEB 2003 |
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| Authors:
B. J. Wicks; R. A. Antoniou; S. L. Slater; J. Hou; AERONAUTICAL AND MARITIME RESEARCH LAB MELBOURNE (AUSTRALIA)
|
| The use of a safe-life methodology to ascribe a replacement interval to gas turbine engine components has been used extensively for over 40 years. However there are inherent limitations in the methodology, resulting in significant under-utilization of component lives, and an inability to account for rogue flaws and other non-representative factors. This paper will present three examples where the safe-life approach was inadequate in predicting the safe working life of ... |
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| Air-Launch TSTO With Subsonic In-Flight Collection-System and Technology Study |
30 JAN 2003 |
181 pages |
| Authors:
Patrick Hendrick; ASBL RENAISSANCE BRUSSELS (BELGIUM)
|
| This report results from a contract tasking ASBL Renaissance as follows: A conceptual aircraft design tool called RDS will be used in parallel with the (Royal Military Academy) RMA-developed trajectory-sizing tool. The purpose will be to analyze the variants of the Gross Weight evolution in flight using the ACES concept together with the loads existing on the aircraft and the influence on the aircraft structural design and thus its empty ... |
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| FLIGHTFAX. Army Aviation Risk-Management Information. Volume 31, Number 1, January 2003. Fratricide: Reducing Self-Inflicted Losses |
JAN 2003 |
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| Authors:
ARMY SAFETY CENTER FORT RUCKER AL
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Aircraft
