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The Aerodynamic Aspect of Wing-Fuselage Fillets

Description: Report discussing model tests prove the feasibility of enhancing the aerodynamic qualities of wing-fuselage fillets by appropriate design of fuselage and wing roots. Abrupt changes from maximum fuselage height to wing chord must be avoided and every longitudinal section of fuselage and wing roots must be so faired and arranged as to preserve the original lift distribution of the continuous wing. Adapting the fuselage to the curvilinear circulation of the wing affords further improvement. The polars of such arrangements are almost the same as those of the "wing alone," thus voiding the superiority of the high-wing type airplane known with conventional design.
Date: February 1935
Creator: Muttray, H.
Partner: UNT Libraries Government Documents Department

The Aerodynamic Wind Vane and the Inherent Stability of Airplanes

Description: Report discussing the design of the wind vane described rests on the following line of reasoning: An airplane, originally in equilibrium about its C.G. is assumed to be deflected from this position through an angle (delta)i, the variation (delta)i being so sudden that the path of the C.G. and the airplane speed do not change while it is taking place. The aerodynamic forces acting on the wings, tail surfaces, fuselage, etc., which, as a whole, exerted a zero moment (M(sub G) = 0) about the center of gravity at the instant of equilibrium, now exert a moment M(sub G) not equal to 0.
Date: February 1931
Creator: Lapresle, A.
Partner: UNT Libraries Government Documents Department

Airplane Flight in the Stratosphere

Description: This brief survey of the problems encountered in high-altitude flight deals in particular with the need for high lift coefficient in the wings, large aspect ratios in the wings, and also the problem of hermetically sealing the cabin.
Date: February 1932
Creator: de Caria, Ugo
Partner: UNT Libraries Government Documents Department

Comparison of Theory With Experiment in the Phenomenon of Wing Flutter

Description: Direct measurements were undertaken at the Aeronautics Laboratory in Turin of the aerodynamic actions on an oscillating wing. The tests conducted had as their essential object the examination of the operation of apparatus designed for this measurement. The values experimentally obtained for the aerodynamic coefficients are in good agreement with the theory of oscillatory motion of the wing of finite span and show clear deviation from the values obtained by theory of plane motion.
Date: February 1939
Creator: Cicala, P.
Partner: UNT Libraries Government Documents Department

Disintegration of a Liquid Jet

Description: 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.
Partner: UNT Libraries Government Documents Department

Effect of Fuselage and Engine Nacelles on Some Aerodynamic Properties of an Airplane Wing

Description: "With the aid of the method of J. Lotz, the writer undertook to solve theoretically the lift distribution along the span of an airplane wing, when the outline of the wing is uneven. This problem arises in the case of a mid-wing monoplane with embedded engine nacelles. The fuselage and the nacelles were considered as aerodynamically profiled, that is, as lift-producing parts. The task was therefore to determine not only the disturbance caused by the fuselage and nacelles, but also their share in the total lift of the wing" (p. 1).
Date: February 1934
Creator: Vladea, Joan
Partner: UNT Libraries Government Documents Department

Experimental Investigations Concerning the Limits of Detonation in Gaseous Mixtures: Part 2

Description: Memorandum presenting an investigation concerning the limits of detonation in gaseous mixtures. In regards to the results, by progressive dilution of the explosive, the course of the chemical reaction becomes slower and slower until finally the transformation within the reaction zone becomes so slow that it is not there completed.
Date: February 1930
Creator: Wendlandt, Rudolf
Partner: UNT Libraries Government Documents Department

Flat Sheet Metal Girders With Very Thin Metal Web. Part 1: General Theories and Assumptions

Description: 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
Partner: UNT Libraries Government Documents Department

Flat Sheet Metal Girders With Very Thin Metal Web. Part 2: Sheet Metal Girders With Spars Resistant to Bending - Oblique Uprights - Stiffness

Description: "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
Partner: UNT Libraries Government Documents Department

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

Description: 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
Partner: UNT Libraries Government Documents Department

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

Ice Formation on Wings

Description: This report makes use of the results obtained in the Gottingen ice tunnel in which the atmospheric conditions are simulated and the process of ice formation photographed. The effect of ice formation is threefold: 1) added weight to the airplane; 2) a change in the lift and drag forces; 3) a change in the stability characteristics.
Date: February 1939
Creator: Ritz, L.
Partner: UNT Libraries Government Documents Department

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 of the values computable with the developed tip vortices starting direct on the wing" (p. 1).
Date: February 1936
Creator: Muttray, H.
Partner: UNT Libraries Government Documents Department

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 facilitate a comprehensive study of the treated problems" (p. 1).
Date: February 1936
Creator: Heck, O. S. & Ebner, H.
Partner: UNT Libraries Government Documents Department

Planing-Surface Tests at Large Froude Numbers - Airfoil Comparison

Description: "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.
Partner: UNT Libraries Government Documents Department

The Process of Separation in the Turbulent Friction Layer

Description: "The separation of the flow which occurs at large angles of attack on the suction side of an airplane wing is attributable to phenomena in the flowing fluid layer adjacent to the surface; the fluid particles slowed up by the friction on the surface can no longer advance against an unduly great pressure rise. It is of vital importance that there exist two types of flow - laminar and turbulent - in the fluid layer flowing in the immediate vicinity of a body. According to Prandtl, by whom the whole theory was developed, we speak in the first case of a laminar boundary layer, in the second, of a turbulent friction layer" (p. 1).
Date: February 1933
Creator: Gruschwitz, E.
Partner: UNT Libraries Government Documents Department

Rate-of-Climb Recorder

Description: 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
Partner: UNT Libraries Government Documents Department

Relation Between the Stability Characteristics and the Controllability of German Airplanes

Description: This survey is intended to give a general approximate idea of the stability and controllability of German airplanes. Both flight characteristics, including the behavior of the airplane under the action of deflected controls and external disturbances, and flight performance, which refers to climbing, speed, take-off, and landing qualities.
Date: February 1930
Creator: Hübner, Walter
Partner: UNT Libraries Government Documents Department

The Relation Between the Tensile Strength and the Hardness of Metals

Description: This report presents methods determining the hardness and tensile strength of metals by showing the effect and dependence of the hardness numbers on the strain-hardening. Relations between the hardness numbers and the ordinary stress-strain diagrams and tensile strength are given. Procedures for finding the Brinell strength are also presented.
Date: February 1930
Creator: Schwarz, O.
Partner: UNT Libraries Government Documents Department

Resonance Vibrations of Aircraft Propellers

Description: 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
Partner: UNT Libraries Government Documents Department