environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high speed civil transport. Significant advances are needed to take off gross weight and allow for both economic attractiveness and environment acceptability. Specific technological requirements were identified to meet these needs. 06 AIRCRAFT INSTRUMENTATION Includes cockpit and cabin display devices; and flight instruments. For related information see also 19 Spacecraft Instrumentation and 35 Instrumentation and Photography. Author N89-27650# N89-27648*# Boeing Commercial Airplane Co., Seattle, WA. HIGH-SPEED CIVIL TRANSPORT STUDY Final Report (Contract NAS1-18377) (NASA-CR-4233; NAS 1.26:4233) Avail: NTIS HC A07/MF A01 CSCL 01C A system study of the potential for a high-speed commercial transport has addressed technological, economic, and environmental constraints. Market projections indicate a need for fleets of transports with supersonic or greater cruise speeds by the year 2000 to 2005. The associated design requirements called for a vehicle to carry 250 to 300 passengers over a range of 5,000 to 6,000 nautical miles. The study was initially unconstrained in terms of vehicle characteristic, such as cruise speed, propulsion systems, fuels, or structural materials. Analyses led to a focus on the most promising vehicle concepts. These were concepts that used a kerosene-type fuel and cruised at Mach numbers between 2.0 to 3.2. Further systems study identified the impact of environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high-speed civil transport; significant advances are required to reduce takeoff gross weight and allow for both economic attractiveness and environmental acceptability. Specific technological requirements were identified to meet these needs. Author N89-27649# Pennsylvania State Univ., University Park. Dept. of Aerospace Engineering. ANALYSIS OF A SYSTEM TO PREVENT HELICOPTER ROTOR BLADE-AIRFRAME STRIKES Final Report, 1 Nov. 1986 - 31 Dec. 1988 1 May 1989 111 p B. W. McCormick and R. G. Melton (Contract DAAL03-87-K-0002) (AD-A209804; ARO-23726.1-EG) Avail: NTIS HC A06/MF A01 CSCL 01/3 Rotor blade-airframe strikes are rare but they do occur. Three areas of the airframe are particularly vulnerable: the tail boom, canopy and, in the case of the underslung, teetoring rotor, the rotor shaft. This latter case is known as mast bumping. This report studies a system to prevent a helicopter rotor blade from striking any part of the airframe. Essentially, the system continuously predicts ahead the rotor blade flapping in response to an input such as pilot control or an atmospheric disturbance. If a blade strike is predicted to occur then an appropriate feedback control is applied to alter the future flapping. The prediction is then begun again with the altered control. In the actual system, an enunciator might warn the pilot at the time that an attempt is made to control input which could be hazardous. Two somewhat independent approaches to the design of the controller are taken. One of the programs is entirely numerical in its approach. The other uses modern control theory and considers the preliminary aspects of implementing the controller in digital hardware. Both methods indicate the feasibility of preventing excessive flapping, although the question of implementation in a dedicated microprocessor is not fully resolved. GRA Advisory Group for Aerospace Research and Development, Neuilly-Sur-Seine (France). Avionics Panel. SYSTEMS ENGINEERING May 1989 132 p In ENGLISH and FRENCH Lecture series held in Kettering, OH, 15-16 May 1989, in Delft, Netherlands, 22-23 May 1989, and in Rome, Italy, 25-26 May 1989 (AGARD-LS-164; ISBN-92-835-0513-1) Copyright Avail: NTIS HC A07/MF A01 Recent AGARD activities have indicated a strong need for more effective avionics system engineering. There is a growing need for reducing development time, effecting savings in costs of ownership, and in extending the life-time of avionics systems. This must be accomplished along with meeting needs of the user faced with a growing threat. With the growing complexity of avionics systems (as well as other systems), it is important to develop and maintain expertise in system planning, architecture, and management. The important systems engineering aspects of requirements, system integration, prototyping, and design are addressed. In addition, the impact of technology on system architecture are discussed. Methodologies are described and actual case histories will serve as practical examples of modern systems engineering. For individual titles, see N89-27651 through N89-27658. N89-27651# Rome Air Development Center, Griffiss AFB, NY. AVIONICS SYSTEM ENGINEERING: AN INTRODUCTION Fred I. Diamond In AGARD, Systems Engineering May 1989 6 p (For primary document see N89-27650 22-06) Copyright Avail: NTIS HC A07/MF A01 System engineering is the process used in the evolution of systems from identification of a need through construction and/or production and deployment