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  • Other Sources  (48)
  • Aerodynamics  (40)
  • Seismology  (8)
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  • LUNAR AND PLANETARY EXPLORATION
  • Limnology
  • 2020-2022
  • 1975-1979
  • 1945-1949  (27)
  • 1940-1944  (21)
  • 1920-1924
  • 1949  (27)
  • 1942  (21)
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  • 2020-2022
  • 1975-1979
  • 1945-1949  (27)
  • 1940-1944  (21)
  • 1920-1924
Year
  • 1
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    California Institute of Technology Pasadena
    In:  Seismological Laboratory Bulletin, Milano, California Institute of Technology Pasadena, vol. 1948, no. 6, pp. 129, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1949
    Keywords: Earthquake catalog ; Seismology ; Seismicity
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  • 2
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    In:  Bull. Seism. Soc. Am., Milano, California Institute of Technology Pasadena, vol. 39, no. 6, pp. 79-92, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1949
    Keywords: Seismology ; BSSA
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  • 3
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    In:  Trans., Am. Geophys. Union, Milano, California Institute of Technology Pasadena, vol. 30, no. 6, pp. 169, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1949
    Keywords: NOISE ; Micro seismicity ; Seismology ; Meteorology ; EOS
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  • 4
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    In:  Trans., Am. Geophys. Union, Milano, California Institute of Technology Pasadena, vol. 30, no. 6, pp. 595-597, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1949
    Keywords: Seismology ; Seismicity ; EOS
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  • 5
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    American Red Cross, 2 pp.
    In:  Princeton, New Jersey, 7 + 273 pp., 1. ed., American Red Cross, 2 pp., vol. 34, no. XVI:, pp. 385-389, (ISBN 0-12-305355-2)
    Publication Date: 1949
    Keywords: Seismology ; Seismicity ; Earthquake precursor: prediction research
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  • 6
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    Princeton Univ. Press
    In:  Princeton, New Jersey, 7 + 273 pp., 1. ed., Princeton Univ. Press, vol. 34, no. XVI:, pp. 385-389, (ISBN 0-12-305355-2)
    Publication Date: 1949
    Keywords: Seismology ; Seismicity ; Textbook of geophysics
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  • 7
    Publication Date: 2019-06-28
    Description: No abstract available
    Keywords: Aerodynamics
    Type: NACA-RM-L9C04
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  • 8
    Publication Date: 2019-06-28
    Description: The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom have been determined. The problem resolves itself into the solution of certain definite integrals, which have been identified as Bessel functions of the first and second kind and of zero and first order. The theory, being based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing-section theory relating to the steady case. The air forces being known, the mechanism of aerodynamic instability has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been arrived at. The solution is of a simple form and is expressed by means of an auxiliary parameter K.
    Keywords: Aerodynamics
    Type: NACA-TR-496
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  • 9
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    In:  CASI
    Publication Date: 2019-07-11
    Description: The purpose of this presentation is to give you a survey of a field of aerodynamics which has for a number of years been attracting an ever growing interest. The subject is the theory of flows with friction, and, within that field, particularly the theory of friction layers, or boundary layers. As you know, a great many considerations of aerodynamics are based on the so-called ideal fluid, that is, the frictionless incompressible fluid. By neglect of compressibility and friction the extensive mathematical theory of the ideal fluid (potential theory) has been made possible.
    Keywords: Aerodynamics
    Type: NACA-TM-1217
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  • 10
    Publication Date: 2019-07-11
    Description: An investigation has been made in the Langley stability tunnel to determine the low-speed static stability and control characteristics of a model of the Bell MX-776. The results of the investigation indicated that the basic model configuration was longitudinally stable in the angle-of-attack range from about -16 deg. to 16 deg. but that the stability was a minimum near O deg angle of attack. The data indicated an aerodynamic-center position about 0.64 body diameters behind the center of gravity at low angles of attack. Reduction in the size of the front horizontal fins increased the longitudinal stability. With 20 percent of the span of the normal front horizontal fins cut off the aerodynamic center was about 1.04 body diameters behind the center of gravity, and with front horizontal fins having the same area as the front vertical fins, the aerodynamic center was 2.26 body diameters behind the center of gravity (at low angles of attack).
