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 Decade: 1940-1949
 Year: 1943
 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
Aerodynamic and hydrodynamic tests of a family of models of flying hulls derived from a streamline body -- NACA model 84 series

Aerodynamic and hydrodynamic tests of a family of models of flying hulls derived from a streamline body -- NACA model 84 series

Date: January 1, 1943
Creator: Parkinson, John B; Olson, Roland E; Draley, Eugene C & Luoma, Arvo A
Description: A series of related forms of flying-boat hulls representing various degrees of compromise between aerodynamic and hydrodynamic requirements was tested in Langley Tank No. 1 and in the Langley 8-foot high-speed tunnel. The purpose of the investigation was to provide information regarding the penalties in water performance resulting from further aerodynamic refinement and, as a corollary, to provide information regarding the penalties in range or payload resulting from the retention of certain desirable hydrodynamic characteristics. The information should form a basis for over-all improvements in hull form.
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Analysis of heat and compressibility effects in internal flow systems and high-speed tests of a ram-jet system

Analysis of heat and compressibility effects in internal flow systems and high-speed tests of a ram-jet system

Date: January 1, 1943
Creator: Becker, John V & Baals, Donald D
Description: An analysis has been made by the NACA of the effects of heat and compressibility in the flow through the internal systems of aircraft. Equations and charts are developed whereby the flow characteristics at key stations in a typical internal system may be readily obtained.
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Derivation of charts for determining the horizontal tail load variation with any elevator motion

Derivation of charts for determining the horizontal tail load variation with any elevator motion

Date: January 1, 1943
Creator: Pearson, Henry A
Description: The equations relating the wing and tail loads are derived for a unit elevator displacement. These equations are then converted into a nondimensional form and charts are given by which the wing- and tail-load-increment variation may be determined under dynamic conditions for any type of elevator motion and for various degrees of airplane stability. In order to illustrate the use of the charts, several examples are included in which the wing and tail loads are evaluated for a number of types of elevator motion. Methods are given for determining the necessary derivatives from results of wind-tunnel tests when such tests are available.
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Determination of general relations for the behavior of turbulent boundary layers

Determination of general relations for the behavior of turbulent boundary layers

Date: January 1, 1943
Creator: Von Doenhoff, Albert E & Tetervin, Neal
Description: An analysis has been made of a considerable amount of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. It was found that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter. This parameter was chosen as the ratio of the displacement thickness to the momentum thickness of the boundary layer. The variables that control the development of the turbulent boundary layer apparently are: (1) the ratio of the nondimensional pressure gradient, expressed in terms of the local dynamic pressure outside the boundary layer and boundary-layer thickness, to the local skin-friction coefficient and (2) the shape of the boundary layer. An empirical equation has been developed in terms of these variables that, when used with the momentum equation and the skin-friction relation, makes it possible to trace the development of the turbulent boundary layer to the separation point.
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The effect of mass distribution on the lateral stability and control characteristics of an airplane as determined by tests of a model in the free-flight tunnel

The effect of mass distribution on the lateral stability and control characteristics of an airplane as determined by tests of a model in the free-flight tunnel

Date: January 1, 1943
Creator: Campbell, John P & Seacord, Charles L , Jr
Description: The effects of mass distribution on lateral stability and control characteristics of an airplane have been determined by flight tests of a model in the NACA free-flight tunnel. In the investigation, the rolling and yawing moments of inertia were increased from normal values to values up to five times normal. For each moment-of-inertia condition, combinations of dihedral and vertical-tail area representing a variety of airplane configurations were tested. The results of the flight tests of the model were correlated with calculated stability and control characteristics and, in general, good agreement was obtained.
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Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