in an operational environment. It is a process that involves the application of appropriate scientific and technical knowledge to transform an operational need into a system configuration with defined parameters, through an iterative process of analysis, design, test, and evaluation; to integrate all performance requirements, including reliability, maintainability, and supportability into the total engineering effort; and to integrate related components to insure interoperability and optimum system performance. It is a process that also considers economic factors such as development and life cycle costs. The life cycle process involves several key steps, many iterative, but in an orderly and controlled manner. These steps include requirements, architecture specification, design, development/construction, test and evaluation, and operational use. With the growing complexity of avionics systems, effective systems engineering is critical. Therefore, greater emphasis is placed on architectures, subsystem design, and interfaces and system integration. Only through a total systems engineering approach from the very initial phases of the system life cycle can a well-engineered system be achieved. The payoff will be reduced cost of ownership and greater mission Author effectiveness. which relentlessly bear on the ultimate system design, development, production, and support. The premise is that avionics requirements are driven by four factors: information and data sources, control opportunities and information needs; concepts and algorithmic techniques; and realization technologies. These four factors are set in a generic systems structure which shows their interrelationships and provides the framework for conceptualizing avionic system solutions to meet particular mission needs. The structure focuses on the role of avionics in providing situation assessment, response selection, response implementation, and communications. With this structures in place, avionic system requirements are then examined within the context of architecture, techniques, technology, producibility, and supportability. N89-27653# British Aircraft Corp., Preston (England). Author A STRUCTURED APPROACH TO WEAPON SYSTEM DESIGN May 1989 J. D. Rowley In AGARD, Systems Engineering 7 p (For primary document see N89-27650 22-06) Copyright Avail: NTIS HC A07/MF A01 A structured approach is described for the design of a weapon system which British Aerospace (BAe) was able to develop and prove during the design of the avionics system for the Experimental Aircraft Program (EAP) demonstrator aircraft. Brief descriptions are given of the EAP avionics system, the main system design tools used, the activities carried out during the systems design process, and the management and control procedures adopted. In addition a series of observations highlighting some of the findings of the project and providing pointers to the design of future weapon systems are given. Author N89-27654# Aeronautical Systems Div., Wright-Patterson AFB, INTEGRATED AVIONICS: CONCEPTUAL DESIGN May 1989 Avionics of modern military aircraft is essential for maximizing performance realization of the total aeronautical system. In the early conceptual phase, aeronautical systems designers give scant attention to the interaction of avionics components. The aircraft design team generally provides weight, volume, and power considerations for the desired avionics functions and assumes that an avionics suite can eventually be assembled. Even less attention is given to the potential synergistic effect avionics can have with the aircraft design process. In contrast, the designers expend a large effort on finding the best balanced combination of airframe and propulsion components which satisfy the design objectives. An attempt is made to show why avionics must be a co-equal member of the aeronautical system along with airframe, propulsion, and armament. In becoming a co-equal partner, avionics must be an element of the system design analysis, commencing with the early conceptual design phase of a new aeronautical system. N89-27655# OH. Author Air Force Avionics Lab., Wright-Patterson AFB, An approach is described for an avionic system design and its application to modular avionic architecture. The approach is to test various candidate architectures using a common functional requirement. The method commences with a requirement analysis carried out in a top-down fashion to arrive at a full functional description. A parallel phase determines the technological base and defines a number of candidate architectures and corresponding component sets (module sets in the case of modular architecture). Thus technological performance and in-place equipment limitations are included at an early stage independent of the requirement. Hence top-down means bottom-up, by taking various architecture candidates and corresponding modular sets and applying the functional description of the requirement, so each architecture