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Flow Phenomena on Plates and Airfoils of Short Span

Description: "Investigations on the flow phenomena at plates and cambered models were carried out with the aid of force measurements, some pressure distribution measurements, and photographic observation. The experimental methods are described and the results given. Section III of this work gives a comprehensive account of the results and enables us to see how nearly the lift line and lift surface theories agree with the experimental results" (p. 1).
Date: June 1936
Creator: Winter, H.
Partner: UNT Libraries Government Documents Department
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Ignition Process in Diesel Engines

Description: This report analyzes the heating and vaporization process of fuel droplets in a compression-ignition engine on the basis of the theory of similitude - according to which, the period for heating and complete vaporization of the average size fuel drop is only a fraction of the actually observed ignition lag. The result is that ignition takes place in the fuel vapor air mixture rather than on the surface of the drop. The theoretical result is in accord with the experimental observations by Rothroc… more
Date: June 1936
Creator: Wentzel, W.
Partner: UNT Libraries Government Documents Department
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Contribution to the problem of airfoils spanning a free jet

Description: After a brief discussion of the work done up to now on an unwarped wing of constant chord spanning a free jet, the computation of the circulation and lift distribution for different forms of warped wings spanning rectangular and circular jets was carried out. The computed values are compared with test values and the agreement is found to be good. The effect of placing the wing eccentrically is slight and may be applied as a correction factor to the data obtained for wing placed in middle of jet. more
Date: June 1936
Creator: Stüper, J.
Partner: UNT Libraries Government Documents Department
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Similitude in Hydrodynamic Tests Involving Planing

Description: The problems of using models in planing tests are addressed. If one passes from the model to a hull of linear dimensions n times greater, the speeds are connected by the law of mechanical similitude. The normal forces given by the hydrodynamic equations (perfect fluid) also follow the law of dynamic similitude (Reech's method) and are multiplied by n(exp 3). A series of tests were performed and the actual results were compared to theoretical results.
Date: May 1936
Creator: Gruson, M. F.
Partner: UNT Libraries Government Documents Department
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Chief Characteristics and Advantages of Tailless Airplanes

Description: This study will be concerned with the critical examination of two main questions, mainly, susceptibility of centering and more generally, the conditions of static stability, longitudinal equilibrium, and the question of dynamic stability, or at least the damping of longitudinal vibrations about a position of equilibrium that may result from a small variation in the angle of attack.
Date: May 1936
Creator: Dufaure De Lajarte, A.
Partner: UNT Libraries Government Documents Department
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General instability criterion of laminar velocity distributions

Description: The present paper describes the results of a stability investigation on symmetrical velocity profiles in a channel and of boundary-layer profiles. The effect of friction was assumed to be vanishing and did not occur in the stability consideration so far as it had been resorted to for preparatory asymptotic considerations. Proceeding on very general premises as regards the form of the velocity distribution, a proof was deduced of the elementary theorem that velocity profiles with inflection poin… more
Date: April 1936
Creator: Tollmien, W.
Partner: UNT Libraries Government Documents Department
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Behavior of Turbulent Boundary Layers on Curved Convex Walls

Description: The system of linear differential equations which indicated the approach of separation and the so-called "boundary-layer thickness" by Gruschwitz is extended in this report to include the case where the friction layer is subject to centrifugal forces. Evaluation of the data yields a strong functional dependence of the momentum change and wall drag on the boundary-layer thickness radius of curvature ratio for the wall. It is further shown that the transition from laminar to turbulent flow occurs… more
Date: April 1936
Creator: Schmidbauer, Hans
Partner: UNT Libraries Government Documents Department
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Ignition and Flame Development in the Case of Diesel Fuel Injection

Description: "To investigate the process of ignition and combustion in the case of spray injection into heated air, a new form of apparatus is developed and the tests carried out with it described. Photographs of the spray before and after ignition are obtained at frequencies of 500 pictures per second. Pressures and temperatures are simultaneously recorded on oscillograms. Information on the initial conditions, ignition time lag, period of complete combustion, place where ignition starts, and general cours… more
Date: March 1936
Creator: Holfelder, Otto
Partner: UNT Libraries Government Documents Department
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Turbulent Jet Expansion

