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  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Collection: Technical Report Archive and Image Library
Aerodynamic characteristics of horizontal tail surfaces

Aerodynamic characteristics of horizontal tail surfaces

Date: 1940
Creator: Silverstein, Abe & Katzoff, S
Description: Collected data are presented on the aerodynamic characteristics of 17 horizontal tail surfaces including several with balanced elevators and two with end plates. Curves are given for coefficients of normal force, drag, and elevator hinge moment. A limited analysis of the results has been made. The normal-force coefficients are in better agreement with the lifting-surface theory of Prandtl and Blenk for airfoils of low aspect ratio than with the usual lifting-line theory. Only partial agreement exists between the elevator hinge-moment coefficients and those predicted by Glauert's thin-airfoil theory.
Contributing Partner: UNT Libraries Government Documents Department
Annual report of the National Advisory Committee for Aeronautics (25th).administrative report including Technical Report nos. 645 to 680

Annual report of the National Advisory Committee for Aeronautics (25th).administrative report including Technical Report nos. 645 to 680

Date: 1940
Creator: unknown
Description: Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
Contributing Partner: UNT Libraries Government Documents Department
The application of basic data on planing surfaces to the design of flying-boat hulls

The application of basic data on planing surfaces to the design of flying-boat hulls

Date: January 1940
Creator: Diehl, Walter S.
Description: Basic lift data on planing surfaces have been analyzed and the data applied to the design of flying-boat hulls. It is shown that a balance between air and water forces requires that the beam of the planing area bear a relation to the wing area that is determined by the lift coefficient of the wing and by the angle of dead rise in the planing surface. It is also shown that the fore-and-aft extent of the required planing area depends on the angle of dead rise. Failure to provide sufficient length of planing area appears to be the main reason for the poor water performance sometimes obtained when a large angle of dead rise is used.
Contributing Partner: UNT Libraries Government Documents Department
Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel

Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel

Date: January 1, 1940
Creator: Becker, John V
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel, Special Report

Boundary-Layer Transition on the N.A.C.A. 0012 and 23012 Airfoils in the 8-Foot High-Speed Wind Tunnel, Special Report

Date: January 1, 1940
Creator: Becker, John V.
Description: Determinations of boundary-layer transition on the NACA 0012 and 2301 airfoils were made in the 8-foot high-speed wind tunnel over a range of Reynolds Numbers from 1,600,000 to 16,800,000. The results are of particular significance as compared with flight tests and tests in wind tunnels of appreciable turbulence because of the extremely low turbulence in the high-speed tunnel. A comparison of the results obtained on NACA 0012 airfoils of 2-foot and 5-foot chord at the same Reynolds Number permitted an evaluation of the effect of compressibility on transition. The local skin friction along the surface of the NACA 0012 airfoil was measured at a Reynolds Number of 10,000,000. For all the lift coefficient at which tests were made, transition occurred in the region of estimated laminar separation at the low Reynolds Numbers and approach the point of minimum static pressure as a forward limit at the high Reynolds Numbers. The effect of compressibility on transition was slight. None of the usual parameters describing the local conditions in the boundary layer near the transition point served as an index for locating the transition point. As a consequence of the lower turbulence in the 8-foot high-speed tunnel, the transition points occurred consistently ...
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The calculated effect of various hydrodynamic and aerodynamic factors on the take-off of a large flying boat

The calculated effect of various hydrodynamic and aerodynamic factors on the take-off of a large flying boat

Date: January 1, 1940
Creator: Olson, R E & Allison, J M
Description: Report presents the results of an investigation made to determine the influence of various factors on the take-off performance of a hypothetical large flying boat by means of take-off calculations. The factors varied in the calculations were size of hull (load coefficient), wing setting, trim, deflection of flap, wing loading, aspect ratio, and parasite drag. The take-off times and distances were calculated to the stalling speeds and the performance above these speeds was separately studied to determine piloting technique for optimum take-off.
Contributing Partner: UNT Libraries Government Documents Department
Coal-Mine Accidents in the United States, 1937

Coal-Mine Accidents in the United States, 1937

Date: 1940
Creator: Adams, William W.; Geyer, L. E. & Parry, M. G.
Description: Report compiled by the U.S. Bureau of Mines including statistics on fatal and non-fatal accidents in coal mines located in the United States as well as data regarding the various operations (e.g., number of miners employed and average production). The information is organized into tables for comparison and the text draws some overall conclusions in the summary.
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Constant-pressure blowers

