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**Partner:**UNT Libraries Government Documents Department

**Serial/Series Title:**NACA Technical Memorandums

**Collection:**National Advisory Committee for Aeronautics Collection

- Accurate calculation of multispar cantilever and semicantilever wings with parallel webs under direct and indirect loading
- In the present report the computation is actually carried through for the case of parallel spars of equal resistance in bending without direct loading, including plotting of the influence lines; for other cases the method of calculation is explained. The development of large size airplanes can be speeded up by accurate methods of calculation such as this. digital.library.unt.edu/ark:/67531/metadc277384/
- Acoustics of a nonhomogeneous moving medium.
- Theoretical basis of the acoustics of a moving nonhomogeneous medium is considered in this report. Experiments that illustrate or confirm some of the theoretical explanation or derivation of these acoustics are also included. digital.library.unt.edu/ark:/67531/metadc65701/
- Activation of hydrocarbons and the octane number
- This report presents an examination of the history of research on engine knocking and the various types of fuels used in the investigations of this phenomenon. According to this report, the spontaneous ignition of hydrocarbons doped with oxygen follows the logarithmic law within a certain temperature range, but not above 920 degrees K. Having extended the scope of investigations to prove hydrocarbons, the curves of the mixtures burned by air should then be established by progressive replacement of pure iso-octane with heptane. Pentane was also examined in this report. digital.library.unt.edu/ark:/67531/metadc63233/
- Additional test data on static longitudinal stability
- The purpose of this investigation was to explore the influence of weights of the controls on the stability with elevator released. The available test data were extended to stability with elevator locked. In this connection the study of the propeller effect seemed of vital importance. digital.library.unt.edu/ark:/67531/metadc63477/
- Aerial convention of October 13, 1919
- The aerial convention delegates are listed as well as the set of rules that were developed during the session. digital.library.unt.edu/ark:/67531/metadc55281/
- Aerial navigation by dead reckoning
- The problem to be solved, as presented to the pilot or observer of an aircraft, is as follows: The aircraft starting from A must land at B, the only data being the speed of the airplane, the altitude and the orientation D of the course. The above data would be amply sufficient, were it not for the fact that the airplane is constantly subjected to a wind of variable direction and strength. digital.library.unt.edu/ark:/67531/metadc55696/
- Aerial navigation : on the problem of guiding aircraft in a fog or by night when there is no visibility
- The use of magnetic fields and wire to navigate aircraft in conditions of poor visibility is presented. This field may be considered to be derived from a double lemniscate, considered in the particular case where the origin is a double point formed from the magnetic field of the slack wire, from the field produced by the return currents and from the field due to the currents induced in the conducting mass. These fields are dephased in two ways, one in the direction of the wire, the other in a direction perpendicular to it. digital.library.unt.edu/ark:/67531/metadc53657/
- Aerial photography : obtaining a true perspective
- 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. digital.library.unt.edu/ark:/67531/metadc277511/
- Aerial transportation
- The origin of air traffic dates from the war. The important development of aeronautic industries and the progress made in recent years, under the impelling force of circumstances, rendered it possible, after the close of hostilities, to consider the practical utilization of this new means of economic expansion. digital.library.unt.edu/ark:/67531/metadc53663/
- Aero dopes and varnishes
- Before proceeding to discuss the preparation of dope solutions, it will be necessary to consider some of the essential properties which should be possessed of a dope film, deposited in and on the surface of an aero fabric. The first is that it should tighten the material and second it should withstand weathering. digital.library.unt.edu/ark:/67531/metadc65251/
- The aerodynamic aspect of wing-fuselage fillets
- 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. digital.library.unt.edu/ark:/67531/metadc63461/
- Aerodynamic characteristics of aircraft with reference to their use
- Economic and design characteristics are examined in the design of airplanes and airships. digital.library.unt.edu/ark:/67531/metadc277393/
- Aerodynamic characteristics of thin empirical profiles and their application to the tail surfaces and ailerons of airplanes