Description: This report was made to study the velocity distribution in an open, in a partially open, and in a partially expanding jet. The open-jet observations reveal minor systematic discrepancies from Tollmien's theoretical velocity distribution. The shearing-stress distribution for the partially open jet was determined. The value derived for the ratio of mixing distance to jet width was found to be in close agreement with the corresponding value for the open-jet boundary.
Date: March 1936
Creator: Förthmann, E.
Partner: UNT Libraries Government Documents Department
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Investigations on the Amount of Downwash Behind Rectangular and Elliptical Wings

Description: "The downwash behind a wing may be computed from the system of vortices created by the wing and which can be substituted for the latter. If the actual rolling-up process of the free vortex sheet is disregarded, the establishment of boundaries for the downwash factors is contingent upon the premise that no rolling up takes place or else that the developed tip vortices start direct on the effective line. The actual downwash factors for the rectangular wing are rather of the approximate magnitude … more
Date: February 1936
Creator: Muttray, H.
Partner: UNT Libraries Government Documents Department
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The Formation of Ice on Airplanes

Description: "The present report examines the problem of ice formation from the point of view of the pilot and the meteorologist. Their experiences prove the ice deposit to be first and foremost a navigational problem and only secondarily a question of de-icing devices. With correct utilization of the meteorological information by the flyer, ice hazard can in many cases be minimized or avoided. Ice formation and the different types of ice deposits are listed and discussed" (p. 1).
Date: February 1936
Creator: Noth, H. & Polte, W.
Partner: UNT Libraries Government Documents Department
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Methods and Formulas for Calculating the Strength of Plate and Shell Constructions as Used in Airplane Design

Description: "This report is a compilation of previously published articles on formulas and methods of calculation for the determination of the strength and stability of plate and shell construction as employed in airplane design. In particular, it treats the problem of isotropic, orthotopic, and stiffened rectangular plates, thin curved panels, and circular cylinders under various loading conditions. The purpose of appending the pertinent literature references following the subjects discussed was to facili… more
Date: February 1936
Creator: Heck, O. S. & Ebner, H.
Partner: UNT Libraries Government Documents Department
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Torsion and buckling of open sections

Description: Following an abstract of the well-known theory of torsion in compression, the writers give directions for the practical calculation of the values of C(sub BT) (resistance to flexure and torsion) and i(sub SP(exp 2)), which determine the torsion. The second part treats the experiments in support of the theory of torsion of plain and flanged angle sections.
Date: January 1936
Creator: Wagner, H. & Pretschner, W.
Partner: UNT Libraries Government Documents Department
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High-speed wind tunnels

Description: Wind tunnel construction and design is discussed especially in relation to subsonic and supersonic speeds. Reynolds Numbers and the theory of compressible flows are also taken into consideration in designing new tunnels.
Date: November 1936
Creator: Ackeret, J.
Partner: UNT Libraries Government Documents Department
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Bending of Beams of Thin Sections

Description: The tendency toward economy of material and lightness of structure has long since led to the increased application of beams having large ratios of moment of area W to cross-sectional area F. This paper tries to provide an answer to how thin the beams can be.
Date: April 1936
Creator: Huber, Maximilian T.
Partner: UNT Libraries Government Documents Department
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Relative Efficiencies and Design Charts for Various Engine-Propeller Combinations, Special Report

Description: "The relative efficiencies of various engine-propeller combinations were the subject of a study that covered the important flight conditions, particularly the take-off. Design charts that graphically correlate the various propeller parameters were prepared to facilitate the solution of problems and also to clarify the conception of the relationships of the various engine-propeller design factors. It is shown that, among the many methods for improving the take-off thrust, the use of high-pitch, … more
Date: September 1936
Creator: Biermann, David
Partner: UNT Libraries Government Documents Department
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Tank Tests of the Effect of Rivet Heads, etc., on the Water Performance of a Seaplane Float, Special Report