Constant-pressure blowers

Date: January 1, 1940
Creator: Sorensen, E
Description: The conventional axial blowers operate on the high-pressure principle. One drawback of this type of blower is the relatively low pressure head, which one attempts to overcome with axial blowers producing very high pressure at a given circumferential speed. The Schicht constant-pressure blower affords pressure ratios considerably higher than those of axial blowers of conventional design with approximately the same efficiency.
Contributing Partner: UNT Libraries Government Documents Department
Correlation Index to Aid in Interpreting Crude-Oil Analyses

Correlation Index to Aid in Interpreting Crude-Oil Analyses

Date: 1940
Creator: Smith, Harold M.
Description: Report issued by the Bureau of Mines discussing the correlation index used for analyses of crude oils. The correlation index is presented and described in detail. This report includes tables, and illustrations.
Contributing Partner: UNT Libraries Government Documents Department
Correlation of cooling data from an air-cooled cylinder and several multicylinder engines

Correlation of cooling data from an air-cooled cylinder and several multicylinder engines

Date: January 1, 1940
Creator: Pinkel, Benjamin & Ellerbrock, Herman H , Jr
Description: The theory of engine-cylinder cooling developed in a previous report was further substantiated by data obtained on a cylinder from a Wright r-1820-g engine. Equations are presented for the average head and barrel temperatures of this cylinder as functions of the engine and the cooling conditions. These equations are utilized to calculate the variation in cylinder temperature with altitude for level flight and climb. A method is presented for correlating average head and barrel temperatures and temperatures at individual points on the head and the barrel obtained on the test stand and in flight. The method is applied to the correlation and the comparison of data obtained on a number of service engines. Data are presented showing the variation of cylinder temperature with time when the power and the cooling pressure drop are suddenly changed.
Contributing Partner: UNT Libraries Government Documents Department
Design charts relating to the stalling of tapered wings

Design charts relating to the stalling of tapered wings

Date: January 1, 1940
Creator: Soule, H A & Anderson, R F
Description: An aid in airplane design, charts have been prepared to show the effects of wing taper, thickness ratio, and Reynolds number on the spanwise location of the initial stalling point. Means of improving poor stalling characteristics resulting from certain combinations of the variables have also been considered; additional figures illustrate the influence of camber increase to the wing tips, washout, central sharp leading edges, and wing-tip slots on the stalling characteristics. Data are included from which the drag increases resulting from the use of these means can be computed. The application of the data to a specific problem is illustrated by an example.
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Determination of ground effect from tests of a glider in towed flight

Determination of ground effect from tests of a glider in towed flight

Date: January 1, 1940
Creator: Wetmore, J W & Turner, L I , Jr
Description: Report presents the results of an investigation made to find the effect of ground on the aerodynamic characteristics of a Franklin PS-2 glider. The lift, the drag, and the angle of attack of the glider in towed flight were determined at several heights from 0.14 to 1.19 span lengths and at various speeds for each height. Two wing arrangements were tested: the plain wing, and the wing with a nearly full-span 30-percent-chord split flap deflected 45 degrees. The experimental results for the plain wing were in good agreement with theoretical values calculated by the method of Wieselsberger for both the angle of attack and the drag coefficient at a height of 0.21 span length; Tani's refinements of the theory had a practically negligible effect on the computed values in this case.
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The development of electrical strain gages

The development of electrical strain gages

Date: January 1, 1940
Creator: De Forest, A V & Leaderman, H
Description: The design, construction, and properties of an electrical-resistance strain gage consisting of fine wires molded in a laminated plastic are described. The properties of such gages are discussed and also the problems of molding of wires in plastic materials, temperature compensation, and cementing and removal of the gages. Further work to be carried out on the strain gage, together with instrument problems, is discussed.
Contributing Partner: UNT Libraries Government Documents Department
DFS dive-control brakes for gliders and airplanes ; and, Analytical study of the drag of the DFS dive-control brake

DFS dive-control brakes for gliders and airplanes ; and, Analytical study of the drag of the DFS dive-control brake

