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Coefficient of Friction, Oil Flow and Heat Balance of a Full-Journal Bearing: Memorandum presenting the coefficient of friction, oil flow, and heat balance of a full-journal bearing.
Coefficients of Flow of Standard Nozzles: We first undertook experiments with air, devoted principally to the investigation of the disturbances due to the differences in the nature of the flow to the nozzle. The difficulty of measuring the air, however, caused us to experiment with water. Due to the possibility of measuring the capacity of the container, this method was much more accurate than measuring with Pitot tobes.
Combating Airplane Fires: This report provides a summary of the important steps to be taken in combating airplane fires. Some considerations and ways of preventing fires from developing are provided.
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).
Combined Pitching and Yawing Motion of Airplanes: This report treats the following problems: The beginning of the investigated motions is always a setting of the lateral controls, i.e., the rudder or the ailerons. Now, the first interesting question is how the motion would proceed if these settings were kept unchanged for some time; and particularly, what upward motion would set in, how soon, and for how long, since therein lie the dangers of yawing. Two different motions ensue with a high rate of turn and a steep down slope of flight path in both but a marked difference in angle of attack and consequently different character in the resultant aerodynamic forces: one, the "corkscrew" dive at normal angle, and the other, the "spin" at high angle.
Combustion of Gaseous Mixtures: This report not only presents matters of practical importance in the classification of engine fuels, for which other means have proved inadequate, but also makes a few suggestions. It confirms the results of Withrow and Boyd which localize the explosive wave in the last portions of the mixture burned. This being the case, it may be assumed that the greater the normal combustion, the less the energy developed in the explosive form. In order to combat the detonation, it is therefore necessary to try to render the normal combustion swift and complete, as produced in carbureted mixtures containing benzene (benzol), in which the flame propagation, beginning at the spark, yields a progressive and pronounced darkening on the photographic film.
Combustion of Liquid Fuels in Diesel Engine: Hitherto, definite specifications have always been made for fuel oils and they have been classified as more or less good or non-utilizable. The present aim, however, is to build Diesel engines capable of using even the poorest liquid fuels and especially the waste products of the oil industry, without special chemical or physical preparation.
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).
Comfort in Flight: Some advances in passenger comfort are discussed, namely, ventilated cabins, heating, seating arrangements, and doors.
Comments on Crankless Engine Types: This report describes the leading crankless engine types, which have appeared in recent years. These types include: the Mitchell crankless motor car engine and the German Michel engine.
Commercial Aircraft in War: The difference between aircraft for commercial and wartime uses is delineated, but the interchangability between the two is also discussed. Airships in both roles are also presented.
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.
Commercial Airplanes and Seaplanes: Thick Wings or Thin Wings - All Metal or Mixed Construction: In this report we will consider, 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.
Commercial Aviation in France: In the present state of things, there are three great problems to be solved, relating respectively to the financial, technical, and commercial aspects of the question of commercial aviation.
Commercial Aviation in Germany: Past and Future: This review of commercial aviation includes postal delivery, package transport, and passenger transport. Both airplanes and airships are covered in this review.
Communications and Beacons on Air Routes: Different systems of navigations beacons are discussed with an emphasis on radiotelegraphy and radiotelephony.
Comparative Results of Tests on Several Different Types of Nozzles: "This paper presents the results of tests conducted to determine the effect of the constructional elements of a Laval nozzle on the velocity and pressure distribution and the magnitude of the reaction force of the jet. The effect was studied of the shapes of the entrance section of the nozzle and three types of divergent sections: namely, straight cone, conoidal with cylindrical and piece and diffuser obtained computationally by a graphical method due to Professor F. I. Frankle. The effect of the divergence angle of the nozzle on the jet reaction was also investigated" (p. 1).
Comparison of Automatic Control Systems: This report deals with a reciprocal comparison of an automatic pressure control, an automatic rpm control, an automatic temperature control, and an automatic directional control. It shows the difference between the "faultproof" regulator and the actual regulator which is subject to faults, and develops this difference as far as possible in a parallel manner with regard to the control systems under consideration. Such as analysis affords, particularly in its extension to the faults of the actual regulator, a deep insight into the mechanism of the regulator process.