may be investigated for its capability to cope with the trial or application system. Assessment of reliability and performance objectives is discussed. Also included is reference to the areas of operating systems and BITE which may form part of the system but are not necessarily directly represented at the boundaries of the system. The philosophy of the approach is evaluated and does not extend to application of the various CASE design tools which exist (or may be specified) in order to carry out such a project in practice. Author N89-27657# Aeritalia S.p.A., Caselle Torinese (Italy). Gruppo RAPID PROTOTYPING OF COMPLEX AVIONICS SYSTEMS 18 P The use of a rapid prototyping approach in the initial stages of complex avionics system design can complement some traditional computer design methods. In fact most of the computer aids in engineering and design are aimed to a better, coherent and, as far as possible, complete description of the project, but not too much is done on the verification of the proposed concept implementation. The advantage of having in the early design a software prototype of the system to highlight undesirable characteristics or possible improvements when the system has a high degree of complexity is discussed. Then a design tool called Expert Consultant for Avionics System Transformation Exploitation (ECATE) is described. ECATE is an expert system that prototypes the information handling architecture of an avionics system. The use of knowledge engineering and, in general, artificial intelligence approach for the rapid prototyping has proven very effective, because of the high flexibility, complex domain mastering capability, and heuristic methods typical of these techniques. Finally a description of a complete, integrated environment for the rapid development of prototypes of avionics systems, by using artificial intelligence and computer tools, is given. Author N89-27659# Army Aviation Engineering Flight Activity, Edwards AFB, CA. VERIFICATION OF THE PRODUCTION SAFE FLIGHT INSTRUMENT CORPORATION OV/RV-1D STALL WARNING SYSTEM Final Report, 17 - 25 Aug. 1988 Joseph C. Miess, Charles Q. Crowell, and Patrick Sullivan 1988 44 p (AD-A207392) Avail: NTIS HC A03/MF A01 CSCL 01/4 Nov. A Safe Flight Instrument Corporation (SFIC) stall warning system and prototype normal acceleration (g) limit aural warning device were evaluated on an OV-1D(C). Fifteen productive test flight hours were completed. Interchangeability of the SFIC stall warning system between aircraft was demonstrated by the good correlation of data between Grumman's test on aircraft and U.S. Army Aviation Engineering Flight Activity's (AEFA's) test on aircraft. Grumman's data shows adequate warning margin for LSSS on. There were, inadequate stall margins with LSSS not installed for dual-engine unaccelerated stalls, drop tanks only, and no-stores configurations. Single engine warning margins were inadequate, especially with the right engine operating near maximum power. Accelerated stall warning margine were satisfactory for all wing stores configurations. If the SFIC system is installed on operational aircraft without LSSS, the SFIC system should be adjusted to provide approximately 3 knots more warning margin for low power GRA stalls. N89-27660# Naval Postgraduate School, Monterey, CA. Leah M. Roust Mar. 1989 105 p (AD-A208651) Avail: NTIS HC A06/MF A01 CSCL 25/3 This study evaluates symbols and formats for the F/A-18 Hornet head-up display (HUD) and Attitude Directional Indicator (ADI) for use by pilots in recovering from unusual aircraft attitudes. Two surveys were conducted to collect pilot opinions on various symbols and formats, based on past experimental research and current recommendations. For the HUD symbols according to the amount of information these symbols provide for the pilot while he is in an unusual attitude. In some cases, the pilots also were asked to choose their preferred symbols. The second survey was based on the results of the first and was administered to 56 F/A-18 pilots. These pilots selected their preferred HUD or ADI display formats, choosing one from two to five possibilities in each case. The specific symbols and formats that were evaluated are described in detail. Survey results are provided, and recommendations are made for display implementation and for further research and testing of symbols and formats. 