Date: January 1, 1940
Creator: Jacobs, Hans & Wanner, Adolf
Description: These two reports are surveys on the progress and present state of development of dive-control flaps for gliders and airplanes. The second article describes how on the basis of wind tunnel and free-flight tests, the drag increase on brake flaps of the type DFS, can be predicted. Pressure records confirm a two-dimensional load distribution along the brake-flap surface Aerodynamically, the location of the brake flaps along the span is of importance for reasons of avoidance of vibration and oscillation phenomena on control and tail surfaces; statically, because of the magnitude of the frontal drag in diving with respect to the bending moments, which may become decisive for the dimensions of the wing attachment and for the wing covering.
Contributing Partner: UNT Libraries Government Documents Department
Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Date: January 1, 1940
Creator: Stickle, George W; Naiman, Irven & Crigler, John L
Description: Report presents the results of an investigation of full-scale nose-slot cowlings conducted in the NACA 20-foot wind tunnel to furnish information on the pressure drop available for cooling. Engine conductances from 0 to 0.12 and exit-slot conductances from 0 to 0.30 were covered. Two basic nose shapes were tested to determine the effect of the radius of curvature of the nose contour; the nose shape with the smaller radius of curvature gave the higher pressure drop across the engine. The best axial location of the slot for low-speed operation was found to be in the region of maximum negative pressure for the basic shape for the particular operating condition. The effect of the pressure operating condition on the available cooling pressure is shown.
Contributing Partner: UNT Libraries Government Documents Department
Effect of fuel-air ratio, inlet temperature, and exhaust pressure on detonation

Effect of fuel-air ratio, inlet temperature, and exhaust pressure on detonation

Date: January 1, 1940
Creator: Taylor, E S; Leary, W A & Diver, J R
Description: An accurate determination of the end-gas condition was attempted by applying a refined method of analysis to experimental results. The results are compared with those obtained in Technical Report no. 655. The experimental technique employed afforded excellent control over the engine variables and unusual cyclic reproducibility. This, in conjunction with the new analysis, made possible the determination of the state of the end-gas at any instant to a fair degree of precision. Results showed that for any given maximum pressure the maximum permissible end-gas temperature increased as the fuel-air ratio was increased. The tendency to detonate was slightly reduced by an increase in residual gas content resulting from an increase in exhaust backpressure with inlet pressure constant.
Contributing Partner: UNT Libraries Government Documents Department
Effect of wing loading, aspect ratio, and span loading of flight performances

Effect of wing loading, aspect ratio, and span loading of flight performances

Date: January 1, 1940
Creator: Gothert, B
Description: An investigation is made of the possible improvements in maximum, cruising, and climbing speeds attainable through increase in the wing loading. The decrease in wing area was considered for the two cases of constant aspect ratio and constant span loading. For a definite flight condition, an investigation is made to determine what loss in flight performance must be sustained if, for given reasons, certain wing loadings are not to be exceeded. With the aid of these general investigations, the trend with respect to wing loading is indicated and the requirements to be imposed on the landing aids are discussed.
Contributing Partner: UNT Libraries Government Documents Department
Effective gust structure at low altitudes as determined from the reactions of an airplane

Effective gust structure at low altitudes as determined from the reactions of an airplane

Date: January 1, 1940
Creator: Donely, Philip
Description: Measurements of gust structure and gust intensity were made in the lower levels of the atmosphere (0 to 3,500 ft.). An Aeronca C-2 airplane was used as the measuring instrument, the gust structure being derived from the recorded motions of the airplane. Data were also obtained on wind velocities and temperatures as functions of altitude for use in attempting to correlate the gust-structure data with various meteorological quantities. The results indicated little or no correlation between the gust velocity and the gradient distance. The data, however, did indicate that an airplane the size of the Aeronca will respond most frequently to gusts having gradient distance of the order of 30 feet. The maximum true gust velocity measured during the investigation was 25 feet per second.
Contributing Partner: UNT Libraries Government Documents Department
Explosion Hazards in Storage-Battery Rooms

Explosion Hazards in Storage-Battery Rooms

Date: 1940
Creator: Jones, G. W.; Campbell, John; Dillon, R. E. & Benson, O. B.
Description: Report issued by the Bureau of Mines discussing the safety and explosion hazards present in storage-battery rooms. Descriptions of storage-battery rooms and methods of ventilation are presented. This report includes tables, illustrations, and photographs.
Contributing Partner: UNT Libraries Government Documents Department
Fire-Retardant Treatments of Liquid-Oxygen Explosives