Comparison of Drop and Wind-Tunnel Experiments on Bomb Drag at High Subsonic Speeds: The drag coefficients of bombs at high velocities velocity of fall was 97 percent of the speed of sound) (the highest are determined by drop tests and compared with measurements taken in the DVL high-speed closed wind tunnel and the open jet at AVA - Gottingen.
Comparison of Nonrigid and Semirigid Airships: "One of the main subjects of airship science consists in establishing cooperation between two vertical forces, the buoyancy of the air and the attraction of gravity. The mechanism for establishing this cooperation must have the minimum weight and offer the minimum head resistance. Starting with this principle, let us consider what improvements can be made in the present type of non-rigid airships" (p. 1).
Comparison of Theory With Experiment in the Phenomenon of Wing Flutter: 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.
Competition for Safety Fuel Tanks: Report describing a competition for safety fuel tanks, including the prizes, requirements that must be fulfilled, some other characteristics, tests, and regulations.
The Compressible Flow Past Various Plane Profiles Near Sonic Velocity: "In an earlier report UM No.1117 by Gothert,the single-source method was applied to the compressible flow around circles, ellipses, lunes, and around an elongated body of revolution at different Mach numbers and the results compared as far as possible with the calculations by Lamla ad Busemann. Essentially, it was found that with favorable source arrangement the single-source method is in good agreement with the calculations of the same degree of approximation by Lamla and Busemann. Near sonic velocity the number of steps must be increased considerably in order to sufficiently approximate the adiabatic curve" (p. 1).
The Compressible Potential Flow Past Elliptic Symmetrical Cylinders at Zero Angle of Attack and with No Circulation: "For the tunnel corrections of compressible flows those profiles are of interest for which at least the second approximation of the Janzen-Rayleigh method can be applied in closed form. One such case is presented by certain elliptical symmetrical cylinders located in the center of a tunnel with fixed walls and whose maximum velocity, incompressible, is twice the velocity of flow. In the numerical solution the maximum velocity at the profile and the tunnel wall as well as the entry of sonic velocity is computed" (p. 1).
Compression Shocks in Two-Dimensional Gas Flows: "The following are arguments on the compression shocks in gas flow start with a simplified representation of the results of the study made by Th. Meyer as published in the Forschungsheft 62 of the VDI, supplemented by several amplifications for the application. In the treatment of compression shocks, the equation of energy, the equation of continuity, the momentum equation, the equation of state of the particular gas, as well as the condition Of the second law of thermodynamics that no decrease of entropy is possible in an isolated system, must be taken into consideration" (p. 1).
Compression Shocks of Detached Flow: "It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated" (p. 1).
Compression Struts With Nonprogressively Variable Moment of Inertia: The buckling failure conditions for a bar with nonprogressively variable moment of inertia J(sub n), although constant over length l(sub n), are developed.
Computation of Cantilever Airplane Wings: The purpose of this treatise is, first of all, the determination of the effect of variously loaded spars on one another, since the neglect of this effect would present an economically very unfavorable computation method. The system of spars and cross-bars alone (whether solid or built-up) does not matter at first, the original assumption being that the spars are rigidly braced by the cross-bars.
Computation of Thin-Walled Prismatic Shells: "We consider a prismatic shell consisting of a finite number of narrow rectangular plates and having in the cross-section a finite number of closed contours (fig. 1(a)). We shall assume that the rectangular plates composing the shell are rigidly joined so that there is no motion of any kind of one plate relative to the others meeting at a given connecting line. The position of a point on the middle prismatic surface is considered to be defined by the coordinate z, the distance to a certain initial cross-section z = O, end the coordinate s determining its position on the contour of the cross-section" (p. 1).
Computative examination of bending strength of girders originally curved and subjected to longitudinal compression: This report examines the stipulation contained in the 1918 BLV, that a girder subjected to longitudinal compression under the influence of half of the specified breaking load, along with Euler bending safety with an initial deflection of 1/200 of the length of the girder can, at most, be subjected to half the stipulated breaking strength.