    Keywords: Aerodynamics
    Type: NACA-RM-SL9G08
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  • 11
    Publication Date: 2019-07-11
    Description: Rocket-powered models were flown at high-subsonic, transonic, and supersonic speeds to determine the zero-lift drag of fin-stabilized parabolic bodies of revolution differing in fineness ratio and in position of maximum diameter. The present paper presents the results for fineness ratio 12.5, 8.91 and 6.04 bodies having maximum diameters located at stations of 20, 40, 60, and 80 percent of body length. All configurations had cut-off sterns and all had equal base, frontal, and exposed fin areas. For most of the supersonic-speed range models having their maximum diameters at the 60-percent station gave the lowest values of drag coefficient. At supersonic speeds, increasing the fineness ratio generally reduced the drag coefficient for a given position of maximum diameter.
    Keywords: Aerodynamics
    Type: NACA-RM-L9I30
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  • 12
    Publication Date: 2019-07-12
    Description: A supersonic compressor design having supersonic velocity at the entrance of the stator is analyzed on the assumption of two-dimensional flow. The rotor and stator losses assumed in the analysis are based on the results of preliminary supersonic cascade tests. The results of the analysis show that compression ratios per stage of 6 to 10 can be obtained with adiabatic efficiency between 70 and 80 percent. Consideration is also given in the analysis to the starting, stability, and range of efficient performance of this type of compressor. The desirability of employing variable-geometry stators and adjustable inlet guide vanes is indicated. Although either supersonic or subsonic axial component of velocity at the stator entrance can be used, the cascade test results suggest that higher pressure recovery can be obtained if the axial component is supersonic.
    Keywords: Aerodynamics
    Type: NACA-RM-L9G06
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  • 13
    Publication Date: 2019-08-13
    Description: In the Institute for Flight Mechanics of the DVL a reactor arrangement with a maximum output of 100 kg was investigated as an expedient for the termination of dangerous spins on an airplane of the FW 56 type. reproduce the influence of a disturbance of the steady spin condition by a pitching or yawing moment. The tests were meant to reproduce the influence of a disturbance of the steady spin condition by a pitching and yawing moment.
    Keywords: Aerodynamics
    Type: NACA-TM-1221 , Zentrale fuer Wissenschaftliches Berichtswesen bei der Deutschen Versuchsanstalt fuer Luftfahrt Nr. 1027
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  • 14
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    In:  CASI
    Publication Date: 2019-07-13
    Description: When auxiliary jet engines are installed on airframes; as well as in some new designs, the jet engines are mounted in such a way that the jet stream exhausts in close proximity to the fuselage. This report deals with the behavior of the jet in close proximity to a two-dimensional surface. The experiments were made to find out whether the axially symmetric stream tends to approach the flat surface. This report is the last of a series of four partial test reports of the Goettingen program for the installation of jet engines, dated October 12, 1943. This report is the complement of the report on intake in close proximity to a wall.
    Keywords: Aerodynamics
    Type: NACA-TM-1214 , Untersuchungen und Mitteilungen; 3057
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  • 15
    Publication Date: 2019-07-13
    Description: In an earlier report UM No.1117 by Gothert,the single-source method was applied to the compressible flow around circles, ellipses, lunes, and around an elongated body of revolution at different Mach numbers and the results compared as far as possible with the calculations by Lamla ad Busemann. Essentially, it was found that with favorable source arrangement the single-source method is in good agreement with the calculations of the same degree of approximation by.Lamla and Busemann. Near sonic velocity the number of steps must be increased considerably in order to sufficiently approximate the adiabatic curve. After exceeding a certain Mach number where local supersonic fields occur already, it was no longer possible, in spite of the substantially increased number of steps, to obtain a systematic solution because the calculation diverged. This result,was interpreted to mean that above this point of divergence the symmetrical type of flow ceases to exist and changes into the unsymmetrical type characterized by compressibility shocks.