- No Description digital.library.unt.edu/ark:/67531/metadc65343/
- Aerodynamic computation of gliders
- In the following discussion, a knowledge of the theoretical principles of airplane construction is assumed, as presented in detail by Vogt and Lippisch. A few quantities will however be otherwise designated, in accordance with the Gottingen symbols. digital.library.unt.edu/ark:/67531/metadc55788/
- Aerodynamic forces and moments of a seaplane on the water
- This report gives the results of wind-tunnel tests with a seaplane model as a contribution to the solution of the aerodynamic problems. In the tests it was assumed that the seaplane rested motionless on the water and was exposed, in various positions with respect to the supposedly flat surface of the water, to a uniform air current 0 to 360 degrees. digital.library.unt.edu/ark:/67531/metadc63510/
- Aerodynamic Forces on a Vibrating Unstaggered Cascade
- The unsteady aerodynamic forces, [based on two-dimensional incompressible flow considerations], are determined for an unstaggered cascade, the blades of which are vibrating in phase in an approach flow parallel to the blades. digital.library.unt.edu/ark:/67531/metadc64042/
- Aerodynamic Heat-Power Engine Operating on a Closed Cycle
- Hot-air engines with dynamic compressors and turbines offer new prospects of success through utilization of units of high efficiencies and through the employment of modern materials of great strength at high temperature. Particular consideration is given to an aerodynamic prime mover operating on a closed circuit and heated externally. Increase of the pressure level of the circulating air permits a great increase of limit load of the unit. This also affords a possibility of regulation for which the internal efficiency of the unit changes but slightly. The effect of pressure and temperature losses is investigated. A general discussion is given of the experimental installation operating at the Escher Wyss plant in Zurich for a considerable time at high temperatures. digital.library.unt.edu/ark:/67531/metadc63985/
- Aerodynamic laboratory at Cuatro Vientos
- This report presents a listing of the many experiments in aerodynamics taking place at Cuatro Vientos. Some of the studies include: testing spheres, in order to determine coefficients; mechanical and chemical tests of materials; and various tests of propeller strength and flexibility. digital.library.unt.edu/ark:/67531/metadc55750/
- Aerodynamic laboratory at Cuatro Vientos
- This report presents a description of the design of the Cuatro Vientes wind tunnel. digital.library.unt.edu/ark:/67531/metadc65237/
- The Aerodynamic Laboratory of the Belgian Service Technique de L'Aeronautique
- This report provides a description of the wind tunnel housing and motors. digital.library.unt.edu/ark:/67531/metadc58832/
- Aerodynamic principles of the direct lifting propeller
- The purpose of this report is to make the complicated processes on the direct-lift propeller amenable to analysis and observation. This is accomplished by placing the physical phenomena, starting with the most elementary process, in the foreground, while limiting the mathematical treatment to the most essential in view of the fundamental defects of the theorems. Comparison with model experiments supplements and corroborates the theoretical results. digital.library.unt.edu/ark:/67531/metadc63503/
- Aerodynamic Research on Fuselages with Rectangular Cross Section
- The influence of the deflected flow caused by the fuselage (especially by unsymmetrical attitudes) on the lift and the rolling moment due to sideslip has been discussed for infinitely long fuselages with circular and elliptical cross section. The aim of this work is to add rectangular cross sections and, primarily, to give a principle by which one can get practically usable contours through simple conformal mapping. In a few examples, the velocity field in the wing region and the induced flow produced are calculated and are compared with corresponding results from elliptical and strictly rectangular cross sections. digital.library.unt.edu/ark:/67531/metadc64001/
- The aerodynamic safety of airplanes
- This report presents several hypotheses regarding airplane safety, mainly concerning the nondimensional coefficient of air, speed, acceleration, and wing area on aerodynamic considerations of safety. digital.library.unt.edu/ark:/67531/metadc63575/
- The aerodynamic wind vane and the inherent stability of airplanes
- 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. digital.library.unt.edu/ark:/67531/metadc277532/
- The aerodynamical laboratory of the Vienna Technical High School
- We will give here only a short explanation of the operation of the plant and deal principally with the question of what it has accomplished. digital.library.unt.edu/ark:/67531/metadc53660/
- Aerodynamics and ballistics
