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  • Aerodynamics
  • Structural Mechanics
  • 1990-1994  (9)
  • 1945-1949  (23)
  • 1990  (9)
  • 1946  (23)
  • 1
    Electronic Resource
    Electronic Resource
    Flight physiology of migrating Urania fulgens (Uraniidae) moths: kinematics and aerodynamics of natural free flight (1990)
    Springer
    Journal of comparative physiology 167 (1990), S. 145-154 
    Details
    ISSN: 1432-1351
    Keywords: Moth ; Flight ; Migration ; Kinematics ; Aerodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Air speeds and wing kinematics were determined for the Neotropical moth Urania fulgens in natural migratory flight over Lake Gatun, Republic of Panama. Morphological parameters are presented for the same insects filmed in free flight. A quasi-steady aerodynamic analysis was used to show that unsteady mechanisms of lift generation are probably not necessary to produce the forces necessary for fast forward flight. Mechanical power requirements of forward flight were estimated from the biomechanical and morphological data. Over an airspeed range of 1.5 to 4.5 m/s, the mechanical power required to fly is predicted to increase dramatically with forward speed. A comparison of estimated metabolic rates with endogenous lipid reserves suggests that U. fulgens feeds extensively on flower nectar during migration from Central into South America.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192414
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The calculation of incompressible separated turbulent boundary layers (1990)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 11 (1990), S. 39-56 
    Details
    ISSN: 0271-2091
    Keywords: Aerodynamics ; Turbulence ; Separation ; CLmax ; Laminar ; Bubble ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The algebraic turbulent model of Baldwin and Lomax was incorporated into the incompressible full Navier-Stokes code FIDAP. This model was extensively tested in the past in finite difference codes. We believe that the incorporation of the model also into the finite element code has resulted in a practical method to compute a variety of separated turbulent 2D flows. Firstly, we use the model to compute the attached flow about an aerofoil. Next, the application of the model to separated flows is presented by computing the flows at high angles of attack up to maximum lift. It is shown that the model is capable of predicting separation, steady stall and CLmax. As a difficult test of the model we compute the laminar separation bubble development directly using the full Navier-Stokes finite element code. As far as we know, this approach has not yet been reported. The importance of using an appropriate upwinding is discussed. When possible, comparison of computed results with experiments is presented and the agreement is good.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650110104
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    Paper (German National Licenses)
    Fulltext
  • 3
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    Structural Analysis (1990)
    In:  CASI
    Details
    Publication Date: 2018-06-09
    Description: NASTRAN basically performs complex analyses of a structural design and predicts how various elements of the design will react to many different conditions of stress and strain. NASTRAN applications include almost every kind of structure and construction, and the program's substructuring capability allows different segments of a structure to be modeled jointly after having been modeled separately. NASTRAN permits the effects of control systems, aerodynamic transfer functions and other nonstructural problems, such as static response to thermal expansion, to be incorporated in the solution of the structural problem. Examples of industrial users of NASTRAN include DeVlieg-Sundstrand, Belvidere, Illinois, Texas Instruments, Temple, Texas and Texas Instrument's Central Research Laboratories. NASTRAN is available to private industry through NASA's Computer Software Management and Information Center.
    Keywords: Structural Mechanics
    Type: Spinoff 1990; 114-115; NASA-NP-138
    Format: application/pdf
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  • 4
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    Stress Analyzer (1990)
    In:  CASI
    Details
    Publication Date: 2018-06-09
    Description: SPATE 900 Dynamic Stress Analyzer is an acronym for Stress Pattern Analysis by Thermal Emission. It detects stress-induced temperature changes in a structure and indicates the degree of stress. Ometron, Inc.'s SPATE 9000 consists of a scan unit and a data display. The scan unit contains an infrared channel focused on the test structure to collect thermal radiation, and a visual channel used to set up the scan area and interrogate the stress display. Stress data is produced by detecting minute temperature changes, down to one-thousandth of a degree Centigrade, resulting from the application to the structure of dynamic loading. The electronic data processing system correlates the temperature changes with a reference signal to determine stress level.
