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Technical Paper

A Preliminary Dynamic Model of Brake Friction Using Pressure and Temperature

2001-10-28
2001-01-3150
Understanding the friction behavior of brake lining materials is fundamental to the ability to predict brake system performance. Of particular interest to the aviation community, where carbon/carbon composite heatsinks are commonly used, is the aircraft response at deceleration onset. There are two performance measures defining brake system performance at braking onset: deceleration onset rate and system response time. The latter is strictly a function of the brake system hydraulics and is not affected by brake lining friction. The former performance measure is a function of both system hydraulics and brake lining friction. Previously to the work herein, carbon heatsink friction was thought to be unpredictable at braking onset. That being the case, a predictive capability for deceleration onset rate was not previously undertaken. This meant that assessment of this performance measure waited until aircraft taxi tests were performed.
Technical Paper

F/A-18 E/F Outer Wing Lean Production System

2001-09-10
2001-01-2608
The Boeing F/A-18 E/F Program Wing Team, Lean Organization and Phantom Works have partnered to develop a “state of the art” lean production system for the Outer Wing that represents an evolutionary change in aircraft design and assembly methodology. This project is focused on improving quality, cycle and cost performance through the implementation of lean principles, technology integration and process improvements. This paper will discuss the approach taken to reach the end state objectives and the technologies and processes being developed to support it. Items to be discussed include lean principles and practices, new tooling concepts, improved part assembly techniques, advanced drilling systems, process flow enhancements and part handling/part delivery systems.
Technical Paper

Specification Reform of Avionics Thermal Design Criteria – An F-15 Case Study

2001-07-09
2001-01-2156
Traditional thermal design criteria for avionics equipment are reviewed. Several studies have recently been conducted on the F-15 to assess accuracy of these design criteria. An overview of the study approach and results are presented. Specific topics investigated include: emergency cooling air provisions, cold start-up, hot start-up, normal and transient bay temperatures, and altitude design. The results indicate that many existing design criteria are overly conservative. The study findings suggest that reform of the existing thermal specification process is needed. Many of these reforms are applicable to the general aerospace industry and may result in significant acquisition cost savings as a result of the trend toward usage of commercial electronic parts. The reforms suggested include a new performance based thermal specification approach that increases emphasis on aircraft usage and frequency of occurrence. New transient design criteria are also recommended.
Technical Paper

EVA Operations Using the Spacelab Logistics Pallet for Hardware Deliveries

2001-07-09
2001-01-2201
There are a large number of space structures, orbital replacement units (ORUs) and other components that must be transported to orbit on a regular basis for the assembly and maintenance of the International Space Station (ISS). Some of this hardware will be ferried on the Spacelab Logistics Pallet (SLP), which has a long and reliable history of space flight successes. The carrier is well used, well qualified, and very adaptable for repeated use in accommodating cargoes of various sizes and shapes. This paper presents an overview of past, present and future hardware design solutions that accommodate EVA operations on the SLP. It further demonstrates how analysis techniques and design considerations have influenced the hardware development, EVA operations, and compliance with human engineering requirements for the SLP.
Technical Paper

Assembly Techniques for Space Vehicles

2000-09-19
2000-01-3028
Assembly techniques for the majority of expendable and reusable launch vehicles have not changed much over the last thirty years. Some progress has been made, specifically on new programs, however, improvements on existing expendable launch vehicle production lines can be difficult to justify; even more so for one or two reusable vehicles. This presentation will focus on techniques and systems used for manual and automated assembly of expendable and reusable launch vehicle primary structures. Today's assembly is characterized by manual operations involving fixtures and templates, and all tasks are carried out primarily with single function hand tools. Typical assembly approaches used for metallic and composite primary structures will be discussed. Potential opportunities for process improvements utilizing advanced hand tools, mechanized and/or automated equipment will be addressed.
Technical Paper

Electric 30,000 RPM Shave Spindle for C Frame Riveter and High Performance Compact Aerospace Drill

