characteristics are described. The analytical procedure is explained and stabilizer loads together with some aircraft motions as functions of autopilot gains within the stability boundaries are determined. The effects of center of gravity location and altitude are considered. Author N74-17743 Royal Aircraft Establishment, Farnborough (England). Avionics Dept. THE DESIGN OF AUTOMATIC FLIGHT CONTROL SYSTEMS ΤΟ REDUCE THE EFFECTS OF ATMOSPHERIC DISTURBANCES M. J. Corbin and K. F. Goddard In AGARD Flight in Turbulence Nov. 1973 16 p refs (For availability see N74-17720 09-02) The design of two experimental automatic flight control systems for the BAC 111 aircraft is described. One system used throttle and elevator controls and the other uses, in addition, direct lift control by means of spoilers. The landing performance of the systems is compared with conventional automatic landing systems. It is stated that discrete gusts experienced at heights below 15 meters can produce large touchdown errors exceeding the capability of the autopilot control. Author N74-17744 Royal Aircraft Establishment, Bedford (England) Aero Flight Div. APPLICATION OF ENERGY MANAGEMENT CONCEPTS TO FLIGHT-PATH CONTROL IN TURBULENCE Nov. 1973 J. G. Jones In AGARD Flight in Turbulence 18 p refs (For availability see N74-17720 09-02) Some effects of turbulence on aircraft flight path control are reviewed. An outline is presented of a strategy for the control of airspeed and flight path of an aircraft, based on the use of the throttle to control total energy error, consisting of a kinetic component associated with airspeed and a potential component associated with height, and the elevator used to distribute the energy error between airspeed and height in an optimum manner. Emphasis is placed on the flight path control in a landing approach. The safety aspects of an aircraft subjected to large gust disturbances are also considered. Author N74-17745 Office National d'Etudes et de Recherches A NEW APPROACH TO GUST ALLEVIATION OF A FLEXIBLE The application of optimization techniques for the purpose of gust alleviation is discussed. The basic approach is an extension of the Wiener's optimization theory to two control parameters and the application to the Caravelle aircraft. A comparison is made between the theoretical responses to a Gaussian stationary excitation and the responses to actual records of turbulence given by an analong computer taking into account the nonlinearities due to limited efficiency of the controls. Author models. The application of this experimental data is problematical. There is a basic interest in establishing a theory for the flow conditions over the flap system during takeoff and landing. The present experimental study attempts to provide the basis for future theoretical models based on detailed measurements over a simple profile which has Fowler flaps and slats. Author N74-17748# National Transportation Safety Board, Washington, D.C. AIRCRAFT ACCIDENT REPORT: OVERSEAS NATIONAL AIRWAYS, INC., MCDONNELL DOUGLAS, DC-8-63, N863F, BANGOR, MAINE, 20 JUNE 1973 7 Feb. 1974 13 p (NTSB-AAR-74-1) Avail: NTIS HC $4.00 A DC-8-63 en route from Tampa, Florida. to Geneva, Switzerland, via Bangor, Maine, and Amsterdam, the Netherlands, was involved in a takeoff accident at the Bangor International Airport, Bangor, Maine, on June 20, 1973. In the emergency evacuation that followed, 34 of the 251 passengers on board were injured. During the takeoff roll, the captain heard a loud. muffled sound, like that of a blown tire, and discontinued the takeoff. A fire broke out in the right main landing gear assembly and right wing root area. The passengers and crew emerged via the airplane emergency escape chute system. The probable cause of the accident was the undetected deflation of a right main landing gear tire as the aircraft was taxiing for takeoff. The additional loads imposed upon two other tires caused them to fail during the takeoff roll. Subsequently, the wheel assemblies were damaged. The fire was ignited by the friction between the metal wheels and the runway pavement. Author N74-17749*# Boeing Commercial Airplane Co., Seattle, Wash. (NASA-CR-114678; D6-41336) Avail: NTIS HC $5.75 CSCL 01C An engineering study to determine the feasibility of applying the NASA (ARC) two-segment approach procedures and avionics to the Boeing fleet of commercial jet transports is presented. This feasibility study is concerned with the speed/path