Description: "A 1/3.5 full-size model of the Mark V float of the Bureau of Aeronautics, Navy Department, was tested in the NACA tank both with smooth painted bottom surfaces and with roundhead rivets, plate laps, and keel plates fitted to simulate the actual bottom of a metal float. The augmentation in water resistance due to the added roughness was found to be from 10-12% at the hum speed and from 12-14% at high speeds. The effect of the roughness of the afterbody was found to be negligible except at high … more
Date: June 4, 1936
Creator: Parkinson, J. B. & Robertson, J. B., Jr.
Partner: UNT Libraries Government Documents Department
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Electrical thermometers for aircraft

Description: Electrical thermometers commonly used on aircraft are the thermoelectric type for measuring engine-cylinder temperatures, the resistance type for measuring air temperatures, and the superheat meters of thermoelectric and resistance types for use on airships. These instruments are described and their advantages and disadvantages enumerated. Methods of testing these instruments and the performance to be expected from each are discussed. The field testing of engine-cylinder thermometers is treated… more
Date: December 15, 1936
Creator: Peterson, John B. & Womack, S. H. J.
Partner: UNT Libraries Government Documents Department
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Heat Transfer to Fuel Sprays Injected Into Heated Gases

Description: This report presents the results of a study made of the influence of several variables on the pressure decrease accompanying injection of a relatively cool liquid into a heated compressed gas. Indirectly, this pressure decrease and the time rate of change of it are indicative of the total heat transferred as well as the rate of heat transfer between the gas and the injected liquid. Air, nitrogen, and carbon dioxide were used as ambient gases; diesel fuel and benzene were the injected liquids. T… more
Date: August 25, 1936
Creator: Selden, Robert F. & Spencer, Robert C.
Partner: UNT Libraries Government Documents Department
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A Theory for Primary Failure of Straight Centrally Loaded Columns

Description: "A theory of primary failure of straight centrally loaded columns is presented. It is assumed that the column cross section and the load are constant throughout the length. Primary failure is defined as any type of failure in which the cross sections are translated, rotated, or translated and rotated but not distorted in their own planes" (p. 141).
Date: August 17, 1936
Creator: Lundquist, Eugene E. & Fligg, Claude M.
Partner: UNT Libraries Government Documents Department
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The Rolling Friction of Several Airplane Wheels and Tires and the Effect of Rolling Friction on Take-Off

Description: This report presents the results of tests made to determine the rolling friction of airplane wheels and tires under various conditions of wheel loading, tire inflation pressure, and ground surface. The effect of wheel-bearing type was also investigated. Six pairs of wheels and tires were tested including two sizes of each of the types designated as standard (high pressure), low pressure, and extra low pressure. The results of calculations intended to show the effect of variations in rolling fri… more
Date: September 19, 1936
Creator: Wetmore, J. W.
Partner: UNT Libraries Government Documents Department
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Strength of Welded Aircraft Joints

Description: "This investigation is a continuation of work started in 1928 and described in NACA-TR-348 which shows that the insertion of gusset plates was the most satisfactory way of strengthening a joint. Additional tests of the present series show that joints of this type could be improved by cutting out the portion of the plate between the intersecting tubes. T and lattice joints in thin-walled tubing 1 1/2 by 0.020 inch have somewhat lower strengths than joints in tubing of greater wall thickness beca… more
Date: August 12, 1936
Creator: Brueggeman, W. C.
Partner: UNT Libraries Government Documents Department
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Span load distribution for tapered wings with partial-span flaps

Description: Tables are given for determining the load distribution of tapered wings with partial-span flaps placed either at the center or at the wing tips. Seventy-two wing-flap combinations, including two aspect ratios, four taper ratios, and nine flap lengths, are included. The distributions for the flapped wing are divided into two parts, one a zero lift distribution due primarily to the flaps and the other an additional lift distribution due to an angle of attack of the wing as a whole. Comparison bet… more
Date: November 21, 1936
Creator: Pearson, H. A.
Partner: UNT Libraries Government Documents Department
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