National Advisory Committee for Aeronautics (NACA) - 90 Matching Results
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- Working Charts for the Selection of Aluminum Alloy Propellers of a Standard Form to Operate With Various Aircraft Engines and Bodies
- "Working charts are given for the convenient selection of aluminum alloy propellers of a standard form, to operate in connection with six different engine-fuselage combinations. The charts have been prepared from full-scale test data obtained in the 20-foot propeller research tunnel of the National Advisory Committee for Aeronautics. An example is also given showing the use of the charts" (p. 3).
- The Effect of Reduction Gearing on Propeller-Body Interference as Shown by Full-Scale Wind-Tunnel Tests
- This report presents the results of full-scale tests made on a 10-foot 5-inch propeller on a geared J-5 engine and also on a similar 8-foot 11-inch propeller on a direct-drive J-5 engine. Each propeller was tested at two different pitch settings, and with a large and a small fuselage. The investigation was made in such a manner that the propeller-body interference factors were isolated, and it was found that, considering this interference only, the geared propellers had an appreciable advantage in propulsive efficiency, partially due to the larger diameter of the propellers with respect to the bodies, and partially because the geared propellers were located farther ahead of the engines and bodies.
- Full-Scale Wind-Tunnel Tests on Several Metal Propellers Having Different Blade Forms
- "This report gives the full-scale aerodynamic characteristics of five different aluminum alloy propellers having four different blade forms. They were tested on an open cockpit fuselage with a radial air-cooled engine having conventional cowling. The results show that (1) the differences in propulsive efficiency due to the differences in blade form were small; (2) the form with the thinnest airfoil sections had the highest efficiency; (3) it is advantageous as regards propulsive efficiency for a propeller operating in front of a body, such as a radial engine, to have its pitch reduced toward the hub" (p. 123).
- The Effect of Supercharger Capacity on Engine and Airplane Performance
- This report presents the results of an investigation to determine the effect of different supercharger capacities on the performance of an airplane and its engine . The tests were conducted on a DH4-M2 airplane powered with a Liberty 12 engine. In this investigation four supercharger capacities, obtained by driving a roots type supercharger at 1.615, 1.957, 2.4, and 3 time engine speed, were used to maintain sea-level pressure at the carburetor to altitudes of 7,000, 11,500, 17,000, and 22,000 feet, respectively. The performance of the airplane in climb and in level flight was determined for each of the four supercharger drive ratios and for the unsupercharged condition.
- Full-Scale Wind-Tunnel Tests With a Series of Propellers of Different Diameters on a Single Fuselage
- "Aerodynamic tests were made with four geometrically similar metal propellers of different diameters, on a Wright "Whirlwind" J-5 engine in an open cockpit fuselage. The results show little difference in the characteristics of the various propellers, the only one of any importance being an increase of efficiency of the order of 1 per cent for a 5 per cent increase of diameter, within the range of the tests" (p. 107).
- Analysis of flight and wind-tunnel tests on Udet airplanes with reference to spinning characteristics
- This report presents an analysis of results of wind-tunnel tests conducted at the D.V.L. Values were determined for the effectiveness of all the controls at various angles of attack. The autorotation was studied by subjecting the rotating model to an air blast.
- The De Havilland D.H. 75 "Hawk Moth" (British): Cabin Monoplane
- The Hawk Moth is designed as a passenger aircraft with comfort in mind. It seats 4. The tail is of metal construction, while the wings are of wood. It has a total loaded weight of 3500 lbs.
- Effect of Stressed Covering on Strength of Internal Girders of a Wing
- In practice the actual maximum stress is greater than the stress determined by the simple girder theory, which overestimates the bearing or supporting capacity of the flange. The fact is that the assumptions of the simple girder theory no longer hold true, since normal transverse and shearing stresses are engendered in the plane of the flange.
- Impact Waves and Detonation: Part 1
- "Among the numerous thermodynamic and kinetic problems that have arisen in the application of the gaseous explosive reaction as a source of power in the internal combustion engine, the problem of the mode or way by which the transformation proceeds and the rate at which the heat energy is delivered to the working fluid became very early in the engine's development a problem of prime importance. The work of Becker here given is a notable extension of earlier investigations, because it covers the entire range of the explosive reaction in gases - normal detonation and burning" (p. i).
