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The Aerodynamic Drag of Flying-Boat Hull Model as Measured in the NACA 20-Foot Wind Tunnel - 1

Description: "The main purpose of this investigation is to make available to the designer useful information with regard to the aerodynamic drag of various types of flying-boat hull models. The present report is the first in a series covering investigation in this field. Through close cooperation between hydrodynamics and aerodynamics divisions it is hoped that results leading to improvements in hull design obtained" (p. 1).
Date: April 1935
Creator: Hartman, Edwin P.
Partner: UNT Libraries Government Documents Department
open access

Spinning Characteristics of Wings 2: Rectangular Clark Y Biplane Cellule: 25 Percent Stagger; 0 Degree Decalage; Gap/Chord 1.0

Description: General methods of theoretical analysis of airplane spinning characteristics have been available for some time. Some of these methods of analysis might be used by designers to predict the spinning characteristics of proposed airplane designs if the necessary aerodynamic data were known. The present investigation, to determine the spinning characteristics of wings, is planned to include variations in airfoil sections, plan forms, and tip shapes of monoplane wings and variations in stagger, gap, … more
Date: April 1935
Creator: Bamber, M. J.
Partner: UNT Libraries Government Documents Department
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Analysis of a Strut With a Single Elastic Support in the Span, With Applications to the Design of Airplane Jury-Strut Systems

Description: Report presenting an analysis of a wing brace with a small auxiliary strut, which is attached to the wing spar at the upper end. The design is quite effective but has some difficult analysis problems. The report is broken into two parts; one is a theoretical investigation and one is an experimental investigation.
Date: May 1935
Creator: Schwartz, A. Murray & Bogert, Reid
Partner: UNT Libraries Government Documents Department
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Weldability of High-Tensile Steels From Experience in Airplane Construction, With Special Reference to Welding Crack Susceptibility

Description: "The concept of welding crack tendency is explained and illustrated with practical examples. All pertinent causes are enumerated, and experimental measures are given through which the secondary effects can be removed and the principal causes analyzed: 1) welding stresses; and 2) material defects. The variations in length and stresses incident to welding a small bar as free weld, with restrained elongation and restrained elongation and contraction, are explored in three fundamental experiments" … more
Date: November 1935
Creator: Müller, J.
Partner: UNT Libraries Government Documents Department
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Wind-tunnel tests of a wing with a trailing-edge auxiliary airfoil used as a flap

Description: "This report gives the characteristics of a wing with an auxiliary airfoil mounted near its trailing edge and used as a flap. The tests were made with a 10 by 60 inch Clark Y main airfoil and an NACA 0012 flap having a chord equal to 15 percent of the main wing chord. The axis of the flap in all cases was on the flap chord and 20 percent back from its leading edge. The optimum location of the flap axis relative to the main wing for maximum lift was found to be 1.25 percent of the main wing chor… more
Date: April 1935
Creator: Noyes, Richard W.
Partner: UNT Libraries Government Documents Department
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The Effect of Depth of Step on the Water Performance of a Flying-Boat Hull Model N.A.C.A. Model 11-C

Description: "NACA model 11-C was tested with four different depths of step to obtain information as to the effect of the depth of step on the water performance. The depths of step were selected to cover the practicable range of depths and in each case the included angle between the forebody and afterbody keels was kept the same 6-1/2 degrees. Small depths of step were found to give lower resistance at speeds below and at the hump speed of the model and greater depths of step lower resistance at high speeds… more
Date: July 1935
Creator: Bell, Joe W.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Interference With Particular Reference to Off-Center Positions of the Wing and to the Downwash at the Tail

Description: "The theory of wind tunnel boundary influence on the downwash from a wing has been extended to provide more complete corrections for application to airplane test data. The first section of the report gives the corrections of the lifting line for wing positions above or below the tunnel center line; the second section shows the manner in which the induced boundary influence changes with distance aft of the lifting line. Values of the boundary corrections are given for off-center positions of the… more
Date: June 28, 1935
Creator: Silverstein, Abe & White, James A.
Partner: UNT Libraries Government Documents Department
open access

Performance tests of a single-cylinder compression-ignition engine with a displacer piston