2000-09-19
2000-01-3017
Two spindles are discussed in this paper. The first spindle was installed on nine C-frame riveters on the 737/757 wing line at the Boeing Renton facility. Due to discontinuing the use of Freon coolant and cutting fluid, the C-frame riveters had difficulty shaving 2034 ice box rivets with the existing 6000 RPM hydraulic spindles. The solution was to install electric 30,000 RPM shave spindles inside the existing 76.2 mm (3 in.) diameter hydraulic cylinder envelope. The new spindle is capable of 4 Nm (35 in. lbs.) of torque at full speed and 110 kgf (250 lbs.) of thrust. Another design of interest is the Electroimpact Model 09 spindle which is used for 20,000 RPM drilling and shaving on wing riveting systems. The Model 09 spindle is a complete servo-servo drilling system all mounted on a common baseplate. The entire spindle and feed assembly is only 6.5″ wide.
Technical Paper

Integrated Metrology & Robotics Systems for Agile Automation

2000-09-19
2000-01-3033
Aircraft manufacturing in the 21st century sees a future much different to that seen one and two decades before. Manufacturers of both military and commercial aircraft are challenged to become Lean, Agile and Flexible. As progress is slowly made toward introducing advanced assembly systems into production, the overall cost of automation is now more closely scrutinized. After spending tens of millions of dollars on large automated systems with deep foundations, many manufacturers find themselves locked into high cost manufacturing systems that have specific, inflexible configurations. This kind of scenario has caused a shift in the attitude of airframe assemblers, to go back to basics. Lean manufacturing is seen as a way to build aircraft with very low investment in equipment and tools. Today's advanced systems developers do understand the need for more affordable assembly systems.
Technical Paper

International Space Station Design for Dexterous Robotics - Inboard Truss Segments

2000-07-10
2000-01-2357
Over 200 International Space Station external high maintenance items have been designed for replacement by a dexterous robotics system in addition to space-suited astronauts. Planning for dexterous robotics maintenance increases flexibility for space station operations with a robot able to execute many tasks in place of a suited crew member, lowering the number of hours crew must spend on Extravehicular Activity (EVA). The five inboard truss segments of the station - S3, S1, S0, P1 and P3 - include 122 of these robot compatible maintenance items or On-orbit Replaceable Units (ORUs). This paper describes the impact robotic compatibility has had on the International Space Station (ISS) design, reviewing the inboard truss items as examples. Diverse challenges exist to verify each genre of ORU meets the dexterous robotics requirements.
Technical Paper

CFD Studies on the ECLSS Airflow and CO2 Accumulation of the International Space Station

2000-07-10
2000-01-2364
During a recent International Space Station (ISS) flight (Flight 2A.1), an improper ventilation event might have occurred and resulted in stuffy air, as reported by the crew. Even though no air samples were analyzed, the accumulation of metabolic CO2 in the ISS was suspected as the cause of the crew sickness. With no possibility of conducting an on-orbit test of this kind, it was decided to utilize Computational Fluid Dynamics (CFD) analysis to investigate this problem. Based on the Flight 2A.1 and 2A.2a configurations, a CFD model of the air distribution system was built to characterize airflow between the ISS elements. This model consists of Inter-module Ventilation (IMV) covering the Functional Cargo Block (FGB), two Pressurized Mating Adapters (PMA-1 and PMA-2), the Node-1, and portions of the Orbiter volume.
Technical Paper

International Space Station Propulsion Module Environmental Control and Life Support System

2000-07-10
2000-01-2296
The United States Propulsion Module (USPM) is a pressurized element and provides reboost, propulsive attitude control, control moment gyro (CMG) desaturation, and collision avoidance functions for the International Space Station (ISS). The USPM will dock with Node 2 at the pressurized mating adapter-2 (PMA-2). After docking with PMA-2, the USPM will provide mechanical and structural interfaces to the Space Shuttle, along with facilities for crew transfer and receiving resupply oxygen, nitrogen, water, helium, and propellants from the Space Shuttle. It is essential that the USPM maintain a safe and functional life support system during crew member passage and maintenance activities. It is complex and costly to design an operational system to satisfy all ISS requirements. This paper details an innovative USPM environmental control and life support system (ECLSS) design that satisfies all ISS requirements at a reduced cost.
Technical Paper