control and systems compability aspects of the procedures. Path performance data are provided for representative Boeing 707/727/737/747 passenger models. Thrust margin requirements for speed/path control are analyzed for still air and shearing tailwind conditions. Certification of the two-segment equipment and possible effects on existing airplane certification are discussed. Operational restrictions on use of the procedures with current autothrottles and in icing or reported tailwind conditions are recommended. Using the NASA/UAL 727 procedures as a baseline, maximum upper glide slopes for representative 707/727/737/747 models are defined as a starting point for further study and/or flight evaluation programs. Author N74-17750*# Boeing Commercial Airplane Co., Seattle, Wash. HIGH TRANSONIC SPEED TRANSport aircRAFT STUDY Final Report, Jun. 1972-May 1973 Robert M. Kulfan, Frank D. Neumann, James W. Nisbet, Alan R. Mulally, James K. Murakami, Elias C. Noble, John P. McBarron, James L Stalter. David W. Gimmestad, and Mark B. Sussman Sep. 1973 205 prefs (Contract NAS2-7031) (NASA-CR-114658) Avail: NTIS HC $13.25 CSCL 01C An initial design study of high-transonic-speed transport aircraft has been completed. Five different design concepts were developed. These included fixed swept wing, variable-sweep wing. delta wing, double-fuselage yawed-wing, and single-fuselage yawed-wing aircraft. The boomless supersonic design objectives of range = 5560 Km (3000 nmi), payload-18 143 kg (40 000lb), Mach 1.2, and FAR Part 36 aircraft noise levels were achieved by the single-fuselage yawed-wing configuration with a gross weight of 211 828 Kg (467 000 lb). A noise level of 15 EPNdB below FAR Part 36 requirements was obtained with a gross weight increase to 226 796 Kg (500 000 lb). Although wing aeroelastic divergence was a primary design consideration for the yawed-wing concepts, the graphite-epoxy wings of this study were designed by critical gust and maneuver loads rather than by divergence requirements. The transonic nacelle drag is shown to be very sensitive to the nacelle installation. A six-degree-offreedom dynamic stability analysis indicated that the control coordination and stability augmentation system would require more development than for a symmetrical airplane but is entirely feasible. A three-phase development plan is recommended to establish the full potential of the yawed-wing concept. Author N74-17751*# Boeing Commercial Airplane Co., Seattle, Wash. DESIGN INTEGRATION AND NOISE STUDIES FOR JET STOL AIRCRAFT. TASK 7A: AUGMENTOR WING CRUISE BLOWING VALVELESS SYSTEM. VOLUME 1: SYSTEM DESIGN AND TEST INTEGRATION F. A. Roepcke and T. B. Nickson Apr. 1973 47 p refs (Contract NAS2-6344) (NASA-CR-114621; D6-40950-Vol-1) Avail: NTIS HC $5.50 CSCL 01C Exploratory design studies conducted to establish the configuration of an augmentor wing vruise blowing (valveless) system in a 150-passenger STOL airplane were reported in NASA CR-114570. Those studies have been updated to incorporate the results of static rig, flow duct, and wind tunnel tests. Minor adjustments in duct flow velocity, flap length, and blowing nozzle geometry were incorporated to provide airplane characteristics that minimize takeoff gross weight and achieve sideline noise objectives for an advanced commercial STOL airplane. Author N74-17752*# Boeing Commercial Airplane Co., Seattle, Wash. DESIGN INTEGRATION AND NOISE STUDIES FOR JET STOL AIRCRAFT. TASK 7C: AUGMENTOR WING CRUISE BLOWING VALVELESS SYSTEM. VOLUME 1: STATIC TESTING OF AUGMENTOR NOISE AND PERFORMANCE J. M. Campbell, D. L. Harkonen, and J. V. OKeefe Nov. 1973 45 prefs (Contract NAS2-6344) (NASA-CR-114622; D6-41216-Vol-1) Avail: NTIS HC $5.25 CSCL 01C Static performance and acoustic tests were conducted on a two-dimensional one-third-scale augmentor flap model that simulated a cruise blowing augmentor system designed for a scale augmentor flap model that simulated a cruise blowing augmentor, which offers a degree of 150-passenger STOL airplane. The cruise blowing augmentor, which offers a degree of simplicity by requiring no fan air diverter valves, was simulated by fitting existing lobe suppressor nozzles with new nozzle fairings. Flow turning performance of the cruise blowing augmentor was measured through a large range of flap deflection angles. The noise suppression characteristics of a multilayer acoustic lining installed in the augmentor were also measured. Author Augmentor wing ducting