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General Theory of Aerodynamic Instability and the Mechanism of Flutter

Description: "The aerodynamic forces on an oscillating airfoil or airfoil-aileron combination of three independent degrees of freedom were determined. The problem resolves itself into the solution of certain definite integrals, which were identified as Bessel functions of the first and second kind, and of zero and first order. The theory, based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing section theory relating to the steady case" (p. 291).
Date: May 2, 1934
Creator: Theodorsen, Theodore
Partner: UNT Libraries Government Documents Department
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Tank Tests of a Model of the NC Flying-Boat Hull - N.A.C.A. Model 44

Description: "A 1/7.06 full-size model of the NC-type hull was tested in the N.A.C.A. tank by both the general method and the specific or free-to-trim method. The results of the tests are given in curves plotted as non dimensional coefficients and are compared with the test results of N.A.C.A. model 11-A. The NC model (N.A.C.A. model 44) shows higher resistance than model 11-A at hump speed but lower resistance at high speeds. Model 44 has a higher best trim angle at the jump and a lower maximum positive tr… more
Date: May 1936
Creator: Bell, Joe W.
Partner: UNT Libraries Government Documents Department
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Tests of N.A.C.A. airfoils in the variable-density wind tunnel. Series 230

Description: The results of tests of six airfoils having the N.A.C.A. 230 mean line and varying in thickness from 0.06c to 0.21c are presented. These results agree with previous findings in showing that aerodynamically the best section is one of moderate thickness. The data are of value mainly in connection with the design of tapered wings having sections based on the N.A.C.A. 230 mean line.
Date: May 1936
Creator: Jacobs, Eastman N. & Pinkerton, Robert M.
Partner: UNT Libraries Government Documents Department
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Compression-ignition engine tests of several fuels

Description: "The tests reported in this paper were made to devise simple engine tests which would rate fuels as to their comparative value and their suitability for the operating conditions of the individual engine on which the tests are made. Three commercial fuels were used in two test engines having combustion chambers with and without effective air flow. Strictly comparative performance tests gave almost identical results for the three fuels. Analysis of indicator cards allowed a differentiation betwee… more
Date: May 1932
Creator: Spanogle, J. A.
Partner: UNT Libraries Government Documents Department
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Wind-tunnel tests of the Fowler variable-area wing

Description: The lift, drag, and center of pressure characteristics of a model of the Fowler variable-area wing were measured in the NACA 7 by 10 foot wind tunnel. The Fowler wing consists of a combination of a main wing and an extension surface, also of airfoil section. The extension surface can be entirely retracted within the lower rear portion of the main wing or it can be moved to the rear and downward. The tests were made with the nose of the extension airfoil in various positions near the trailing ed… more
Date: May 1932
Creator: Weick, Fred E. & Platt, Robert C.
Partner: UNT Libraries Government Documents Department
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The Effect of Propellers and Nacelles on the Landing Speeds of Tractor Monoplanes

Description: "This paper reports wind-tunnel tests giving the lift coefficients of large-scale wing-nacelle combinations both with and without the propeller. The tests were made to show the effect of nacelles, and idling and stopped propellers on the landing speeds of tractor monoplanes. Four types of nacelles with various cowlings were used in numerous positions with respect to both a Clark Y and a thick airfoil. The effect of both the idling and stopped propeller on lift, and consequently on landing speed… more
Date: May 1932
Creator: Windler, Ray
Partner: UNT Libraries Government Documents Department
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The Nature of Air Flow About the Tail of an Airplane in a Spin

Description: "Air flow about the fuselage and empennage during a high-angle-of-attack spin was made visible in flight by means of titanium-tetrachloride smoke and was photographed with a motion-picture camera. The angular relation of the direction of the smoke streamer to the airplane axes was computed and compared with the angular direction of the motion in space derived from instrument measurement of the spin of the airplane for a nearly identical mass distribution. The results showed that the fin and upp… more
Date: May 1932
Creator: Scudder, N. F. & Miller, M. P.
Partner: UNT Libraries Government Documents Department
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The Aerodynamic Characteristics of a Model Wing Having a Split Flap Deflected Downward and Moved to the Rear

