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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Technical Notes
 Collection: Technical Report Archive and Image Library
An investigation of the experimental aerodynamic loading on a model helicopter rotor blade

An investigation of the experimental aerodynamic loading on a model helicopter rotor blade

Date: May 1, 1953
Creator: Meyer, John R , Jr; Falabella, Gaetano, Jr & NACA
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Adaptor for measuring principal strains with Tuckerman strain gage

Adaptor for measuring principal strains with Tuckerman strain gage

Date: January 1, 1943
Creator: Mcpherson, A E
Description: An adapter is described which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.
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Calculations of the effect of wing twist on the air forces acting on a monoplane wing

Calculations of the effect of wing twist on the air forces acting on a monoplane wing

Date: January 1, 1935
Creator: Datwyler, G
Description: A method is presented for calculating the aerodynamic forces on a moncylane wing, taking into account the elastic twisting of the wing due to these forces. The lift distribution along the span is calculated by the formulas of Amstutz as a function of the geometrical characteristics of the wing and of the twist at stations 60 and 90 percent of the semispan. The twist for a given lift distribution is calculated by means of influence lines. As a numerical example, the forces on a Swiss military D.2V airplane are calculated. Comparisons with the strip method and with the ordinary stress-analysis method are also given.
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Stress distribution in and equivalent width of flanges of wide, thin-wall steel beams

Stress distribution in and equivalent width of flanges of wide, thin-wall steel beams

Date: January 1, 1940
Creator: Winter, George
Description: The use of different forms of wide-flange, thin-wall steel beams is becoming increasingly widespread. Part of the information necessary for a national design of such members is the knowledge of the stress distribution in and the equivalent width of the flanges of such beams. This problem is analyzed in this paper on the basis of the theory of plane stress. As a result, tables and curves are given from which the equivalent width of any given beam can be read directly for use in practical design. An investigation is given of the limitations of this analysis due to the fact that extremely wide and thin flanges tend to curve out of their plane toward the neutral axis. A summary of test data confirms very satisfactorily the analytical results.
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Empirical relation between induced velocity, thrust, and rate of descent of a helicopter rotor as determined by wind-tunnel tests on four model rotors

Empirical relation between induced velocity, thrust, and rate of descent of a helicopter rotor as determined by wind-tunnel tests on four model rotors

Date: October 1, 1951
Creator: Castles, Walter, Jr. & Gray, Robin B.
Description: The empirical relation between the induced velocity, thrust, and rate of vertical descent of a helicopter rotor was calculated from wind tunnel force tests on four model rotors by the application of blade-element theory to the measured values of the thrust, torque, blade angle, and equivalent free-stream rate of descent. The model tests covered the useful range of C(sub t)/sigma(sub e) (where C(sub t) is the thrust coefficient and sigma(sub e) is the effective solidity) and the range of vertical descent from hovering to descent velocities slightly greater than those for autorotation. The three bladed models, each of which had an effective solidity of 0.05 and NACA 0015 blade airfoil sections, were as follows: (1) constant-chord, untwisted blades of 3-ft radius; (2) untwisted blades of 3-ft radius having a 3/1 taper; (3) constant-chord blades of 3-ft radius having a linear twist of 12 degrees (washout) from axis of rotation to tip; and (4) constant-chord, untwisted blades of 2-ft radius. Because of the incorporation of a correction for blade dynamic twist and the use of a method of measuring the approximate equivalent free-stream velocity, it is believed that the data obtained from this program are more applicable to free-flight calculations than ...
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The factors that determine the minimum speed of an airplane

The factors that determine the minimum speed of an airplane

Date: March 1, 1921
Creator: Norton, F H
Description: The author argues that because of a general misunderstanding of the principles of flight at low speed, there are a large number of airplanes that could be made to fly several miles per hour slower than at present by making slight modifications. In order to show how greatly the wing section affects the minimum speed, curves are plotted against various loadings. The disposition of wings on the airplane slightly affects the lift coefficient, and a few such cases are discussed. Another factor that has an effect on minimum speed is the extra lift exerted by the slip stream on the wings. Also discussed are procedures to be followed by the pilot, especially with regard to stick movements during low speed flight. Also covered are stalling, yaw, rolling moments, lateral control, and the effectiveness of ailerons and rudders.
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The testing of aviation engines