Date: January 1, 1943
Creator: Pinkel, Benjamin; Turner, Richard; Voss, Fred & Humble, Leroy V
Description: This report presents the results of an investigation conducted on the effect of exhaust-stack nozzle area, shape, and length on engine power, jet thrust, and gain in net thrust (engine propeller plus jet). Single-cylinder engine data were obtained using three straight stacks 25, 44, and 108 inches in length; an S-shaped stack, a 90 degree bend, a 180 degree bend, and a short straight stack having a closed branch faired into it. Each stack was fitted with nozzles varying in exit area from 0.91 square inch to the unrestricted area of the stack of 4.20 square inches. The engine was generally operated over a range of engine speeds from 1300 to 2100 r.p.m, inlet-manifold pressures from 22 to 30 inches of mercury absolute, and a fuel-air ratio of 0.08. The loss in engine power, the jet thrust, and the gain in net thrust are correlated in terms of several simple parameters. An example is given for determining the optimum nozzle area and the overall net thrust.
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The flow of a compressible fluid past a curved surface

The flow of a compressible fluid past a curved surface

Date: January 1, 1943
Creator: Kaplan, Carl
Description: An iteration method is employed to obtain the flow of a compressible fluid past a curved surface. The first approximation which leads to the Prandtl-Glauert rule, is based on the assumption that the flow differs but little from a pure translation. The iteration process then consists in improving this first approximation in order that it will apply to a flow differing from pure translatory motion to a greater degree. The method fails when the Mach number of the undisturbed stream reaches unity but permits a transition from subsonic to supersonic conditions without the appearance of a compression shock. The limiting value at which potential flow no longer exits is indicated by the apparent divergence of the power series representing the velocity of the fluid at the surface of the solid boundary.
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Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine

Date: January 1, 1943
Creator: Miller, Cearcy D & Olsen, H Lowell
Description: Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.
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The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Date: January 1, 1943
Creator: Rothrock, Addison M; Krsek, Alois, Jr & Jones, Anthony W
Description: Report presents the results of investigations conducted on a full-scale air-cooled aircraft-engine cylinder of 202-cubic inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. For a range of fuel-air and water-fuel ratios, the engine inlet pressure was increased until knock was detected aurally, the power was then decreased 7 percent holding the ratios constant. The data indicated that water was a very effective internal coolant, permitting large increases in engine power as limited by either knock or by cylinder temperatures.
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Jet-boundary corrections for reflection-plane models in rectangular wind tunnel

Jet-boundary corrections for reflection-plane models in rectangular wind tunnel

Date: January 1, 1943
Creator: Swanson, Robert S & Toll, Thomas A
Description: A detailed method for determining the jet-boundary corrections for reflection-plane models in rectangular wind tunnels is presented. The method includes the determination of the tunnel span local distribution and the derivation of equations for the corrections to the angle of attack, the lift and drag coefficients, and the pitching-, rolling-, yawing-, and hinge-moment coefficients. The principle effects of aerodynamic induction and of the boundary-induced curvature of the streamlines have been considered. An example is included to illustrate the method. Numerical values of the more important corrections for reflection-plane models in 7 by 10-foot closed wind tunnels are presented.
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The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

The Measurement of Fuel-Air Ratio by Analysis for the Oxidized Exhaust Gas

Date: January 1, 1943
Creator: Gerrish, Harold C. & Meem, J. Lawrence, Jr.
Description: An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy fuel Specification No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs for the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124.
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A method for calculating heat transfer in the laminar flow region of bodies

A method for calculating heat transfer in the laminar flow region of bodies

Date: January 1, 1943
Creator: Allen, H Julian & Look, Bonne C
Description: This report has been prepared to provide a practical method for determining the chordwise distribution of the rate of heat transfer from the surface of a wing or body of revolution to air. The method is limited in use to the determination of heat transfer from the forward section of such bodies when the flow is laminar. A comparison of the calculated average heat-transfer coefficient for the nose section of the wing of a Lockheed 12-A airplane with that experimentally determined shows a satisfactory agreement. A sample calculation is appended.
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A method of estimating the knock rating of hydrocarbon fuel blend

A method of estimating the knock rating of hydrocarbon fuel blend

Date: January 1, 1943
Creator: Sanders, Newell D
Description: The usefulness of the knock ratings of pure hydrocarbon compounds would be increased if some reliable method of calculating the knock ratings of fuel blends was known. The purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends.
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A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blends

