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Technical Paper

Concorde Development - Powerplant Installation and Associated Systems

1991-09-01
912181
Responsibilities for the various aspects of the design of Concorde were shared between Aerospatiale and British Aerospace. This paper covers some of the lessons learnt during the design, development and in-service phases of the last 30 years in the fields covered by BAe, namely the power plant installation and its services - fuel, fire precautions, engine-intake compatibility, control systems etc. Structural problems have been dealt with extensively elsewhere. The experience gained so far in 150,000 hours of operation of which 112,500 hours have been at supersonic speeds with approximately 100,000 hours at Mach 2.0 have provided a very sound basis for the development and operation of the next series of supersonic transports.
Technical Paper

Concorde Propulsion - Did We Get It Right? The Rolls-Royce/Snecma Olympus 593 Engine Reviewed

1991-09-01
912180
Abstract The Olympus 593 together with its reheat, primary nozzle and secondary nozzle systems was designed and developed jointly by Rolls-Royce in Britain and Snecma in France. The design objectives were met so that the Concorde aircraft still carries a full payload of 100 passengers between Europe and America. 600,000 hours of operational experience, over half at Mach 2.0, have shown the control philosophies adopted were correct and are showing that the most significant difference between civil subsonic and supersonic engines is the cruise at high inlet air temperatures which has produced some unexpected mechanical affects.
Technical Paper

Challenging Power Density Requirements for Future Fighter APUs

1991-09-01
912177
Future fighters will require more compact, lighter weight, small gas turbine auxiliary power units (APUs) capable of faster starting, and operation, up to altitudes of 50,000 ft. The US Air Force is currently supporting an Advanced Components Auxiliary Power Unit (ACAPU) research program to demonstrate the technologies that will be required to accomplish projected secondary power requirements for these advanced fighters. The requirements of the ACAPU Program represent a challenging task requiring significant technical advancements over the current state-of-the-art, prominent among which are: Small high heat release high altitude airbreathing combustors. High temperature monolithic ceramic and metallic small turbines. Capability to operate, and transition from non-airbreathing to airbreathing modes. This paper discusses these challenging requirements and establishes technology paths to match and exceed the required goals.
Technical Paper

Advanced Power Generation Systems for More Electric Aircraft

1991-09-01
912186
This paper describes the technologies pursuant to more electric aircraft. The title “More Electric Aircraft” is an appropriate appellation to describe the inexorable trend towards the use of more electrics in future advanced military and commercial aircraft. This trend is sponsored and supported by the U.S. Air Force/WRDC, USN/NADC and NASA. Most recently, the Department of the Air Force issued a solicitation with the acronym MADMEL: Power Management and Distribution for More Electric Aircraft. This is a major multi-year program which includes a MADMEL ground demonstrator and flight testing of electric technologies that will replace the several multiple power sources now resident in current aircraft.
Technical Paper

Auxiliary Power System Requirements for Commercial Air Transports - Past, Present and Future

1991-09-01
912188
The auxiliary power unit (APU) requirements for commercial air transports have evolved from those of a convenience item to those of a highly integrated, heavily utilized, automated and sometimes essential, airplane system. This evolution has been driven by increasing demands for reliable airframe electrical and pneumatic power, fuel and weight efficiency, reduced crew workload, maintainability, and environmental accordance. Moreover, with the growth of extended range twin operations (ETOPS), the APU has become an essential back-up to primary airframe systems. This paper reviews the APU design criteria of past and present Boeing commercial jet transports and suggests the direction of future installations.
Technical Paper

High Speed Civil Transport Electrical Power System Technology Requirements

1991-09-01
912185
Abstract The Boeing Company is investigating a High Speed Civil Transport (HSCT) aircraft which will transport 300 passengers at speeds up to Mach 2.4. Such a high speed, high altitude aircraft presents unique environmental and safety requirements. The aircraft electrical power system configuration must provide the required redundancy and reliability necessary to supply power for fly-by-wire flight control buses as well as other aircraft loads. Emergency power backup must be considered for various power failure conditions. This paper presents some of the issues affecting the electrical power system design, and some of the possible solutions which will be considered.
Technical Paper

270-Vdc/Hybrid 115-Vac Electric Power Generating System Technology Demonstrator Evolution to a Dual-Channel, More Electric Aircraft Technology Development Testbed

1991-09-01
912183
Abstract Sundstrand has been investigating 270-Vdc/hybrid 115-Vac electrical power generating systems (EPGS) technology in preparation for meeting the electrical power generating system (EPGS) requirements for future aircraft (1). Systems such as the one being investigated are likely to be suitable for the More-Electric Aircraft (MEA) concepts presently under industry and military study. The present Sundstrand single-channel testbed is being further expanded to better understand the electrical system performance characteristics and power quality requirements of an MEA in which traditional mechanical subsystems are replaced by those of a “more-electric” nature. This paper presents the most recent Sundstrand 270-Vdc system transient performance data, and describes the modifications being made to the 270-Vdc/hybrid 115-Vac testbed.
Technical Paper