The testing of aviation engines

Date: December 1, 1924
Creator: Dubois, R N
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Shear Lag in a Plywood Sheet-Stringer Combination Used for the Chord Member of a Box Beam

Shear Lag in a Plywood Sheet-Stringer Combination Used for the Chord Member of a Box Beam

Date: March 1, 1948
Creator: Borsari, Palamede & Yu, Ai-Ting
Description: Theoretical and experimental investigations were made of the distribution of strains in a plywood sheet-stringer combination used as the chord member of a box beam acted upon by bending loads. The theoretical solution was obtained with the help of the principle of minimum potential energy and certain simplifying assumptions. Strain measurements were made on a build-up box beam by means of electrical-resistance strain gages connected with strain indicators. A very satisfactory agreement between the theoretical and experimental strains was obtained.
Contributing Partner: UNT Libraries Government Documents Department
Empirical Relation Between Induced Velocity, Thrust, and Rate of Descent of a Helicopter Rotor as Determined by Wind-Tunnel Tests on Four Model Rotors

Empirical Relation Between Induced Velocity, Thrust, and Rate of Descent of a Helicopter Rotor as Determined by Wind-Tunnel Tests on Four Model Rotors

Date: October 1, 1951
Creator: Castles, Walter, Jr & Gray, Robin B
Description: The empirical relation between the induced velocity, thrust, and rate of vertical descent of a helicopter rotor was calculated from wind tunnel force tests on four model rotors by the application of blade-element theory to the measured values of the thrust, torque, blade angle, and equivalent free-stream rate of descent. The model tests covered the useful range of C(sub t)/sigma(sub e) (where C(sub t) is the thrust coefficient and sigma(sub e) is the effective solidity) and the range of vertical descent from hovering to descent velocities slightly greater than those for autorotation. The three bladed models, each of which had an effective solidity of 0.05 and NACA 0015 blade airfoil sections, were as follows: (1) constant-chord, untwisted blades of 3-ft radius; (2) untwisted blades of 3-ft radius having a 3/1 taper; (3) constant-chord blades of 3-ft radius having a linear twist of 12 degrees (washout) from axis of rotation to tip; and (4) constant-chord, untwisted blades of 2-ft radius. Because of the incorporation of a correction for blade dynamic twist and the use of a method of measuring the approximate equivalent free-stream velocity, it is believed that the data obtained from this program are more applicable to free-flight calculations than ...
Contributing Partner: UNT Libraries Government Documents Department
Theory of Lifting Surfaces, Part 2

Theory of Lifting Surfaces, Part 2

Date: August 1, 1920
Creator: Prandtl, L.
Description: A mathematical model is presented towards a theory of lifting and resistance on wings. It consists of a theory of multiplanes, conditions of flow at a great distance from the wing, lifting systems of minimum resistance, and free stream and stream limited by walls.
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Tables and Charts of Flow Parameters Across Oblique Shocks

Tables and Charts of Flow Parameters Across Oblique Shocks

Date: August 1948
Creator: Neice, Mary M.
Description: Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.
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Two-Dimensional Subsonic Compressible Flows Past Arbitrary Bodies by the Variational Method

Two-Dimensional Subsonic Compressible Flows Past Arbitrary Bodies by the Variational Method

Date: March 1951
Creator: Wang, Chi-Teh
Description: Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.
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Summary of 65-Series Compressor-Blade Low-Speed Cascade Data by Use of the Carpet-Plotting Technique

Summary of 65-Series Compressor-Blade Low-Speed Cascade Data by Use of the Carpet-Plotting Technique

