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This paper is focusing on considerations pertaining to riveting/fastening systems and assembly methodology currently in use for large aircraft fuselage structures. Discussion of process principles on which current systems are based is addressing distribution of rivets along the aircraft structure, riveting/fastening systems and equipment flexibility. An attempt was made to predict the most probable future equipment development trends based on the need for more efficiency in all aircraft structural assembly and in high level and final assembly areas.

Airframe manufacturers have radically changed their operational approach to improve the affordability of their products. The deployments and use of automated fastening equipment has changed as well. Many manufacturers have adopted a cellular manufacturing flow model as a method to reduce cost, inventories and work-in-process. Automated fastening equipment can be integrated into a cellular manufacturing environment as free-standing service cells or dedicated to a specific cell. The operational techniques and the machine capability requirements differ from the traditional factory operation and layout.

The multiple axis flexible CNC riveting cell consists of three major systems: a multi-axis part positioner, a multiple head drill and rivet machine and a multi-bowl rivet feed system. The CNC positioner has seven axis of control; the five common axis of X, Y, Z, Alpha, and Beta plus lower ram position and tool position on the knee style lower ram. The six function rivet head contains a pre-drill spindle, a rotary spin dimple spindle, a final drill spindle, a sealant applicator, a rivet insertion station and a rivet shave spindle. The unique lower knee style ram will allow the machine to fasten small radius high curvature parts as well as flat panels with minimal changes. The fastener feed system utilizes a bank of vibratory bowls that feed fasteners through a single feed tube. The fasteners are allowed to tumble and then are aligned prior to insertion into the anvil fingers. Countersunk fasteners as small as -4-3 will be fed by the system.

Machine vision systems, having been in use for a number of years on specialized applications, are now being more commonly used in new machines to enhance accuracy and in older systems to achieve today's tolerance requirements without major mechanical refurbishment. Additionally, the data received from such systems is being used to create custom machine routines which provide useful tools on parts where complete numerical data is not available for programming. This paper will discuss how the need for such a system arose at Northrop Grumman and the solution developed.

A new freshman course is currently being developed and taught on a pilot basis to approximately 40 cadets per semester at the United States Air Force Academy. The purpose of the course is to better address the educational outcomes desired in Academy graduates. Problem Base Learning is used to present engineering as a problem solving process that involves a variety of interdisciplinary issues. The pedagogical setting for student teams is an Air Force System Program Office responsible for planning a deployment mission to put a research team on Mars. Students are guided by mentor-instructors to identify the relevant tasks and engineering requirements pertinent to the plan. Traditional instruction is used sparingly only to present tools that enhance students' learning. An integrated assessment program is also part of the course development. It is being used to determine the value of this instructional approach, and how well the educational outcomes are being met.

The commercial aviation maintenance industry has been changing rapidly for the past ten years. Declining demand and overcapacity, shifting market/financial forces, and issues of personnel training and technology have combined to drastically change the business of maintaining air transport fleets. This has placed great stress on existing maintenance organizations who must struggle to survive. This paper describes one approach which can be used by aviation overhaul and maintenance service providers to devise new growth and management strategies. The approach, known as Market Driven Maintenance, uses classic product marketing strategies to help aircraft maintenance centers adjust scheduling and marketing strategies to attract new and more profitable market segments.

The permanently increasing demands for rationalization in all production areas find in many cases a solution in automation. More and more still existing solutions of inflexible automated systems are substituted by flexible automated systems. Especially in the branch of suppliers for the automotive industry, with its rapid changes due to always shorter life-time cycles of the products, these solutions are required. Industrial robots are in many cases the ideal solution. The use of industrial robots requires a perfect planning and selection of the adequate system. During the planning phase, not only the type of robot has to be considered but also the necessary peripheric equipment.

This paper describes the Integrated Product Development (IPD) strategy and details its five basic elements: Strategic Commitment; Organizational Structure based on Multi-functional teams; Adequate Environment; Integrated Planning; and Simultaneous and Systematic Processes. It shows the importance of having all of these elements concurrently. It also details the role of the corporate training in the IPD context, which is to provide the necessary ability (knowledge and skill) for the team members in four different areas (technical, managerial, interpersonal and IPD characteristics), according to their role in the development cycle. Finally, this paper highlights the importance of having a training plan based on the professional profile, execution planning and results evaluation.

