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Flat Sheet Metal Girders With Very Thin Metal Web. Part 3: Sheet Metal Girders With Spars Resistant to Bending - the Stress in Uprights - Diagonal Tension Fields
This report continues the work presented in NACA-TM 605 and expands the scope to include the change in specific number of wrinkles from direction x to z, so that b and f become variable in direction z. Moreover, it seems likely that b and f increase from the edge toward the center if the sheet is infinitely thin.
Date:
February 1931
Creator:
Wagner, Herbert
System:
The UNT Digital Library
Flat Sheet Metal Girders With Very Thin Metal Web. Part 2: Sheet Metal Girders With Spars Resistant to Bending - Oblique Uprights - Stiffness
"Noting that the stiffness of the girder increases very rapidly as Beta increases, the result can be summed up as follows: When the cross stress preponderates in one direction and when the web plate is to be given the dimensions commensurate to its stresses, it is advisable (regardless of any ensuing structural difficulties) to set the uprights at about Beta = 120 degrees, thereby lowering the weight of the plate wall 15 percent (in contrast to Beta = 90 degrees), and raising the stiffness 55 percent. But, when the cross stresses alternate and are approximately of the same intensity in both directions, or, if the web plate thickness is determined by other structural reasons, then Beta = 90 degrees should be chosen" (p. 1).
Date:
February 1931
Creator:
Wagner, Herbert
System:
The UNT Digital Library
Flat Sheet Metal Girders With Very Thin Metal Web. Part 1: General Theories and Assumptions
The object of this report was to develop the structural method of sheet metal girders and should for that reason be considered solely from this standpoint. The ensuing methods were based on the assumption of the infinitely low stiffness in bending of the metal web. This simplifies the basis of calculations to such an extent that many questions of great practical importance can be examined which otherwise cannot be included in any analysis of the bending stiffness of the buckled plate. This report refers to such points as the safety in buckling of uprights to the effect of bending flexibility of spars, to spars not set parallel, etc.
Date:
February 1931
Creator:
Wagner, Herbert
System:
The UNT Digital Library
Disintegration of a Liquid Jet
This report presents an experimental determination of the process of disintegration and atomization in its simplest form, and the influence of the physical properties of the liquid to be atomized on the disintegration of the jet. Particular attention was paid to the investigation of the process of atomization.
Date:
February 1932
Creator:
Haenlein, A.
System:
The UNT Digital Library
Problems Involved in the Choice and Use of Materials in Airplane Construction
The present state of the problem of materials in airplane construction is studied on the basis of data giving the principal characteristics of different materials and showing how they affect the form of airplane parts.
Date:
February 1932
Creator:
Brenner, Paul
System:
The UNT Digital Library
Resonance Vibrations of Aircraft Propellers
On the basis of the consideration of various possible kinds of propeller vibrations, the resonance vibrations caused by unequal impacts of the propeller blades appear to be the most important. Their theoretical investigation is made by separate analysis of torsional and bending vibrations. This method is justified by the very great difference in the two natural frequencies of aircraft propeller blades. The calculated data are illustrated by practical examples.
Date:
February 1932
Creator:
Liebers, Fritz
System:
The UNT Digital Library
Calculation of the Lateral-Dynamic Stability of Aircraft
"Graphs and formulas are given with the aid of which all the aerodynamic coefficients required for computing the lateral dynamic stability can be determined. A number of numerical examples are given for obtaining the stability derivatives and solving the characteristic-stability equation. Approximate formulas are derived with the aid of which rapid preliminary computations may be made and the stability coefficients corrected for certain modifications of the airplane" (p. 1).
Date:
February 1952
Creator:
Raikh, A.
System:
The UNT Digital Library
Rate-of-Climb Recorder
The chief advantage of the instrument lies in the degree of accuracy obtainable with suitably flexible capsule (dynamic pressure recorder with small test range) and in its sensitivity for recording static-pressure changes. A description and hook-up of the instrument is provided along with calculations of error.
Date:
February 1938
Creator:
Danielzig, Helmut
System:
The UNT Digital Library
Planing-Surface Tests at Large Froude Numbers - Airfoil Comparison
"The take-off capacity of a flying boat depends upon the design of the hull bottom ahead as well as aft of the step. Systematic tests - largely made by industry itself - had proved the benefit accruing from a well designed hull bottom long before theoretical insight into the flow phenomena involved had been obtained. The theoretical framing of the problem was beset with serious difficulties and, though restricted to the processes within range of the planing bottom ahead of the step, the solutions do not yet afford a comprehensive survey" (p. 1).
Date:
February 1938
Creator:
Sambraus, A.
System:
The UNT Digital Library
The stress distribution in shell bodies and wings as an equilibrium problem
This report treats the stress distribution in shell-shaped airplane components (fuselage, wings) as an equilibrium problem; it includes both cylindrical and non-cylindrical shells. In particular, it treats the stress distribution at the point of stress application and at cut-out points.
Date:
February 1937
Creator:
Wagner, H.
System:
The UNT Digital Library
Evaporation, Heat Transfer, and Velocity Distribution in Two-Dimensional and Rotationally Symmetrical Laminar Boundary-Layer Flow
The fundamental boundary layer equations for the flow, temperature and concentration fields are presented. Two dimensional symmetrical and unsymmetrical and rotationally symmetrical steady boundary layer flows are treated as well as the transfer boundary layer. Approximation methods for the calculation of the transfer layer are discussed and a brief survey of an investigation into the validity of the law that the Nusselt number is proportional to the cube root of the Prandtl number is presented.
