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Tank Tests of Model 36 Flying Boat Hull

Description: "N.A.C.A. Model 36, a hull form with parallel middle body for half the length of the forebody and designed particularly for use with stub wings, was tested according to the general fixed-trim method over the range of practical loads, trims, and speeds. It was also tested free to trim with the center of gravity at two different positions. The results are given in the form of nondimensional coefficients. The resistance at the hump was exceptionally low but, at high planing speeds, afterbody inter… more
Date: March 1938
Creator: Allison, John M.
Partner: UNT Libraries Government Documents Department
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A preliminary investigation of boundary-layer transition along a flat plate with adverse pressure gradient

Description: From Summary: "Boundary-layer surveys were made throughout the transition region along a smooth flat plate placed in an airstream of practically zero turbulence and with an adverse pressure gradient. The boundary-layer Reynolds number at the laminar separation point was varied from 1,800 to 2,600. The test data, when considered in the light of certain theoretical deductions, indicated that transition probably began with separation of the laminar boundary layer."
Date: March 1938
Creator: von Doenhoff, Albert E.
Partner: UNT Libraries Government Documents Department
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Interference of Wing and Fuselage From Tests of the 18 Combinations in the N.A.C.A. Variable-Density Tunnel - Combination With Split Flaps

Description: "As part of the wing-fuselage interference investigation in progress in the N.A.C.A. variable density wind tunnel, the effects of various split-flap arrangements applied to wing-fuselage combinations were determined. Split flaps were found to exert their influence independently of the interference, and their effects on the aerodynamic characteristics of rectangular-airfoil combinations appeared to be more or less proportional to their exposed span lengths. The interference, moreover, showed the… more
Date: March 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department
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Interference of Wing and Fuselage From Tests of 17 Combinations in the N.A.C.A. Variable-Density Tunnel Combination With Special Junctures

Description: "As part of the wing-fuselage interference program in progress in the NACA variable-density wind tunnel, a method of eliminating the interference bubble associated with critical mid wing combinations was investigated. The interference bubble of the critical mid wing combination was shown to respond to modification at the nose of the juncture and to be entirely suppressed with little or no adverse effect on the high-speed drag by special leading edge fillets" (p. 1).
Date: March 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department
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Interference of Wing and Fuselage From Tests of Eight Combinations in the N.A.C.A. Variable-Density Tunnel Combinations With Tapered Fillets and Straight-Side Junctures

Description: "The round fuselage of an unfilleted low-wing combination was modified to incorporate straight-side junctures. The resulting combination, with or without horizontal tail surfaces, had practically the same aerodynamic characteristics as the corresponding round-fuselage tapered-fillet combination" (p. 1).
Date: March 1938
Creator: Sherman, Albert
Partner: UNT Libraries Government Documents Department
open access

Design of NACA Cowlings for Radial Air-Cooled Engines

Description: "The information on the propeller-cowling-nacelle combinations, presented in Technical Reports nos. 592, 593, and 596 and in Technical Note 620, is applied to the practical design of NACA cowlings. The main emphasis is placed on the method of obtaining the dimensions of the cowling; consequently, the physical functioning of each part of the cowling is treated very briefly. A practical method of designing cowlings and some examples are presented" (p. 383).
Date: March 5, 1938
Creator: Stickle, George W.
Partner: UNT Libraries Government Documents Department
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Twisting of Thin Walled Columns Perfectly Restrained at One End

Description: "Proceeding from the basic assumptions of the Batho-Bredt theory on twisting failure of thin-walled columns, the discrepancies most frequently encountered are analyzed. A generalized approximate method is suggested for the determination of the disturbances in the stress condition of the column, induced by the constrained warping in one of the end sections" (p. 1).
Date: March 1938
Creator: Lazzarino, Lucio
Partner: UNT Libraries Government Documents Department
open access

Effect of Air-Fuel Ratio on Detonation in Gasoline Engines

Description: Memorandum presenting a study of the effect of mixture strength on detonation, which may be divided into two parts, namely: a) the measurement of the effect in engines; and b) the explanation of the effect. This is because of the richness of the mixture has a very pronounced effect on the detonation in a gasoline engine.
Date: March 1938
Creator: Peletier, L. A.
Partner: UNT Libraries Government Documents Department
open access

Systematic airfoil tests in the large wind tunnel of the DVL

Description: The present report is a description of systematic tests at maximum lift on airfoils with and without split flap and of profile drag at low lift. In order to obtain an opinion as to the suitability of the airfoils with flaps, the maximum-lift measurements were repeated on airfoils with split flaps. The profile drag at low lift was arrived at by direct weighing and momentum measurements and, since the profiles were of unusual depth, extended to large Reynolds numbers.
Date: March 1938
Creator: Doetsch, H. & Kramer, M.
Partner: UNT Libraries Government Documents Department
open access