Historically simulation models were used exclusively in the design phase of a project. With the increasing flexibility of agile systems there is a need for simulation and simulation tools to assist personnel in the day-to-day decision making process. More and more simulation is used to reduce development time for products, production processes and complete systems especially in the automotive industry and gets his fixed places in the areas of simultaneous engineering or rapid prototyping. The benefits can be seen in shorter development cycles, determination of the production process already in the planning phase without the necessity to invest already in construction, balancing of the process, optimization of intermediate storage and with this capital invested, better material flow and more.

This paper presents results from a study on speciation of the emission profiles and on the ozone forming potential of heavy-duty diesel exhaust under steady state engine operation. Very limited attempts have been made at determining the ozone forming potential of heavy duty diesel exhaust emissions. In this study a proportional sample of the dilute exhaust was drawn from a CFV-CVS system using a temperature controlled sampling line. The particulate matter was collected on a 70 mm Teflon coated glass fiber filter (TX40HI20WW), the semi-volatiles on XAD-2 copolymer resin and volatiles in Tedlar bags. The samples were analyzed by gas chromatography after conditioning and chemical extractions. The initial phase of the study was directed towards developing techniques and establishing protocols to determine the ozone forming potential of heavy-duty diesel exhaust. A pre-chamber naturally aspirated engine was tested on steady-state modes 1, 3, 5, 7 and 8 of the ISO 8 mode cycle.

This paper presents the design, fabrication, and testing of a 50HP, 30000 rpm induction motor for a next generation large aircraft spoiler. The motor is characterized by high power density, developing over 8.5 pounds per square inch of airgap surface area with only 13 pounds electromagnetic weight. Detailed designs, including magnetic material selection, electromagnetic parameters, and finite element thermal analyses are presented and compared to test data. Testing was obtained using a high speed hydraulic dynamometer with digital data acquisition. The motor and actuator are designed and built by AlliedSignal for participation in the NASA Redundant Effector Program and NASA Power-by-Wire Electromechanical Actuation (EMA) Spoiler Program. The program emphasizes the demonstration of power electronic motor drive and actuation technologies for aerospace applications.

The Liteflex™ composite spring has been manufactured by Delphi Chassis Systems, a division of Delphi Automotive Systems, since 1981 when it was introduced on the Chevrolet Corvette. In its early history, applications concentrated on passenger cars and vans. Over the past decade, however, composite engineering development has also focused on heavy duty suspension applications for tractors and trailers. The results include a Liteflex™ trailer suspension spring, a Liteflex™ tractor steer axle spring a Liteflex™ tractor drive axle spring, and a Litecast™ suspension link. A typical tandem axle trailer suspension incorporates four 3-leaf steel springs. Replacing each with a 13 kg lighter Liteflex™ spring offers a weight savings of 52 kg (115 lb.). This includes the assembly and mounting hardware. For the tractor, replacing two 2-leaf steel steer axle springs with Liteflex™ springs offers a combined weight savings of 55 kg (120 lb.).

Torsional motion of a truck driveline system is coupled with other motions of its components. In this paper, a comprehensive model of the truck driveline and body for vibration analysis was developed. Coupling of the torsional vibration of the truck driveline system with the body fore-aft and vertical vibrations was investigated. A mathematical model, including the torsional vibration of the driveline system and the whole body vibrations of the truck, was constructed. The driveline system was modelled as a set of inertia discs linked together by massless springs and the tyre was represented as having massless circumferential band which is elastically connected to the carcass with the bands being subject to longitudinal forces at the road surface. System behaviour at steady and transient runs was developed.

