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The 1929 Rhon soaring-flight contest
The limitation of the 1929 contest to performance gliders necessitated the establishment of a formula which would make it possible to distinguish between performance gliders and school and training gliders. The sinking speed was therefore adopted as the basis for such a distinction, and the requirement was made that the sinking speed of a performance glider should not exceed 0.8 m/s. The rest of the report details the different entries with regard to design and performance.
Date:
April 1930
Creator:
Lippisch, Alexander
System:
The UNT Digital Library
Abstracts from the German Technical Press: Rates for Flights Organized by the State
Report presenting tariffs that are written for all aircraft manufacturing companies to follow regarding aircraft orders.
Date:
April 1921
Creator:
United States. National Advisory Committee for Aeronautics.
System:
The UNT Digital Library
Aerial photography : obtaining a true perspective
Report discussing a demonstration was given within the last few days at the British Museum by Mr. J. W. Gordon, author of "Generalized Linear Perspective" (Constable and Co.), a work describing a newly-worked-out system by which photographs can be made available for the purpose of exactly recording the dimensions of the objects photographed even when the objects themselves are presented foreshortened in the photograph.
Date:
April 1923
Creator:
United States. National Advisory Committee for Aeronautics.
System:
The UNT Digital Library
Aeromechanical Experimentation (Wind Tunnel Tests)
The following report endeavors to show that aeromechanical experimentation has become an important aid to theory. Experiments can be tried with separate parts of airplanes or with models of whole airplanes, with propellers, and with anything else that comes into contact with moving air.
Date:
April 1929
Creator:
Katzmayr, R.
System:
The UNT Digital Library
Aeronautical education and research at the Swiss Institute of Technology in Zurich
Progress in the scientific and practical fields of aviation has caused the Swiss Institute of Technology to organize lectures and practical training courses in all three branches of aeronautics and to found centers of scientific research, laboratories, etc., in order to supply the government and industries with scientifically and technically trained engineers.
Date:
April 1931
Creator:
Karner, L. & Ackeret, J.
System:
The UNT Digital Library
Amplitude distribution and energy balance of small disturbances in plate flow
From Introduction: "The present report, therefore, deals first, with the distribution of the amplitude of the disturbance over the flow section, that is, the calculation of the characteristic functions and second, with the study of the energy distribution and energy balance of the disturbance motion. The investigations are based upon the disturbances of the laminar flow past a flat plate which are situated exactly at the boundary between amplification and damping (neutral oscillations)."
Date:
April 1950
Creator:
Schlichting, H.
System:
The UNT Digital Library
Apparatus for Measurements of Time and Space Correlation
The report describes a brief review is made of improvements to an experimental apparatus for time and space correlation designed for study of turbulence. Included is a description of the control of the measurements and a few particular applications.
Date:
April 1955
Creator:
Favre, Alexandre; Gaviglio, J. & Dumas, R.
System:
The UNT Digital Library
Application of the Theory of Free Jets
Based upon Kirchoff's theory of free jets the flow through different screen arrangements of flat plates, as chiefly encountered with turbines in the cavitation zone is defined. It is shown by experiments that these theoretical results are very well representative in most cases of the conditions of discharge from water in air and consequently by cavitation. In addition, the experiments reveal a picture of the discrepancies between the actual flow and the theory of discharge of air in air (of water in water without cavitation).
Date:
April 1932
Creator:
Betz, A. & Petersohn, E.
System:
The UNT Digital Library
Applying the results of experiments on small models in the wind tunnel to the calculation of full-sized aircraft
This report presents the attempt to develop a law which will permit the use of results obtained on small models in a tunnel for the calculation of full-sized airplanes, or if it exists, a law of similitude relating air forces on a full-sized plane to those on a reduced scale model.
Date:
April 1922
Creator:
Robert
System:
The UNT Digital Library
Behavior of Turbulent Boundary Layers on Curved Convex Walls
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 at somewhat higher Reynolds Numbers at the convex wall than at the flat plate, due to the stabilizing effect of the centrifugal forces.
Date:
April 1936
Creator:
Schmidbauer, Hans
System:
The UNT Digital Library
Bending of Beams of Thin Sections
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.
System:
The UNT Digital Library
Boundary Layer Removal by Suction
Flight-test data and wind-tunnel data on suction profiles are substantially in agreement. The lift values found in the model test can be actually flown and used as a basis for the design. To visualize the action of the suction, the flow conditions with and without suction on the upper surface were photographed; figures 12 to 15 are sections of the film.
Date:
April 1941
Creator:
Schrenk, O.
System:
The UNT Digital Library
Boundary Layer Theory, Part 2, Turbulent Flows
From Summary: "The flow laws of the actual flows at high Reynolds numbers differ considerably from those of the laminar flows treated in the preceding part. These actual flows show a special characteristic, denoted as turbulence. The character of a turbulent flow is most easily understood the case of the pipe flow. Consider the flow through a straight pipe of circular cross section and with a smooth wall. For laminar flow each fluid particle moves with uniform velocity along a rectilinear path."
