Mach numbers from 0.55 to 0.85 and angles of attack from about 2 deg to 6 deg. The Reynolds number based on wing mean aerodynamic chord varied from 0.00000225 to 0.00000270. The effects of model-component buildup, horizontal-tail effectiveness, boundary-layer transition, and wing and nacelle modifications were measured. The model was mounted by using a sting-strut arrangement with the strut entering the model through the underside of the fuselage approximately 65 percent of the fuselage length rearward of the model nose. Strut-interference effects were measured and applied as a correction to the data. Author N70-40690*# National Aeronautics and Space Administration. Langley Research Center, Langley Station, Va. GROUND-EFFECTS INVESTIGATION OF A STOL AIR-SEA TRANSPORT MODEL WITH BLOWING OVER THE CANARD AND WING FLAPS Raymond D. Vogler Washington Oct. 1970 44 p refs (NASA-TN-D-5988; L-7193) Avail: NTIS CSCL01C Compressed air was used for blowing over the flaps of the canard and wing. The total mass flow over the flaps was varied as well as the distribution of the flow between the canard and wing. Data were obtained through an angle-of-attack range and an angle-of-sideslip range with the model at various heights above a moving ground plane. Interference effects between canard and wing were obtained by comparing complete model data with data for the wing alone and canard alone. Author Following a brief discussion of the mission of AGARD. it is stated that the object of the symposium is to highlight the methods and techniques of preliminary airplane design and to explore those compromises involved in the early design stage. The stages usually found in a development program are outlined. Feasibility studies concerning a generalized requirement are undertaken to investigate the various possible technical solutions, together with indications of timescale and cost. An initial study of the relative cost effectiveness of alternative proposals may be determined. A firm requirement may then be produced, which is the technical solution chosen from the feasibility study. Project studies are subsequently carried out against the full requirement; from these, a complete aircraft specification with detailed performance, development, and production time scales and costs is drawn up. Thus, the major compromises and decisions are made prior to the design go-ahead. P.A.B. N70-40707# Royal Aircraft Establishment, Farnborough (England). SOME FLUID-DYNAMICS CONSIDERATIONS RELATING TO THE PRELIMINARY DESIGN OF COMBAT AIRCRAFT John Williams and Robert K. Page In AGARD Prelim. Design Aspects of Mil. Aircraft Mar. 1970 14 prefs Avail: NTIS Some of the fluid dynamics considerations which arise in the early design stages of advanced combat aircraft are examined. After some performance considerations of this type of aircraft. including comparisons between fixed wing and variable sweep layouts, reference is made to aerodynamic problems in the design of variable sweep aircraft. A brief outline is given of some of the outstanding problems of wing design, wing-body interference, and the estimation of wave drag. Some questions arising in the choice of engine intakes are mentioned, along with the many jet and afterbody problems, including the possible effects of jet temperature on the base drag. Author N70-40708# Aeronautical Systems Div., Wright-Patterson AFB. Ohio. FUTURE ADVANCES IN THE AERODYNAMICS OF MILITARY STRIKE AIRCRAFT Richard H. Klepinger, John W. Carlson, and William M. Stout In AGARD Prelim. Design Aspects of Mil. Aircraft Mar. 1970 18 p refs Avail: NTIS The primary mission requirements of an air superiority fighter are reviewed, and the factors which affect performance and maneuverability are discussed. The aerodynamic features which have a strong influence on fighter capability are indicated. The effect of the rapid development of numerical solution techniques, using the digital computer, on aerodynamic design methods is noted. The current trend toward configurations with minimum basic aerodynamic stability and extensive stability augmentation is discussed. The need for improved aerodynamic stability is emphasized, and some of the current flight problems of supersonic fighter aircraft are described. It is shown that stability augmentation can cause adverse effects in some flight regimes. The analyses and test programs that are essential before an aerodynamic design is committed to Author production are summarized. N70-40709# Hawker Siddeley Aviation, Ltd., London (England). DESIGNER'S VIEW OF POWERPLANT PROBLEMS R. S. Hopper In AGARD Prelim. Design Aspects of Mil. Aircraft Mar. 1970 18 p Avail: NTIS The problems of installing the powerplant in the airframe are examined, including the overall problem of layout along with the detailed problems arising at the engine/ airframe interface, and limited to the jet engine as installed in fighter type aircraft. The development of the jet fighter is briefly traced from the end of the piston engined era, with Hawker Siddeley aircraft used as examples. Engine starting, gyroscopic coupling, foreign object damage, fuel systems, intake design, exhaust design, and powerplant cost are considered, with recommendations for both the airframe and engine designers. N70-40710# General Electric Co., Cincinnati, Ohio. THE DESIGN PROCESS P.A.B. James E. Worsham In AGARD Prelim. Design Aspects of Mil. Aircraft Mar. 1970 8 p Avail. NTIS The