    Keywords: Aerodynamics
    Type: NACA-TM-1203 , Untersuchungen und Mitteilurgen; 1471
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  • 16
    Publication Date: 2019-07-13
    Description: The problem of the motion of an elongated body of revolution in an incompressible fluid may, as is known, be solved approximately with the aid of the distribution of sources along the axis of the body. In determining the velocity field, the question of whether the body moves uniformly or with an acceleration is no factor in the problem. The presence of acceleration must be taken into account in determining the pressures acting on the body. The resistance of the body arising from the accelerated motion may be computed either directly on the basis of these pressures or with the aid of the so-called associated masses (inertia coefficients). A different condition holds in the case of the motion of bodies in a compressible gas. In this case the finite velocity of sound must be taken into account.
    Keywords: Aerodynamics
    Type: NACA-TM-1230 , Prikladnaya Matematika I Mekhanika; 10; 4; 521-524
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  • 17
    Publication Date: 2019-07-11
    Description: Various ways were tried recently to decrease the friction drag of a body in a flow; they all employ influencing the boundary layer. One of them consists in keeping the boundary layer Laminar by suction; promising tests have been carried out. Since for large Reynolds numbers the friction drag of the laminar boundary layer is much lower than that of the turbulent boundary layer, a considerable saving in drag results from keeping the boundary layer laminar, even with the blower power required for suction taken into account. The boundary layer is kept laminar by suction in two ways: first, by reduction of the thickness of the boundary layer and second, by the fact that the suction changes the form of the velocity distribution so that it becomes more stable, in a manner similar to the change by a pressure drop. There by the critical Reynolds number of the boundary layer (USigma*/V) (sub crit) becomes considerably higher than for the case without suction. This latter circumstance takes full effect only if continuous suction is applied which one might visualize realized through a porous wall. Thus the suction quantities required for keeping the boundary layer laminar become so small that the suction must be regarded as a very promising auxiliary means for drag reduction.
    Keywords: Aerodynamics
    Type: NACA-TM-1216
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  • 18
    Publication Date: 2019-07-11
    Description: Four component measurements of 12 wings of symmetric profile having flaps with chord ratios t(sub R)/t(sub L) = 0.3 and t(sub R)/t(sub L) = 0.2 are treated in this report. As a result of the investigations, the effects of plan form and gap between fixed surface and control surface have been clarified. Lift, drag, pitching moment, and hinge moment were measured in the control-surface deflection range: -23 deg 〈 or = beta 〈 or = 23 deg and the range of angle of attack: -20 deg 〈 or = alpha 〈 or = 20 deg. Six wings with flaps of small chord (t(sub R)/t(sub L) 〈 0.1) were investigated at large flap settings.
    Keywords: Aerodynamics
    Type: NACA-TM-1206 , ZWB Forschungsbericht; Rept-552/4
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  • 19
    Publication Date: 2019-07-11
    Description: The present report describes a new method for the prediction of the flow pattern of a gas in the two-dimensional and axially symmetrical case. It is assumed that the expansion of the gas is adiabatic and the flow stationary. The several assumptions necessary of the nozzle shape effect, in general, no essential limitation on the conventional nozzles. The method is applicable throughout the entire speed range; the velocity of sound itself plays no singular part. The principal weight is placed on the treatment of the flow near the throat of a converging-diverging nozzle. For slender nozzles formulas are derived for the calculation of the velocity components as function of the location.