Concerning the Flow About Ring-Shaped Cowlings 12: Two New Classes of Circular Cowls: "For application in practice for annular radiator fairings and similar arrangements, two new classes of circular cowls are developed by theoretical method, and investigated in a systematic test series regarding their behavior under various working conditions" (p. 1).
Concerning the Flow About Ring-Shaped Cowlings of Finite Thickness: Part 1: "It is shown how one may obtain, in a simple manner, the forms of ring-shaped bodies from existing tables of functions according to the customary method of superposition of flow due to singularities and parallel flow. A number of examples of the forms and pressure distributions of annular source bodies with and without hub body are given, and the inlet conditions of such ring-shaped cowlings are investigated. Furthermore, the annular bodies of finite length are indicated that correspond to Joukowsky profiles for the two-dimensional case" (p. 1).
Concerning the Flow About Ring-Shaped Cowlings Part 2: Annular Bodies of Infinite Length With Circulation for Smooth Entrance: The investigations carried out in a previous report (NACA TM 1325) concerning the flow about ring-shaped cowlings were extended by taking a circulation about the cowling into consideration. The present second report treats bodies of infinite length with approximately smooth entrance. The circulation was caused by distributing vortex rings of constant density over a stream surface extending to infinity. Furthermore, the influence of a hub body on such cowlings was dealt with.
Concerning the Flow About Ring-Shaped Cowlings Part 6: Further Measurements on Inlet Devices: "The present report presents as a supplement to the fourth report (available as ATI 5045, Air Materiel Command) in the series of investigations concerning the flow about ring-shaped cowlings further wind-tunnel measurements on inlet devices which are to show the influence of the radius of the nose of the cowling on the flow conditions. Moreover, a simple rule for the design of such arrangements, containing a hub in the interior, is suggested" (p. 1).
Concerning the Flow About Ring-Shaped Cowlings Part 8: Further Measurements on Annular Profiles: "The measurements of part V (reference 1) of this series of reports, which concerned comparatively long ring profiles, are supplemented by measurements on shorter rings as they are used for shrouded propellers and cowlings of ring-shaped radiators. Mass-flow coefficients and profile drags are given. Furthermore, it has to be determined how far the potential theory describes the flow phenomenon with sufficient accuracy and whether the present theory for the calculation of thin annular profile yields useful profile forms and is suitable for determination of the mass flow for thick profiles" (p. 1).
Concerning the Flow About Ring-Shaped Cowlings Part 9: The Influence of Oblique Oncoming Flow on the Incremental Velocities and Air Forces at the Front Part of Circular Cowls: The dependence of the maximum incremental velocities and air forces on a circular cowling on the mass flow and the angle of attack of the oblique flow is determined with the aid of pressure-distribution measurements. The particular cowling tested had been partially investigated in NACA TM 1327.
Concerning the Flow on Ring-Shaped Cowlings Part 13: The Influence of a Projecting Hub: "The influence of thickness and length of a hub projecting from an inlet opening was investigated on one of the two new classes of circular cowls reported in NACA TM 1360" (p. 1).
Concerning the Velocity of Evaporation of Small Droplets in a Gas Atmosphere: "The evaporation velocity of liquid droplets under various conditions is theoretically calculated and a number of factors are investigated which are neglected in carrying out the fundamental equation of Maxwell. It is shown that the effect of these factors at the small drop sizes and the small weight concentrations ordinarily occurring in fog can be calculated by simple corrections. The evaporation process can be regarded as quasi-stationary in most cases" (p. 1).
Concrete Airship Sheds at Orly, France Part 1: General Aspect of the Problem, Basic Principles of the Final Project, Principal Structural Elements: This report details the contest to design and build concrete airship hangers. The difficulty lies in the magnitude of the absolute dimensions. An airship shed must withstand two principal types of stresses: those resulting from its own weight and those due to the wind. This report discusses both problems in detail.
Concrete Airship Sheds at Orly, France Part 2: Supporting Structure and Method of Moving, Mechanism for Moving the Centering, Apparatus for Handling the Materials, Remarks on Construction Details: This report deals mainly with the methods of construction employed when after the plan had been approved. The foundation, side walls, doors and roof are all discussed and the economic savings resulting from this method of construction.