- Impact Waves and Detonation: Part 2
- A continuation of a previous technical memorandum regarding impact waves and detonation. This particular report focuses on the applications to detonation under several different conditions, including variations in pressure.
- Mechanical Control of Airplanes
- "Before undertaking a detailed description of an automatic-control mechanism, I will state briefly the fundamental conditions for such devices. These are: 1) it must be sensitive at one or more reference values; 2) it must stop the angular motions of the airplane not produced by the pilot; and 3) it must be possible to switch it off and on by a simple hand lever" (p. 1).
- Morane-Saulnier 180 Light Airplane (French): A Single-Seat Training Monoplane
- Circular describing the Morane-Saulnier 180 light airplane, which is a single-seat training monoplane. A description of the components, design, characteristics, theoretical performance, drawings, and photographs are provided.
- Nieuport-Delage 640 (French): Commercial High-Wing Monoplane
- The Nieuport Delage 640 is a single engine commercial high-wing monoplane of all wood construction, including the fuselage and tail. It's landing gear is hinged in two parts.
- The Measurement of Maximum Cylinder Pressures
- "The work presented in this report was undertaken at the Langley Memorial Aeronautical Laboratory of the National Advisory Committee for Aeronautics to determine a suitable method for measuring the maximum pressures occurring in aircraft engine cylinders. The study and development of instruments for the measurement of maximum cylinder pressures has been conducted in connection with carburetor and oil engine investigations on a single cylinder aircraft-type engine. Five maximum cylinder-pressure devices have been designed, and tested, in addition to the testing of three commercial indicators" (p. 311).
- The prediction of airfoil characteristics
- This report describes and develops methods by which the aerodynamic characteristics of an airfoil may be calculated with sufficient accuracy for use in airplane design. These methods for prediction are based on the present aerodynamic theory and on empirical formulas derived from data obtained in the N. A. C. A. variable density wind tunnel at a Reynolds number corresponding approximately to full scale. (author).
- The 1926 German Seaplane Contest
- The report discusses the problem of rating the various seaplane designs from the 1926 seaplane contest. The whole process of rating consists in measuring the climbing speed, flying weight and carrying capacity of a seaplane and then using these data as the basis of a construction problem.
- Calculation of Airplane Performances Without the Aid of Polar Diagrams
- For good profiles the profile-drag coefficient is almost constant in the whole range which comes into consideration for practical flight. This is manifest in the consideration of the Gottingen airfoil tests and is confirmed by the investigations of the writer (measurements of the profile drag during flight by the Betz method), concerning which a detailed report will soon be published. The following deductions proceed from this fact. The formulas developed on the assumptions of a constant profile-drag coefficient afford an extensive insight into the influences exerted on flight performances by the structure of the airplane.
- A Comparison of Propeller and Centrifugal Fans for Circulating the Air in a Wind Tunnel
- The tests described in this paper afford a direct comparison of the efficiency and smoothness of flow obtained with propeller fan and multiblade centrifugal fan drives in the same wind tunnel. The propeller fan was found to be superior to the centrifugal fan in that the efficiency was about twice as great, and the flow much smoother.
- Drag of exposed fittings and surface irregularities on airplane fuselages
- Measurements of drag were made on fittings taken from a typical fuselage to determine whether the difference between the observed full size fuselage drag and model fuselage drag could be attributed to the effects of fittings and surface irregularities found on the full size fuselage and not on the model. There are wide variations in the drag coefficients for the different fittings. In general those which protrude little from the surface or are well streamlined show very low and almost negligible drag. The measurements show, however, that a large part of the difference between model and full scale test results may be attributed to these fittings.
- A Few More Mechanical-Flight Formulas Without the Aid of Polar Diagrams
- The reliability of the assumption of a parabolic shape of the polar curve is investigated and found satisfactory for all practical purposes. It is further shown that the aerodynamically best possible or "ideal" airplane is produced on this assumption. Lastly, detailed suggestions are given on the possibilities of application of this method of calculation. It especially simplifies the design and evaluation of structural changes and the determination of the limits of technical possibilities. The present report deals only with the relations of the airfoils. The mutual action of the airfoils, engine and propeller will be treated in a subsequent report.