    Keywords: Structural Mechanics
    Type: Spinoff 1990; 140-141; NASA-NP-138
    Format: application/pdf
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  • 5
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    Secondary frequencies in the wake of a circular cylinder with vortex shedding (1990)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A detailed numerical study of two-dimensional flow past a circular cylinder at moderately low Reynolds numbers was conducted using three different numerical algorithms for solving the time-dependent compressible Navier-Stokes equations. It was found that if the algorithm and associated boundary conditions were consistent and stable, then the major features of the unsteady wake were well-predicted. However, it was also found that even stable and consistent boundary conditions could introduce additional periodic phenomena reminiscent of the type seen in previous wind-tunnel experiments. However, these additional frequencies were eliminated by formulating the boundary conditions in terms of the characteristic variables. An analysis based on a simplified model provides an explanation for this behavior.
    Keywords: Aerodynamics
    Type: NASA-CR-181998 , NAS 1.26:181998 , ICASE-90-16 , AD-A227099
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  • 6
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    Active Optics for a Segmented Primary Mirror on a Deep-Space Optical Receiver Antenna (DSORA) (1990)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: This article investigates the active optical control of segments in the primary mirror to correct for wavefront errors in the Deep-Space Optical Receiver Antenna (DSORA). Although an exact assessment of improvement in signal blur radius cannot be made until a more detailed preliminary structural design is completed, analytical tools are identified for a time when such designs become available. A brief survey of appropriate sensing approaches is given. Since the choice of control algorithm and architecture depends on the particular sensing system used, typical control systems, estimated complexities, and the type of equipment required are discussed. Once specific sensor and actuator systems are chosen, the overall control system can be optimized using methods identified in the literature.
    Keywords: Structural Mechanics
    Type: JPL-TDA-PR-42-103
    Format: application/pdf
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  • 7
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    Predicting The Compression Strength Of Impact-Damaged Sandwich Panels (1990)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The objective of this work was to develop a technique for predicting the residual compression strength of sandwich panels containing impact damage in one facesheet. The technique was tailored to predict the strength of specimens that exhibit a failure mode involving the formation of kink bands at locations of peak strain in the region of impact damage. Under continued compression loading, the kink bands propagate in a stable manner perpendicular to the applied load. When a critical kink-band length is reached, growth becomes unstable corresponding to panel failure. The analysis follows in two sections. The first section calculates the far-field stress required for stable kink-band growth and the second calculates that required for unstable growth. The residual strength prediction is made when the stress for stable growth becomes equal to that for unstable kink-band growth. Initial comparisons between analysis and experiment show good agreement.
    Keywords: Structural Mechanics
    Type: 15th International Conference on Composite Materials; Jun 27, 2005 - Jul 01, 2005; Durban; South Africa
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  • 8
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    A Mechanical Model for Elastic Fiber Microbuckling (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A two-dimensional mechanical model is presented to predict the compressive strength of unidirectional fiber composites using technical beam theory and classical elasticity. First, a single fiber resting on a matrix half-plane is considered. Next, a more elaborate analysis of a uniformly laminated, unidirectional fiber composite half-plane is presented. The model configuration incorporates a free edge which introduces a buckling mode that originates at the free edge and decays into the inferior of the half-plane. It is demonstrated that for composites of low volume fraction (less than 0.3), this decay mode furnishes values of buckling strain that are below the values predicted by the Rosen (1965) model. At a higher volume fraction the buckling mode corresponds to a half wavelength that is in violation of the usual assumptions of beam theory. Causes for deviations of the model prediction froi?i existing experimental results are discussed.