    Keywords: Aerodynamics
    Type: NACA-TM-1215 , Luftfahrtforschung; 91-102
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  • 20
    Publication Date: 2019-07-11
    Description: An investigation has been conducted in the Langley 20-foot free-spinning tunnel of a 1/29-scale model of the Republic XF-91 airplane with a.conventional-tail arrangement installed. Previously, tests were made on the model with a vee tail installed. The erect spin and recovery characteristics of the model were determined for the normal loading with the wing installed at various amounts of incidence. The spin investigation also included inverted-spin tests, spin-recovery-parachute tests, tests with the center of gravity moved rearward, and tests with external fuel tanks added to the model. In addition, several tail.modifications were tested,on the model in an attempt, to improve the model's spin-recovery characteristics. The results indicate that any fully developed spin obtained on the airplane with the conventional tail installed will be satisfactorily terminated if rudder reversal is accompanied by moving the ailerons with the spin (stick right in a right spin).Decreasing the wing incidence from 6deg to -2deg should have a beneficial effect on the recovery characteristics of the airplane. Recovery characteristics by normal use of controls (full rudder reversal followed by moving the elevators down) will be satisfactory if the wing incidence,of the airplane is -2deg. Installation of external fuel tanks (with or without fuel) will have a somewhat adverse effect on the recovery characteristics of the airplane, but if the recovery technique includes movement of the ailerons to full with the spin, the spin rotation will be terminated rapidly. Varying the position of the center of gravity within the limits indicated to be possible on the airplane should not affect the recovery characteristics.
    Keywords: Aerodynamics
    Type: NACA-RM-SL9E20
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  • 21
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    In:  CASI
    Publication Date: 2019-07-11
    Description: The plane problem of the vibrating airfoil in supersonic flow is dealt with and solved within the scope of a linearized theory by the method of the acceleration potential.
    Keywords: Aerodynamics
    Type: NACA-TM-1238 , ZWB Forschungsbericht Nr. 1903; Rept-1903
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  • 22
    Publication Date: 2019-07-11
    Description: A supplementary investigation on the stabilization of the Jettisonable nose section of the X-2 airplane has been conducted in the Langley 20-foot free-spinning tunnel. It was found that the nose section could be stabilized by the addition of curved fins which could be folded against the fuselage for normal flight.
    Keywords: Aerodynamics
    Type: NACA-RM-L9F22
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  • 23
    Publication Date: 2019-07-11
    Description: The characteristics of a cargo-dropping device having extensible rotating blades as load-carrying surfaces have been studied in simulated vertical descent in the Langley 20-foot free-spinning tunnel. The investigation included tests to determine the variation in vertical sinking speed with load. A study of the blade characteristics and of the test results indicated a method of dynamically balancing the blades to permit proper functioning of the device.
    Keywords: Aerodynamics
    Type: NACA-RM-L9G14
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  • 24
    Publication Date: 2019-07-12
    Description: A 0.1-size powered dynamic model of a large, high-speed flying boat was landed in Langley tank no. 1 into oncoming waves 4 feet high (full size). The model was tested with two afterbodies of differing lengths (4.12 and 6.63 beams). The short afterbody had a constant angle of dead rise of 22.5deg and a keel angle of 6.5deg. The long afterbody had warped dead rise and a keel angle of 8.5deg. The vertical accelerations were slightly greater and the maximum angular accelerations and maxim= trims were slightly less for the model with the long afterbody than for the model with -the short afterbody. A wave length of 210 feet (full size) imposed the highest accelerations on the model with either the long or the short afterbody.
    Keywords: Aerodynamics
    Type: NACA-RM-SL9B09
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  • 25
    Publication Date: 2019-07-12
    Description: The inlet wide vanes for the supersonic compressor of the XJ55-FF-1 engine were studied as a separate component in order to determine the performance prior to installation in the compressor test rig. Turning angles approached design values, and increased approximately to through the inlet Mach number range from 0.30 to choke. A sharp break in turning angle was experienced when the choke condition was reached. The total-pressure loss through the guide vanes was approximately 1 percent for the unchoked conditions and from 5 to 6 percent when choked.