Date:
February 1958
Creator:
Frössling, Nils
System:
The UNT Digital Library
Gas-Dynamic Investigations of the Pulse-Jet Tube, Parts 1 and 2
"Based upon a simplified representation of the mode of operation of the pulse-jet tube, the effect of the influences mentioned in the title were investigated and it will be shown that, for a jet tube with a form designed to be aerodynamically favorable, the ability to operate is at least questionable" (p. 1).
Date:
February 1947
Creator:
Shultz-Grunow, F.
System:
The UNT Digital Library
The Strength of Shell and Tubular Spar Wings
The report is a survey of the strength problems arising on shell and tubular spar wings. The treatment of the shell wing strength is primarily confined to those questions which concern the shell wing only; those pertaining to both shell wing and shell body together have already been treated in TM 838. The discussion of stress condition and compressive strength of shell wings and tubular spar wings is prefaced by several considerations concerning the spar and shell design of metal wings from the point of view of strength.
Date:
February 1940
Creator:
Ebner, H.
System:
The UNT Digital Library
Theoretical and Experimental Investigations of the Drag of Installed Aircraft Radiators
The present report proposes the determination of the absolute magnitude of the total radiator drag and, in addition, of the different causes of the radiator drag.
Date:
February 1940
Creator:
Barth, W.
System:
The UNT Digital Library
Testing of High-Octane Fuels in the Single-Cylinder Airplane Engine
"One of the most important properties of aviation fuels for spark-ignition engines is their knock rating. The CFR engine tests of fuels of 87 octane and above does not always correspond entirely to the actual behavior of these fuels in the airplane engine. A method is therefore developed which, in contrast to the octane number determination, permits a testing of the fuel under various temperatures and fuel mixture conditions. The following reference fuels were employed: 1) Primary fuels; isooctane and n-heptane; 2) Secondary fuels; pure benzene and synthetic benzine" (p. 1).
Date:
February 1940
Creator:
Seeber, Fritz
System:
The UNT Digital Library
Experimental Contribution to the Study of Combustion in Compression-Ignition Engines
The purpose of this paper is to explain the differences in thermodynamic qualities of two oils and to try to make this differentiation clear enough so that it can be applied to two oils extremely alike, as, for instance a given oil and the same oil to which a small amount of another substance has been added.
Date:
February 1940
Creator:
Duchene, R.
System:
The UNT Digital Library
Aerodynamics of Rotating-Wing Aircraft With Blade-Pitch Control
"In the present report, with the aid of the usual computation methods, a rotor is investigated the pitch of whose blades is capable of being controlled in such a manner that it varies linearly with the flapping angle. To test the effect of this linkage on the aircraft performance, the theory is applied to an illustrative example" (p. 1).
Date:
February 1940
Creator:
Pflüger, A.
System:
The UNT Digital Library
Investigations on the Amount of Downwash Behind Rectangular and Elliptical Wings
"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 of the values computable with the developed tip vortices starting direct on the wing" (p. 1).
Date:
February 1936
Creator:
Muttray, H.
System:
The UNT Digital Library
The Formation of Ice on Airplanes
"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.
System:
The UNT Digital Library
Methods and Formulas for Calculating the Strength of Plate and Shell Constructions as Used in Airplane Design
"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 facilitate a comprehensive study of the treated problems" (p. 1).
Date:
February 1936
Creator:
Heck, O. S. & Ebner, H.
System:
The UNT Digital Library
On Combustion in a Turbulent Flow
"The characteristics introduced by the turbulence in the process of the flame propagation are considered. On the basis of geometrical and dimensional considerations an expression is obtained for the velocity of the flame propagation in a flow of large scale of turbulence" (p. 1).
Date:
February 1947
Creator:
Shelkin, K. I.
System:
The UNT Digital Library
The Oscillating Circular Airfoil on the Basis of Potential Theory
"Proceeding from the thesis by W. Kinner the present report treats the problem of the circular airfoil in uniform airflow executing small oscillations, the amplitudes of which correspond to whole functions of the second degree in x and y. The pressure distribution is secured by means of Prandtl's acceleration potential. It results in a system of linear equations the coefficients of which can be calculated exactly with the aid of exponential functions and Hankel's functions" (p. 1).
Date:
February 1947
Creator:
Schade, T. & Krienes, K.
System:
The UNT Digital Library
The Monoplane as a Lifting Vortex Surface
"In Prandtl's airfoil theory the monoplane was replaced by a single lifting vortex line and yielded fairly practical results. However, the theory remained restricted to the straight wing. Yawed wings and those curved in flight direction could not be computed with this first approximation; for these the chordwise lift distribution must be taken into consideration. For the two-dimensional problem the transition from the lifting line to the lifting surface has been explained by Birnbaum. In the present report the transition to the three-dimensional problem is undertaken" (p. 1).
Date:
February 1947
Creator:
Blenk, Hermann
System:
The UNT Digital Library
Scale Effect and Optimum Relations for Sea Surface Planning
"From the general dimensional and mechanical similarity theory it follows that a condition of steady motion of a given shape\bottom with constant speed on the surface of water is determined by four nondimensional parameters. By considering the various systems of independent parameters which are applied in theory and practice and special tests, there is determined their mutual relations and their suitability as planning characteristics. In studying the scale effect on the basis of the Prnndtl formula for the friction coefficient for a turbulent condition the order of magnitude is given of the error in applying the model data to full scale in the case of a single-step bottom" (p. 1).
Date:
February 1947
Creator:
Sedov, L.
System:
The UNT Digital Library