Cones in Supersonic Flow: "In the case of cones in axially symmetric flow of supersonic velocity, adiabatic compression takes place between shock wave and surface of the cone. Interpolation curves betwen shock polars and the surface are therefore necessary for the complete understanding of this type of flow. They are given in the present report by graphical-numerical integration of the differential equation for all cone angles and airspeeds" (p. 1).
Considerations on Propeller Efficiency: The propeller cannot be considered alone, but the mutual interference between propeller and airplane must be considered. These difficulties are so great when the joint action of propeller and airplane is considered, that the aerodynamic laboratory at Gottingen originally abandoned the idea of applying the efficiency conception of the test results. These difficulties and the methods by which they are overcome are outlined in this report.
Constant-Pressure Blowers: "The conventional axial blowers operate on the high-pressure principle. One drawback of this type of blower is the relatively low pressure head, which one attempts to overcome with axial blowers producing very high pressure at a given circumferential speed. The Schicht constant-pressure blower affords pressure ratios considerably higher than those of axial blowers of conventional design with approximately the same efficiency" (p. 1).
The Constructional Design of Metal Flying-Boat Hulls: Part 1 & Workshop Notes on the Building of Metal Hulls: Part 2: Part I of this paper covers the constructional design of metal flying-boat hulls and does not elaborate any further. Part II deals with the actual construction process of the hull.
Contribution to the Aerodynamics of Rotating-Wing Aircraft: "The chief defect of the investigations up to now was the assumption of a more or less arbitrary "mean" drag coefficient for a section of the blade. This defect is remedied through replacement of the constant coefficient by a function of higher order which corresponds to the polar curve of the employed profile. In that way it is possible to extend the theory to include the entire range from "autogyro" without power input to the driven "helicopter" with forward-tilted rotor axis. The treatment includes the twisted rectangular blade and a non-twisted tapered blade" (p. 1).
Contribution to the Aerodynamics of Rotating-Wing Aircraft: Part 2: "The interrelations established in an earlier report (NACA-TM-921) are used to study the best assumptions for hovering and horizontal flight. The effect of the twisted and tapered blade on the rotor efficiency is analyzed and the gliding coefficient at different stages (from autogyro to helicopter) of horizontal flight compared. To the extent that model or full-scale test data are available, they are included in the comparison" (p. 1).
Contribution to the Aileron Theory: "In an attempt to treat theoretically the effect of ailerons, difficulty arises because an aileron may begin at any point of the wing. Hence the question arises as to how the transition of the lift distribution proceeds at such a point, since the effect of the aileron (i.e., the moment generated about the longitudinal axis) depends largely on this distribution. In order to answer this question regarding the lift distribution during irregular variations in the angle of attack at first independently of other influences, especially those of the wing tips, we have taken as the basis of the following theoretical discussion a wing of infinite span and constant chord which exhibits at one point an irregular variation in the angle of attack" (p. 1).
Contribution to the Design and Calculation of Fuel Cams and Fuel Valves for Diesel Engines: In this work I have attempted to find a basis for the design of fuel cams, which will serve equally for large and small engines, both high-speed and low-speed.
Contribution to the Design of Plywood Shells: "The writer sets out to prove by calculation and experiment that by extensive utilization of the skin to carry axial load (reduction of stringer spacing) the stringer sections can be made small enough to afford a substantial saving in structural weight. This saving ranges from 5 to about 40 percent" (p. 1).
Contribution to the ideal efficiency of screw propellers: From Summary: "The stipulation of best thrust distribution is applied to the annular elements of the screw propeller with infinitely many blades in frictionless, incompressible flow and an ideal jet propulsion system derived possessing hyperbolic angular velocity distribution along the blade radius and combining the advantage of uniform thrust distribution over the section with minimum slipstream and rotation losses. This system is then compared with a propeller possessing the same angular velocity at all blade elements and the best possible thrust distribution secured by means of an induced efficiency varying uniformly over the radius. Lastly, the case of the lightly loaded propeller also is discussed."

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