Description: "Tests were made on a model wing with three different sized split trailing-edged flaps, in the NACA 7 by 10 foot wind tunnel. The flaps were formed of the lower rear portion of the wing and were rotated downward about axes at their front edges. The lift, drag, and center of pressure were measured with the axis in its original position and also with it moved back in even steps to the trailing edge of the main wing, giving in effect an increase in area. The split flaps when deflected about their … more
Date: May 1932
Creator: Weick, Fred E. & Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
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Calculated Effect of Various Types of Flap on Take-Off Over Obstacles

Description: "In order to determine whether or not flaps could be expected to have any beneficial effect on take-off performance, the distances required to take off and climb to an altitude of 50 feet were calculated for hypothetical airplanes, corresponding to relatively high-speed types and equipped with several types of flap. The types considered are the Fowler wing, the Hall wing, the split flap, the balanced split flap, the plain flap, and the external-airfoil flap. The results indicate that substantia… more
Date: May 1936
Creator: Wetmore, J. W.
Partner: UNT Libraries Government Documents Department
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Boosted Performance of a Compression-Ignition Engine With a Displaced Piston

Description: From Summary: "Performance tests were made using a rectangular displacer arranged so that the combustion air was forced through equal passages at either end of the displacer into the vertical-disk combustion chamber of a single-cylinder, four-stroke-cycle compression-ignition test engine. After making tests to determine optimum displacer height, shape, and fuel-spray arrangement, engine-performance tests were made at 1,500 and 2,000 r.p.m. for a range of boost pressures from 0 to 20 inches of m… more
Date: May 1936
Creator: Moore, Charles S. & Foster, Hampton H.
Partner: UNT Libraries Government Documents Department
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Wind tunnel research comparing lateral control devices, particularly at high angles of attack 11: various floating tip ailerons on both rectangular and tapered wings

Description: Discussed here are a series of systematic tests being conducted to compare different lateral control devices with particular reference to their effectiveness at high angles of attack. The present tests were made with six different forms of floating tip ailerons of symmetrical section. The tests showed the effect of the various ailerons on the general performance characteristics of the wing, and on the lateral controllability and stability characteristics. In addition, the hinge moments were mea… more
Date: May 1933
Creator: Weick, Fred E. & Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
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Full-Scale Wind-Tunnel Research on Tail Buffeting and Wing-Fuselage Interference of a Low-Wing Monoplane

Description: Some preliminary results of full scale wind tunnel testing to determine the best means of reducing the tail buffeting and wing-fuselage interference of a low-wing monoplane are given. Data indicating the effects of an engine cowling, fillets, auxiliary airfoils of short span, reflexes trailing edge, propeller slipstream, and various combinations of these features are included. The best all-round results were obtained by the use of fillets together with the National Advisory Committee for Aerona… more
Date: May 1933
Creator: Hood, Manley J. & White, James A.
Partner: UNT Libraries Government Documents Department
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The Effect of Rivet Heads on the Characteristics of a 6 by 36 Foot Clark Y Metal Airfoil

Description: "An investigation was conducted in the N.A.C.A. full-scale wind tunnel to determine the effects of exposed rivet heads on the aerodynamic characteristics of a metal-covered 6 by 36 foot Clark Y airfoil. Lead punching simulating 1/8 inch rivet heads were attached in full-span rows at a pitch of 1 inch at various chord positions. Tests were made at velocities varying from 40 to 120 miles per hour to investigate the scale effect" (p. 1).
Date: May 1933
Creator: Dearborn, Clinton H.
Partner: UNT Libraries Government Documents Department
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Strength tests of thin-walled duralumin cylinders of elliptic section

Description: This report is the fifth of a series presenting the results of strength tests of thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results obtained from torsion tests on 30 cylinders, pure bending tests on 30 cylinders, and combined transverse shear and bending tests on 60 cylinders. All the cylinders tested were elliptic section with the ends clamped to rigid bulkheads. In the pure bending and combined transverse shear and bending tests the loads were … more
Date: May 1935
Creator: Lundquist, Eugene E. & Burke, Walter F.
Partner: UNT Libraries Government Documents Department
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Wind-tunnel tests of a cyclogiro rotor