    Keywords: Aerodynamics
    Type: NACA-RM-SE9E03
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  • 26
    Publication Date: 2019-07-13
    Description: During the past several years it has been necessary for aeronautical research workers to exert a good portion of their effort in developing the means for conducting research in the high-speed range. The transonic range particularly has presented a very acute problem because of the choking phenomena in wind tunnels at speeds close to the speed of sound. At the same time, the multiplicity of design problems for aircraft introduced by the peculiar flow problems of the transonic speed range has given rise to an enormous demand for detail design data. Substantial progress has been made, however, in developing the required research techniques and in supplying the demand for aerodynamic data required for design purposes. In meeting this demand, it has been necessary to resort to new techniques possessing such novel features that the results obtained have had to be viewed with caution. Furthermore, the kinds of measurements possible with these various techniques are so varied that the correlation of results obtained by different techniques generally becomes an indirect process that can only be accomplished in conjunction with the application of estimates of the extent to which the results of measurements by any given technique are modified by differences that are inherent in the techniques. Thus, in the establishment of the validity and applicability of data obtained by any given technique, direct comparisons between data from different sources are a supplement to but not a substitute for the detailed knowledge required of the characteristics of each technique and fundamental aerodynamic flow phenomena.
    Keywords: Aerodynamics
    Type: NASA-TM-X-56649 , NACA Conference on Aerodynamic Problems of Transonic Airplane Design; Sep 27, 1949 - Sep 29, 1949; Hampton, VA; United States
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  • 27
    Publication Date: 2019-07-13
    Description: Lately it has been proposed to reduce the friction drag of a body in a flow for the technically important large Reynolds numbers by the following expedient: the boundary layer, normally turbulent, is artificially kept laminar up to high Reynolds numbers by suction. The reduction in friction drag thus obtained is of the order of magnitude of 60 to 80 percent of the turbulent friction drag, since the latter, for large Reynolds numbers, is several times the laminar friction drag. In considering the idea mentioned one has first to consider whether suction is a possible means of keeping the boundary layer laminar. This question can be answered by a theoretical investigation of the stability of the laminar boundary layer with suction. A knowledge, as accurate as possible, of the velocity distribution in the laminar boundary layer with suction forms the starting point for the stability investigation. E. Schlichting recently gave a survey of the present state of calculation of the laminar boundary layer with suction.
    Keywords: Aerodynamics
    Type: NACA-TM-1205 , Schriften der Deutschen Akademie der Luftfahrtforschung; 8; 1
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  • 28
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    In:  Bull. Seism. Soc. Am., Milano, Gustav Fischer, vol. 32, no. 6, pp. 163-192, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1942
    Keywords: Seismology ; Magnitude ; Energy (of earthquakes) ; Intensity ; Strong motions ; BSSA ; FROTH ; (abstract)
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  • 29
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    In:  Bull. Geol. Soc. Am., Milano, Gustav Fischer, vol. 53, no. 6, pp. 1818-1819, pp. L24306, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1942
    Keywords: Seismology ; Earth model, also for more shallow analyses ! ; CRUST
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  • 30
    Publication Date: 2018-06-05
    Description: As part of the program of flight tests of airplane propellers to determine compressibility effects at high speeds, preliminary flights have been made with a conventional three-blade propeller (Hamilton Standard 3155-6) on a Bell YP-39 airplane. This preliminary report presents the high-speed data obtained thus far with a brief analysis of the results.
