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Viewing 1 to 25 of 25
2007-05-15
Technical Paper
2007-01-2312
Guillaume Cousineau-Bouffard
A process is implemented to propagate uncertainties inherent to the Statistical Energy Analysis (SEA) modeling practice to variance in predictions. A Monte Carlo based approach is scripted for the VA-One environment to account for uncertainties in gross parameters of SEA model subsystems. The variance module of the commercial software is used to estimate possible variations in local modal properties. A first-order expansion solution is applied to integrate uncertainties in the power inputs of the system. The impact of each type of source is assessed in computing overall variance in predictions. The process is applied to analysis of in-flight interior cabin noise predictions using a simplified aft fuselage section SEA model.
1991-09-01
Technical Paper
911989
Ronald L. Bengelink, Paul E. Rubbert
CFD now stands alongside the wind tunnel in terms of importance to aerodynamic design. Its usage by engineering designers involves many thousands of runs per year, and the rate is increasing. For the simpler aerodynamic flows where viscous effects are modest, CFD has become the dominant tool for aerodynamic design. The primary role of the wind tunnel for such flows is for validation of a design and for determination of aerodynamic characteristics over the broad flight envelope. For more complex flows that are dominated by strong viscous effects, CFD is beginning to make a contribution. It is thought by many that the principle challenge for the future is to develop better computers and algorithms in order to better address the computation of complex flows over complex airplane geometries. But recent experiences involving the application of CFD to the design of the new Boeing 777 airplane has taught us that the challenge for the future is really much broader.
2016-03-02
Book
Mark Ahlers
This set is comprised of two titles, Aircraft Thermal Management: Systems Architectures and Aircraft Thermal Management: Integrated Energy Systems Analysis both edited by Mark Ahlers.
2008-09-16
Journal Article
2008-01-2291
Harinder Oberoi, Paul Gehlsen, Douglas McCoy
This paper discusses the process development and implementation of an Electric Boring process for boring the Frame Lug for the Main Landing Gear (MLG) Swing Link bushing on the 777 Airplane. Due to the process reliability issues associated with the equipment traditionally used for this process, primarily air driven right angle motors, a boring process using electric motors was developed and implemented for this application. The process development focused on equipment selection based on horsepower/torque requirements, laboratory testing for cutting parameters and bore quality generation, equipment reliability testing under operational loads and process efficiency validation. The implementation programme involved the detail design and fabrication of protective enclosure (explosion proof) hardware to prevent the electric motor and its connections from being contaminated by various fluids used in processes in the vicinity of this application.
2015-09-15
Journal Article
2015-01-2581.01
Paul Dees, Scott Eberhardt
The original paper published mistakenly did not include Paul Dees, Boeing in the author listing.
2015-06-15
Technical Paper
2015-01-2130
Melissa Bravin, J. Walter Strapp, Jeanne Mason
Abstract In the last several years, the aviation industry has improved its understanding of jet engine events related to the ingestion of ice crystal particles. Ice crystal icing has caused powerloss and compressor damage events (henceforth referred to as “engine events”) during flights of large transport aircraft, commuter aircraft and business jets. A database has been created at Boeing to aid in analysis and study of these engine events. This paper will examine trends in the engine event database to better understand the weather which is associated with events. The event database will be evaluated for a number of criteria, such as the global location of the event, at what time of day the event occurred, in what season the event occurred, and whether there were local meteorological influences at play. A large proportion of the engine events occur in tropical convection over the ocean.
2014-09-16
Journal Article
2014-01-2270
Jason Rediger, Joseph Malcomb, Craig Sylvester
Abstract A new portable floor drilling machine, the 767AFDE, has been designed with a focus on increased reach and speed, ease-of-use, and minimal weight. A 13-foot wide drilling span allows consolidation of 767 section 45 floor drilling into a single swath. A custom CNC interface simplifies machine operations and troubleshooting. Four servo-driven, air-cooled spindles allow high rate drilling through titanium and aluminum. An aluminum space frame optimized for high stiffness/weight ratio allows high speed operation while minimizing aircraft floor deflection. Bridge track tooling interfaces between the machine and the aircraft grid. A vacuum system, offline calibration plate, and transportation dolly complete the cell.