- The "Gloster IV" Seaplane (British)
- Circular describing the Glouster IV, which is a biplane designed for high maximum speeds. A description of the components, design, controls, performance, drawings, and photographs are provided.
- Motion of Fluids With Very Little Viscosity
- Report presenting a discussion of the laws of motion of a fluid with very low viscosity. Mathematical formulas that have been created in order to compensate for this lack of viscosity and the circumstances under which viscosity can be disregarded are provided.
- Note on Research Work by Helmholtz and Wien Relating to the Form of Waves Propagated Along the Surface of Separation of Two Liquids
- This report presents a clearer understanding of Helmholtz's work on the calculation of waves along the separation of two different liquids.
- Resistance of streamline wires
- "This note contains the results of tests to determine the resistance of four sizes of streamline wire. The investigation was conducted in the six-inch wind tunnel of the National Advisory Committee for Aeronautics. The tests were made at various velocities and it was found that the resistance of streamline wires was considerably less than that of round wires of equivalent strength. Scale effect was also found since, with an increase of Reynolds Number, a decrease in the resistance coefficient was obtained" (p. 1).
- The Short "Calcutta": First British All-Metal Commercial Seaplane
- The Calcutta is a large seaplane, with seating for 16 and a payload of 3,400 pounds. A description of the design, construction features, engine installation, specifications, performance, and photographs are provided.
- Supermarine S.5 Seaplane (British): Winner of the 1927 Schneider Cup Race
- The S.5 is equipped with Napier Lion racing engine, all duralumin floats and has a top speed in excess of 300 M.P.H. A description of its design, flight characteristics, and some photographs are provided.
- The Heat Treatment of Duralumin
- When certain light aluminum alloys are heat-treated, quenched and aged, there is considerable improvement in their tensile properties. This paper presents different methods of accomplishing these heat treatments.
- High-Speed Oil Engines for Vehicles Part 2
- "Further progress toward the satisfactory solution of the difficult problem of the distribution and atomization of the injected fuel was made by extensive experimentation with various fuel valves, nozzles, and atomizing devices. Valuable information was also obtained through numerous experimental researches on the combustion of oils and the manner of introducing the combustion air into the cylinder, as well as on the physical processes of atomization, the determination of the size of drops, etc. These researches led to the conclusion that it is possible, even without producing great turbulence in the combustion chamber and at moderate pump pressure, if the degree of atomization and the penetrative power of the fuel jet are adapted to the shape of the combustion chamber and to the dimensions of the cylinder" (p. 1).
- Macchi M.39 Seaplane: Single-Seat Racer With an 800 Hp. Fiat "A-S2" Engine
- The M. 39 was designed by Castoldi to compete in the Schneider Cup Race of 1926 (Norfolk, VA). It is a monoplane with engine mounted in the fuselage, resting on two wing and hull mounted floats.
- Permanent Commission of Aeronautical Studies Report No. 4
- Recent accidents, which were the result of structural failure in flight, revealed the necessity of a closer examination of the conditions under which the resistance of airplane structures may be calculated.
- The Protection of Duralumin From Corrosion
- Different types of coatings to protect duralumin from corrosion are discussed. Plating, etching, brushing, coloring, painting and varnishing are all investigated.
- Richard-Penhoet Commercial Seaplane
- This is a multi-engine monoplane with a central hull and without external bracing. The trim of the seaplane on the water is assured by two wing floats, one on each side of the hull 9 m. from its axis. It has a total power of 2100 HP. from 5 air cooled Jupiter radial engines.
- Savoia Seaplane S.55: Military or Commercial
- The S.55 is a two engine twin hull seaplane built by Societa Idrovolanti Alta Italia (Seaplane Company of Upper Italy). The S.55 (Santa Maria) is to be used for an around the world flight In 1927. It will have a useful load of 7,500 lbs. and a cruising speed of 100 MPH.
- Structural Details From 1926 Paris Aero Salon
- Memorandum presenting a description of the structural details of airplanes presented at the 1926 Paris Aero Salon.
- Vojenska-Smolik S.16 Airplane: All-Metal Long-Distance Observation Bi-Plane
- Circular presenting a description of the Vojenska-Smolik all-metal two-seater airplane. The design and flight characteristics are described and blueprints and photographs of the aircraft are provided.