    Keywords: Aerodynamics
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  • 31
    Publication Date: 2019-06-28
    Description: Test of a ducted body with Internal flow were made in the 8-foot high-speed wind tunnel for the purpose of studying the effects on external drag and an critical speed of the addition of efficient inlet and outlet openings to a basic streamline shape. Drag tests of a 13.6- inch-diameter streamline body of fineness ratio 6.14 were made at Mach numbers ranging from 0.20 to 0.75. The model was centrally mounted on a 9-percent-thick airfoil and was designed to have an efficient airfoil-body juncture and a high critical speed. An air inlet at the nose and various outlets at the tail were added: drag and internal-flow data were obtained over the given speed range. The critical speed of the ducted bodies was found to be as high as that of the streamline body. The external - drag with air flow through the body did not exceed the drag of the basic streamline shape. No appreciable variation in the efficiency of the diffuser section of the internal duct occurred throughout the Mach number range of the tests.
    Keywords: Aerodynamics
    Type: NACA-WR-L-486
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  • 32
    Publication Date: 2019-06-28
    Description: Data taken from tests at constant speed to establish trim limits of stability, tests at accelerated speeds to determine stable limits of center of gravity shift, and tests at decelerated speeds to obtain landing characteristics of several model hull forms were used to establish hull design effect on longitudinal stability of porpoising. Results show a reduction of dead rise angle as being the only investigated factor reducing low trim limit. Various methods of reducing afterbody interference increased upper trim limit
    Keywords: Aerodynamics
    Type: NACA-WR-L-468
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  • 33
    Publication Date: 2019-06-28
    Description: Two airfoil plans were used for propeller blades. One is modified Clark Y section designed for structural reliability and the second an NACA 16 airfoil section designed to produce minimum aerodynamic losses. At low air speeds, the propeller designed for aerodynamic effects showed a gain of from 1.5 to 4.0 percent in propulsive efficiency over the conventional type depending on the pitch. Because of the numerous variables involved, the effect of each one on the aerodynamic characteristics of the propellers could not be isolated.
    Keywords: Aerodynamics
    Type: NACA-WR-L-404
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  • 34
    Publication Date: 2019-06-28
    Description: Porpoising characteristics were observed on V-body fitted with tail surfaces for different combinations of load, speed, moment of inertia, location of pivot, elevator setting, and tail area. A critical trim was found which was unaltered by elevator setting or tail area. Critical trim was lowered by moving pivot either forward or down or increasing radius or gyration. Increase in mass and moment of inertia increased amplitude of oscillations. Complete results are tabulated and shown graphically.
    Keywords: Aerodynamics
    Type: NACA-WR-L-479
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  • 35
    Publication Date: 2019-06-28
    Description: Tests were conducted on hydrofoil assemblies approximating an arrangement for use under seaplanes or surface boats. A series of hydrofoils, each supported by two struts, was towed at various depths ranging from partial submersions to a depth of 5-chord lengths. At depths greater than 4 or 5 chords, the influence of the surface of the water is small; hydrofoils operating at low speed will have characteristics similar to those of airfoils of the same section.
    Keywords: Aerodynamics
    Type: NACA-WR-L-758
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  • 36
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    In:  CASI
    Publication Date: 2019-06-28
    Description: Analysis was made to determine characteristics required of a balancing-tab system for ailerons in order to reduce aileron stick forces to any desired magnitude. Series of calculations based on section data were made to determine balancing-tab systems of various chord tabs and ailerons that will give, for a particular airplane, zero rate of aileron hinge moment with aileron deflection and yet will produce same maximum rate of roll as a plain unbalanced 15-percent chord aileron of same span. Effects of rolling velocity and of forces in tab link on aileron hinge moments have been included.
    Keywords: Aerodynamics
    Type: NACA-WR-L-346
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  • 37
    Publication Date: 2019-06-28
    Description: Investigations were undertaken to improve the ailerons of a P-51 fighter so as to obtain greater effectiveness without increasing the stick forces. Modifications consisted of increasing the deflection range of the aileron to 70 percent and changing the original concave section to a thick section with beveled trailing edge. Results of the modified ailerons showed an increase in effectiveness over the original aileron of 70 percent at low speed and 55 percent at high speeds.