Date:
April 1949
Creator:
Schlichting, H.
System:
The UNT Digital Library
Calculation of Centrally Loaded Thin-Walled Columns Above the Buckling Limit
"When thin-walled columns formed from flanged sheet, such as used in airplane construction, are subjected to axial load, their behavior at failure varies according to the slenderness ratio. On long columns the axis deflects laterally while the cross section form is maintained; buckling results. The respective breaking load in the elastic range is computed by Euler's formula and for the plastic range by the Engesser- Karman formula. Its magnitude is essentially dependent upon the length" (p. 1).
Date:
April 1945
Creator:
Reinitzhuber, F.
System:
The UNT Digital Library
The Calculation of Lateral Stability With Free Controls
The discussion of the structural methods for obtaining lateral stability discloses the remarkable influence of the constant fuselage and wing proportions to the yawing moments. For the effectiveness of modifications in vertical tail surfaces and tail length, these quotas - little observed heretofore, in this connection - are decisive. This also applies to the amount of dihedral of the wing with regard to the roll stability of the complete wing already existing without angle of the dihedral.
Date:
April 1934
Creator:
Mathias, Gotthold
System:
The UNT Digital Library
The Cathode Oscillograph for the Study of Low, Medium, and High Frequencies
The object of this work has been to construct an apparatus for obtaining oscillogram of voltages and currents which are variable with respect to time and of the frequency which is constantly met in radio.
Date:
April 1924
Creator:
Dufour, A.
System:
The UNT Digital Library
The Combination of Internal-Combustion Engine and Gas Turbine
"While the gas turbine by itself has been applied in particular cases for power generation and is in a state of promising development in this field, it has already met with considerable success in two cases when used as an exhaust turbine in connection with a centrifugal compressor, namely, in the supercharging of combustion engines and in the Velox process, which is of particular application for furnaces. In the present paper the most important possibilities of combining a combustion engine with a gas turbine are considered. These "combination engines " are compared with the simple gas turbine on whose state of development a brief review will first be given" (p. 1).
Date:
April 1947
Creator:
Zinner, K.
System:
The UNT Digital Library
Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines
"The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined" (p. 1).
Date:
April 1932
Creator:
Schnauffer, Kurt
System:
The UNT Digital Library
Commercial Airplanes and Seaplanes
This report considers as the dominating characteristic, either the load carried, the speed, the radius of action, the fuel consumption, the activity of transport, or, lastly, the qualities of comfort and safety. The first four factors determine the theoretical efficiency, while the others determine its practical efficiency.
Date:
April 1922
Creator:
Royer, Etienne
System:
The UNT Digital Library
Contribution to the Systematic Investigation on Joukowsky Profiles
"This article resulted from the need of showing, in a simple way, how the aerodynamic properties of airfoils are affected by the shape of their profiles. No general solution of this problem could be found, since the profile shapes cannot ordinarily be expressed by simple mathematical formulas. This advantage is possessed only by the Joukowsky profiles and this discussion of the problem is therefore limited to them" (p. 1).
Date:
April 1928
Creator:
Loew, Gottfried
System:
The UNT Digital Library
Contribution to the Theory of the Heated Duct Radiator
A method is developed with no neglect of certain factors in mass flow of air and in the drag of the heated radiator, i.e., one under actual operating conditions, as compared with the corresponding values in the cold state, may be simply computed. Although a symmetrical duct radiator has been used to bring out the flow relations, the results apply equally as well to the unsymmetrical radiator shapes usual in airplane construction.
Date:
April 1939
Creator:
Winter, H.
System:
The UNT Digital Library
The Coupling of Engines
This report examines the idea of coupling numerous engines together to turn a single propeller, which the author feels would free aircraft design from the problems of multi-engine and propeller design.
Date:
April 1921
Creator:
Boccaccio, Paul
System:
The UNT Digital Library
The Critical Shear Load of Rectangular Plates
This report gives formulas for analyzing the critical shear load of a simply supported square, isotropic (simple flat plate), or orthogonal anisotropic plate (a plate in which the rigidity in two directions perpendicular to each other is different, i.e. plywood or corrugated sheet), these formulas, although arrived at by approximation method, seem to agree fairly well with experimental results.
Date:
April 1933
Creator:
Seydel, Edgar
System:
The UNT Digital Library
The design of floats
Following a summary of the multiplicity of domestic and foreign floats and a brief enumeration of the requirements of floats, the essential form parameters and their effect on the qualities of floats are detailed. On this basis a standard float design is developed which in model families with varying length/beam ratio and angle of dead rise is analyzed by an experimental method which permits its best utilization on any airplane.
Date:
April 1938
Creator:
Sottorf, W.
System:
The UNT Digital Library