Description: During an extensive study of all types of rotating wings, the NACA examined the cyclogiro rotor and made an aerodynamic analysis of that system (reference 1). The examination disclosed that such a machine had sufficient promise to justify an experimental investigation; a model with a diameter and span of 8 feet was therefore constructed and tested in the 20-foot wind tunnel during 1934. The experimental work included tests of the effect of the motion upon the rotor forces during the static-lift… more
Date: May 1935
Creator: Wheatley, John B. & Windler, Ray
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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Moments of inertia of several airplanes

Description: This paper, which is the first of a series presenting the results of such measurements, gives the momental ellipsoids of ten army and naval biplanes and one commercial monoplane. The data were obtained by the use of a pendulum method, previously described. The moments of inertia are expressed in coefficient as well as in dimensional form, so that those for airplanes of widely different weights and dimensions can be compared.
Date: May 1931
Creator: Miller, Marvel P. & Soulé, Hartley A.
Partner: UNT Libraries Government Documents Department
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Effect of High Air Velocities on the Distribution and Penetration of a Fuel Spray

Description: "By means of the NACA Spray Photography Equipment high speed moving pictures were taken of the formation and development of fuel sprays from an automatic injection valve. The sprays were injected normal to and counter to air at velocities from 0 to 800 feet per second. The air was at atmosphere temperature and pressure. The results show that high air velocities are an effective means of mixing the fuel spray with the air during injection" (p. 1).
Date: May 1931
Creator: Rothrock, A. M.
Partner: UNT Libraries Government Documents Department
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An integrating manometer for use in wind tunnel pressure distribution measurements

Description: A multiple manometer designed to integrate automatically the normal force over an airfoil section is described and its mathematical theory explained. The development of this instrument was conducted at the Langley Memorial Aeronautical Laboratory.
Date: May 1931
Creator: Noyes, Richard W.
Partner: UNT Libraries Government Documents Department
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Comparison of Weights of 17ST and Steel Tubular Structural Members Used in Aircraft Construction

Description: Although the strong aluminum alloys have proved themselves to be very efficient in aircraft construction there is a growing competition from the high-strength steels for certain parts, especially for tubular members. This tendency is being reflected in research work carried on at the Bureau of Standards. This study will be based largely on data given in Technical Note No. 307 of the NACA.
Date: May 1931
Creator: Hartmann, E. C.
Partner: UNT Libraries Government Documents Department
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The pressure distribution over a semicircular wing tip on an airplane in flight

Description: This note presents the results of flight pressure distribution tests on the right upper wing panel of a Douglas M-3 airplane equipped with a semicircular wing tip. The results are given in tables and curves in such form that the load distribution for any force coefficient within the usual range encountered in flight may easily be determined.
Date: May 1931
Creator: Rhode, Richard V. & Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department
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Refrigerated wind tunnel tests on surface coatings for preventing ice formation

Description: "This investigation was conducted to determine the effectiveness of various surface coatings as a means for preventing ice formations on aircraft in flight. The substances used as coatings for these tests are divided into two groups: compounds soluble in water, and those which are insoluble in water. It was found that certain soluble compounds were apparently effective in preventing the formation of ice on an airfoil model, while all insoluble compounds which were tested were found to be ineffe… more
Date: May 1930
Creator: Knight, Montgomery & Clay, William C.
Partner: UNT Libraries Government Documents Department
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Full Scale Drag Tests on Various Parts of Fairchild (FC-2W2) Cabin Monoplane

Description: "The drag due to the various parts of a Fairchild (FC-2W2) cabin monoplane was measured at air speeds varying from 50 to 100 m.p.h., in the Twenty-Foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics. It was found that the largest drag was due to the radial air-cooled engine. The measured drag due to the landing gear was also large, being about 4/5 of that due to the engine" (p. 1).
Date: May 1930
Creator: Herrnstein, William H., Jr.
Partner: UNT Libraries Government Documents Department
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Some effects of air and fuel oil temperatures on spray penetration and dispersion

Description: Presented here are experimental results obtained from a brief investigation of the appearance, penetration, and dispersion of oil sprays injected into a chamber of highly heated air at atmospheric pressure. The development of single sprays injected into a chamber containing air at room temperature and at high temperature was recorded by spray photography equipment. A comparison of spray records showed that with the air at the higher temperature, the spray assumed the appearance of thin, transpa… more
Date: May 1930
Creator: Gelalles, A. G.
Partner: UNT Libraries Government Documents Department
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