07 AIRCRAFT PROPULSION AND POWER GRA Includes prime propulsion systems and systems components, e.g., gas turbine engines and compressors; and onboard auxilliary power plants for aircraft. For related information see also 20 Spacecraft Propulsion and Power, 28 Propellants and Fuels, and 44 Energy Production and Conversion. N89-27661# Advisory Group for Aerospace Research and BLADING DESIGN FOR AXIAL TURBOMACHINES 212 P Lecture series held in Toronto, Ontario, 1-2 Jun. 1989, in Cologne, Fed. Republic of Germany, 15-16 Jun. 1989, and in Ecully, France, 19-20 Jun. 1989 (AGARD-LS-167; ISBN-92-835-0512-3) Copyright Avail: NTIS HC A10/MF A01 The efficiency and performance of the turbomachinery components of future aero engines can considerably be improved by applying recent advances in understanding the flow behavior of axial compressor and turbine bladings. Thus, the optimal profile new blading design methods pressure distribution as input for L. Fottner In AGARD, Blading Design for Axial Turbomachines May 1989 13 p (For primary document see N89-27661 22-07) Copyright Avail: NTIS HC A10/MF A01 Based on the design objectives for the bladings of highly-loaded, high Mach number turbocomponents the main problem areas to be taken into account during the design process are derived. These refer to the flow field conditions with respect to the effect of the Mach number on the profile contour shape, the aerodynamic loading, especially compressor bladings, and the boundary-layer behavior. In addition, blading design has to account for the Author secondary flow effects and unsteady flow conditions. N89-27664# Office National d'Etudes et de Recherches Aeronautiques, Paris (France). OVERVIEW ON BLADING DESIGN METHODS G. Meauze In AGARD, Blading Design for Axial Turbomachines 22-07) Rather than presenting an exhaustive catalog on the design method calculations, the possible ways to use the calculation methods are discussed, as well as the problems of their practical applications. The complexity of the flow behavior is recalled through a turbomachine and the simplifications which must be adopter, i.e., a mean axisymmetric steady through flow hypothesis. The particular case of an isolated blade row with the possible use of a full 3-D design approach is presented. The well-known quasi 3-D approach combining the mean through flow and the blade-to-blade calculations is discussed where some details are given on direct and inverse methods for both through flow and Author cascade flow. Turbomachines May 1989 N89-27661 22-07) 19 p (For primary document see Copyright Avail: NTIS HC A10/MF A01 The performance of compressor and turbine blading must be predicted in all levels of a conventional design system, beginning in the preliminary design phase before blade row geometry is defined. Because of this requirement, many levels of complexity exist in both input and output of prediction methods, and alternative methods exist within each phase of design. A brief review of performance prediction problems and current solutions is presented. Because details of equations and methods cannot and should not be included, reference to original documents in readily available sources are classified according to their place in configuration design and analysis. It is concluded that both quasi-three-dimensional and three-dimensional computation methods have a potential for future development in terms of configuration optimization. Additionally, it is concluded that experimental data correlation is not dead, and that improvement potential exists in every area of the performance estimation problem. N89-27666# Rolls-Royce Ltd., Derby (England). Author Copyright Avail: NTIS HC A10/MF A01 Computer aided turbomachinery blade design is discussed with the emphasis on the mathematical models that are needed in order to account for the important physical phenomena. The various aspects of a typical balde design system are presented covering through-flow and blade-to-blade analysis. The through-flow discussion coveres linked through-flow-blade-to-blade analysis, blade loss models, end-wall boundary layers, secondary flow analysis, and spanwise mixing models. Blade section design using mixed design and analysis methods is covered together with loss prediction using coupled inviscid boundary layer approaches. Limitations of the coupled approach are discussed together with the emerging role of Reynolds averaged Navier-Stokes methods aimed at removing these limitations. The need for fully three-dimensional methods is covered together with their incorporation into the design system. Finally areas for future development and application are discussed. Author N89-27661 22-07) Copyright Avail: NTIS HC A10/MF A01 A design is presented for axial compressor stages for which the achievement of high performance is both critical from the standpoint of a thermodynamic cycle and also difficult because of high aerodynamic loading, Mach number, or both. The type of method of interest is often termed a through-blade design procedure. The general methodology employed is covered including the computational framework. The kinds of information derived from empiricism is discussed, followed by those areas where design guidance is lacking and logical assumptions are used. The foregoing can theoretically result in an infinite range of solutions. An optimization critieria is presented through striving to obtain the one best solution. Three examples are shown covering the Mach number range of about 0.7 to 1.6 to illustrate the success of the approach. Several other factors which