Primary Fabrication Processes for Nickel and Iron Aluminides

1991-09-01
912194
Alloys based on the intermetallic compounds Ni3Al and Fe3Al have been developed. Intermetallic compounds are characteristically brittle at room temperature, and some are also brittle at elevated temperatures. Nickel-aluminide alloys have been made ductile by alloying with a small amount of boron (200 ppm by weight) and adjusting the aluminum content to 24 at. % or less. Iron-aluminide alloys are ductile when chromium is added (>wt 2%) and the aluminum is adjusted to 28 at. %. These alloys begin ordering upon solidification; therefore, a greater shrinkage must be accommodated during casting. The hot-working temperature “window” for the nickel-aluminide alloy is very narrow; however, the alloy can be cold-worked large amounts. Iron-aluminide alloys have a very broad hot-working temperature range but have limited ductility (<20%) at room temperature. The strength and oxidation resistance of these alloys are such that many potential applications exist. Commercialization is in progress.
Technical Paper

Concorde Flight Testing - Powerplant and Performance Flying

1991-09-01
912192
The certification of the Western world's first supersonic civil transport did not have the benefit of past experience as has been the case in the subsonic field. Supersonic experience was limited to military aircraft which possessed in the main a relatively short duration supersonic dash capability. Concorde has been in Airline service since 1976 and has built up over 150,000 hours of which over 112,000 are at supersonic speeds on a worldwide basis. This achievement came about following a flight development and certification programme covering approximately 5,500 hours over six and a half years. This wealth of experience creates a totally different scene to that existing at the time of Concorde's conception and many lessons are available for the next generation of supersonic civil transport.
Technical Paper

Concorde, Fifteen Years on the Front Line

1991-09-01
912193
In 1962 British and French Governments committed funds for the design, testing and production of a supersonic airliner. Fourteen were completed. These aircraft are currently in their sixteenth year of passenger service and, judged on their reliability, have carved out a niche in the air transport market. Behind this success lay the problems of maintaining a radically different aircraft that operates in a radically different environment.
Technical Paper

Secondary Power System Preliminary Design

1991-09-01
912189
Commercial gas turbine auxiliary power unit (APU) requirements are in many respects more demanding than those for propulsion engines of a similar power level. The successful modern APU design must provide high reliability and durability in a flight weight package which also satisfies diverse and often conflicting performance requirements. The preliminary design phase represents the first crucial step towards meeting these objectives. This paper examines how the primary APU requirements influence turbomachinery configuration selection, and then flow down through the preliminary design process into individual APU component and sub-system design criteria, using a load compressor APU example.
Technical Paper

Development and Evaluation of an Onboard Aircraft Cabin Water Spray System for Postcrash Fire Protection

1991-09-01
912224
This paper outlines a program that could ultimately lead to design standards for an onboard aircraft cabin water spray system to suppress postcrash fires. A brief summary of the program and the status of current activities is presented. The latter includes full-scale effectiveness tests, a study of possible problems arising from the inadvertent (or intentional) discharge of the system, and computation of the potential benefits (lives saved) from the mandatory requirement of such a system. The bulk of the paper describes the results of full-scale tests under several postcrash fire scenarios to measure the increased survival rate when using a water spray system. It is shown that a water spray system may provide passengers 2 to 3 minutes of additional time to escape under certain postcrash fire scenarios.
Technical Paper

AIRCRAFT GROUND DEICING

1991-09-01
912222
Deicing and anti-icing of aircraft prior to flight in hazardous precipitation including snow, freezing rain, freezing drizzle and other conditions conducive to aircraft surface icing has become the main method for removing and preventing the freezing of contaminants on aircraft wings, control surfaces and other critical components. In turn the Federal Aviation Administration (FAA) has promulgated requirements that endorse a “Clean Aircraft Concept” for aircraft that operate under the various Federal Aviation Regulations. Recent advances in aircraft deicing and anti-icing methodologies, materials, equipments and procedures have fostered the need for a review and possible updating of FAA advisory and regulatory materials and other information on the subject. This paper discusses, in general, ongoing efforts to enhance aviation safety relative to aircraft ground deicing and anti-icing, and related ground operations in hazardous weather conditions conducive to aircraft icing.
Technical Paper

