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Airplane drag
It has been less well understood that the induced drag (or, better said, the undesired increase in the induced drag as compared with the theoretical minimum calculated by Prandtl) plays a decisive role in the process of taking off and therefore in the requisite engine power. This paper seeks to clarify the induced drag.
The balance of moments and the static longitudinal stability of airplanes
A nomogram is developed which renders it possible by drawing a few lines, to determine: the location of the center of gravity for zero wing and tail moments; the longitudinal dihedral angle; the tail coefficient F(sub h) iota/F(sub t). Moreover there is no difficulty in determining the magnitude of the restoring moment or of the unstable moment.
Calculation of the pressures on aircraft engine bearings
For aircraft engines the three principal operating conditions are idling speed, cruising speed, and diving with the engine stopped. In what follows, we will discuss a method which affords a good idea of the course of pressure for the above mentioned operating conditions. The pressures produced in the driving gear are of three kinds; namely, the pressure due to gases, the pressure due to the inertia of the rotating masses, and the pressure due to the inertia of the reciprocating masses.
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. As regards the mathematical treatment, we will first consider a wing with periodically recurring angle of attack.
The Morane Sauliner 222 airplane (French) : a single-seat pursuit monoplane
No Description Available.
Some effects of air flow on the penetration and distribution of oil sprays
Tests were made to determine the effects of air flow on the characteristics of fuel sprays from fuel injection valves. Curves and photographs are presented showing the airflow throughout the chamber and the effects of the air flow on the fuel spray characteristics. It was found that the moving air had little effect on the spray penetration except with the 0.006 inch orifice. The moving air did, however, affect the oil particles on the outside of the spray cone. After spray cut-off, the air flow rapidly distributed the atomized fuel throughout the spray chamber.
Wind tunnel pressure distribution tests on a series of biplane wing models Part III : effects of charges in various combinations of stagger, gap, sweepback, and decalage
A concept for the calculation of the vortex lift of sharp-edge delta wings is presented and compared with experimental data. The concept is based on an analogy between the vortex lift and the leading-edge suction associated with the potential flow about the leading edge. This concept, when combined with potential-flow theory modified to include the nonlinearities associated with the exact boundary condition and the loss of the lift component of the leading-edge suction, provides excellent prediction of the total lift for a wide range of delta wings up to angles of attack of 20 degrees or greater.
Cantilever Wings for Modern Aircraft: Some Aspects of Cantilever Wing Construction with Special Reference to Weight and Torsional Stiffness
In the foregoing remarks I have made an attempt to touch on some of the structural problems met with in cantilever wings, and dealt rather fully with a certain type of single-spar construction. The experimental test wing was a first attempt to demonstrate the principles of this departure from orthodox methods. The result was a wing both torsionally stiff and of light weight - lighter than a corresponding biplane construction.
The effect of fuel consumption on cylinder temperatures and performance of a cowled Wright J-5 engine
Given here are the results of tests made to determine the effect of fuel consumption on the cylinder temperatures and the performance of a cowled Wright J-5 engine. The results of these tests indicate that enriching the mixture by increasing the carburetor size results in a reduction in cylinder head and barrel temperatures. The cylinders shielded by the magnetos or the points on the cylinder that do not receive a free flow of cooling air increase most rapidly in temperature as the mixture is leaned. A free flow of air past the cylinders is essential for satisfactory operation on a lean mixture. The results of these tests show that the Wright J-5 engine can withstand severe temperatures for short periods of operation. The test results also show to what extent destructive temperatures may be avoided by enriching the mixture.
Mathematical and experimental investigation of heat control and power increase in air-cooled aircraft engines
In order to understand the numerical relations between the air velocity, temperature of the cylinder walls, heat dissipation, cylinder dimensions and type of construction an experimental plant was installed in the Siemens and Halske laboratory. The experimental cylinder was exposed to the air stream of a wind tunnel. The compression chamber was heated by an electrically heated oil bath kept constantly in motion by a stirrer. The wall temperatures were measured by thermocouples. The air stream was produced a seven-watt blower. The air flowed through a current rectifier (honeycomb), diffuser, air chamber with quieting sieves and a nozzle.
The Saunders "Cutty Sark" commercial seaplane (British) : a high-wing monoplane flying boat
No Description Available.
Some studies on the aerodynamic effect of the gap between airplane wings and fuselages
The general result indicated by this study is that if desirable from any viewpoint the gap between wing and fuselage may be closed without detrimental aerodynamic effects, and with a given monoplane there is less drag if the wing is directly on top of the fuselage than if it is parasol.