must be taken into account in a design are mentioned. Also, several glaring weaknesses in the present design methods are identified. The lecture concludes with some comments on current design trends and computational goals. Author N89-27668# Centre de Villaroche, Moissy (France). P. F. Bry In AGARD, Blading Design for Axial Turbomachines 42 P N89-27661 May 1989 (For primary document see 22-07) Copyright Avail: NTIS HC A10/MF A01 The past fifty years have seen the tremendous development of jet engine propulsion. Testing has become very complex and has paralleled the increasing complexity observed in the domain of computational methods. The best compromise must be found for the inner and outer shapes of the nozzles and blades. This can only be achieved if internal and external designs are performed by an integrated team of specialists. Tools are described that are available for helping design engineers to reach this objective. Examples of what can be achieved are presented. Both theoretical and experimental aspects are addressed since they are an integral part of the design process. Author AERODYNAMIC DESIGN OF LOW PRESSURE TURBINES In May 1989 Copyright Avail: NTIS HC A10/MF A01 The aerodynamic requirements for low pressure (LP) turbines covering a wide range of Mach and Reynolds numbers are derived from the applications for turbofan, shaft, and propfan engines. Designing turbines for high performance levels is based on extensive experience and modern prediction techniques. Methodology, experimental background, measurement techniques, and design systems are reviewed. The merits and limitations of present computation procedures are discussed. The close interaction between research and industrial development is discussed and the differences are pointed out. Two-dimensional pressure distributions can be predicted by a variety of very efficient inviscid methods. Boundary layer prediction is handicapped by complexity including separation and transition. The characteristic of the Prandtl boundary layer is developed and the physical model leading to the concept of Controlled Boundary Layer (CBL) design is presented. The effects of unsteadiness and turbulence in turbomachinery as well as the extension to transonic flow are considered. The understanding of the inviscid 3-D aerodynamics and their introduction in the design systems is presented. Secondary flows and their direct and indirect effects on losses are discussed. The problems to be addressed in the intermediate and long term research and development work are listed and their significance commented upon. Author N89-27670*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. MACH 5 INLET CFD AND EXPERIMENTAL RESULTS Lois J. Weir, D. R. Reddy, and George D. Rupp (Sverdrup Technology, Inc., Cleveland, OH.) Jul. 1989 16 p Presented at the 25th Joint Propulsion Conference, Monterey, CA, 10-12 Jul. 1989; sponsored in part by AIAA, ASME, SAE, and ASEE (NASA-TM-102317; E-5011; NAS 1.15:102317; AIAA-89-2355) Avail: NTIS HC A03/MF A01 CSCL 21E An experimental research program was conducted in the NASA Lewis Research Center 10 x 10 ft supersonic wind tunnel. The 2-D inlet model was designed to study the Mach 3.0 to 5.0 speed range for an over-under turbojet plus ramjet propulsion system. The model was extensively instrumented to provide both analytical code validation data as well as inlet performance information. Support studies for the program include flow field predictions with both 3-D parabolized Navier-Stokes (PNS) and 3-D full Navier-Stokes (FNS) analytical codes. Analytical predictions and experimental results are compared. Author 08 AIRCRAFT STABILITY AND CONTROL Includes aircraft handling qualities; piloting; flight controls; and autopilots. For related information see also 05 Aircraft Design, Testing and Performance. N89-27671*# National Aeronautics and Space Administration. SUMMARY OF LONGITUDINAL STABILITY AND CONTROL (NASA-TM-101605; NAS 1.15:101605) Avail: NTIS HC Estimates of longitudinal stability and control parameters for the space shuttle were determined by applying a maximum likelihood parameter estimation technique to Challenger flight test data. The parameters for pitching moment coefficient, C(m sub alpha), (at different angles of attack), pitching moment coefficient, C(m sub delta e), (at different elevator deflections) and the normal force coefficient, C(z sub alpha), (at different angles of attack) describe 90 percent of the response to longitudinal inputs during Space Shuttle Challenger flights with C(m sub delta e) being the dominant parameter. The values of C(z sub alpha) were found to be input dependent for these tests. However, when C(z sub alpha) was set at preflight predictions, the values determined for C(m sub delta e) changed less than 10 percent from the values obtained when C(z sub alpha) was estimated as well. The preflight predictions for C(z sub alpha) and C(m sub alpha) are acceptable values, while the values of C(z sub