    Keywords: Structural Mechanics
    Type: Journal of Applied Mechanics; 57; 138-149
    Format: text
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  • 9
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    The Importance of the Measurement of the Unsteady Wake of the Aeroassist Flight Experiment Vehicle: A White Paper (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-10
    Description: The High Frequency Radiometer (HFR) is the only instrument on the Aeroassist Flight Experiment (AFE) with sufficient temporal resolution to discern the frequency of unsteady wake oscillations. Determining both the frequency and amplitude of wake unsteadiness during AFE atmospheric entry is essential for reliably predicting the geometry and motion of the wake of future Aeroassisted Space Transfer Vehicles (ASTV). These parameters directly affect the location and size of the pay- load and the weight of the required afterbody heat protection. The purpose of the AFE is to validate the technologies required for the design of ASTVs, which will be used to exploit Earth-lunar space. This validation will be conducted at a combination of vehicle size, altitude, and velocity not obtainable in ground-based facilities. The AFE will provide the experimental flight data needed to improve our understanding of hypersonic-wake physics and to validate computational predictions of the aerodynamic and heating loads, including afterbody radiative heating loads, on an ASTV. Reliable prediction of ASTV wake flows will ensure that payloads are located within the shear-layer envelope and will determine the amount of thermal protection the payloads require. Specifically, understanding the temporal nature of the wake unsteadiness is important for two reasons. Most importantly, analysis of ground-based experiments suggests that wake unsteadiness results in a variation of as much as +/- 5 deg in the shear-flow turning angle. This angle must be reliably predicted to avoid shear-layer impingement on the vehicle afterbody, which would result in heating rates of about 10 W/sq cm, of the same order as on the forebody stagnation point. Secondly, the energy associated with wake unsteadiness will reduce the static enthalpy of the wake fluid and cause an error of as much as 30% in the amount of predicted wake radiative heating. Therefore, the HFR flight data, which will quantify the frequency and amplitude of the wake unsteadiness, are required for the verification of computational models of ASTV flowfields. Measurement of wake unsteadiness has been endorsed by the Peer Science Steering Group and the AFE Computational Fluid Dynamics (CFD) Working Group. The Peer Science Steering Group has stressed that a reliable measurement of the wake unsteadiness is fundamental because incorporating unsteadiness represents a substantial challenge to the CFD community, and a reliable measurement will raise confidence in the computer simulation. The AFE CFD Working Group has stated that 44 any data which would prove the existence and effects of unsteady flow would be extremely valuable.
    Keywords: Aerodynamics
    Type: A-90321
    Format: text
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  • 10
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    The Lagrangian Multiplier Method of Finding Upper and Lower Limits to Critical Stresses of Clamped Plates (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The theory of Lagrangian multipliers is applied to the problem of finding both upper and lower limits to the true compressive buckling stress of a clamped rectangular plate. The upper and lower limits thus bracket the truss, which cannot be exactly found by the differential-equation approach. The procedure for obtaining the upper limit, which is believed to be new, presents certain advantages over the classical Raleigh-Rite method of finding upper limits. The theory of the lower-limit procedure has been given by Trefftz but, in the present application, the method differs from that of Trefftz in a way that makes it inherently more quickly convergent. It is expected that in other buckling problems and in some vibration problems problems the Lagrangian multiplier method finding upper and lower limits may be advantageously applied to the calculation of buckling stresses and natural frequencies.
    Keywords: Structural Mechanics
    Type: AD-A301132 , NACA-TR-848 , NASA-TM-111368 , NAS 1.15:111368
    Format: application/pdf
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  • 11
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    Effect of the NACA Injection Impeller on the Mixture Distribution of a Double-row Radial Aircraft Engine (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: For the normal range of engine power the impeller provided marked improvement over the standard spray-bar injection system. Mixture distribution at cruising was excellent, maximum cylinder temperatures were reduced about 30 degrees F, and general temperature distribution was improved. The uniform mixture distribution restored the normal response of cylinder temperature to mixture enrichment and it reduced the possibility of carburetor icing, while no serious loss in supercharger pressure rise resulted from injection of fuel near the impeller outlet. The injection impeller also furnished a convenient means of adding water to the charge mixture for internal cooling.
    Keywords: Aerodynamics
    Type: NACA-TN-1069
    Format: application/pdf
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  • 12
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    Correlation Tests of the Ditching Behavior of an Army B-24D Airplane and a 1/16-size Model (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Behaviors of both model and full-scale airplanes were ascertained by making visual observations, by recording time histories of decelerations, and by taking motion picture records of ditchings. Results are presented in form of sequence photographs and time-history curves for attitudes, vertical and horizontal displacements, and longitudinal decelerations. Time-history curves for attitudes and horizontal and vertical displacements for model and full-scale tests were in agreement; maximum longitudinal decelerations for both ditchings did not occur at same part of run; full-scale maximum deceleration was 50 percent greater.
    Keywords: Aerodynamics
    Type: NACA-WR-L-617 , NACA-MR-L6A03
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  • 13
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    The Knock-Limited Performance of Fuel Blends Containing Spiropentane, Methylenecyclobutane, Di-Tert-Butyl Ether, Methyl Tert-Butyl Ether, and Triptane (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Tests show that at inlet-air temperatures of 250 deg F and 100 deg F the knock-limited performance of the base fuel of blends, leaded with 4 ml TEL per gallon and containing 20 percent spiropentane, was reduced at fuel/air ratios below 0.085. The 20 percent methylenecyclobutane reduced the knock-limited power of the base fuel at fuel/air ratios below 0.112. Di-tert-butyl ether, methyl-tert-butyl ether, and triptane increased the knock-limited power of the base fuel at all fuel/air ratios and at both temperatures.