development of a modern multi-mission fighter engine requires a weapon system design approach, with close integration of the engine and aircraft manufacturers, to assure a successful program. Some of the key decision points that are vital to such a program, including the conceptual approach, technology improvement programs, compatibility requirements,final selection of technology, and engine size selection are discussed. The criteria for full program initiation is a total system defined by firm specifications, definitive interface agreements, verified technical approach, and firm schedule and cost. These criteria can be satisfied by the proper system design process. Author The aircraft designer has the obligation to analyze carefully the specific requirements and then to present an optimum approach to a weapon system within a reasonable number of iterations. Accurate data are imperative for optimizing the structure, especially in the fields of weight prediction, materials, design research, and production methods. These problems are discussed by means of a number of examples, and development trends are demonstrated. Recommendations are issued concerning in which way and by what means preliminary design, with special attention to structural design, should be improved. Author N70-40713# British Aircraft Corp., Preston (England). B. J. Beele In AGARD Prelim. Design Aspects of Mil. Aircraft Avail: NTIS Within the areas of load estimation and aeroelasticity, the essential needs during the initial design stages of an aircraft are the rapid provision of realistic loading information and the exertion of a favorable aeroelastic influence on the design. These needs are examined in terms of three basic steps, namely, data acquisition, aircraft stability assessment, and response calculations, with special reference to the problems posed by typical advanced combat aircraft configurations and requirements. The design of such aircraft highlights the need for an approach which integrates the various aerodynamic and structural disciplines, with the major problem being the acquisition of aerodynamic data, particularly for loading Author purposes. Currently available materials are reviewed, and their limitations and future potentials discussed. New materials and their application and development programs, which were initiated to validate their design potentials as well as to establish confidence in their structural impact on future military aircraft, are highlighted. It is found that significant potential savings are possible if new metals are utilized to the fullest extent and that revolutionary advances in aircraft design and performance can be made by the utilization of the new advanced filament composite materials. It is also noted that many potential advances have not been made because of low cost effectiveness potential, lack of confidence in the new material, extensive data requirements, the requirement for large capital investment in new machine tools, and the presence of a highly skilled labor force. Finally, the requirements for a better mutual understanding between the technical specialists, which is necessary if these new materials are to be integrated into new military aircraft, are outlined. N70-40715# Author North American Rockwell Corp., El Segundo, Calif. AIRFRAME SYSTEMS DESIGN EVALUATION Lawrence P. Greene In AGARD Prelim. Design Aspects of Mil. Aircraft Mar. 1970 13 p Avail: NTIS A general view of the compromises a designer must make in aircraft subsystems to achieve the correct and optimum effectiveness of the total aircraft system is presented. The emphasis is directed at resolution of problems relating to flight mechanics functions. It is intended to identify the contribution an imaginative systems designer can make to an effective flying machine, which in turn is recognized to be one of the necessary assets of military aircraft. The essence of any successful design is the understanding the proponents of each associated discipline exercises when dealing with others of the design team. Examples of design ingenuity are shown to illustrate some of the areas where innovation provided reasonable answers to otherwise troublesome problems. General observations of the requirements imposed on supporting airframe systems are developed, with particular attention to control system options, power sources, environmental problems, and total system dependability. Author N70-40716# Service Technique de l'Air, Paris (France). ADVANCED STUDIES IN THE FIELD OF FLIGHT CONTROLS [ETUDES AVANCEES DANS LE DOMAINE DES COMMANDES DE VOL] In AGARD Prelim. Design Aspects of Mil. Aircraft Mar. 1970 35 P In FRENCH Prepared in cooperation with sud-Aviation, Paris Avail: NTIS Problems met in the design of modern combat aircraft are discussed, including the increase of the power necessary for activating the control surfaces, variations of stability and controllability characteristics, the introduction of severe perturbations linked, for example, to the Mach number, structural deformations, and safety problems. Some possible solutions to the problems are examined. The system of flight control of the civil supersonic transport aircraft Concorde is then investigated, with reference to performance objectives and objectives of reliability, in the sense of navigability and operational utilization. Application of these objectives to the general design of the system and to its technology