Payload Attach System for the ISS - Development and Verification for EVA Operations

1999-07-12
1999-01-2037
The process of developing a Payload Attach System (PAS) which will support a wide range of experimental and commercial payloads on the International Space Station (ISS) has experienced an interesting evolution during its design, development, test and evaluation (DDT&E) phase. This evolution has been caused in large measure by requirements intended to insure compatibility of the PAS with the extravehicular activity (EVA) crewmember during nominal and contingency operations in and around the PAS sites. As the design of the ISS transitioned from its Freedom predecessor, the effort to keep costs down by preserving as much of the original Freedom design as possible led to design decisions that challenged engineering thinking.
Technical Paper

Space Station Lab Flight Test Article Results and Analytical Model Correlations

1999-07-12
1999-01-2196
The International Space Station (ISS) Temperature and Humidity Control/Intermodule Ventilation (THC/IMV) system for the U.S. Lab provides required cooling air for the U.S. Lab and also provides “parasitic” cooling air for Node 1 and its attached elements. This scheme provides cooled air from the Lab THC directly to Node 1 and also to elements attached to Node 1, at different stages of Space Station assembly. This paper reports on the results of Open Hatch ECLSS/ TCS Tests for International Space Station’s Lab Module. The hardware tested is referred to as proto-flight hardware. Upon satisfactorily passing these Open Hatch and later Closed Hatch, imposed ground based, proto-flight tests, the proto-flight hardware will become flight hardware. The Lab Module is scheduled for launch during late 1999. The particular ECLSS/TCS equipment discussed here are the Temperature Humidity and Control (THC) equipment and Intermodule Ventilation (IMV) equipment.
Technical Paper

Inlet Hot Gas Ingestion (HGI) and Its Control in V/STOL Aircraft

1997-10-01
975517
A successful methodology was developed at Boeing Company to investigate hot-gas ingestion in vertical take-off and landing aircraft. It involves sub-scale model testing using specialized test facilities and test techniques. The baseline characteristics of hot-gas ingestion (HGI) and the performance of various HGI reduction techniques were qualitatively evaluated in the Boeing Hover Research Facility. Potential HGI reduction devices were then further tested at scaled pressures and temperatures in HGI facilities at NASA Lewis, Rolls Royce and British Aerospace. One of the successful HGI reduction devices was flight tested. This paper describes the application of Boeing HGI reduction methodology to three specific aircraft configurations.
Technical Paper

Space Station THC/IMV Development Test/Analysis Correlations and Flight Predictions

1997-07-14
972565
The International Space Station (ISS) Temperature and Humidity Control/Intermodule Ventilation (THC/IMV) system for the U.S. Lab provides required cooling air for the U.S. Lab and also provides “parasitic” cooling air for Node 1 and its attached elements. This scheme provides cooled air from the Lab THC directly to Node 1 and also to elements attached to Node 1, at different stages of Space Station assembly. A development test of the U.S. Lab and Node 1/attached elements' integrated THC/IMV ducting system was performed in the summer of 1995. This test included the U.S. Lab's development level Common Cabin Air Assembly (CCAA), which removes sensible and latent heat from the circulated and ducted cabin air. A referenced 1996 ICES Paper contains the initial correlation results. An analytical model has been developed, which has been used to predict flow and pressure drop performance of the system for several potential and actual changes from the Development Test configuration.
Technical Paper

Temperature Control Analysis for the U.S. Lab, Node 1, and Elements Attached to Node 1