- Ballistics is a science hundreds of years old and this report is an attempt to show how these older principles can be used in the newer science of aerodynamics. digital.library.unt.edu/ark:/67531/metadc55683/
- 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. digital.library.unt.edu/ark:/67531/metadc63215/
- Aerodynamics of the Fuselage
- The present report deals with a number of problems, particularly with the interaction of the fuselage with the wing and tail, on the basis of simple calculating method's derived from greatly idealized concepts. For the fuselage alone it affords, in variance with potential theory, a certain frictional lift in yawed flow, which, similar to the lift of a wing of small aspect ratio, is no longer linearly related to the angle of attack. Nevertheless there exists for this frictional lift something like a neutral stability point the position of which on oblong fuselages appears to be associated with the lift increase of the fuselage in proximity to the zero lift, according to the present experiments. The Pitching moments of the fuselage can be determined with comparatively great reliability so far as the flow conditions in the neighborhood of the axis of the fuselage can be approximated if the fuselage were absent, which, in general, is not very difficult. For the unstable contribution of the fuselage to the static longitudinal stability of the airplane it affords comparatively simple formulas, the evaluation of which offers little difficulty. On the engine nacelles there is, in addition a very substantial wing moment contribution induced by the nonuniform distribution of the transverse displacement flow of the nacelle along the wing chord; this also can be represented by a simple formula. A check on a large number of dissimilar aircraft types regarding the unstable fuselage and nacelle moments disclosed an agreement with the wind-tunnel tests, which should be sufficient for practical requirements. The errors remained throughout within the scope of instrumental accuracy. digital.library.unt.edu/ark:/67531/metadc63732/
- Aeroelastic Problems of Airplane Design
- The technical memorandum briefly summarizes the growth of interest in aeroelastic phenomena as aircraft speed increased and wing designs changed for faster aircraft. Different types of aircraft vibrations are then introduced, and the mathematical basis for the theory behind them is described. Special attention is given to static oscillations, wing flutter, and the flutter of skin panels. The last section of the memorandum deals with the prevention of flutter by design specifications. digital.library.unt.edu/ark:/67531/metadc63886/
- Aeromechanical experimentation (wind tunnel tests)
- The following report endeavors to show that aeromechanical experimentation has become an important aid to theory. digital.library.unt.edu/ark:/67531/metadc277465/
- Aeronautic instruction in Germany
- This report contains a list of the courses relating to aeronautics announced in Germany, both in the technical high schools and in the universities. digital.library.unt.edu/ark:/67531/metadc53650/
- Aeronautic instruments
- The development of aeronautic instruments. Vibrations, rapid changes of the conditions of flight and of atmospheric conditions, influence of the air stream all call for particular design and construction of the individual instruments. This is shown by certain examples of individual instruments and of various classes of instruments for measuring pressure, change of altitude, temperature, velocity, inclination and turning or combinations of these. digital.library.unt.edu/ark:/67531/metadc277462/
- Aeronautic insurance
- The problem of insuring the emerging commercial aeronautic industry is detailed. The author also motes that a complete solution cannot be obtained until the necessary statistics are compiled. digital.library.unt.edu/ark:/67531/metadc54177/
- 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. digital.library.unt.edu/ark:/67531/metadc277429/
- The aeronautical laboratory of the Stockholm Technical Institute
- This report presents a detailed analysis and history of the construction and operation of the aeronautical laboratory of the Stockholm Technical Institute. Engines and balances are discussed and experimental results are also given. digital.library.unt.edu/ark:/67531/metadc63458/
- Aeronautical museums
- Different methods of presenting aeronautical artifacts are examined. digital.library.unt.edu/ark:/67531/metadc55809/
- Aeronautical record : no. 1 (to June, 1923)
- "...considerations have prompted us to pay special attention to the development of aeronautical industries and aerial navigation as a commercial enterprise and to publish an analytical review of events in the aeronautical world and of the attendant problems.". digital.library.unt.edu/ark:/67531/metadc277519/
- Air admixture to exhaust jets