A Method of Estimating the Knock Rating of Hydrocarbon Fuel Blends

Date: January 1, 1943
Creator: Sanders, Newell D.
Description: The usefulness of the knock ratings of pure hydrocarbon compounds would be increased if some reliable method of calculating the knock ratings of fuel blends was known. The purpose of this study was to investigate the possibility of developing a method of predicting the knock ratings of fuel blends.
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Methods used in the NACA tank for the investigation of the longitudinal-stability characteristics of models of flying boats

Methods used in the NACA tank for the investigation of the longitudinal-stability characteristics of models of flying boats

Date: January 1, 1943
Creator: Olson, Roland E & Land, Norman S
Description: Report presents the results of tests of longitudinal stability characteristics of models of several flying boats conducted in the NACA Tank No. 1. These investigations were made for the purpose of (1) determining suitable methods for evaluating the stability characteristics of models of flying boats, and (2) determining the design parameters which have an important effect on the porpoising. This report is mainly concerned with the construction of suitable models, the apparatus, and methods used in the tests. The effect of changes in some design parameters is discussed.
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NACA Investigation of a Jet-Propulsion System Applicable to Flight

NACA Investigation of a Jet-Propulsion System Applicable to Flight

Date: September 17, 1943
Creator: Ellis, Macon C. & Brown, Clinton E.
Description: Following a brief history of the NACA investigation of jet propulsion, a discussion is given of the general investigation and analysis leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made.
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On a new method for calculating the potential flow past a body of revolution

On a new method for calculating the potential flow past a body of revolution

Date: January 1, 1943
Creator: Kaplan, Carl
Description: A new method is presented for obtaining the velocity potential of the flow about a body of revolution moving uniformly in the direction of its axis of symmetry in a fluid otherwise at rest. This method is based essentially on the fact that the form of the differential equation for the velocity potential is invariant with regard to conformal transformation of the meridian plane. By means of the conformal transformation of the meridian profile into a circle a system of orthogonal curvilinear coordinates is obtained, the main feature of which is that one of the coordinate lines is the meridian profile itself. The use of this type of coordinate system yields a simple expression of the boundary condition at the surface of the solid and leads to a rational process of iteration for the solution of the differential equation for the velocity potential. It is shown that the velocity potential for an arbitrary body of revolution may be expressed in terms of universal functions which, although not normal, are obtainable by means of simple quadratures. The general results are applied to a body of revolution obtained by revolving a symmetrical Joukowski profile about its axis of symmetry. A numerical example ...
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Operating temperatures of a sodium-cooled exhaust valve as measured by a thermocouple

Operating temperatures of a sodium-cooled exhaust valve as measured by a thermocouple

Date: January 1, 1943
Creator: Sanders, J C; Wilsted, H D & Mulcahy, B A
Description: Report presents the results of a thermocouple installed in the crown of a sodium-cooled exhaust valve. The valve was tested in an air-cooled engine cylinder and valve temperatures under various engine operating conditions were determined. A temperature of 1337 degrees F. was observed at a fuel-air ratio of 0.064, a brake mean effective pressure of 179 pounds per square inch, and an engine speed of 2000 r.p.m. Fuel-air ratio was found to have a large influence on valve temperature, but cooling-air pressure and variation in spark advance had little effect. An increase in engine power by change of speed or mean effective pressure increased the valve temperature. It was found that the temperature of the rear-spark-plug bushing was not a satisfactory indication of the temperature of the exhaust valve.
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Performance of NACA eight-stage axial-flow compressor designed on the basis of airfoil theory

Performance of NACA eight-stage axial-flow compressor designed on the basis of airfoil theory