2015-09-15
Journal Article
2015-01-2492
Michael Assadi, Samuel Dobbs, Brian Stewart, Sean Hollowell, Joseph Elsholz
Abstract Developing the most advanced wing panel assembly line for very high production rates required an innovative and integrated solution, relying on the latest technologies in the industry. Looking back at over five decades of commercial aircraft assembly, a clear and singular vision of a fully integrated solution was defined for the new panel production line. The execution was to be focused on co-developing the automation, tooling, material handling and facilities while limiting the number of parties involved. Using the latest technologies in all these areas also required a development plan, which included pre-qualification at all stages of the system development. Planning this large scale project included goals not only for the final solution but for the development and implementation stages as well. The results: Design/build philosophy reduced project time and the number of teams involved.
2015-09-15
Journal Article
2015-01-2436
Anapathur V. Ramesh
Abstract Fault-tolerance in commercial aircraft applications is typically achieved by redundancy. In such redundant systems the primary component is checked before the start of a flight to see if it operates correctly. The aircraft will not take off unless the primary is functioning. Airplane manufacturers must certify the airplane systems to be safe for flight. One means of safety certification is by safety analysis which shows that the probability of failure in a typical flight is bounded. The probability bound requirement for a system is based on the criticality of system failure. Usually backup components are checked at intervals that span multiple flights. The first backup may be checked more frequently than the second or higher levels. This leads to flights where the system may have latent faults in the backup components. The probability of failure in such cases varies from flight to flight due to the different exposure times for components in the system.
2015-06-15
Technical Paper
2015-01-2086
Matthew Grzych, Terrance Tritz, Jeanne Mason, Melissa Bravin, Anna Sharpsten
Abstract The significant problem of engine power-loss and damage associated with ice crystal icing (ICI) was first formally recognized by the industry in a 2006 publication [1]. Engine events described by the study included: engine surge, stall, flameout, rollback, and compressor damage; which were triggered by the ingestion of ice crystals in high concentrations generated by deep, moist convection. Since 2003, when ICI engine events were first identified, Boeing has carefully analyzed event conditions documenting detailed pilot reports and compiling weather analyses into a database. The database provides valuable information to characterize environments associated with engine events. It provides boundary conditions, exposure times, and severity to researchers investigating the ICI phenomenon. Ultimately, this research will aid in the development of engine tests and ICI detection/avoidance devices or techniques.
2011-06-13
Technical Paper
2011-38-0094
Jeanne G. Mason, Matthew Grzych
This paper presents the latest findings resulting from ongoing research on jet engine ice crystal icing. It specifically focuses on the challenges for pilots to identify and potentially avoid weather associated with this type of engine icing. The case will be made that jet engine power loss and damage events are not only still occurring, but the overall number of events per year is increasing. Several case studies will be presented to illustrate that each event can vary significantly when viewed from the flight deck even though weather conditions are similar for each. Findings will be presented related to new events that are occurring on engines that were not previously affected along with new engine symptoms. Ongoing meteorological research has shed new light on how to identify weather associated with engine events utilizing infrared satellite imagery combined with atmospheric temperature profiles.
2017-09-19
Technical Paper
2017-01-2057
Robert E. Voros, David Merdgen, Andrew Wallington
Abstract In the last several years, technical advances and regulatory pressures have motivated the need for flexible, simple, and performance-based solutions for conducting development assurance in support of a system safety assessment process. Additionally, the affected design space for commercial vehicles has been growing beyond the conventional regulations for airplanes, rotorcraft, engines, and propellers, addressed by current Aerospace Recommended Practices (ARPs). This space is beginning to include commercial technologies such as unmanned aerial systems, multi-stage spacecraft systems, and road-able aircraft. These developing areas are each accompanied with their own development assurance expectations in support of their safety criteria. Concurrently, the industry and regulators are working to simplify guidance for system safety and development assurance, which has been foundational in the aircraft industry for decades.