Abrasive-Waterjet Machining of Ceramic-Coated Materials

1991-09-01
912231
This paper addresses an experimental investigation on the feasibility of using abrasive-waterjets (AWJs) for the precision drilling of small-diameter holes in advanced aircraft engine components. These components are sprayed with ceramic thermal barrier coating (TBC), and the required holes are typically 0.025 inch in diameter with a drilling angle of 25°. The parameters of the AWJ were varied to study their effects on both quantitative and qualitative hole drilling parameters. The unique techniques of assisting the abrasive feed process, ramping the waterjet pressure during drilling, and varying the jet dwell time after piercing were effectively implemented to control hole quality and size. The results of the experiments indicate the accuracy and repeatability of the AWJ technique in meeting the air flow and hole size requirements. Production parts were drilled for prototype engine testing.
Technical Paper

British Airways Airbus A320 Pilots' Autothrust Survey

1991-09-01
912225
The Airbus A320 has an autothrust system which is unique among transport aircraft in not having feedback movement provided to the pilots' thrust levers. There has been some controversy in the airline world over the operational aspects of this system. As British Airways was one of the earliest operators of the type, a survey was conducted to determine the views of line pilots as to the advantages and disadvantages of the system compared with conventional moving levers. This paper contains the results of that survey. It was concluded that the A320 design provides advantages in respect to engagement and selection of rated power settings, and that movement provides better disengagement and information on system function. BA concludes that from a Flight Operations perspective a future system should consider providing movement between the idle and climb power positions, whilst retaining the A320 thrust setting and engagement “detents” technique.
Technical Paper

Damage Tolerance Philosophy for Fiber/Metal Laminates

1991-09-01
912233
In this paper, structural advantages relating to the fatigue-insensitive, tear-resistant behavior of fiber/metal laminates are discussed in the context of future aircraft design needs. High-altitude aircraft (41,000 feet plus) will have special fuselage design requirements because a rapid decompression could be lethal to passengers. The likelihood of such an incident would be significantly reduced by the use of fatigue-resistant materials. A rational damage tolerance philosophy is proposed for fiber/metal laminate structures in order to ensure ultimate load capability throughout the design life with reduced inspection requirements compared to monolithic materials. Attributes of the proposed method are compared to conventional fatigue and damage tolerance approaches.
Technical Paper

Configuration Design and Recovery Considerations for a Staged SST

1991-09-01
912232
The design and recovery considerations are presented for a staged supersonic transport (SSST). It is shown that the SSST offers economic benefits over the conventional SST. The SSST benefits from the ability to “optimize” the design for minimum drag during supersonic cruise without the penalties of: landing gear, extensive flaps for landing, and the meeting of FAR 36 noise requirements. The recovery considerations are also presented to validate the SSST concept.
Technical Paper

Implementing Data Link Across the Pacific

1991-09-01
912235
Material for this paper was developed in conjunction with an ADS and Two-Way ATC Data Communications Engineering Trials program involving primarily the FAA Technical Center, ARINC, and United Airlines under the terms of a Memorandum of Agreement signed in September 1989 by the Administrator of the FAA and the Chairman and CEO of United Airlines, Stephen A. Wolf. It was agreed that the focus of effort would be directed to long-range operations over the Pacific Ocean utilizing the SATCOM system developed by Collins Radio, installed and certified by the Boeing Company on a 747-400 aircraft, and an INMARSAT satellite with digital data communications service provided by the COMSAT Corporation.
Technical Paper

The Induced Thrust Effect; A Propulsion Method

1991-09-01
912234
This paper deals with a thrust generation method which can be applied to nuclear as well as chemical propulsion systems. It takes into consideration both incompressible and compress-ible flow cases, however both of these cases are based on one dimensional flow within an ideal rocket framework. In the case of constant area duct steady state flow the obtained Induced Thrust (IT) formula is: where p1 and p2 are opposing pressure fields and u* is a function of u2, p2 and u1 (u1 and u2 being opposing gas efflux velocities). For the compressible and incompressible flow fields, IT formulas are obtained but they are not as reliable. One feasible application for this launch-propulsion method is the Joined-Ship model. In this model the combustion chamber pressure within one space vehicle acts as the back pressure of the joined space vehicle and vice-versa.
Technical Paper

Compressed Natural Gas-Fueled Mercedes-Benz Urban Buses

1991-09-01
911714
SUMMARY In view of the great gas reserves in Argentina, that have become the basis of the governmental policies on substitution of oil-derived liquid fuel, Mercedes-Benz Argentina launched the first urban bus manufactured in the country that is compressed natural gas (CNG)-fueled. This paper explains the process followed for building the engine, analyzing the alternatives of the combustion cycle and defining the stage of maximum power and minimum consumption for a 1,18 lambda, using conventional technology which is ideal for meeting the current needs of the market. The results of the tests carried out with four vehicles driven by urban bus lines are hereinafter described, defining the performance of the vehicle. Finally, an analysis of the results with respect to the Diesel- engine vehicle enables to reach conclusions on the steps to be taken concerning the evolution of the CNG-propelled urban bus.
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