Description: Engine performance was investigated using a rectangular displacer on the piston crown to cause a forced air flow in a vertical-disk combustion chamber of a single-cylinder, 4-stroke-cycle compression-ignition engine. The optimum air-flow area was determined first with the area concentrated at one end of the displacer and then with the area equally divided between two passages, one at each end of the displacer. Best performance was obtained with the two-passage air flow arranged to give a calcul… more
Date: February 1935
Creator: Moore, C. S. & Foster, H. H.
Partner: UNT Libraries Government Documents Department
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Calculations of the Effect of Wing Twist on the Air Forces Acting on a Monoplane Wing

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" (p. 1).
Date: March 1935
Creator: Dätwyler, G.
Partner: UNT Libraries Government Documents Department
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Tension fields in originally curved, thin sheets during shearing stresses

Description: The analysis of the stresses in the sheet and stiffeners is predicated upon the direction of the wrinkles, particularly the tensile stresses (principal stresses). This analysis and the calculation of stresses after buckling form the subject of the present article. It includes: 1) metal cylinders with closely spaced longitudinal stiffeners; 2) metal cylinders with closely spaced transverse rings.
Date: August 1935
Creator: Wagner, H. & Ballerstedt, W.
Partner: UNT Libraries Government Documents Department
open access

The Compressibility Burble

Description: "Simultaneous air-flow photographs and pressure-distribution measurements have been made of the NACA 4412 airfoil at high speeds in order to determine the physical nature of the compressibility bubble. The flow photographs were obtained by the Schlieren method and the pressures were simultaneously measured for 54 stations on the 5-inch-chord wing by means of a multiple-tube photographic manometer. Pressure-measurement results and typical Schlieren photographs are presented" (p. 1).
Date: October 1935
Creator: Stack, John
Partner: UNT Libraries Government Documents Department
open access

The Denis-Gruson Six-Component Wind-Tunnel Balance

Description: The 6.C.1 balance is the first fully automatic balance assuring a continuous and simultaneous record of the aerodynamic characteristics of an airfoil in a wind tunnel. Because of the rapidity of the measurements a complete polar (six components) requires only about three minutes of wind, that is to say, of motive power, which is of interest for wind tunnels with high efficiency factors and may lead to the economical design of large size wind tunnels.
Date: July 1935
Partner: UNT Libraries Government Documents Department
open access

Hydrodynamic Tests of Models of Seaplane Floats

Description: "This report contains the results of tank tests carried out at free trim on seventeen hulls and floats of various types. The data as to the weight on water, trim, and relative resistance for each model are plotted nondimensionally and are referenced both to the total weight and to the weight on water. Despite the fact that the experiments were not made systematically, a study of the models and of the test data permits nevertheless some general deductions regarding the forms of floats and their … more
Date: May 1935
Creator: Eula, Antonio
Partner: UNT Libraries Government Documents Department
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The Interdependence of Profile Drag and Lift With Joukowski Type and Related Airfoils

Description: "On the basis of a systematic investigation of Gottingen wind-tunnel data on Joukowski type and related airfoils, it is shown in what manner the profile drag coefficient is dependent on the lift coefficient. The individual factors for the construction of the profile drag polars are given. They afford a more accurate calculation of the performance coefficients of airplane designs than otherwise attainable with the conventional assumption of constant drag coefficient" (p. 1).
Date: March 1935
Creator: Muttray, H.
Partner: UNT Libraries Government Documents Department
open access

Gliding in Convection Currents

Description: "A survey of the possibilities of gliding in convection currents reveals that heretofore only the most simple kind of ascending convection currents, that is, the "thermic" of insolation, has been utilized to any extent. With the increasing experience in gliding, the utilization of the peculiar nature of the "wind thermic" and increased glider speed promises further advances. Evening, ocean, and height "thermic" are still in the exploration stage, and therefore not amenable to survey in their ef… more
Date: January 1935
Creator: Georgii, W.
Partner: UNT Libraries Government Documents Department
open access