    Keywords: Aerodynamics
    Type: NACA-WR-E-222 , NACA-RB-E6D22
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  • 14
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    Flight Investigation to Improve the Dynamic Longitudinal Stability and Control-Feel Characteristics of the P-63A-1 Airplane (AAF No. 42-68889) with Closely Balanced Experimental Elevators (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results of flight tests of a control-feel aid presented. This device consisted of a spring and dashpot connected in series between the control stick and airplane structure. The device was tested in combination with an experimental elevator and bobweight which had given unsatisfactory dynamic stability and control-feel characteristics in previous tests. The control-feel aid effected marked improvement in both the control-feel characteristics and the control-feel dynamic longitudinal stability of the airplane.
    Keywords: Aerodynamics
    Type: NACA-WR-L-730 , NACA-MR-L6E20
    Format: application/pdf
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  • 15
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    Field of Flow About a Jet and Effect of Jets on Stability of Jet-Propelled Airplanes (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A theoretical investigation was conducted on jet-induced flow deviation. Analysis is given of flow inclination induced outside cold and hot jets and jet deflection caused by angle of attack. Applications to computation of effects of jet on longitudinal stability and trim are explained. Effect of jet temperature on flow inclination was found small when thrust coefficient is used as criterion for similitude. The average jet-induced downwash over tail plane was obtained geometrically.
    Keywords: Aerodynamics
    Type: NACA-WR-L-213 , NACA-ACR-L6C13
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  • 16
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    High-Speed Wind-Tunnel Tests of a Twin-Fuselage Pursuit Airplane (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: At the request of the Air Technical Service Command, U.S. Army Air Forces, a 0.22-scale model of a twin-fuselae pursuit airplane was built and tested at the Ames Aeronautical Laboratory. The tests of this model were made in order that the aerodynamic characteristics of the airplane, especially at high speed, might be predicted. The results shown in this report consist of force data for the model and critical Mach numbers of parts of the model as determined from pressure-distribution measurements. The results indicate that a diving tendency of the airplane can be expected at Mach numbers above 0.70 at lift co-efficients from 0 to 0.4. There is an indication that the Mach number at which the airpolane would first experience a diving tendency for lift coefficients from 0 to 0.2 can be increased if the critical speed of the radiator enclosures is increased, and the wing-fuselage-juncture fillets are improved.
    Keywords: Aerodynamics
    Type: NACA-WR-A-75 , NACA-MR-A6D03
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  • 17
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    Flight Investigation at High Speeds of Profile Drag of Wing of a P-47D Airplane Having Production Surfaces Covered with Camouflage Paint (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Wing section outboard of flap was tested by wake surveys in Mach range of 0.25 - 0.78 and lift coefficient range 0.06 - 0.69. Results indicated that minimum profile-drag coefficient of 0.0097 was attained for lift coefficients from 0.16 to 0.25 at Mach less than 0.67. Below Mach number at which compressibility shock occurred, variations in Mach of 0.2 had negligible effect on profile drag coefficient. Shock was not evident until critical Mach was exceeded by 0.025.
    Keywords: Aerodynamics
    Type: NACA-WR-L-98 , NACA-ACR-L6B21
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  • 18
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    Comparison of Wind-Tunnel and Flight Measurements of Stability and Control Characteristics of a Douglas A-26 Airplane (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Tests in Langley pressure tunnel of model XA-26 bomber were compared with those of A-26B (twin-engine attack bomber) and showed that static longitudinal stability, indicated by elevator-fixed neutral points, and variation of elevator deflection in straight and turning flight were good. Airplane possessed improved stability at low speeds which was attributed to pronounced stalling at root of production wing. At rudder-force reversal at speeds higher than those in flight tests, agreement in rudder-fixed and rudder-free static directional stability was good. Hinge moment obtained at zero sideslip was satisfactory for determining aileron forces in sideslip.