system studies conducted on a valveless system configuration that provides cruise thrust from the augmentor nozzles have shown that most of the duct system pressure loss would occur in the strut-wing duct y-junction and the wing duct-augmentor lobe nozzles. These components were selected for development testing over a range of duct Mach numbers and pressure ratios to provide a technical basis for predicting installed wing thrust loading and for evaluating design wing loading of a particular wing aspect ratios. The flow characteristics of ducting components with relatively high pressure loss coefficients were investigated. The turbulent pressure fluctuations associated with flows at high Mach numbers were analyzed to evaluate potential duct fatigue problems. Author N74-17754*# National Aeronautics and Space Administration. Mississippi Test Facility, Bay Saint Louis. METHODS AND COSTS ASSOCIATED WITH OUTFITTING The results from testing of a 0.3 scale model center duct inlet (S duct) for the Pratt and Whitney Aircraft JT8D-100 engines are presented. The objective of this test was to demonstrate that the required airflow of the JT8D-100 engine (480 lb/sec as compared to 334 lb/sec for JT8D-15) can be achieved with minimum modifications to the existing 727 airplane structure at acceptable levels of total pressure recovery and distortion. Steady-state pressure recovery, steady-state pressure distortion, and dynamic pressure measurements were taken at the engine face station. Surface static pressure measurements were taken along the duct. Test results indicated that the required airflow was achieved with acceptable pressure recovery (comparable to the current 727-200 S duct). Inlet inflow angle variation within the 727 airplane operating regime (minus 5 to 5 degrees) had no effect on the inlet performance. Pressure distortion at static and forward speed at takeoff airflow conditions are within P and WA limits for the Phase II duct when equipped with vortex generators. Static crosswind operation between 10 knots and 25 knots appears feasible at full takeoff power. Author (NASA-CR-2342) Avail: NTIS HC $4.75 CSCL 20A An experimental investigation of the aerodynamic noise and flow field characteristics of internal-flow jet-augmented flap configurations (abbreviated by the term jet flap throughout the study) is presented. The first part is a parametric study of the influence of the Mach number (subsonic range only), the slot nozzle aspect ratio and the flap length on the overall radiated sound power and the spectral composition of the jet noise, as measured in a reverberation chamber. In the second part, mean and fluctuating velocity profiles, spectra of the fluctuating velocity and space correlograms were measured in the flow field of jet flaps by means of hot-wire anemometry. Using an expression derived by Lilley, an attempt was made to estimate the overall sound power radiated by the free mixing region that originates at the orifice of the slot nozzle (primary mixing region) relative to the overall sound power generated by the free mixing region that originates at the trailing edge of the flap (secondary mixing region). It is concluded that at least as much noise is generated in the secondary mixing region as in the primary mixing region Furthermore, the noise generation of the primary mixing region appears to be unaffected by the presence of a flap. Author 01C Results of a series of experimental studies regarding the improvement of the maneuverability of fighter aircraft. The applicability of slotted and unslotted leading edge and trailing edge flaps was tested up to the transonic region on a wind tunnel model as a geometrically variable configuration variant. As a geometrically fixed configuration variant, strakes, or high sweepback leading edge modifications, were attached to the basic delta wing at the wing root and were tested in the entire Mach number range of a fighter aircraft. Through a combination of the maneuver aids improvements of more than 100% over the basic wing could be achieved in certain flight ranges. The efficiency of the strake in the range of high angles of attack considerably exceeds that of the flap system. Author N74-17758*# National Aeronautics and Space Administration. Langley Research Center, Langley Station, Va. WIND TUNNEL INVESTIGATION OF SIMULATED HELICOPTER ENGINE EXHAUST INTERACTING WITH WINDSTREAM | Craig S. Shaw and John C. Wilson Washington Mar. 1974 36 p refs Prepared