Date: January 1, 1943
Creator: Sinnette, John T; Schey, Oscar W & King, J Austin
Description: The NACA has conducted an investigation to determine the performance that can be obtained from a multistage axial-flow compressor based on airfoil research. A theory was developed; an eight-stage axial-flow compressor was designed, constructed, and tested. The performance of the compressor was determined for speeds from 5000 to 14,000 r.p.m with varying air flow at each speed. Most of the tests were made with air at room temperature. The performance was determined in accordance with the Committee's recommended procedure for testing superchargers. The expected performance was obtained, showing that a multistage compressor of high efficiency can be designed by the application of airfoil theory.
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The problem of longitudinal stability and control at high speeds

The problem of longitudinal stability and control at high speeds

Date: January 1, 1943
Creator: Hood, Manley J & Allen, H Julian
Description: In high-speed dives many airplanes exhibit a dangerous tendency to continue diving in spite of the application of large control forces. Wind-tunnel tests have confirmed that these difficulties are not peculiar to any particular configuration, so that the problem is of interest to all designers of high-speed airplanes. The purpose of this report is to acquaint designers with the cause of difficulties and with the means now known for their alleviation.
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Requirements for satisfactory flying qualities of airplanes

Requirements for satisfactory flying qualities of airplanes

Date: January 1, 1943
Creator: Gilruth, R R
Description: Report discusses the results of an analysis of available data to determine what measured characteristics are significant in defining satisfactory flying qualities, what characteristics are reasonable to require of an airplane, and what influence the various design features have on the observed flying qualities.
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Review of flight tests of NACA C and D cowlings on the XP-42 airplane

Review of flight tests of NACA C and D cowlings on the XP-42 airplane

Date: January 1, 1943
Creator: Johnston, J Ford
Description: Results of flight tests of the performance and cooling characteristics of three NACA D cowlings and of a conventional NACA D cowling on the XP-42 airplane are summarized and compared. The D cowling is, in general, characterized by the use of an annular inlet and diffuser section for the engine-cooling air. The D cowlings tested were a long-nose high-inlet-velocity cowling, a short-nose high-inlet-velocity cowling, and a short-nose low inlet-velocity cowling. The use of wide-chord propeller cuffs or an axial-flow fan with the D cowlings increased the cooling pressure recoveries in the climb condition at the expense of some of the improvement in speed.
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Tests of airfoils designed to delay the compressibility burble

Tests of airfoils designed to delay the compressibility burble

Date: January 1, 1943
Creator: Stack, John
Description: Fundamental investigations of compressibility phenomena for airfoils have shown that serious adverse changes of aerodynamic characteristics occur as the local speed over the surface exceeds the local speed of sound. These adverse changes have been delayed to higher free-stream speeds by development of suitable airfoil shapes. The method of deriving such airfoil shapes is described, and aerodynamic data for a wide range of Mach numbers obtained from tests of these airfoils in the Langley 24-inch high-speed tunnel are presented. These airfoils, designated the NACA 16-series, have increased critical Mach number. The same methods by which these airfoils have been developed are applicable to other airplane components.
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A theoretical investigation of the lateral oscillations of an airplane with free rudder with special reference to the effect of friction

A theoretical investigation of the lateral oscillations of an airplane with free rudder with special reference to the effect of friction

Date: January 1, 1943
Creator: Greenberg, Harry & Sternfield, Leonard
Description: Charts showing the variation in dynamic stability with the rudder hinge-moment characteristics are presented. A stabilizing rudder floating tendency combined with a high degree of aerodynamic balance is shown to lead to oscillations of increasing amplitude. This dynamic instability is increased by viscous-friction in the rudder control system. The presence of solid friction in the rudder control system will cause steady oscillations of constant amplitude if the floating angle of the rudder per unit angle of sideslip is stabilizing and greater than a certain critical value that depends on other airplane parameters, such as vertical-tail area and airplane moment of inertia about the vertical axis. The amplitude of the steady oscillation is proportional to the amount of friction and is generally quite small but increases as the condition of dynamic instability is approached. An approximate method of calculating the amplitudes of the steady oscillation is explained and is illustrated by a numerical example. A more accurate step-by-step calculation of the motion is also made and it is shown that the agreement with the approximate method is good.
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