A review of current flight control system design for combat aircraft is given, highlighting the reliance placed on forms of electrical signalling of the flying control surfaces and the increasing use of feedback control techniques to achieve satisfactory handling qualities. In all current systems, however, a mechanical backup system is retained. A description of a possible electrical signalling system design is given, including maneuver demand control characteristics, and some of its advantages are discussed. The conclusion is reached that, although some experience is being gained in service of forms of electrical signaling, aircraft designers have not yet the confidence to eliminate mechanical reversion systems; these often compromise the primary electrical signalling system performance. Recent system developments should lead to the abandoning of these mechanical reversion systems in future project designs and the full benefits of feedback control can then be obtained. These include the optimization of the overall airframe, taking advantage of feedback control, and new cockpit layouts. taking advantage of the use of small side controllers. Author Techniques for assuring proper reliability, maintainability. human factors, and system safety considerations in the initial design phase are considered. The definition of the problem, development of a prediction capability, and the formulation of these disciplines in such a manner that they are useful in the overall design process are discussed. In each of the four areas, a formal program plan is required; the techniques used to accomplish the program include the translation of general requirements into specifics, design definition inputs, design surveillance, and participation in design reviews and trade studies, as well as the use of mockups and P.A.B. simulator studies. Avail: NTIS The development planning process as a method for identifying, advocating, and obtaining approval for military system and equipment programs needed for new and improved operational capabilities is discussed. The experience of the U.S. Air Force in development planning is used as the example. The changes within the development planning process, the activities, and the tools used in the process are examined. A specific review of the technology plot tool is presented as a means of improving communications among the user (the operational command), the design engineer, and the planner. Development planning evolved as the disciplined process which directs the talents and techniques of operational planners, system analysts, engineers, designers, and technologists toward the goal of providing effective and valid proposals for new systems and equipment for meeting the operational capability needs of the future. Author N70-40736# Advisory Group for Aerospace Research and Development, Paris (France). AGARD SPECIALISTS' MEETING ON THE AERODYNAMICS OF ATMOSPHERIC SHEAR FLOWS Technical Evaluation Report J. E. Cermak and B. W. Marschner May 1970 9 p refs Conf. held at Munich, 15-17 Sep. 1970 (AGARD-AR-24-70) Avail: NTIS The purpose of this meeting was to coordinate the efforts of atmospheric scientists and aeronautical engineers. The common language of fluid dynamics was used in attacking the basic and applied problems of atmospheric motion near the earth's surface. One of the main recommendations is for a coordinated field and laboratory study to verify similarity between wind tunnel generated flow and the corresponding atmospheric shear flow. A list of the papers presented is included, with brief comments on their content and value. Author N70-40743*# National Aeronautics and Space Administration. Langley Research Center, Langley Station, Va. AN APPROACH GUIDANCE METHOD USING A SINGLE ONBOARD OPTICAL MEASUREMENT Harold A. Hamer and Katherine G. Johnson Washington Oct. 1970 82 p refs (NASA-TN-D-5963; L-7053) Avail: NTIS CSCL 17G An empirical method was developed for onboard guidance within the sphere of influence of a celestial body. For guidance maneuvers made at a relatively large distance from the body, only one preselected measurement from a star to the body is required. Although the method is designed to control the magnitude of the periapsis radius (or entry angle), the periapsis position and velocity automatically remain close to the nominal values. For lunar approach, error analysis with an assumed one-sigma error of 10 N70-40748# Federal Aviation Administration. Washington D.C. Office of the Associate Administrator for Engineering and Development. RESEARCH AND DEVELOPMENT PLAN TO INCREASE AIRPORT AND AIRWAY SYSTEM CAPACITY: PROGRAM DESCRIPTION May 1970 62 p (AD-707186) Avail: NTIS The research and development activity described is to achieve the national goal of providing an air transportation system for all categories of aviation commensurate with projected growth of the air transportation industry. This objective requires an accelerated effort to substantially upgrade the existing airport and airway systems by developing and introducing new concepts and technologies which are adpated to the needs while tempered by evolutionary, sociological, and economic factors Prior studies and experience provide a substantial foundation of understanding requirements and technical opportunities from which this program evolves. The urgency to proceed expeditiously stems from the basic fact that aviation growth is rapidly outpacing the capacity