in cooperation with Army Air Mobility R and D Lab., Hampton, Va. Film Supplement Number L-1139 to this report is available on request from NASA. Langley Res. Center Attn: Photographic Branch, Mail Stop 171, Hampton, Va. 23665 (NASA-TM-X-3016; L-9430) Avail: NTIS HC $3.25 CSCL 01C A wind tunnel investigation of the windstream-engine exhaust flow interaction on a light observation helicopter model has been conducted in the Langley V/STOL tunnel. The investigation utilized flow visualization techniques to determine the cause to determine the cause of exhaust shield overheating during cruise and to find a means of eliminating the problem. Exhaust flow attachment to the exhaust shield during cruise was found to cause the overheating. Several flow-altering devices were evaluated to find a suitable way to correct the problem. A flow deflector located on the model cowling upstream of the exhaust in addition to aerodynamic shield fairings provided the best solution. Also evaluated was heat transfer concept employing pin fins to cool future exhaust hardware. The primary flow visualization technique used in the investigation was a newly developed system employing neutrally buoyant helium-filled bubbles. The resultant flow patterns were recorded on motion picture film and on television magnetic tape. Author N74-17759*# National Aeronautics and Space Administration. Langley Research Center, Langley Station, Va. | COMPUTED LATERAL POWER SPECTRAL DENSITY RESPONSE OF CONVENTIONAL AND STOL AIRPLANES TO RANDOM ATMOSPHERIC TURBULENCE Jacob H. Lichtenstein Washington Mar. 1974 90 p refs (NASA-TN-D-7444; L-9035) Avail: NTIS HC $4.00 CSCL 01C A method of computing the power spectral densities of the lateral response of airplanes to random atmospheric turbulence was adapted to an electronic digital computer. By use of this program, the power spectral densities of the lateral roll, yaw. and sideslip angular displacement of several conventional and STOL airplanes were computed. The results show that for the conventional airplanes, the roll response is more prominent than that for yaw or sideslip response. For the STOL airplanes, on the other hand, the yaw and sideslip responses were larger than the roll response. The response frequency of the STOL airplanes generally is higher than that for the conventional airplanes. This combination of greater sensitivity of the STOL airplanes in yaw and sideslip and the frequency at which they occur could be a factor causing the poor riding qualities of this class of airplanes. Author N74-17760# Centre d'Essai Aeronautique, Toulouse (France). LABORATORY SIMULATION OF KINETIC HEATING EFFECTS ON THE STRUCTURE OF CONCORDE AIRCRAFT [RESTITUTION EN LABORATOIRE DES EFFETS DE L'ECHAUFFEMENT C INETIQUE SUR LA STRUCTURE DE L'AVION CONCORDE] M. Perrais 1973 18 p In FRENCH Presented at the Intern. Colloq. Simulation and Space, Toulouse, 10-14 Sep. 1973 Avail: NTIS HC $4.00 The kinetic heating effects on the Concorde aircraft structure were simulated by means of an infrared radiation facility. The simulation of convection flux effects by radiation flux poses a problem in that the radiation flux is practically unaffected by surface temperature, whereas the convection flux is. The radiation flux is therefore adapted to the surface as a function of the required temperature by subdividing the surface in heating zones on which a group of IR tubes radiates equal fluxes at given moments. For the Concorde structure 150 such groups were utilized. The thermal stress results obtained were compared to inflight stresses, and good concordance was found. ESRO A simplified two-dimensional peripheral jet theory for the equilibrium performance of an air cushion vehicle is investigated. The proposed theory intends to yield a rapid prediction of the actual flow rate and actual power requirements for an air cushion landing system in the hover condition. Nine specific nozzle configurations were tested to determine which resulted in the best power-height performance and whether the theory is able to predict the experimental performance. Three single peripheral jet configurations were tested at a trunk pressure of 80 psfg. Six distributed jet configurations were tested at a trunk pressure of 40 psfg. Effects of inward flow injection angles of 30 degrees and 60 degrees were investigated. (Modified author abstract) GRA N74-17762# Human Factors Research, Inc., Goleta, Calif. COLOR PERCEPTION IN THE TRANSITIONAL ZONES OF TRICOLOR