Technical details in the structural development of Rohrbach seaplanes
The recent trial flights and acceptance tests of the Rohrbach "Romar," the largest seaplane in the world, have yielded results fully confirming the principles followed in its development. Its take-off weight of 19,000 kg, its beating the world record for raising the greatest useful load to 2000 m by almost 2500 kg and its remarkable showing in the seaworthiness tests are the results of intelligent researches, the guiding principles of which are briefly set forth in this article.
Unsymmetrical forces in an airplane cell
This paper calls attention to the desirability of expanding airplane building regulations to include proof of safety for cases of unsymmetrical loading, at least in the structural members which are thereby specially stressed.
The A. B. Flygindustri "K 37" (Swedish Junkers) : a low-wing all-metal military airplane
Report discusses the characteristics of the K 37 all-metal long-wing monoplane and its use for long-distance scouting, as a day bomber, and as a heavy fighting airplane. Its engines, climbing capacity, action radius, bombing installation, fuselage, controls, and landing gear are explored in depth.
The Bristol "Bulldog" (British): A Single-Seat All-Steel Fighter
No Description Available.
The drag and interference of a nacelle in the presence of a wing
A wing interference investigation was conducted to determine why the N.A.C.A. cowling did not yield the expected increase in speed when adapted to the outboard nacelles of trimotored airplanes.
The effect of the wings of single engine airplanes on propulsive efficiency as shown by full scale wind tunnel tests
An investigation was conducted to determine the effect of the wings on propulsive efficiency. The wings are shown to cause a reduction of 1 percent to 3 percent in propulsive efficiency, which is about the same for monoplane as well as biplane wings.
Experiments with a wing model from which the boundary is removed by suction
The present report deals with a series of tests made for the purpose of improving flow conditions about wings by applying the suction principle (increase of the lift coefficient and reduction of the drag about very thick wing sections). Though not conclusive, the report contains interesting results.
Farman two-engine commercial biplane F.180 (French)
The F180 was designed for reliable long distance travel in stages of 500, 1000, 1500 km, carrying loads of 2500, 2000, and 1500 kg respectively. At maximum load it can carry 20 passengers.
Fire prevention on airplanes. Part I
Various methods for preventing fires in airplanes are presented with most efforts centering around prevention of backfires, new engine and carburetor designs, as well as investigations on different types of fuels.
Fire prevention on airplanes. Part II
This part of the report presents a detailed examination of spark prevention, fire extinguishers, and fuel tank location and design. A continued program of investigations and research is also proposed.
Handley Page metal construction
In this report Handley Page construction techniques are shown such as: solid-drawn tubular duralumin spars are used in the stabilizer; plain channel sections are used extensively for minor components; and the manner of assembling them into a stabilizer compression strut is shown.
The impact on seaplane floats during landing
In order to make a stress analysis of seaplane floats, and especially of the members connecting the floats with the fuselage, it is of great importance to determine the maximum pressure acting on the floats during landing. Here, the author gives a formula for maximum pressures during landing that permits one to apply experimental results to different bodies and different velocities. The author notes that the formula checks very well with experimental results.
Information obtained from airplane flight tests in the year 1927-1928
The information obtained from flight tests in 1927-1928 covers chiefly the effect of the structural features of an airplane on its stability, controllability, maneuverability and spinning characteristics.
Structural details of the giant Dornier seaplane "Do X."
No Description Available.
Wind tunnel pressure distribution tests on a series of biplane wing models Part II : effects of changes in decalage, dihedral, sweepback and overhang
This preliminary report furnishes information on the changes in the forces on each wing of a biplane cellule when the decalage, dihedral, sweepback and overhang are separately varied. The data were obtained from pressure distribution tests made in the Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. Since each test was carried up to 90 degree angle of attack, the results may be used in the study of stalled flight and of spinning and in the structural design of biplane wings.
Wind tunnel pressure distribution tests on an airfoil with trailing edge flap
This report deals with pressure distribution tests on an airfoil with a conventional trailing edge flap. These tests were conducted in the Atmospheric Wind Tunnel of the National Advisory Committee for Aeronautics. Maximum chord loadings were obtained with the flap displaced downward and with the airfoil at large angles of attack. Greater changes were produced in the normal force and in the center of pressure travel by up-flap than by an equal down-flap displacement.
Wind tunnel tests on airfoil boundary control using a backward opening slot
This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil equipped with a backward opening slot. Various slot locations, widths of opening, and pressures, were used. The tests were conducted in the Five-Foot Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. The greatest increase in maximum lift was 96 per cent, the greatest decrease in minimum drag was 27 per cent, and the greatest increase in the ratio, maximum lift coefficient/minimum drag coefficient, was 151 per cent.