2016-03-02
Book
Mark Ahlers
The simultaneous operation of all systems generating, moving, or removing heat on an aircraft is simulated using integrated analysis which is called Integrated Energy System Analysis (IESA) for this book. Its purpose is to understand, optimize, and validate more efficient system architectures for removing or harvesting the increasing amounts of waste heat generated in commercial and military aircraft. In the commercial aircraft industry IESA is driven by the desire to minimize airplane operating costs associated with increased system weight, power consumption, drag, and lost revenue as cargo space is devoted to expanded cooling systems. In military aircraft thermal IESA is also considered to be a key enabler for the successful implementation of the next generation jet fighter weapons systems and countermeasures. This book contains a selection of papers relevant to aircraft thermal management IESA published by SAE International.
2016-03-02
Book
Mark Ahlers
Aircraft thermal management (ATM) is increasingly important to the design and operation of commercial and military aircraft due to rising heat loads from expanded electronic functionality, electric systems architectures, and the greater temperature sensitivity of composite materials compared to metallic structures. It also impacts engine fuel consumption associated with removing waste heat from an aircraft. More recently the advent of more electric architectures on aircraft, such as the Boeing 787, has led to increased interest in the development of more efficient ATM architectures by the commercial airplane manufacturers. The ten papers contained in this book describe aircraft thermal management system architectures designed to minimize airplane performance impacts which could be applied to commercial or military aircraft.
2001-09-10
Technical Paper
2001-01-2594
Gary R. Weber, Michael S. Hurd
Process development work was conducted to develop a machined fuselage frame concept for a small (5 abreast) commercial airplane. To minimize detail fabrication cost and to facilitate lean manufacturing, roll forming was identified as the preferred forming process. To reduce assembly costs, long frame segments were desired to minimize the number of frame splices. Since plate stock is limited to lengths of approximately 3.66 meters (12 feet), formed aluminum extrusions were selected as the raw material form. Roll forming and stretch forming process paths were screened for both J section and rectangular bar extrusions. The post machining distortion produced in formed extrusion and plate hog-out frame segments was compared to each other and to process standards governing allowable fit-up forces. As a result of this process development activity, a producible roll forming process path was developed.
2000-09-19
Technical Paper
2000-01-3031
James Norton, Mike Bodach
Current practice for assembly of wing skins to wing stringers utilizes temporary aluminum lock bolts prior to squeeze riveting. Removing and replacing these fasteners is time consuming and hazardous. We have automated the wing riveters to perform this replacement process. This paper discusses the four areas of development that were carried out to accomplish this: tack fastener installation, machine vision system development, drill development and new tooling. Testing results and new findings will be discussed.
2003-09-08
Technical Paper
2003-01-2909
Gary R. Weber, Jeffrey D. Morgan
One recent evolution in commercial transport structure has been the emergence of monolithic structure applications. Monolithic structure reduces the number of parts that must be managed, eliminates sub-assembly operations and contributes strongly to determinant assembly practices. The cost of three components from the Boeing 737-200 and their counterparts on the Boeing 737-600 will be compared. The mid 1960's 737-200 components were assembled from sheet metal details. The mid 1990's 737-600 components are monolithic designs and utilize superplastic forming, casting and NC machining technologies. The built-up solutions and the monolithic solutions are compared based on cost infrastructures from the 1960's and the 1990's.
2002-10-01
Technical Paper
2002-01-2646
Clayton Munk
Determinant Spar Assembly Cell (DSAC) has been developed by Boeing to help reduce the cost of building commercial airplanes. This revolutionary system uses a state of the art 5 axis NC machine in conjunction with quick-change multi-function end effectors and a reconfigurable fixture, to provide the capability to assemble any Boeing heritage commercial airplane spar. This paper describes the high level aspects of this unique system.
2002-09-30
Technical Paper
2002-01-2640
Thomas D. Hall, Ronald J. Collins
Historically the manufacturing of aircraft fuselages with capacities of 100+ passengers requires large panels and assemblies to be integrated through processes of manipulating them into proper alignment to one another, and then fastening the panels and assemblies together. The manipulating and alignment processes typically incorporate large handling devices and cranes to move the large panels and monolithic tools or measurement alignment systems to precisely align the aircraft components. After the individual panels and assemblies are properly aligned, they can be fastened together. Normally, the fastening process is performed manually with the aid of fastener location templates. There are problems with these processes. They require high capital investments for tooling and facilities; up to two shifts (16 hours) to complete the loading, indexing, and fastening operations; and depend on a highly skilled and knowledgeable work force to minimize discrepancies.