Some magnesium detergents in engine oil are reported to form sludge of needle crystals in the presence of carbon dioxide and water We tried to reproduce needle crystals in a beaker test and studied factors in needle crystal formation by magnesium detergents We found that overbased components of magnesium detergents dissolved in carbonic acid water formed needle crystals recrystallizing We also found the quantities of needle crystals increased when both carbon dioxide and water content in oil increased Moreover we clarified the quantities and sizes of needle crystals differed by magnesium detergents

A PC-based program module was developed to simultaneously optimize an aircraft for thrust-to-weight ratio, wing loading, aspect ratio, sweep, taper ratio, and thickness ratio, in the presence of performance constraints, to a selected weight or cost measure-of-merit. A simple yet robust optimization scheme was employed, relying on the ever-increasing power of personal computers to permit exhaustive searching by a simple gradient method rather than using some more-sophisticated but more complex and perhaps less-robust optimization strategy. Results indicate the program works, within the limitations of the classical analysis methods used.

Understanding mixture formation phenomena during the first few cycles of an engine cold start is extremely important for achieving the minimum engine-out emission levels at the time when the catalytic converter is not yet operational. Of special importance is the structure of the charge (film, droplets and vapour) which enters the cylinder during this time interval as well as its concentration profile. However, direct experimental studies of the fuel behaviour in the inlet port have so far been less than fully successful due to the brevity of the process and lack of a suitable experimental technique. We present measurements of the hydrocarbon (HC) concentration in the manifold and port of a production SI engine using the Fast Response Flame Ionisation Detector (FRFID).

As the consequence of air quality detenoration and the car overpopulation in Bangkok Metropolitan Area, unleaded gasoline was introduced in 1991 In using unleaded gasoline for cars with soft exhaust valve seats, their recession was found to be excessive after only 3000 - 12 000 km of usage on the highway at 120 km/h Such cars represented about 15 percent of the national car population in 1993 Using an anti-valve seat recession additive is one solution used to prevent valve seat recession An engine test simulating field conditions to evaluate additive effectiveness was implemented Potassium-based and sodium-based additives were tested and the test results led to the conclusion that the effective anti-valve seat recession additive treat rate suitable for car population and driving condition in Thailand was 10 mg of potassium or sodium per kg of fuel Unleaded gasoline with anti-valve seat recession additive has replaced leaded gasoline in Thai market as of 1995 Finally, leaded gasoline was completely phased out as of January 1, 1996 by Government regulation

The Partnership for a New Generation Vehicle (PNGV) is in the midst of narrowing technology options for our new generation of automobiles, and one technology which has appeal to the major auto-makers is the use of advanced compression-ignition engines. Ford has announced that the Synergy 2010 concept car (new version of Ford Taurus) would have a 20 1 compression-ratio, compression-ignition engine with preferred fuels including gasoline, diesel, and methanol. At these conditions, cetane improvers are necessary for the optimal performance of methanol and gasoline. In general, cetane improver technology has an important role in PNGV fuels, cleaner burning diesel, and current premium diesel markets. This paper reviews published data on cetane improvers including nitrates, peroxides, amines, and soluble metal-based catalysis. In addition, methods relating cetane numbers, blending cetane numbers, and ignition delay times are reviewed.

A commercial four stroke spark ignition engine has been tested at steady conditions, with three different compression ratios, namely: 10, 11.5 and 13. Exhaust Gas Recycle (EGR) has been varied in the range 0% - 20 %. Air/fuel ratio has been maintained at stoichiometric by a closed loop control with Exhaust Gas Oxygen sensor feedback. Significant gains on fuel economy and CO emission index have been achieved at medium and high loads by the simultaneous adoption of EGR and high compression ratios. In these conditions the sum of HC and NOx emission indices attains significant reductions at any load. The tests have shown that EGR allows to avoid knock even at wide open throttle and Maximum Brake Torque timing.

Experimental studies have been carried out on a spark ignition engine with port fuel injection to examine the influence of injector type and to contrast this with the effects of fuel composition. Intake port fuel transport characteristics and engine-out emissions for fully-warm and warm-up engine operating conditions have been examined as indicators of performance. The investigation has encompassed four types of injector and five gasoline blends. Fuel transport has been characterised using the τ and X parameters. The influence of injector type on these is of similar significance as that of changes in gasoline composition between summer and winter grades. The latter will limit the in-service accuracy of open-loop mixture control during transients. Injector type has a small effect on engine-out emissions under fully-warm operating conditions but has a significant influence on emissions during the early stages of warm-up.