GLIDE-SLOPE INDICATORS (GSI'S) Technical Report, 29 Jun. 29 Nov. 1973 Robert T. Hennessy and Gail J. Borden Nov. 1973 66 prefs (Contract NO0156-73-C-1008) (AD-771422; Rept-1751) Avail: NTIS CSCL 01/2 The report describes an investigation of color perception in the transitional zones of tricolor glide-slope indicators (GSI's) designed to aid helicopter night approaches to non-aviation ships. In GSI's with colors arranged, from top to bottom, yellow, green, red (YGR), an anomalous yellow or white appears in the transitional zones between the green and red color regions. This anomalous color can be misinterpreted as a too high signal and lead to a potentially hazardous descent maneuver. It was experimentally determined that the anomalous color zone occurs over an angular extent of at least 319 degrees in the GSI unit tested. (Modified author abstract) GRA N74-17763# Army Aviation Systems Test Activity, Edwards AFB, Calif. INSTRUMENTATION SPECIFICATION FOR CLIMATIC LABORATORY TESTS Kenneth R. Ferrell and Thomas L. Lynch Aug. 1973 10 p (AD-771053; USAASTA-73-41) Avail: NTIS CSCL 01/3 The specification defines the test instrumentation requirements for Climatic Laboratory tests conducted by the United States Army Aviation Systems Test Activity (USAASTA). This document is intended to provide guidance to contractors and activities that are required to instrument and support Climatic Laboratory tests conducted at Eglin Air Force Base, Florida. GRA N74-17764# United Aircraft Corp., Stratford, Conn. Sikorsky Aircraft Div. DYNAMIC MODEL WIND TUNNEL TESTS OF A VARIABLEDIAMETER, TELESCOPING-BLADE ROTOR SYSTEM (TRAC ROTOR) Evan A. Fradenburgh, Robert J. Murrill, and Edmond F. Kiely Jul. 1973 217 p refs (Contract DAAJ02-68-C-0074; DA Proj. 1F1-62204-A-139) (AD-771037; SER-50797; USAAMRDL-TR-73-32) Avail: NTIS CSCL 01/3 An analytical and experimental program was conducted to establish feasibility and determine characteristics of the Sikorsky TRAC rotor system, which is a unique variable-diameter, telescoping-blade concept for advanced rotary-wing aircraft. The program included a preliminary design study of a full-scale blade, wind tunnel tests of a dynamically scaled rotor model in various flight modes, and correlation of experimental results with theory. Feasibility was established for the TRAC rotor operating both as a high-speed compound helicopter and as a stopped/stowed rotor configuration. The basic blade structural design and the retraction system were verified with the model, which was scaled for operation at full tip speeds and forward speeds. (Modified author abstract) GRA N74-17765# AiResearch Mfg. Co., Torrance, Calif. MECHANICAL COMPONENT FAILURE PROGNOSIS STUDY Final Report Hans K. Ziebarth, Jee-Da Chang, and Joseph Kukel Jun. 1973 103 p refs Avail: (Contract DAAJ02-71-C-0049; DA Proj. 1F1-62203-A-434) (AD-771033; Rept-72-8745; USAAMRDL-TR-73-26) NTIS CSCL 01/3 The report presents the results of a study of failure prognosis of mechanical components of propulsive transmissions and gearboxes of Army aircraft. The step from on-line determination of component current mechanical condition by inferential, or diagnostic, methods to condition prognosis appears feasible if diagnostic techniques of the signature-composite interpretive type are used and diagnostic information is blended with inputs from the areas of component design theory, tribology, system abnormal physiology, and life predictive theory. For current component status determination, use of dynamic and lubricant-carried particle content signatures was found to be of greatest value. Use of the composite exceedance method in the dynamic data interpretation area and use of statistical methods recently developed in fluid-borne particle metrology in the lubricant particle content area would be indicated for attaining prognostic objectives. Author (GRA) N74-17766# Ketron, Inc., Wayne, Pa. William A. Meroney and Michael G. Temple (Contract N62269-72-C-0924) 15 Aug. 1973 (AD-771416; KTR-655-1) Avail: NTIS CSCL 01/3 The document describes, and gives user instructions for, two programs developed by KETRON to provide aircraft readiness and part availability data for the CASEE simulation model. These programs have been developed and tested on a CDC 6600 with 64K words of core. They are coded in FORTRAN 4, with the exception of COMPASS subroutines used to read the 3-M MAF and READY tapes. Conversion of the FORTRAN code to a programming environment where these