Wind tunnel tests on an airfoil equipped with a split flap and a slot
The investigation described in this report is concerned with the changes in the aerodynamic characteristics of an airfoil which are produced by a gauze-covered suction slot, located near the leading edge, and connected by an air passage to a split flap at the trailing edge. The tests were conducted at the Langley Memorial Aeronautical Laboratory. At the larger values of lift coefficient where the action of the slot might be expected to be most effective, the pressure differences were such that the air flowed out of the slot rather than in through it, and in consequence, the maximum lift coefficient was decreased.
The A.B.C. "Robin" (British) : a single-seat cabin monoplane
Report discussing the A.B.C. Motors Robin, a single-seat monoplane that was built for pilot comfort, speed, and fuel efficiency. Information about the structural design, dimensions, weight, performance, and rough blueprints is included.
The Fairey III.F (British): a General Purpose Biplane
No Description Available.
Full scale investigation of the drag of a wing radiator
Tests were made on the 1927 Williams racer in order to determine the effect of the wing radiator on the airfoil characteristics. It was found that the radiator doubled the minimum drag of the portion of the wing it covered, and also reduced the lift somewhat.
Metal construction development. Part IV : moments of inertia of thin corrugated sections
No Description Available.
Some experiments on autorotation of an airfoil
These experiments show that the rate of auto rotation of a monoplane airfoil is reduced by sweepback, ceasing entirely when the sweepback is 30 degrees. In addition a very serious increase in rate and range of auto rotation with yaw is shown.
Tests of four racing type airfoils in the twenty-foot propeller research tunnel
Tests were made on four racing type airfoils in order to determine the high speed characteristics of the wings.
Travel of the center of pressure of airfoils transversely to the air stream
The experiments here described were performed for the purpose of obtaining the essential facts concerning the distribution of the air force along the span. We did not follow, however, the time-consuming method of point-to-point measurements of the pressure distribution on the wing surfaces, but determined directly the moment of mean force about an axis passing through the middle of the span parallel to the direction of flight.
Viscosity of diesel engine fuel oil under pressure
In the development of Diesel engine fuel injection systems it is necessary to have an approximate knowledge of the absolute viscosity of the fuel oil under high hydrostatic pressures. This report presents the results of experimental tests conducted by Mr. Jackson Newton Shore, utilizing the A.S.M.E. high pressure equipment.
Welding of stainless materials
It would appear that welds in some stainless steels, heat-treated in some practicable way, will probably be found to have all the resistance to corrosion that is required for aircraft. Certainly these structures are not subjected to the severe conditions that are found in chemical plants.
Welding rustproof steels
The following experimental results will perhaps increase the knowledge of the process of welding rustproof steels. The experiments were made with two chrome-steel sheets and with two chrome-steel-nickel sheets having the composition shown in Table I.
Wind tunnel tests on a model of a monoplane wing with floating ailerons
This report describes preliminary wind tunnel tests on a model of a monoplane wing equipped with wing tip floating ailerons. Lift and drag, as well as rolling and yawing moments, were measured.
Buckling tests of light-metal tubes
I will attempt to determine mathematically the buckling-strength curves of various centrally loaded light-metal tubes which exhibit conspicuous differences of behavior under compressive loads. For this purpose I will employ Von Karman's method, after adapting it to special conditions.
The formation of ice upon airplanes in flight
This report describes the atmospheric conditions under which ice is formed upon the exposed parts of airplanes in flight. It identifies the formation found under different conditions, and describes some studies of preventative means.
The "K 47" of the A.B. Flygindustri : An Armored Pursuit Monoplane
No Description Available.
Lautal as a material for airplane construction
Lautal is a refinable aluminum alloy which, unlike duralumin, contains no magnesium. According to the statements of the Lauta Works, lautal contains: aluminum, 94%; copper, 4%; silicon, 2%. The use of lautal as a construction material is discussed in relation to specific weight, production methods, and riveting tests.
Metal construction development. Part I : strip metal construction - fuselage
No Description Available.
Metal construction development. Part II : strip metal construction - wing spars
No Description Available.
Metal construction development. Part III : strip metal construction - wing ribs
Strip metal construction of wing spars are presented as well as workshop practices.
The Parnall "Pipit" (British) : A Single-Seat Ship's Fighter
The Parnall Pipit is a single-seat ships fighter equipped with a Rolls Royce "F" type engine and armed with two synchronized Vickers guns. It can also be configured to carry bombs under the wings.
Sphere drag tests in the variable density wind tunnel
The air forces on a twenty-centimeter sphere were measured after it had been rebuilt as an open throat type. The results from tests made at widely different densities and airspeeds and also on a smaller sphere are given.