    Keywords: Aerodynamics
    Type: NACA-WR-L-99 , NACA-ARR-L5H11a
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  • 19
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    Analysis of V-G Records from the SNB-1 Airplane (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Availability data obtained on SNB-1 trainer-class airplanes were analyzed and results presented as flight envelopes which predict occurrences of large values of air speed and acceleration. Comparison is made with SNJ-4 trainer-class airplane data analyzed by the same method. It is concluded that flight envelopes are satisfactory; that the two types show large differences in flight loads and speeds experience; and that SNB-1 will seldom, if ever, exceed design limit load factor and restricted speed, which SNJ-4 can be expected to exceed design-limit load factor and restricted speed in a very small number of flight hours.
    Keywords: Aerodynamics
    Type: NACA-WR-L-759 , NACA-MR-L6F27a
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  • 20
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    The Knock-Limited Performance of Fuel Blends Containing Aromatics V : N-Propylbenzene, N-Butylbenzene, Isobutylbenzene, M-Xylene, and 1-Isopropyl-4-Methylbenzene (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Results are reported of knock-limited tests of five aromatics, each individually blended with selected base fuels and tested with and without TEL, using 17.6, F-4, and F-3 small-scale engines. The five aromatics rated in the following order of decreasing antiknock effectiveness at fuel/air ratio 0.10: m-xylene, 1-isopropyl-4-methylbenzene, n-propylbenzene, isobutylbenzene, and n-butylbenzene.
    Keywords: Aerodynamics
    Type: NACA-WR-E-237 , NACA-ARR-E6C05
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  • 21
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    An Experimental Investigation of Flow Conditions in the Vicinity of an NACA D(sub S)-type Cowling (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Data are presented of the flow conditions in the vicinity of an NACA D sub S -type cowling. Tests were made of a 1/2 scale-nacelle model at inlet-velocity ratios ranging from 0.23 to 1.02 and angles of attack from 6 deg to 10 deg. The velocity and direction of flow in the vertical plane of symmetry of the cowling were determined from orifices and tufts installed on a board aligned with the flow. Diagrams showing velocity ratio contours and lines of constant flow angles are given.
    Keywords: Aerodynamics
    Type: NACA-WR-L-747 , NACA-MR-L6H14
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  • 22
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    Development of Wing Inlets (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Lift, drag, internal flow, and pressure distribution measurements were made on a low-drag airfoil incorporating various air inlet designs. Two leading-edge air inlets are developed which feature higher lift coefficients and critical Mach than the basic airfoil. Higher lift coefficients and critical speeds are obtained for leading half of these inlet sections but because of high suction pressures near exist, slightly lower critical speeds are obtained for the entire inlet section than the basic airfoil.
    Keywords: Aerodynamics
    Type: NACA-WR-L-727 , NACA-ACR-L6B18
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  • 23
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    Critical Mach Numbers of Thin Airfoil Sections with Plain Flaps (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Critical Mach number as function of lift coefficient is determined for certain moderately thick NACA low-drag airfoils. Results, given graphically, included calculations on same airfoil sections with plain flaps for small flap deflections. Curves indicate optimum critical conditions for airfoils with flaps in such form that they can be compared with corresponding results for zero flap deflections. Plain flaps increase life-coefficient range for which critical Mach number is in region of high values characteristic of low-drag airfoils.
    Keywords: Aerodynamics
    Type: NACA-WR-W-2 , NACA-ACR-6A30
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  • 24
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    Analysis of Effect of Rolling Pull-Outs on Wing and Aileron Loads of a Fighter Airplane (1946)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: An analysis was made to determine the effect of rolling pull-out maneuvers on the wing and aileron loads of a typical fighter airplane, the P-47B. The results obtained indicate that higher loads are imposed upon wings and ailerons because of the rolling pull-out maneuver, than would be obtained by application of the loading requirements to which the airplane was designed. An increase of 102 lb or 15 percent of wing weight would be required if the wing were designed for rolling pull-out maneuver. It was also determined that the requirements by which the aileron was originally designed were inadequate.
