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Switching controls are those that can switch between control or plant modes to perform their functions. They have the advantage of being simpler to design than an equivalent control system with a single mode. However, the transients between those modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the control or the plant. So, the smoothing of such transients is vital for their reliability and mantainability. This is can be of extreme importance in the aerospace and automotive fields, plenty of switchings between manual and autopilot modes via relays, or among gears via clutches, for example. In this work, we present a first strategy for smoothing transients in switching controls of aerospace and automotive systems.

New technologies, evolving customer requirements, different process procedures, part changes, inequities between CAD model and actual fixtures and parts, and other problems all require a flexible process environment. However, increased process complexities place a burden on production operators. CIMCORP has developed a flexible environment for drilling, routing and waterjet cutting composites. The system accepts off-line CAD/CAM generated part programs, allows on-line creation and editing of programs, integrates customer expertise to help optimize production, yet maintains a simple production level environment. The environment utilizes pop-up menus and pull down interaction windows to reduce operator input to known values. An on-line RS-274 editor, communication with intelligent peripheral devices, and system administration screens for reconfiguration of process parameters are also included.

Superoxides can be used in self-contained, emergency self-rescuers, both as sources of chemically stored oxygen and as carbon dioxide scrubbers. In the work described here, a single-pass flow-system test facility was employed to evaluate the reactivity of calcium superoxide, Ca(O2)2, with respiratory gases (H2O,CO2), in concentrations simulating exhaled breath. When compared with commercial preparations of potassium superoxide, KO2, 55–60% Ca(O2)2 was found to evolve oxygen and absorb carbon dioxide at significantly lower rates under conditions where each of the superoxides was reacted with 5% CO2 streams having dew points of 37°C. Whereas O2 evolution and CO2 absorption occurred simultaneously in the case of KO2 beds, CO2 absorption lagged O2 evolution when beds of Ca(O2)2 were reacted with moisture and CO2.

This paper describes a framework for developing an Integrated Electrical Power System (EPS) Health Management System. The framework is based on the perspective that health management, unlike other capabilities, is not a self-contained, stand-alone system, but is rather an integral part of every aircraft subsystem, system, and the entire platform. Ultimately, the objective is to improve the entire maintenance, logistics and fleet operations support processes. This perspective requires a new mindset when applying systems engineering design principles. The paper provides an overview description of the framework, the potential benefits of the approach and some critical design and implementation issues based on current development efforts.

This paper presents a frequency domain multi-input/multi-output (MIMO) identification method. The accuracy, reliability and ability of handling repeated modes are verified by computer simulation and practical structures. The applications in an aircraft Ground Vibration Test (GVT) is given. The results have shown that compared with traditional multipoint sine excitation phase resonance method, operation is simplified, testing time is reduced reliability is improved and compared with time domain MIMO methods developed over the past several years, the order of the system (the number of modes) can be identified directly so that the calculating time is reduced and the user's judgement of distinguishing between structural modes and noise modes is avoided.

Solar proton events (SPEs) represent the single-most significant source of acute radiation exposure during space missions. Historically, an exponential in rigidity (particle momentum) fit has been used to express the SPE energy spectrum using GOES data up to 100 MeV. More recently, researchers have found that a Weibull fit better represents the energy spectrum up to 1000 MeV (1 GeV). In addition, the availability of SPE data extending up to several GeV has been incorporated in analyses to obtain a more complete and accurate energy spectrum representation. In this paper we discuss the major SPEs that have occurred over the past five solar cycles (~50+ years) in detail - in particular, Aug 1972 and Sept & Oct 1989 SPEs. Using a high-energy particle transport/dose code, radiation exposure estimates are presented for various thicknesses of aluminum. The effects on humans and spacecraft systems are also discussed in detail.

The factors involved in the selection of a quick-disconnect are grouped into the following classifications for the purpose of discussion: (a) Functional considerations. (b) Weight considerations. (c) Environmental performance factors. (d) End fitting types. (e) Additional considerations.

The factors involved in the selection of a quick-disconnect are grouped into the following classifications for the purpose of discussion: (a) Functional considerations. (b) Weight considerations. (c) Environmental performance factors. (d) End fitting types. (e) Additional considerations.

An effective ground station is vital to the successful implementation of an EMS and is a fundamental part of the total monitoring system design. Unlike on-board processing systems which principally use data to indicate when engine maintenance is required, ground stations offer much greater processing power to analyse and manipulate EMS data more comprehensively for both maintenance and logistics purposes. This document reviews the main EMS functions and discusses the operating requirements which will determine the basic design of a ground station, including the interfaces with other maintenance or logistics systems. A brief discussion is also included on some of the more recent advances in EMS ground station technology which have been specifically developed to provide more effective diagnostic capabilities for gas turbine engines. Finally, this document addresses the program management requirements associated with the initial development and on-going support of a ground station.

The factors involved in the selection of a quick-disconnect are grouped into the following classifications for the purpose of discussion: a Functional considerations. b Weight considerations. c Environmental performance factors. d End fitting types. e Additional considerations. A quick-disconnect coupling as used in this AIR is one that can be rapidly and repetitively connected and disconnected without excessive fluid loss. The relative importance of the design factors depends upon the fluid medium of the particular system in which quick-disconnect is to be used. The effect of the fluid media on each factor is discussed in this report where applicable.