Fire-Retardant Treatments of Liquid-Oxygen Explosives

Date: 1940
Creator: Denues, A. R. T.
Description: From Introduction Present Investigation: "The scope of the investigation was limited to study of the effects of fire-retardant treatments on the resistance to ignition, physical characteristics, and practical hazards of handling the liquid-oxygen explosive prepared from the granular carbonaceous absorbent mentioned, from wrappers of a triple-filled canvas, and from a liquid oxygen of standard high purity."
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Flame speeds and energy considerations for explosions in a spherical bomb

Flame speeds and energy considerations for explosions in a spherical bomb

Date: January 1, 1940
Creator: Fiock, Ernest F; Marvin, Charles F , Jr; Caldwell, Frank R & Roeder, Carl H
Description: Simultaneous measurements were made of the speed of flame and the rise in pressure during explosions of mixtures of carbon monoxide, normal heptane, iso-octane, and benzene in a 10-inch spherical bomb with central ignition. From these records, fundamental properties of the explosive mixtures, which are independent of the apparatus, were computed. The transformation velocity, or speed at which flame advances into and transforms the explosive mixture, increases with both the temperature and the pressure of the unburned gas. The rise in pressure was correlated with the mass of charge inflamed to show the course of the energy developed.
Contributing Partner: UNT Libraries Government Documents Department
Free-spinning wind-tunnel tests of a low-wing monoplane with systematic changes in wings and tails V : effect of airplane relative density

Free-spinning wind-tunnel tests of a low-wing monoplane with systematic changes in wings and tails V : effect of airplane relative density

Date: January 1, 1940
Creator: Seidman, Oscar & Neihouse, A I
Description: The reported tests are a continuation of an NACA investigation being made in the free-spinning wind tunnel to determine the effects of independent variations in load distribution, wing and tail arrangement, and control disposition on the spin characteristics of airplanes. The standard series of tests was repeated to determine the effect of airplane relative density. Tests were made at values of the relative-density parameter of 6.8, 8.4 (basic), and 12.0; and the results were analyzed. The tested variations in the relative-density parameter may be considered either as variations in the wing loading of an airplane spun at a given altitude, with the radii of gyration kept constant, or as a variation of the altitude at which the spin takes place for a given airplane. The lower values of the relative-density parameter correspond to the lower wing loadings or to the lower altitudes of the spin.
Contributing Partner: UNT Libraries Government Documents Department
The frequencies of cantilever wings in beam and torsional vibrations

The frequencies of cantilever wings in beam and torsional vibrations

Date: January 1, 1940
Creator: Burgess, C P
Description: Methods are described for calculating the period and frequency of vibration of cantilever wings and similar structures in which the weight and moment of inertia vary along the span. Both the beam and torsional frequencies may be calculated by these methods. The procedure is illustrated by examples. It is shown that a surprisingly close approximation to the beam frequency may be obtained by a very brief calculation in which the curvature of the wing in vibration is assumed to be constant. A somewhat longer computation permits taking account of the true curvature of the beam by a series of successive approximations which are shown to be strongly convergent. Analogous methods are applied to calculations of the torsional frequency. For the first approximation it is assumed that the angle of twist varies linearly alone the semispan. True variation of the twist is computed by successive approximations which are strongly convergent, as in the case of beam vibrations.
Contributing Partner: UNT Libraries Government Documents Department
Investigations on the incompletely developed plane diagonal-tension field

Investigations on the incompletely developed plane diagonal-tension field

Date: January 1, 1940
Creator: Kuhn, Paul
Description: This report presents the results of an investigation on the incompletely developed diagonal-tension field. Actual diagonal-tension beams work in an intermediate stage between pure shear and pure diagonal tension; the theory developed by wagner for diagonal tension is not directly applicable. The first part of the paper reviews the most essential items of the theory of pure diagonal tension as well as previous attempts to formulate a theory of incomplete diagonal tension. The second part of the paper describes strain measurement made by the N. A. C. A. to obtain the necessary coefficients for the proposed theory. The third part of the paper discusses the stress analysis of diagonal-tension beams by means of the proposed theory.
Contributing Partner: UNT Libraries Government Documents Department
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