The Initial Torsional Stiffness of Shells With Interior Webs

Description: "A method of calculating the stresses and torsional stiffness of thin shells with interior webs is summarized. Comparisons between experimental and calculated results are given for 3 duralumin beams, 5 stainless steel beams and 2 duralumin wings. It is concluded that if the theoretical stiffness is multiplied by a correction factor of 0.9, experimental values may be expected to check calculated values within about 10 percent" (p. 1).
Date: September 1935
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department
open access

Comparative Tests of Pitot-Static Tubes

Description: "Comparative tests were made on seven conventional Pitot-static tubes to determine their static, dynamic, and resultant errors. The effect of varying the dynamic opening, static opening, wall thickness, and inner-tube diameter was investigated. Pressure-distribution measurements showing stem and tip effects were also made. A tentative design for a standard Pitot-static tube for use in measuring air velocity is submitted" (p. 1).
Date: November 1935
Creator: Merriam, Kenneth G. & Spaulding, Ellis R.
Partner: UNT Libraries Government Documents Department
open access

Modification of Wing-Section Shape to Assure a Predetermined Change in Pressure Distribution

Description: "In order to find an airfoil for a predetermined pressure distribution, the problem must be posed so that the pressure distribution creates no drag. Another fundamental difficulty is that it is impossible to specify a pressure distribution without first knowing the place where these pressures are to be applied, i.e., the wing-section shape. This difficulty may be avoided by directing the pressure distribution along the contour of the wing section. Then it becomes possible to define the change i… more
Date: March 1935
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department
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Aerodynamic Characteristics of Several Airfoils of Low Aspect Ratio

Description: "This paper presents the results of wind-tunnel tests of several airfoils of low aspect ratio. The airfoils included three circular Clark Y airfoils with different amounts of dihedral, two Clark Y airfoils with slots in their portions, and three flat-plate airfoils. Lift, drag, and pitching-moment characteristics of the slotted airfoils with slots open and closed; pitching moment characteristics of one of the slotted airfoils with slots open and closed; and lift characteristics of the flat-plat… more
Date: August 1935
Creator: Zimmerman, C. H.
Partner: UNT Libraries Government Documents Department
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Principal Effects of Axial Load on Moment-Distribution Analysis of Rigid Structures

Description: "This thesis presents the method of moment distribution modified to include the effect of axial load upon the bending moments. This modification makes it possible to analyze accurately complex structures, such as rigid fuselage trusses, that heretofore had to be analyzed by approximate formulas and empirical rules. The method is simple enough to be practicable even for complex structures, and it gives a means of analysis for continuous beams that is simpler than the extended three-moment equati… more
Date: July 1935
Creator: James, Benjamin Wylie
Partner: UNT Libraries Government Documents Department
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A preliminary determination of normal accelerations on racing airplanes

Description: "Rules and methods for insuring safe structural strength of racing airplanes used in the major air meets in this country have recently been considered. Acceleration records made in racing airplanes during actual air races were therefore considered desirable, and the NACA undertook the measurement of acceleration of loads on airplanes during all conditions of flight. Accelerations were measured on four airplanes at the Miami All-American Races in January 1934 and January 1935" (p. 1).
Date: August 1935
Creator: Scudder, N. F. & Kirschbaum, H. W.
Partner: UNT Libraries Government Documents Department
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Strength Tests of Thin-Walled Duralumin Cylinders in Combined Transverse Shear and Bending

Description: "This report is the fourth of a series presenting the results of strength tests on thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results on 100 thin-walled Duralumin cylinders of circular section with ends clamped to rigid bulkheads. The tests show that as the ratio of moment to shear varies from small to large values the failure changes from a shear to a bending type. In the report a chart is presented that shows the corresponding changes in streng… more
Date: April 1935
Creator: Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department
open access

Tank tests of model 11-G flying-boat hull

Description: "The NACA model 11-G flying-boat hull, a modification of NACA model 11-A was tested over a range of loadings. The planing bottom of model 11-G has a variable-radius flare, or concavity, at the chines in contrast to the straight V planing bottom of model 11-A. The results are given as curves of resistance and trimming moment plotted against speed for various angles of trim" (p. 1).
Date: June 1935
Creator: Parkinson, J. B.
Partner: UNT Libraries Government Documents Department
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