tapes could be read directly in FORTRAN (e.g., IBM System 360 OS), would eliminate the need for the assembly language subroutines. Author (GRA) N74-17767# AeroVironment, Inc., Pasadena, Calif. P. B. S. Lissaman, S. C. Crow, P. B. MacCready, Jr., I. H. Tombach, and E. R. Bate, Jr. Oct. 1973 211 p refs Sponsored in part by Transportation Sys. Center (AD-771311; TSC-FAA-73-20) Avail: NTIS CSCL 01/1 Aircraft vortex wake descent and decay in a real atmosphere is studied analytically. Factors relating to encounter hazard, wake generation, wake descent and stability, and atmospheric dynamics are considered. Operational equations for encounter hazard, wake generation, and atmospheric dynamics are given, including a brief description of a possible automatic meteorological system to provide atmospheric data for an airport wake forecasting program. A new analysis for Crow instability in ambient turbulence is given, expressing time-to-linkage as an explicit function of the turbulent dissipation. GRA N74-17768# Goodrich (B. F.) Co., Brecksville, Ohio. AN EXPERIMENTAL STUDY OF THE PURE-YAW FREQUENCY RESPONSES OF THE 18 X 5.5 TYPE 7 AIRCRAFT TIRES Final Technical Report, Oct. 1971 May 1973 Fang-Haui H. Ho and Michael F. Hall Jun. 1973 150 p refs (Contract F33615-72-C-1268; AF Proj. 1369) (AD-771490; AFFDL-TR-73-79) Avail: NTIS CSCL 01/3 The steady-state yawed rolling parameters and the frequency responses of the tire forces and moments are obtained for a group of six (6) 18x5.5 type 7 aircraft tires. This group includes tires with rib and dimple tread designs, 8 ply and 14 ply carcass ratings, relatively new and worn tread conditions, as well as radial and bias carcass constructions. With various load, camber. yaw amplitude and frequency test conditions, the results are presented in fifty-nine (59) sets of frequency response curves The effects of various test conditions are discussed. A comparison of the radial, shimmy, and non-shimmy tires is given. Correlations between the experimental data of the aircraft tires and the well-known stretched string tire model has also been carried out and discussed in the report. Author (GRA) N74-17770# Environmental Protection Agency, Washington. D.C. Office of Noise Abatement and Control. 27 Jul. 1973 183 p The report is a result of an extensive task force effort to gather all available data pertinent to review and analysis of present and planned FAA noise regulatory actions and their consequences regarding aircraft and airport operations. It represents the interpretation of such data by the task group chairman responsible for this specific report. It does not necessarily reflect the official views of EPA and does not constitute a standard, specification or regulation. GRA 1 N74-17773# United Aircraft Corp., Stratford, Conn. Sikorsky Aircraft Div. THE EVALUATION OF A STALL-FLUTTER SPRING-DAMPER PUSHROD IN THE ROTATING CONTROL SYSTEM OF A CH-54B HELICOPTER Final Report David O. Adams Aug. 1973 104 p refs (Contract DAAJ02-71-C-0058) (AD-771962; SER-64372; USAAMRDL-TR-73-55) Avail: NTIS CSCL 01/3 The report describes a program conducted to evaluate the effect of rotating control system damping on stall-induced control loads and on aircraft handling qualities in stall. Such damping was introduced in the CH-54B control system by replacing the standard pushrods by a spring-damper assembly. The CH-54B helicopter was chosen as the test vehicle because it exhibits stall-induced loads. Dynamic analyses defined pushrod stiffness and damping characteristics required to reduce the high-frequency torsional response of the main rotor blades. Spring-damper pushrods exhibiting the desired characteristics were designed, : fabricated, and laboratory tested to assure that design requirements were met. The spring-damper pushrods were installed on a test rotor head and tested on the Sikorsky main rotor whirl tower. (Modified author abstract) GRA | N74-17774# United Aircraft Corp., Stratford, Conn. Sikorsky Aircraft Div. AEROELASTIC ANALYSIS OF A TELESCOPING ROTOR BLADE Final Report Raymond G. Carlson and Sebastian J. Cassarino Aug. 1973 122 p refs (Contract DAAJ02-72-C-0025; DA Proj. 1F1-63204-D-157) (AD-771963; USAAMRDL-TR-73-48) Avail: NTIS CSCL 01/3 Two computer programs were developed to evaluate the aeroelastic response of a telescoping rotor blade (TRAC). The first program calculates the uncoupled blade natural frequencies for flatwise, edgewise, and torsional degrees of freedom. The second program