of the existing system. Accordingly, the philosophy of this program is to proceed simultaneously from the outset with hardware development for early implementation based on current knowledge and assumptions, and, concurrently, with system engineering analyses which will refine performance requirements, detail system integration and interface specifications for both the present and next generation systems. Author N70-40751*# National Aeronautics and Space Administration. WIND TUNNEL STUDIES OF EFFECTS OF CONSTRUCTION Paul G. Fournier and William C. Sleeman, Jr. Washington Oct. 1970 92 p (NASA-TN-D-5974; L-7013) Avail: NTIS CSCL 01C A low-speed wind-tunnel investigation was conducted to determine the effects of canopy construction methods, design details, and canopy slots on the static longitudinal aerodynamic characteristics of all-flexible parawings. Construction details such as type of nonporous canopy fabric, glued or sewed seams, tape reinforcement, or cloth-weave orientation had little effect on maximum lift-drag ratios and resultant-force coefficients. The maximum lift-drag ratios varied from 2.2 to 2.5 for the various single-keel unslotted parawings, and from 2.2 to 2.4 for the slotted canopy parawings. Incremental reductions in the lengths of all the suspension lines caused corresponding reductions in the resultant-force coefficients and maximum lift-drag ratios. The available range for modulation of resultant-force coefficient and lift-drag ratio by shortening the control lines was very limited. Author N70-40756# Cornell Aeronautical Lab, Inc., Buffalo, N.Y. AN INVESTIGATION OF ROTATING STALL PHENOMENA IN TURBINE ENGINE COMPRESSORS Final Report, Mar. 1967-Mar. 1970 Gary R Ludwig, Joseph P Nenni, and Roy S Rice, Jr. Wright-Patterson AFB, Ohio AFAPL May 1970 212 p refs (Contract F33615-67-C-1552) (AD-708484; CAL-DE-2422-S-12; AFAPL-TR-70-26) Avail: NTIS CSCL 21/5 The work encompasses both theoretical and experimental studies of rotating stall and an investigation of the requirements for a stall control system. The theoretical studies approached the problem primarily from the point of view that rotating stall is the consequence of an instability of the mean flow to small disturbances. Both two-dimensional flows and a certain class of three-dimensional flows with wheel-type swirl were studied. In addition, numerical experiments were performed with a computer program for a two-dimensional cascade of discrete flat plate blades. Of the theoretical models, only the two-dimensional small disturbance approach exhibited an instability which might lead to rotating stall. The experimental program was performed to provide fundamental data prior to and during rotating stall for comparison with theory and for use as a guide in improving the theoretical model. Extensive investigations of the conditions for inception and the properties of rotating stall were performed on a row of stator blades in an annular cascade. The effects of blade profile shape, blade stagger angle and blade row spacing were studied in the cascade. In addition, several methods for detecting unsteady pressures were studied to determine their suitability as a generator of a rotating stall signature which could be used in a closed loop control system. It was found that a pressure tap located on the suction surface of a stator blade near the quarter-chord showed promise of providing a satisfactory signal. Author (TAB) N70-40765# Federal Aviation Administration, Washington, D.C. Office of Management Services. ENROUTE IFR AIR TRAFFIC SURVEY, PEAK DAY, FY 1969 1969 213 p refs (AD-710762) Avail: NTIS CSCL 17/7 Statistical data on peak day instrument flight rules (IFR) departures from the enroute air traffic facilities operated by the Federal Aviation Administration (FAA) are presented in tabular and graphic form. The peak day for a facility is the day during the fiscal year when the largest number of IFR departures is recorded at the facility. It is not the same date for all facilities. Therefore, national totals, which summarize all individual facility peak day figures, represent IFR departures on a theoretical, rather than on an actual peak day. Author 1 N70-40766*# Center for the Environment and Man, Inc., Hartford, Conn CLOUD AND SYNOPTIC PARAMETERS ASSOCIATED WITH (NASA-111778, CEM-7496-413) Avail: NTIS CSCL 04B Research was initiated to determine relationships between clear air turbulence (CAT) in the stratosphere and upper troposphere. and meteorological variables, circulation features and cloud characteristics For this purpose, a total of 372 cases of CAT occurrence and nonoccurrence were analyzed using aircraft instrumented reports of CAT in the 45.000 70,000 ft layer as obtained by the US Air Force in Project HICAT from 1966 through 1968 Light to moderate or more intense CAT occurs frequently when the vertical temperature profile about the level of interest is irregular and includes both strong inversions and layers in which the temperature decreases rapidly with height. Consistent numerical relationships were determined for a number of meteorological variables describing this condition Implementation of these results for the development of CAT detection instrumentation is discussed The analysis of circulation features showed that significant stratospheric CAT was associated with large horizontal temperature gradients at upper-level surfaces Cloud characteristics associated |