    Keywords: Aerodynamics
    Type: NACA-WR-L-270
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  • 25
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    Free-Spinning Tunnel Tests of a 1/20-Scale Model of the Chance Vought XF6U-1 Airplane, TED No. NACA 2390 (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: A spin investigation has been conducted in the Langley 20-foot free-spinning tunnel on a 1/20-scale model of the Chance Vought XF6U-1 airplane, The effects of control settings and movements upon the erect and inverted spin and recovery characteristics of the model were determined for the normal-fighter condition. The investigation also included tests for the take-off fighter condition (wing-tip tanks plus fuel added) spin-recovery parachutes, and simulated pilot escape. In general, for the normal-fighter condition, the model was extremely oscillatory in roll, pitch, and yaw. The angles of the fuselage varied from extremely flat to inverted attitudes, and the model rotated with the rudder in a series of short turns and glides. Recoveries by rudder reversal were rapid but the model would immediately go into a spin in the other direction. Recoveries by merely neutralizing the rudder were satisfactory when the elevator and ailerons were set to neutral, the ensuing flight path being a steep glide. Thus, it is recommended that all controls be neutralized for safe recovery from spins obtained on the airplane. With the external wing-tip tanks installed, the spins were somewhat less oscillatory in roll but recovery could not be obtained unless full-down elevator was used in conjunction with the rudder. If a spin is entered inadvertently with the full-scale airplane with external wing-tip tanks installed and if recovery is not imminent after a recovery attempt is made, it is recommended that the tanks be jettisoned and the controls neutralized.
    Keywords: Aerodynamics
    Type: NACA-RM-L6H27
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  • 26
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    Free-Spinning-Tunnel Tests of a 1/20-Scale Model of the Northrop N-9M Airplane (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Spin tests of a 1/20-scale model of the Northrop N-9M airplane have been performed in the Langley 20-foot free-spinning tunnel. The erect and inverted spin and recovery characteristics were determined for various loading conditions and the effect of deflecting the flaps and of extending the landing gear was investigated. The investigation also included tests to determine the size parachute required for satisfactory spin recovery by parachute action alone. The tests were performed at an equivalent spin altitude of 15,000 feet. A specialized recovery technique consisting of rapid full reversal of the rudder pedals against the spin combined with turning the wheel against the spin and movement of the stick forward is recommended for all loadings and configurations of the airplane. The results also indicated that a 7-foot-diameter spin-recovery parachute having a drag coefficient of 0.7 attached to the outboard wing tip with a towline of 10 to 30 feet or an 8.8-foot-diameter parachute attached to the fixed portion of the wing between the elevons and the pitch flaps with a 30-foot towline would provide satisfactory recovery from demonstration spins by parachute action alone. It appears possible that the first N-9M airplane may have crashed because of failure to recover from a spin.
    Keywords: Aerodynamics
    Type: NACA-RM-L6G30
    Format: application/pdf
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  • 27
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    Investigation of the Behavior of Thin-Walled Panels with Cutouts (1946)
    In:  CASI
    Details
    Publication Date: 2019-08-17
    Description: The present paper deals with the computation and methods of reinforcement of stiffened panels with cutouts under bending loads such as are applied to the sides of a fuselage. A comparison is maade between the computed and test results. Results are presented of tests on panels with cutouts under tensile and compressive loads.
    Keywords: Structural Mechanics
    Type: NACA-TM-1094 , ; 454
    Format: application/pdf
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  • 28
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    Calibration Tunnel for High Speed (1946)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: For the nvestigation of measuring instruments at higher speeds up to a Mach number 0.7 a tunnel with closed test section was built in 1942 which was as simple and cheap as possble. The blower was a radial blower with straight sheet vanes of 800-millimeter diameter the tips of which were bent backward a little. The blower sucks the air through a honeycomb of diameter 1.2 neter with wide meshes. The air is then accelerated in a short cone with smooth transition to the test section. The cylindrical test section of 200-milimeter diameter has two windows (which are displaced 180 deg from each other. The instruments may be introduced and observed through and observed through these windows. . The cross section is then enlarged by a straight diffuser 3.5 meters long and reaches the ninefold cross section. The air flows back into the room through a disk diffuser of 2-meter diameter. The maximum speed in the jet is 250 m/s for a drive power of 35 kT., if there are no installations in the jet. The velocity is determined by pressure holed along the test section.