1997-07-14
972564
The International Space Station (ISS) Temperature and Humidity Control (THC) system has been designed with the intent of supplying the air cooling needs of various elements from the U.S. Lab heat exchanger assembly. Elements without independent air cooling capability are known as “parasitic” elements; these are Node 1, the Cupola, and the Mini Pressurized Logistics Module (MPLM). Analysis results are presented which show expected temperatures in the MPLM, and Node 1, as various heat loads are present in the respective elements. Analyses within this paper are coordinated with the results obtained from the Development Test of the complex USL/Node 1 integrated ducting system. This test was conducted in the summer of 1995, at the McDonnell Douglas test facility in Huntington Beach, California.
Technical Paper

Evolution to Lean Manufacturing A Case Study of Boeing of Spokane

1997-06-03
972235
The evolution of a manufacturing organization toward “Lean” manufacturing does not necessarily come cheaply or quickly. It is the experience at Boeing that technology and different visions can dramatically impact the evolutionary process-consuming great amounts of time and resources. The Boeing of Spokane case study, where aircraft floor panels are manufactured1, is but one of several case studies that suggests moving to “Lean” manufacturing is usually done in large steps, not small ones. These initial steps can be costly unless the systems (equipment and workforce) are flexible. Workforce flexibility is dependent on the attitude in the workforce as both touch and support labor move from their comfort zone to try new approaches and job descriptions. The workforce must be properly motivated to make the change. The equipment must also be flexible in adapting to new line layouts, product mixes, and process change or large cost penalties will be incurred.
Technical Paper

Development of Cold Working Process for 4340M Steel

1995-09-01
952167
A new process has been developed to cold work fastener holes on commercial aircraft flap tracks fabricated of 4340M steel. The process consists of pressing a high strength solid mandrel through a previously prepared hole in a defined manner. This process exhibits high tool life, low overall cost and eliminates the necessity for a final ream operation.
Technical Paper

Modular Rack Design for Multiple Users

1994-06-01
941587
The Space Station program was faced with a unique design environment-to design a common systems and payload support structure that could accommodate changeout for repair or technology growth over a 30-year lifetime. The vibration environment and weight allocation for rack structure necessitated a lightweight, yet stiff structure. The design answer was a modular rack structure using graphite/epoxy composites and selected aluminum components that could support a wide variety of systems, payload and stowage functions. A modular set of mounting locations allow the installation of a wide variety of secondary structures without permanent modifications to the rack. Aircraft-style seat track rails on the front edges of the rack permit attachment of handrails, foot restraints and accessories such as lights, fans, clipboards or computers to the rack face.
Technical Paper

Dew Point Analysis Developments for Space Station

1994-06-01
941511
This paper reviews the recent G189A computer program developments in the area of humidity control for the U.S. Lab Module in the Space Station. The humidity control function is provided as an indirect or passive function by the Common Cabin Air Assemblies (CCAA) in pressurized elements or modules in the Space Station. The CCAAs provide active cabin temperature control through implementation of a digital/electromechanical control system (i.e., a proportional/integral (PI) control system). A selected cabin temperature can be achieved by this control system as long as the sensible and latent heat loads are within specified limits. In this paper three pertinent analytical cases directed to determining minimum or maximum dew point temperatures are discussed. In these cases the basic sensible heat loads are set at constant values.
Technical Paper

Detailed Integration Analysis of the Space Station Life Support System

1994-06-01
941510
A considerable amount of integrated Environmental Control and Life Support System (ECLSS) analysis has been performed and documented for the proposed habitable Space Station. Earlier analytic activities have resulted in highly refined models simulating Temperature and Humidity Control (THC) and Atmosphere Revitalization (AR) hardware. As the mechanisms by which these items affect the Space Station environment have become better understood (along with the effects due to operation of various Man Systems utilities), the next stage of the integrated analysis task has been accomplished; i.e., the simulation of the Atmosphere Control and Supply (ACS) subsystem. The focus of the present paper is upon the ACS function in the overall life support system. Modeling of the ACS is unique among the life support disciplines in that it requires accurate representation of all other ECLSS subsystems that interact with the cabin atmosphere (which has now been achieved) in order to be realistic.
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