delta e) should be about 30 percent less negative than the preflight predictions near Mach 1, and 10 percent less negative, otherwise. Author N89-27672*# Sverdrup Technology, Inc., Cleveland, OH. 32 P (NASA-CR-182302; E-4853; NAS 1.26:182302) Avail: NTIS HC A03/MF A01 CSCL 01C A methodology to improve the stability robustness of feedback control systems designed using direct eigenspace assignment techniques is presented. The method consists of considering the sensitivity of the minimum singular value of the return difference transfer matrix at the plant input to small changes in the desired closed-loop eigenvalues and the specified elements of the desired closed-loop eigenvectors. Closed-form expressions for the gradient of the minimum return difference singular value with respect to desired closed-loop eigenvalue and eigenvector parameters are derived. Closed-form expressions for the gradients of the control feedback gains with respect to the specified eigenspace parameters are obtained as an intermediate step. The use of the gradient information to improve the guaranteed gain and phase margins in eigenspace assignment based designs is demonstrated by application to an advanced fighter aircraft. Author 09 RESEARCH AND SUPPORT FACILITIES (AIR) Includes airports, hangars and runways; aircraft repair and overhaul facilities; wind tunnels; shock tubes; and aircraft engine test stands. For related information see also 14 Ground Support Systems and Facilities (Space). N89-27673# Central State Univ., Wilberforce, OH. Dept. of Manufacturing Engineering. THEORETICAL MODEL FOR STABILIZATION OF CLAY-SILT AIRPORT PAVEMENT SUBGRADE SYSTEMS. PHASE 1: LABORATORY INVESTIGATION. PHASE 2: RUTTING TESTS Final Report William A. Grissom, Abayomi J. Ajayi-Majebi, L. Shelbert Smith, Carl L. White, Mahmoud A. Abd-Allah, and Eugene E. Jones (Tractell, Inc., Dayton, OH.) May 1989 327 p (Contract DTFA01-84-C-00023) (DOT/FAA/PM-87/20-Phase-1/2) Avail: NTIS HC A15/MF A01 Theoretical models for low-volume airport pavement stabilization of clay-silt systems are documented. A non-traditional method of soil stabilization is presented for improving the subgrade strength of poorly graded clay-silt. The research (Phase 1) focuses on: (1) identification of a chemical additive capable of increasing the load bearing strength of clay-silt soil; (2) additive application to a clay-silt soil system leading to increased bearing strength; and (3) development of mathematical models for soil strength prediction. Phase 2 focuses on field validation of the test results through studies of pavement rutting. Among several effective non-traditional organic additives tested in this research, the two-part epoxy system, bisphenol A/epichlorohydrin resin plus a polyamide hardener gave the best result as measured by the dry California Bearing Ratio (CBR) test. The choice of the dry CBR test performed to ASTM specification was motivated by a need to capture optimum moisture content as a variable in addition to percent additive, clay-silt ratio, temperature and dry density, using a full factorial experimental design. The statistical regression models developed support the hypothesis that only additive percentage, moisture content and temperature are significant variables influencing the strength of the clay-silt soil system tested. The nomograph developed for CBR prediction enables quick estimates of dry CBR. The marginal increase in CBR values due to percent increase in epoxy resin application is 11.1 and the marginal degradation of CBR due to a percent increase in moisture level is 5.6. In phase 2, the rutting validation study confirmed the effectiveness of the chemical stabilizing agent identified for strengthening a clay-silt soil at the 4 percent level of additive application. Based on the results of the rutting test conducted on a tire force machine (TFM), the stabilized pavement will sustain an aircraft load of 10,000 lbs applied through 1000 wheel load passes while meeting the 1/2 inch rutting criteria. N89-27674*# Naples Univ. (Italy). Author AN EVALUATION OF THREE EXPERIMENTAL PROCESSES (Contract NCC1-47) (NASA-CR-181871; NAS 1.26:181871) Avail: NTIS HC A04/MF A01 CSCL 14B The aerodynamic measurements in conventional wind tunnels usually suffer from the interference effects of the sting supporting the model and the test section walls. These effects are particularly severe in the transonic regime. Sting interference effects can be overcome through the Magnetic Suspension technique. Wall effects can be alleviated by: testing airfoils in conventional, ventilated tunnels at relatively small model to tunnel size ratios; treatment of the tunnel wall boundary layers; or by utilization of the Adaptive Wall Test Section (AWTS) concept. The operating capabilities and results from two of the foremost two-dimensional, transonic, AWTS facilities in existence are assessed. These facilities are the NASA 0.3-Meter Transonic Cryogenic Tunnel and the ONERA T-2 facility |