    Keywords: Aerodynamics
    Type: NACA-WR-L-636
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  • 38
    Publication Date: 2018-06-05
    Description: Tests were made in the NACA two-dimensional low-turbulence tunnel of three gun ports with a height of approximately 4 percent of the chord faired into an NACA 66,2-213 low-drag-airfoil section by bulging the section at the gun port. Gun ports faired in this manner had practically no effect on the maximum lift and the critical compressibility speed of the section and showed only small increase in the drag in the range of lift coefficients for high-speed and cruising-flight conditions.
    Keywords: Aerodynamics
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  • 39
    Publication Date: 2019-06-28
    Description: Several airfoils, Including a conventional NACA 23021 and some low-drag airfoils for which the thickness had been increased to the point that they were considered doubtfully conservative with respect to separation, were investigated as smooth airfoils and after the application of a standard roughness. The results show some of the airfoils to be critical to separation resulting from such flow disturbances. It is concluded, pending the further investigation of separation difficulties, that airfoil sections falling definitely within the conservative range should be used.
    Keywords: Aerodynamics
    Type: NACA-WR-L-659
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  • 40
    Publication Date: 2019-08-17
    Description: This report deals with the development of a method which gives a lucid and convenient solution of the flow conditions in the vicinity of a common, thick airfoil section wherein the thickness of the profile is taken into account. The method consists in making the airfoil the streamline in a parallel flow by disposing on its mean line certain source and vortex distributions the fields of which are superposed on the parallel flow. These distributions of singularities are secured for the generalized Karman-Trefftz profile by means of conformal transformation from the flow about a circle. Five different distribution functions are afforded for the density of superposition, which combine in a specified manner to the necessary distributions of singularity and represent a generalized Karman-Trefftz profile in parallel flow. For these profiles the speed for each of the five distributions is then computed independently of the angle of attack.
    Keywords: Aerodynamics
    Type: NACA-TM-1023
    Format: application/pdf
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  • 41
    Publication Date: 2019-08-14
    Description: Wing pressure distribution diagrams for several angles of attack and flap deflections of 0 degrees, 20 degrees, and 40 degrees are presented. The normal force coefficients agree with lift coefficients obtained in previous test of the same model, except for the maximum lifts with flap deflection. Pressure distribution measurements were made at Reynolds Number of about 6,000,000.
    Keywords: Aerodynamics
    Type: NACA-WR-L-678
    Format: application/pdf
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  • 42
    Publication Date: 2019-08-07
    Description: At the request of the Army Air Forces, Materiel Command, tests were made in the two-Dimensional low-turbulence tunnel of a mode l submitted by Bell Aircraft Corporation as the tip section of the wing of the xp-63 airplane. " The model was a NACA 66, 2x-2l6 a = 0.6 airfoil section of 50-inch chord and made of dural according to standard sheet-metal practice. The model was fitted for an internal-balance aileron with a tab and a Frise type aileron. Several alterations of the skirts and balance on the internal- balance aileron were tested to obtain the various aerodynamic characteristics of the aileron.
    Keywords: Aerodynamics
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  • 43
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    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: The present report deals with a number of problems, particularly with the interaction of the fuselage with the wing and tail, on the basis of simple calculating method's derived from greatly idealized concepts. For the fuselage alone it affords, in variance with potential theory, a certain frictional lift in yawed flow, which, similar to the lift of a wing of small aspect ratio, is no longer linearly related to the angle of attack. Nevertheless there exists for this frictional lift something like a neutral stability point the position of which on oblong fuselages appears to be associated with the lift increase of the fuselage in proximity to the zero lift, according to the present experiments. The Pitching moments of the fuselage can be determined with comparatively great reliability so far as the flow conditions in the neighborhood of the axis of the fuselage can be approximated if the fuselage were absent, which, in general, is not very difficult. For the unstable contribution of the fuselage to the static longitudinal stability of the airplane it affords comparatively simple formulas, the evaluation of which offers little difficulty. On the engine nacelles there is, in addition a very substantial wing moment contribution induced by the nonuniform distribution of the transverse displacement flow of the nacelle along the wing chord; this also can be represented by a simple formula. A check on a large number of dissimilar aircraft types regarding the unstable fuselage and nacelle moments disclosed an agreement with the wind-tunnel tests, which should be sufficient for practical requirements. The errors remained throughout within the scope of instrumental accuracy.