Engines and Propellers for Powered Gliders and Light Airplanes

Description: The object of the present paper is to consider the interaction of engine, propeller, and airplane for the low-power range. The discussion is presented in a form so as to provide the engine builder with a basis in his selection in the type of engine required, a suitable selection being possible only in connection with considerations on the best possible propeller.
Date: March 1938
Creator: Gropp, H.
Partner: UNT Libraries Government Documents Department
open access

Twisting Failure of Centrally Loaded Open-Section Columns in the Elastic Range

Description: In the following report a complete theory of twisting failure by the energy method is developed, based on substantially the same assumptions as those employed by Wagner and Bleich. Problems treated in detail are: the stress and strain condition under St. Venant twist and in twist with axial constraint; the concept of shear center and the energy method for problems of elastic stability.
Date: March 1938
Creator: Kappus, Robert
Partner: UNT Libraries Government Documents Department
open access

Preliminary Full-Scale Wind-Tunnel Investigation of Wing Ducts for Radiators, Special Report

Description: "Wing ducts for liquid-cooled engine radiators have been investigated in the N.A.C.A. full-scale wind tunnel on a large model airplane. The tests were made to determine the relative merits of several types of duct and radiator installations for an airplane of a particular design. In the test program the principal duct dimensions were systematically varied, and the results are therefore somewhat applicable to the general problems of wing duct design, although they should be considered as prelimi… more
Date: March 1938
Creator: Silverstein, Abe & Nickle, F. R.
Partner: UNT Libraries Government Documents Department
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Correction of Profile-Drag Results From Variable-Density Tunnel and the Effect on the Choice of Wing-Section Thickness

Description: "Profile-drag coefficients published from tests in the N.A.C.A. variable-density tunnel (Technical Reports Nos. 460, 537, 586, and 610, references 1 to 4) have tended to appear high as compared with results from the N.A.C.A. full-scale tunnel (Technical Report No. 530, reference 5) and from foreign sources (references 6 to 8). Such discrepancies were considered in Technical Report No. 586, and corrections for turbulence and tip effects were derived that tended to reduce the profile-drag coeffic… more
Date: March 18, 1938
Creator: Jacobs, Eastman N.
Partner: UNT Libraries Government Documents Department
open access

The Torsional and Bending Deflection of Full-Scale Duralumin Propeller Blades Under Normal Operating Conditions, Special Report

Description: "The torsional deflection of the blades of three full-scale duralumin propellers operating under various loading conditions was measured by a light-beam method. Angular bending deflections were also obtained as an incidental part of the study. The deflection measurements showed that the usual present-day type of propeller blades twisted but a negligible amount under ordinary flight conditions. A maximum deflection of about 1/10th of a degree was found at V/nD of 0.3 and a smaller deflection at … more
Date: March 1938
Creator: Hartman, Edwin P. & Biermann, David
Partner: UNT Libraries Government Documents Department
open access

On some reciprocal relations in the theory of nonstationary flows

Description: In the theory of nonstationary flows about airfoils, the "indicial lift" function ksub1(s) of Wagner and the "alternating lift" function c(k) of Theodorsen have fundamental significance. This paper reports on some interesting relations of the nature of Fourier transforms that exist between these functions. General problems in transient flows about airfoils may be given a unified broad treatment when these functions are employed. Certain approximate results also are reported which are of notable… more
Date: March 28, 1938
Creator: Garrick, I. E.
Partner: UNT Libraries Government Documents Department
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The Crinkling Strength and the Bending Strength of Round Aircraft Tubing

Description: "The upper limit of the column strength of structural members composed of thin material is the maximum axial stress such members can carry when short enough to fail locally, by crinkling. This stress is a function of the mechanical properties of the material and of the geometrical shape of the cross section. The bending strength, as measured by the modulus of rupture, of structural members is also a function of these same variables. Tests were made of round tubes of chromium-molybdenum steel an… more
Date: March 28, 1938
Creator: Osgood, William R.
Partner: UNT Libraries Government Documents Department
open access

Pressure distribution over an NACA 23012 airfoil with a slotted and a plain flap

Description: Report presents the results of pressure-distribution of an NACA 23012 airfoil equipped with a slotted flap and with a plain flap conducted in the 7 by 10-foot wind tunnel. A test installation was used in which the 7-foot-span airfoil was mounted vertically between the upper and lower sides of the closed test section so that two-dimensional flow was approximated. The pressures were measured on the upper and lower surfaces at one chord section both on the main airfoil and on the flaps for several… more
Date: March 17, 1938
Creator: Wenzinger, Carl J. & Delano, James B.
Partner: UNT Libraries Government Documents Department
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