- Wall interference in closed type wind tunnels
- "A series of tests has been conducted by the National Advisory Committee for Aeronautics, in the variable density wind tunnel on several airfoils of different sizes and sections to determine the effect of tunnel wall interference and to determine a correction which can be applied to reduce the error caused thereby. The use of several empirical corrections was attempted with little success. The Prandtl theoretical correction gives the best results and its use is recommended for correcting closed wind tunnel results to conditions of free air" (p. 1).
- Functioning of Reduction Gears on Airplane Engines
- "In undertaking to analyze the functioning conditions of a reduction gear on an aviation engine, we will consider an ordinary twelve-cylinder V-engine. The reduction gear employed consists either of a pair of spur gears, one of which is integral with the engine shaft and the other with the propeller shaft, or of a planetary system of gears" (p. 1).
- The Lateral Failure of Spars
- It was concluded that after the critical span or depth-breadth ratio has been reached, the modulus of rupture varies approximately inversely as the first power of the span and of the depth-breadth ratio. The direction of the lateral deflection is alternate between successive supports. For this reason, we believe that rib spacing along the spar is more important in reducing lateral deflection than the distance between supports at the strut points.
- Lioré-Olivier Airplane: Type 12 Night-Bomber or Type 20 Commercial
- Report presenting a description of the Lioré-Olivier Type 12 night bomber, which can also be converted into the Type 20 commercial. A description of the cell of the wings, fuselage, power plant, landing gear, and flight characteristics is provided.
- Recent Experiments With Large Seaplanes
- This report covers the following aspects of large seaplane design and construction: heavy wing loading; propeller design; how the motion of the airplane is affected by increasing the dihedral angle; power plants; floats; and the hull.
- Slip Stream Effect
- "The horizontal tail surfaces of a new airplane usually are proportional so that the curve of moment about the center of gravity, combined with a similar curve for the wings alone, gives a composite curve which provides a certain specified degree of static stability. With the application of power three additional factors must be considered in calculations: the moment of the propeller thrust; the change in the velocity of the air over the tail due to the slipstream; and the change in direction of the air over the tail due to the slipstream. The last two factors are considered in this report" (p. 1).
- Tests for determining the effect of a rotating cylinder fitted into the leading edge of an airplane wing
- Experiments were performed with a wing model, to which a rotary cylinder had been fitted. The rotation of the cylinder had a remarkable effect on the aerodynamic properties of the wing.
- Altitude of equilibrium of an airship
- This report details the procedure followed in establishing a general formula enabling the calculation of the maximum altitude attainable statically.
- The Calculation of Wing Float Displacement in Single-Float Seaplanes
- Note presenting an exploration of the calculation of wing float displacement in single-float seaplanes. An explanation of a formula that can be used is provided.
- Calculation of Wing Spars of Variable Cross-Section and Linear Load
- "The calculation of wing spars of constant cross-section and load has been thoroughly treated by a large number of authors. Such is not the case,however, regarding the calculation of wing spars whose section and linear load diminish toward the ends, as in wings of trapezoidal contour and decreasing section" (p. 1).
- Note on the Air Forces on a Wing Caused by Pitching.
- Report containing information on the air forces on a wing produced by its pitching at a finite rate of angular velocity. The condition of smooth flow at the region of the trailing edge is maintained. The wing then experiences the same lift as if moving with the momentary velocity of the rear edge.
- Preliminary investigation of the effect of a rotating cylinder in a wing
- Into the leading edge of a wing with arbitrary cross-section, there is introduced a cylinder, which can be rotated by an electric motor by means of a cord. Observations were made in the wind tunnel on how the lift at different wind velocities was affected by rotating this cylinder.
- Suggestions for Courses of Instruction in Aviation
- Suggestions are presented for the establishment of lecture courses on aviation. An outline of some courses that have previously been given is provided.
- The Velocity Distribution Caused by an Airplane at the Points of a Vertical Plane Containing the Span
- "A formula for the computation of the vertical velocity component on all sides of an airplane is deduced and discussed. The formation is of value for the interpretation of such free flight tests where two airplanes fly alongside each other to facilitate observation" (p. 1).
- Effect of Changing the Mean Camber of an Airfoil Section
- Methodical experiments with the series of airfoil sections of the same relative thickness and of variable relative cambers can be utilized for determining the effect of the camber on the aerodynamic properties of airfoil sections.