    Keywords: Aerodynamics
    Type: NACA-TM-1036 , Luftfahrtforschung; 18; 3-Feb; 52-56
    Format: application/pdf
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  • 44
    Publication Date: 2019-07-12
    Description: This report covers tests of a 5-foot model of the NACA 66,2-420 low-drag airfoil at high speeds including the critical compressibility speed. Section coefficients of lift, drag, and pitching moment, and extensive pressure-distribution data are presented. The section drag coefficient at the design lift coefficient of 0.4 increased from 0.0042 at low speeds to 0.0052 at a Mach number of 0.56 (390 mph at 25,000 ft altitude). The critical Mach number was about 0.60. The results cover a Reynold number range from 4 millions to 17 millions.
    Keywords: Aerodynamics
    Type: NACA-ACR-234 , NACA-SR-234
    Format: application/pdf
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  • 45
    Publication Date: 2019-07-12
    Description: Tests were made in the NACA 19-foot pressure tunnel of a simplified twin-engine bomber model with an NACA low-drag wing primarily to obtain an indication of the effects of engine nacelles on the characteristics of the model both with and without simple split trailing-edge flaps. Nacelles with conventional-type cowlings representative of those used on an existing high-performance airplane and with NACA high-speed type E cowlings were tested. The tests were made without propeller slipstream. The aerodynamic effects of adding the nacelles to the low-drag wing were similar to the effects commonly obtained by adding similar nacelles to conventional wings. The maximum lift coefficient without flaps was slightly increased, but the increment in maximum lift due to deflecting the flaps was somewhat decreased. The stalling characteristics were improved by the presence of the nacelles. Addition of the nacelles had a destabilizing effect on the pitching moments, as is usual for nacelles that project forward of the wing. The drag increments due to the nacelles were of the usual order of magnitude, with the increment due to the nacelles with NACA type E cowlings approximately one-third less than that of the nacelles with conventional cowlings with built-in air scoops.
    Keywords: Aerodynamics
    Type: NACA-ACR-225 , NACA-SR-225
    Format: application/pdf
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  • 46
    Publication Date: 2019-07-12
    Description: An investigation was made in the LWAL 7- by 10-foot tunnel of internally balanced, sealed ailerons for the Curtiss XP-60 airplane. Ailerons with tabs and. with various amounts of balance were tested. Stick forces were estimated for several aileron arrangements including an arrangement recommended for the airplane. Flight tests of the recommended arrangement are discussed briefly in an appendix, The results of the wind-tunnel and flight tests indicate that the ailerons of large or fast airplanes may be satisfactorily balanced by the method developed.
    Keywords: Aerodynamics
    Type: NACA-ACR-257 , NACA-SR-257
    Format: application/pdf
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  • 47
    Publication Date: 2019-07-12
    Description: As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required.
    Keywords: Aerodynamics
    Type: NACA-ACR-220 , NACA-SR-220
    Format: application/pdf
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  • 48
    Publication Date: 2019-07-12
    Description: Tests were made in the NACA two-dimensional low turbulence pressure tunnel of a highly cambered low-drag airfoil (NACA 65,3-618) with a plain flap designed for lift control. The results indicate that such a combination offers attractive possibilities for obtaining low profile-drag coefficients over a wide range of lift coefficients without large reductions of critical speed.
    Keywords: Aerodynamics
    Type: NACA-ACR-242 , NACA-SR-242
    Format: application/pdf
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