    Keywords: Aerodynamics
    Type: NACA/TM-1103
    Format: application/pdf
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  • 29
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    Theoretical and Experimental Data for a Number of NACA 6A-Series Airfoil Sections (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: The NACA 6A-series airfoil sections were designed to eliminate the trailing-edge cusp which is characteristic of the NACA 6-series sections. Theoretical data are presented for NACA 6A-series basic thickness forms having the position of minimum pressure at 30-, 40-, and 50-percent chord and with thickness ratios varying from 6 percent to 15 percent. Also presented are data for a mean line designed to maintain straight sides on the cambered sections. The experimental results of a two dimensional wind tunnel investigation of the aerodynamic characteristics of five NACA 64A-series airfoil sections and two NACA 63A-series airfoil sections are presented. An analysis of these results, which were obtained at Reynolds numbers of 3 x 10(exp 6), 6 x 10(exp 6), and 9 x 10(exp 6), indicates that the section minimum drag and maximum lift characteristics of comparable NACA 6-series and 6A-series airfoil sections are essentially the same. The quarter-chord pitching-moment coefficients and angles of zero lift of NACA 6A-series airfoil sections are slightly more negative than those of corresponding NACA 6-series airfoil sections. The position of the aerodynamic center and the lift-curve slope of smooth NACA 6-series sections. The addition of standard leading-edge roughness causes the lift-curve slope of the newer sections to decrease with increasing airfoil thickness ratio.
    Keywords: Aerodynamics
    Type: NACA-RM-L6J01
    Format: application/pdf
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  • 30
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    Plane and Three-Dimensional Flow at High Subsonic Speeds (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: For two- and three-dimensional flow in a compressible medium, a simple relation is given by which, to a first approximation, the quantitative influence of compressibility upon the velocities and pressures can be understood in a clear manner. In the application of this relation the distinct behaviors of two-dimensional and axially symmetric three-dimensional flow with increasing Mach number are brought out. For slender elliptic cylinders and ellipsoids of revolution, calculations are made of the critical Mach number; that is, the Mach number at which local sonic velocity is achieved on the body. As a further example, the lifting wing of finite span is considered, and it is shown that the increase of wing lift with Mach number at a given angle of attack is greatly dependent upon the aspect ratio b(exp 2)/F.
    Keywords: Aerodynamics
    Type: NACA-TM-1105 , Lilienthal Gesellschaft; 127; 97-101
    Format: application/pdf
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  • 31
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    Wind-Tunnel Tests of a Modified Koppers Aeromatic Impeller-Generator Combination, TED No. NACA ARR 2901 (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: An investigation was conducted in the 6- by 6-foot test section of the Langley stability tunnel on a modified Koppers Aeromatic wind-driven impeller-generator combination. This investigation consisted of a few fixed pitch tests and a series of variable pitch tests, The fixed pitch tests indicated that the impeller should operate between the blade-pitch angles of 20 and 32deg at the specified output of 11.7 kilowatts in order to remain within the specified rotational speed of from 5000 to 8000 rpm for airspeeds of from 130 to 175 miles per hour. The requirement that the impeller maintain rotational speeds of - between 5000 and 8000 rpm as the impeller output varied from 0 to ll.7 kilowatts at airspeeds of from 130 to 175 miles per hour was not met at any tims during the variable pitch tests. The main difficulty seemed to be the inability of the impeller blades to change blade-pitch angle smoothly and quickly as load conditions varied. There was some indication that the vibration normally occurring on an airplane might cause the impeller to operate satisfactorily.
    Keywords: Aerodynamics
    Type: NACA-RM-L6K19
    Format: application/pdf
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  • 32
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    Wind-Tunnel Investigation of the Stability of the Jettisonable Nose Section of the X-3 Airplane (1946)
    In:  CASI
    Details
    Publication Date: 2019-07-11
    Description: Because previous work has indicated that jettisonable nose sections of airplanes may be inherently unstable, and thus may cause dangerous centripetal accelerations on a pilot after jettisoning during high-speed flight, an investigation has been conducted in the Langley 20-foot free-spinning tunnel to determine the behavior in descent of a model of the jettisonable nose section of the Douglas X-3 airplane. The effects of varying the center-of-gravity position, of attaching fins of various sizes, and of installing a stabilizing parachute were investigated. In the investigation the model descended with its front and trimmed 36 deg above the horizontal and rotated about a vertical wind axis while rolling about its longitudinal body axis. The nose section was made to descend in a stable front-down attitude when stabilizing fins were installed in conjunction with movement of the center of gravity forward or when a stable parachute was attached to the model.
    Keywords: Aerodynamics
    Type: NACA-RM-L8K18a
    Format: application/pdf
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