Date: February 1957
Creator: Felix, A. Richard
Description: Carpet plots included permit the selection of the blade camber and the design angle of attack required to fulfill a design vector diagram. Other carpet plots provide means for the prediction of off-design turning angles.
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Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers

Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers

Date: April 1947
Creator: Dryden, Hugh L.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Considerations of the Total Drag of Supersonic Airfoil Sections

Considerations of the Total Drag of Supersonic Airfoil Sections

Date: July 1947
Creator: Ivey, H. Reese & Klunker, E. Bernard
Description: The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.
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Design criteria for axisymmetric and two-dimensional supersonic inlets and exits

Design criteria for axisymmetric and two-dimensional supersonic inlets and exits

Date: January 1, 1956
Creator: Connors, James F & Meyers, Rudolph C
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The design of brittle-material blade roots based on theory and rupture tests of plastic models

The design of brittle-material blade roots based on theory and rupture tests of plastic models

Date: September 1, 1956
Creator: Meyer, Andre J , Jr; Kaufman, Albert & Caywood, William C
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Calculation of transonic flows past thin airfoils by integral method

Calculation of transonic flows past thin airfoils by integral method

Date: July 1, 1950
Creator: Perl, William
Description: None
Contributing Partner: UNT Libraries Government Documents Department
An approximate method of determining the subsonic flow in an arbitrary stream filament of revolution cut by arbitrary turbomachine blades

An approximate method of determining the subsonic flow in an arbitrary stream filament of revolution cut by arbitrary turbomachine blades

Date: June 1, 1952
Creator: Wu, Chung-Hua; Brown, Curtis A & Prian, Vasily D
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Drag coefficients for droplets and solid spheres in clouds accelerating in airstreams

Drag coefficients for droplets and solid spheres in clouds accelerating in airstreams

Date: September 1, 1956
Creator: Ingebo, Robert D
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Driving standing waves by heat addition

Driving standing waves by heat addition

Date: August 1, 1952
Creator: Blackshear, Perry L , Jr
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Drop-size distribution for cross current breakup of liquid jets in airstreams

Drop-size distribution for cross current breakup of liquid jets in airstreams

Date: October 1, 1957
Creator: Ingebo, Robert D & Foster, Hampton H
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Drop-size distributions for impinging-jet breakup in airstreams simulating the velocity conditions in rocket combustors

Drop-size distributions for impinging-jet breakup in airstreams simulating the velocity conditions in rocket combustors

Date: March 1, 1958
Creator: Ingebo, Robert D
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Droplet Impingement and Ingestion by Supersonic Nose Inlet in Subsonic Tunnel Conditions

Droplet Impingement and Ingestion by Supersonic Nose Inlet in Subsonic Tunnel Conditions

Date: May 1, 1958
Creator: Gelder, Thomas F.
Description: The amount of water in cloud droplet form ingested by a full-scale supersonic nose inlet with conical centerbody was measured in the NACA Lewis icing tunnel. Local and total water impingement rates on the cowl and centerbody surfaces were also obtained. All measurements were made with a dye-tracer technique. The range of operating and meteorological conditions studied was: angles of attack of 0 deg and 4.2 deg, volume-median droplet diameters from about 11 to 20 microns, and ratios of inlet to free-stream velocity from about 0.4 to 1.8. Although the inlet was designed for supersonic (Mach 2.0) operation of the aircraft, the tunnel measurements were confined to a free-stream velocity of 156 knots (Mach 0.237). The data are extendable to other subsonic speeds and droplet sizes by dimensionless impingement parameters. Impingement and ingestion efficiencies are functions of the ratio of inlet to free-stream velocity as well as droplet size. For the model and range of conditions studied, progressively increasing the inlet velocity ratio from less than to greater than 1.0 increased the centerbody impingement efficiency and shifted the cowl impingement region from the inner- to outer-cowl surfaces, respectively. The ratio of water ingested by the inlet plane to that contained ...
Contributing Partner: UNT Libraries Government Documents Department
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