An effective GSS is vital to the successful implementation of an EMS and is a fundamental part of the total monitoring system design, including asset management. Unlike the on-board part of the EMS which principally uses real time data to indicate when engine maintenance is required, a GSS can offer much greater processing power to comprehensively analyze and manipulate EMS data for both maintenance and logistics purposes. This document reviews the main EMS functions and discusses the operating requirements used to determine the basis design of a GSS, including the interfaces with other maintenance or logistic systems. A brief discussion is also included on some of the more recent advances in GSS technology that have been specifically developed to provide more effective diagnostic capabilities for gas turbine engines.

The authors review the requirements, describe some of the unusual design features and characteristics, and present the performance and weight data for the new McCulloch TSIR-5190 aircraft engine. This powerplant is a highly turbosupercharged, two-stroke cycle, direct fuel injection, liquid cooled, 5 cyl radial engine of 190 cu in. displacement. Maximum rated horsepower is 270 at 3600 rpm, and the brake specific fuel consumption, over the range from half-to full power, is below 0.5 lb/bhp-hr. The estimated “ready to fly” weight for the production engine is 365 lb. Some comparisons are made with currently available engines.

A highly reliable alternative source for aircraft +28Vdc power is presented. This alternative uses a permanent magnet generator (PMG) and an electronic converter/regulator (C/R). The power system includes such features as independence from the main power system, high power quality with terminal or remote point of regulation (POR), light weight, and constant power availability from engine idle to maximum rpm. Included is a brief system description, a review of steady state and transient performance, and a conclusion with a perspective on future expectations.

This paper is a review of the literature covering the history of the use of lubricants. The uses of oils derived from animals, vegetables and minerals are placed in perspective from ancient times to the Wright Brothers' flight in 1903. After that period, the discussion is confined largely to the lubrication of aircraft piston engines. The paper attempts to explain the preference for castor oil in European and British engines and the more general, but by no means exclusive, use of petroleum-based mineral oils in the United States. The British Air Ministry, in 1929, reached a decision to abandon castor oil due to availability and cost of petroleum-based oils. The simultaneous U.S. Army Air Corps recognition of the advantages of the very flat viscosity-temperature curve of Pennsylvania oils for hot running engines and for cold starting led to the world-wide use of these lubricating oils.

Modern rotorcraft must have the capability to operate in all-weather conditions. Sikorsky Aircraft has conducted icing research and ice protection system development for helicopters over the past 58 years and the pace of that work has accelerated during the past two decades. Sikorsky participated in several helicopter icing flight tests, conducted wind tunnel tests of scale models and full-scale components, tested simulated ice shapes, and developed analytical tools for use in the design, certification, and qualification for flight in icing conditions. Engine inlets, airspeed systems, main rotor droop stops, and windshields are generally protected by thermal anti-icing systems. When rotor ice protection is required, rotors are protected with electrothermal deice systems. The UH-60A BLACK HAWK electrothermal rotor ice protection system, developed in the late 1970s, has been installed in 2400 H-60 helicopters and it remains one of the most effective rotor ice protection systems.

Flying wing aircraft predate the First World War. The flying wing theoretically offers both aerodynamic efficiency and structural simplicity. Early efforts to develop the flying wing concept led to an increased interest in tailless and semi-tailless aircraft that eventually led to delta wings and swept wing planforms. Early flying wings were plagued by stability and control problems that have not been fully addressed until recently. The flying wing approach, however, still appears to be suitable only for aircraft that do not need to have high maneuverability and agility capabilities, such as long-range bombers or perhaps large transports. This paper surveys the long history of attempts to create flying wing aircraft.

After several decades of human spaceflight, the community of space-faring nations has accumulated a diverse and sometimes harrowing history of toxicological events that have plagued human space endeavors almost from the very beginning. Some lessons have been learned in ground-based test beds and others were discovered the hard way - when human lives were at stake in space. From such lessons one can build a risk-management framework for toxicological events to minimize the probability of a harmful exposure, while recognizing that we cannot predict all possible events. Space toxicologists have learned that relatively harmless compounds can be converted by air revitalization systems into compounds that cause serious harm to the crew.

This paper presents an overview of digital microprocessor-based Environmental Control System (ECS) controller development and validation at Boeing. The application of a hybrid computer simulation laboratory to the development of real-time simulation capability for ECS is described. The approach used to develop microprocessor-based ECS controllers is illustrated by describing the steps which led to the implementation of a fully automatic cabin pressure control system. The approach to validating ECS digital controllers is also discussed.

Experience has shown that process and system level thinking enables significant reductions in design cycle time by avoiding technically correct but irrelevant calculations. Irrelevance often arises when the correct analysis is performed at the wrong stage in the product definition. Current iterative approaches to engineering design require considerable duplication of effort, much of which comes from modeling multiple design abstractions for varied levels and types of analyses. To ensure that appropriate domain knowledge is available at the appropriate time, skills and experience with tools that enable more robust trade studies for increasingly detailed design with inputs from increasingly diverse disciplines are required. Vehicle-focused efforts have broad appeal for attracting high quality, diverse students and facilitate strategic alignment of teaching and research.

This paper provides an overview of the development of an organic matrix composite housing for an aircraft generator. The specific component discussed is the main housing for the F/A-18 C/D Generator Convenor Unit (GCU). This component fulfills both structural and thermal functions. The composite housing will be a direct replacement for the existing aluminum component, and will offer lighter weight and improved thermal performance, at a comparable cost. The composite housing will be consolidated by matched metal net molding, and will demonstrate the use of embedded metallic pin fins within the composite material to improve thermal performance. The paper addresses the design development, thermal and structural design verification analyses, material compatibility testing, and fabrication process development and tooling design.