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Technical Paper

747 Shuttle Carrier Aircraft/Space Shuttle Orbiter Mated Ground Vibration Test: Data via Transient Excitation and Fast Fourier Transform Analysis

The experimental procedure employed to define the natural modes of vibration of the 747 Shuttle Carrier Aircraft and Space Shuttle Orbiter mated configuration is described. A discussion of test results and comparison to structural analysis results is also included. Random transient signals were used as inputs to electromagnetic shakers to provide excitation to the mated vehicle test configuration. Acceleration signals were processed via the Fast Fourier Transform algorithm. Magnitude and phase transfer functions were formed and processed to produce modal frequencies, damping, and modal displacements.
Technical Paper

A Preliminary Dynamic Model of Brake Friction Using Pressure and Temperature

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

A Progress Report on the Development of an Augmentor Wing Jet STOL Research Aircraft

The joint development of an augmentor wing jet STOL research aircraft by NASA and the Canadian Government Department of Industry, Trade, and Commerce has progressed to the point that the design of the modifications to the de Havilland C-8A Buffalo are complete and the engines are being tested. The predicted performance shows that the airplane will be able to take off and land in less than 1500 ft. Simulation studies indicate that the handling qualities of the airplane, with stability augmentation, will be acceptable for STOL research missions.
Technical Paper

Advanced Graphite Composites in the 757/767

The new 757/767 transports will be the first Boeing Commercial aircraft to commit advanced graphite composite material to initial production. Composite materials, mainly fiberglass in an epoxy matrix, have been used in Boeing military and commercial aircraft in ever increasing amounts for the past twenty (plus) years. Recently, the state-of-the-art of Advanced Composites (graphite and graphite/Kevlar hybrids in an epoxy matrix) progressed to the level that it could be committed to full-scale production. This production commitment resulted in a multi-year, multi-million dollar development program. This was to assure technical and production readiness, and product reliability to meet the stringent performance and safety standards of modern commercial transport.
Technical Paper

Aircraft Noise, Its Source and Reduction

Since the advent of the turbojet engine, there has been much research by aircraft and engine manufacturers into the source of aircraft noise and its reduction. A review of this research is presented delineating the transition from turbojet engines to turbofan engines to the high by-pass ratio engines being introduced today, and the progress that has been made. Application of the current state-of-the-art to existing airplanes through engine replacement, nacelle retrofit, and flight procedures are also discussed.
Technical Paper

Assembly Techniques for Space Vehicles

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

Boeing Research Aerodynamic/Icing Tunnel Capabilities and Calibration

Flight testing of aircraft under natural icing conditions can be extremely tedious, time consuming, costly, and somewhat risky. However, such testing has been required to demonstrate the effectiveness of anti-icing systems and to certify new aircraft models. To reduce the need for extensive flight testing, Boeing has built a new icing tunnel that has the capability for developing ice shapes and evaluating anti-icing features on full scale sections of critical parts of the aircraft. The icing tunnel was made by modifying an existing 5 ft by 8 ft Boeing Wind Tunnel to add icing capabilities. This paper describes the design specifications, the tunnel capabilities, and the major equipment systems and presents the results of the tunnel calibration relative to the specified requirements.
Technical Paper

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

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

Comparative Test Data Assessment and Simplified Math Modelling for the Vapor Compression Distillation Subsystem

Space Station Freedom (SSF) has an extended mission duration of 30 years. Trade studies for extended missions of manned spacecraft almost invariably show that large resupply weight and consequent cost savings can be achieved by recovering potable water from wastewater sources. This rationale has led to the present baseline Water Recovery and Management (WRM) system for the Permanently Manned Capability (PMC) phase of SSF. The baseline WRM includes the Vapor Compression Distillation (VCD) subsystem for recovering water from urine. This process serves as a preliminary processing step in achieving potable water from wastewater sources. The basic principle of the VCD is that water is evaporated from urine and then condensed in a zero-gravity device containing an evaporator and a condenser in a rotating drum. The VCD was selected for the baseline WRM following the assessment of test results from competitive urine processing subsystems obtained from the Comparative Test (CT) program.
Technical Paper

Composite Structure for Orbiting Space Stations

An overview of composite structure required for manned orbiting space stations is presented. Following a brief introduction of typical configurations and major subsystems, the major structural areas requiring composite structure and their particular functions and requirements are discussed. A summary weight breakdown is presented to assess the dependence of launch weight on these areas. To illustrate, the primary wall composite structure is presented in detail. The design interplay of boost, pressure, meteoroid, radiation, and thermal control requirements are presented. Resultant composite structure for each remaining major structural area is presented in summary form with a brief description of typical design compromises required.
Technical Paper

Design Trade-Offs that Determine Fastener Selection

Fastener selection entails two functions, a staff function to select a group of fasteners for consideration and a design function to select the most suitable fastener for a specific function. This paper itemizes in detail the considerations that enter into each function in selecting fasteners for commercial and military aircraft, military unmanned vehicles, and space vehicles. Characteristics of specific bolts and fasteners are also tabulated.
Technical Paper

Detailed Integration Analysis of the Space Station Life Support System

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.
Technical Paper

Development of Cold Working Process for 4340M Steel

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

Dew Point Analysis Developments for Space Station

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

EVA Operations Using the Spacelab Logistics Pallet for Hardware Deliveries

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

Economic and Safety Aspects of Short Haul V/STOL Aircraft on High Density Routes

Intercity automobile travel has a direct effect on the volume of short haul air travel. Automobile transportation is quicker and more economical as compared with the long ground waiting time and higher rates of short air trips. A multistop system, using the V/STOL aircraft, between cities may save passengers time by closer departure points, and increased passenger miles may reduce rates. Advantages of speed and less cost enjoyed by automobile travelers may well be offset by these developments. A mere 15% transfer of short haul trips to aircraft could result in as much as 106% increase in air revenue passenger miles.
Technical Paper

Effective Planetary Exploration, Part 1: A Heuristic Method to Estimate EVA Walkback Range

This study examines the lunar environment, the lunar rover mission, and the factors that influence EMU walkback range in the event of a rover failure many kilometers from base. A heuristic method to estimate walkback range of EVA astronauts is presented. An attempt is made to quantify the EVA walkback factors that influence the total walkback range of the lunar EVA astronaut given a fixed duration of the EMU. A walkback range estimate can then be used to carefully structure EVA missions and will help in future designs of EMUs.
Technical Paper

Engine Cycle Considerations for Future Transport Aircraft

Recent noise technology advancements have provided an increased understanding of true engine noise “floor” levels. This has led to changes in necessary engine cycle requirements for low-noise commercial airplanes. Updated prediction techniques for the core and jet noise sources are described, and lining technology improvements are reviewed. The need for further work in the core noise area is emphasized. The impact of these noise technology revisions on the best engine cycle for obtaining low noise is presented. It is concluded that engines with lower bypass ratios than previously anticipated may be acceptable.
Technical Paper

Engine Maintenance Cost Reduction Through Improved Component Design and Development

High maintenance costs of the three 40,000 lb. thrust class aircraft engines manufactured by Pratt and Whitney, General Electric, and Rolls-Royce are discussed. Primary emphasis is on existing engine problems which contribute to high shop visit rate. Maintenance cost in terms of monetary value is not discussed. Concludes that increased emphasis on total life cycle durability is necessary by the engine manufacturers. Recommends higher level of priority be given durability in design and analysis, pre-production proof-of-design testing, and engine program management.
Technical Paper

Evolution to Lean Manufacturing A Case Study of Boeing of Spokane

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.