- The problem of thrust increase by air admixture to exhaust jets of rockets, turbojet, ram- and pulse-jet engines is investigated theoretically. The optimum ratio of mixing chamber pressure to ambient pressure and speed range for thrust increase due to air admixture is determined for each type of jet engine. digital.library.unt.edu/ark:/67531/metadc62929/
- Air cooling : an experimental method of evaluating the cooling effect of air streams on air-cooled cylinders
- In this report is described an experimental method which the writer has evolved for dealing with air-cooled engines, and some of the data obtained by its means. Methods of temperature measurement and cooling are provided. digital.library.unt.edu/ark:/67531/metadc65234/
- Air-flow experiments
- This report describes the apparatus used to take air-flow photographs. The photographs show chiefly the spiral course of the lines of flow near the tip of the wing. They constitute therefore a visual presentation of the phenomena covered by airfoil theory. digital.library.unt.edu/ark:/67531/metadc58543/
- Air forces and air-force moments at large angles of attack and how they are affected by the shape of the wing
- No Description digital.library.unt.edu/ark:/67531/metadc65288/
- Air Forces Exerted on Streamlined Bodies with Round or Square Cross- Sections, When Placed Obliquely to the Airstream
- The question of behavior of a streamlined body with round or square cross-sections is of importance in determining the shape to give an airplane fuselage. It is our task here to show how the lift and drag are affected, with the object placed obliquely to the air stream. digital.library.unt.edu/ark:/67531/metadc58643/
- Air forces on airfoils moving faster than sound
- We are undertaking the task of computing the air forces on a slightly cambered airfoil in the absence of friction and with an infinite aspect ratio. We also assume in advance that the leading edge is very sharp and that its tangent lies in the direction of motion. digital.library.unt.edu/ark:/67531/metadc59216/
- Air reactions to objects moving at rates above the velocity of sound with application to the air propeller
- There has been a tradition general among aeronautical engineers that a critical point exists for tip speeds at or near the velocity of sound, indicating a physical limit in the use of propellers at higher tip speeds; the idea being that something would occur analogous to what is known in marine propellers as cavitation. In the examination of the physics pertaining to both propellers and projectiles moving at or above 1100 feet per second, the conclusion was reached by the author that there is no reason for the existence of such a critical point and that, if it had been noted by observers it was not inherent in the phenomena revealed, but rather due to a particular shape or proportion of the projectile and that, with properly proportioned sections, it would not exist. digital.library.unt.edu/ark:/67531/metadc56168/
- Air traffic
- This report presents a recounting of the steps taken by France to establish national and international regulation over air traffic. digital.library.unt.edu/ark:/67531/metadc55206/
- Air transport
- I purpose (sic) in this paper to deal with the development in air transport which has taken place since civil aviation between England and the Continent first started at the end of August 1919. A great deal of attention has been paid in the press to air services of the future, to the detriment of the consideration of results obtained up to the present. digital.library.unt.edu/ark:/67531/metadc277549/
- Air transport by gliders : some technical observations
- This short analysis may be useful in determining the real tactical possibilities of "glider trains" and in adopting the course to be followed in possible studies of these questions. In this analysis most prominent are: (a) the power required for the train in level flight; (b) its speed; (c) climb; and (d) the type of airplane best suited for towing as well as design requirements for transport gliders. digital.library.unt.edu/ark:/67531/metadc63139/
- Air transport economics
- The report presents a determination of air transport costs with and without subsidies. digital.library.unt.edu/ark:/67531/metadc55798/
- Air-water analogy and the study of hydraulic models
- The author first sets forth some observations about the theory of models. Then he established certain general criteria for the construction of dynamically similar models in water and in air, through reference to the perfect fluid equations and to the ones pertaining to viscous flow. It is, in addition, pointed out that there are more cases in which the analogy is possible than is commonly supposed. digital.library.unt.edu/ark:/67531/metadc62926/
- Airfoil measurements in the DVL high-speed wind tunnel (2.7-meter diameter)
- Report is a brief summary of investigations on symmetrical and cambered airfoils in the DVL high-speed tunnel. Some information on the effects of low aspect ratio are also included. digital.library.unt.edu/ark:/67531/metadc65415/