is a forced-response program and is a modification of the computer program provided to the Army under Contract DAAJ02-71-C-0024. It calculates the time history of the response of either a single blade or the complete rotor on a rigid-body airframe. Both steady-state and transient response can be analyzed. The forced-response program uses blade mode shapes and natural frequencies calculated from the natural frequency program. The mathematical model used reflects the unique structure of the TRAC blade, which consists of torque tube, outboard blade, jackscrew, and two tension straps. (Modified author abstract) GRA The design of an on-board gross weight and center of gravity measurement system applicable to the CH-47 and UH-1 helicopters was developed, and a prototype CH-47 system was evaluated in the laboratory. Gross weight accuracies of plus or minus 1.6% of maximum design weight were achieved in a laboratory simulation of the environment. A flightworthy prototype was subsequently fabricated and evaluated in flight tests on a CH-47 helicopter at the U.S. Army Aviation Systems Test Activity. Edwards AFB, California. The results show accuracies of plus or minus 1% full scale with the helicopter in a rotors-static condition. With rotors-in-motion, however, errors up to 5000 lb occurred in the gross weight due to the inaccuracy of the rotor lift measurement. It is concluded that the method of measuring rotor lift via rotor structural stresses is viable, but further investigation is required into the nature of the thermal stresses and dynamic forces induced by hot lubricants and pitch actuator cylinder. Author (GRA) N74-17776# Air Force Systems Command, Wright-Patterson M. Rozenblat 28 Nov. 1973 12 P (AD-771632; FTD-HT-23-534-74) Avail: NTIS CSCL 01/3 In the last 10-15 years the aeronautical engineering characteristics of cargo aircraft have changed considerably. There has been a sharp increase in the ranges of possible flight velocities and flying weights and flight safety requirements have been raised. However, the method of using aerodynamic corrections to the velocity indicator retained a number of tolerances which were valid earlier. Under modern conditions these tolerances lead to considerable errors in information on flight velocity under certain important flight modes, in particular under the conditions of take-off. GRA N74-17777# Carnegie-Mellon Univ., Pittsburgh, Pa. Dept. of DEVELOPMENT OF DESIGN AND ANALYTICAL TECH- The work includes: continuing development of universityindustry interaction; development of educational material including reports on manufacturing methods, Weibull statistics, and stresses due to an elliptical hole in an anisotropic plate; and, advanced research into synthesis procedures for mechanically fastened joints and elastic fracture mechanics for laminated composite plates. The research projects demonstrate useful design capabilities, new analystic and numerical results, and experimental data. (Modified author abstract) GRA N74-17778# Army Foreign Science and Technology Center, Charlottesville, Va. AIR MOBILE TECHNICAL MAINTENANCE UNIT V. Yurev 16 Nov. 1973 6 р Transl. into ENGLISH from Aviat. Kosmonavt. (Moscow), no. 1, 1972 p 22 (AD-771786; FSTC-HT-23-2102-72) Avail: NTIS CSCL 01/3 The report describes a typical maintenance facility and maintenance problems extant in a Soviet helicopter unit. GRA N74-17779# Battelle Columbus Labs., Ohio. GENERAL AVIATION COST IMPACT STUDY. VOLUME 1: EXECUTIVE SUMMARY Final Report J. W. Chadwick, T. W. Hall, E. T. Yeager, and R. W. Cote Jun. 1973 36 p refs (Contract DOT-FA72WA-3118) (AD-771603) Avail: NTIS CSCL 01/3 The report in four volumes presents the results of an analysis of the effects of cost changes on general aviation activity. The major objectives of the study were to investigate ownership and operating costs in each segment of general aviation, and to develop methodology for evaluating the cost impact of regulatory changes on general aviation activity. The study effort included compilation of a cost and activity data base, definition of fixed and variable cost centers, determination of cost sensitivity relationships and determination of cost impact relationships. Volume 1 provides a summary of the overall study. (Modified GRA author abstract) N74-17780# Battelle Columbus Labs., Ohio. GENERAL AVIATION COST IMPACT STUDY. VOLUME 2: RESEARCH METHODOLOGY Final Report J. W. Chadwick, T. W. Hall, E. T. Yeager, and R. W. Cote Jun. |