2007-09-17
Technical Paper
2007-01-3927
Peter A. Schoot, Keith Badgley, Dan Christiansen, Meishelle Haverkamp
New and derivative commercial jetliner programs face increased pressure to reduce cost, shorten development cycles, increase production rates, and create an increasingly fuel efficient aircraft. The industry also has limited engineering resources and suppliers with manufacturing capacity constraints. Designing parts right the first time, while concurrently taking into account available and proven manufacturing techniques, is crucial to meeting product development schedule and profitability goals. New, knowledge-based software solutions bridge the gap between design, manufacturing, and the supply chain, assuring timely, cost effective, and correctly manufactured products. Boeing Commercial Airplanes used a unique knowledge-based software solution to analyze one of the most complicated jetliner parts: the titanium part joining the wing to the aircraft body.
2008-09-16
Technical Paper
2008-01-2298
Paul Thompson, Harinder Oberoi, Alan Draper
Flex Track Drilling systems are being used increasingly in aerospace applications providing low cost, highly efficient automated drilling systems. Certain applications like circumferential splice drilling on large size airplane fuselages require multi spindle flex track systems working in tandem to meet production efficiency requirements. This paper discusses the development of a multi spindle flex track drilling system for a circumferential splice drilling on the 777 airplane. The multi spindle system developed uses a variety of flex track carriages attached to the flexible vacuum tracks to allow for offset or wide inside drilling. Segmented machine programmes allow these multiple machines to be deployed on the same circumferential splice on the airplane providing the multi spindle system. Interfacing of the multiple spindles is achieved by a custom OEM interface using a single screen thereby ensuring simplicity of operation.
2009-11-10
Technical Paper
2009-01-3151
Emily Schwartz, Steven L. Baughcum, David L. Daggett
Recent work has shown that when an aircraft encounters ambient ice-supersaturated conditions (where contrails may form and persist), it may be possible to avoid contrail formation by shifting cruise altitude up or down 2000 feet. If an aircraft's cruise altitude is shifted from the optimal profile during a portion of the mission, fuel consumption increases. Because on average approximately 20% of distance flown by commercial airliners is through ice-supersaturated regions, this study quantifies the fuel burn penalties for the notional scenario of flying the same fraction of cruise at altitude displacements of +2000, -2000, and -4000 ft. Present aircraft performance data was used to generate accurate fuel burn penalty estimates. This study finds that the net penalties for existing aircraft to fly contrail avoidance shifts vary between 0.2% and 0.7% increase in block fuel consumption.
2009-11-10
Technical Paper
2009-01-3090
Harinder Oberoi, Alan Draper, Paul Thompson
With the recent development of a multi spindle flex track drilling system for aerospace applications, the challenges of testing and implementation on existing airplane programmes require unique technical methodologies and solutions. This paper discusses the technical approach, problems encountered and methodologies/solutions used to successfully implement a multi spindle flex track drilling system for circumferential splice drilling on the 777 airplane. The multi spindle system uses varieties of flex track carriages attached to flexible vacuum tracks for wide inside drilling. The hardware and software challenges encountered during the interfacing of the multi spindles are discussed as well as the complex problem of indexing and locating all detailed components of the splice accurately and with high repeatability.
2007-05-15
Technical Paper
2007-01-2169
Heng-Yi Lai
The objectives of this work are to search for a structure-borne sound power measurement method that can be consistently deployed among different test facilities, and to investigate how test results can be compared at different test stands. A series of experimental tests are conducted to compare selected test methods by measuring structure-borne power transmitted from simulated mechanical sources to a supporting plate through single contact and multiple contacts, respectively. The frequency range of interest in these tests is a broad range from 100Hz to 10 kHz. Test methods under this experimental study include the cross-spectral method, the mobility method and the reverberant plate method. In addition, simplified mobility methods based on ideal sources and the synthesized force are also examined. Advantages and limitations of each test methods are discussed from a practical industrial standpoint.
2004-09-21
Technical Paper
2004-01-2837
Paul R. Stone
An innovative reconfigurable fixture was developed by the Boeing Company to hold spars while performing fastening and drilling operations, reducing cost, maintenance and increasing accuracy.
Viewing 1 to 25 of 25

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