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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Serial/Series Title: NACA Technical Notes
 Collection: Technical Report Archive and Image Library
The effect of curvature on the transition from laminar to turbulent boundary layer

The effect of curvature on the transition from laminar to turbulent boundary layer

Date: September 1, 1937
Creator: Clauser, M. & Clauser, F.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Hydrodynamic and aerodynamic tests of a family of models of seaplane floats with varying angles of dead rise

Hydrodynamic and aerodynamic tests of a family of models of seaplane floats with varying angles of dead rise

Date: July 1, 1939
Creator: Parkinson, John B.; Olson, Roland E. & House, Rufus O.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
An Application of the Von Karman-millikan Laminar Boundary-layer Theory and Comparison With Experiment

An Application of the Von Karman-millikan Laminar Boundary-layer Theory and Comparison With Experiment

Date: October 1, 1935
Creator: Doenhoff, A. E. V.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
A comparison of the aerodynamic characteristics of the normal and three reflexed airfoils in the variable density wind tunnel

A comparison of the aerodynamic characteristics of the normal and three reflexed airfoils in the variable density wind tunnel

Date: August 1, 1931
Creator: Defoe, George L
Description: An investigation was made of the aerodynamic effects of reflexing the trailing edge of three commonly used airfoils. Six airfoils were used in the investigation: three having the normal profiles of the Navy 60, the Boeing 106, and the Gottingen 398, and three having these profiles modified to obtain a reflexed trailing edge with the mean camber line changed to give Cmc/4=0. The tests were conducted at a value of the Reynolds Number of approximately 3,100,000 in the variable density wind tunnel of the National Advisory Committee for Aeronautics. Measurements of lift, drag, and pitching moment were made on each of the six airfoils. The expected reduction of the center of pressure travel was obtained. The maximum lift was reduced approximately 12 per cent and the minimum profile drag approximately 4 per cent.
Contributing Partner: UNT Libraries Government Documents Department
An investigation of airplane landing speeds

An investigation of airplane landing speeds

Date: September 1, 1930
Creator: Ridley, Kenneth F
Description: This paper describes an investigation on airplane landing speeds which was made to determine the applicability of accepted aerodynamic theory to the prediction of this particular performance characteristic. The experimental work consisted in measuring the landing speed of several monoplanes by a new photographic method. The results of these tests supplemented by available information regarding biplanes were compared with predictions made with basic aerodynamic theory. The prediction makes use of the fundamental relation between wing loading, lift coefficient, and speed of level flight, and the effects of aspect ratio and proximity to the ground on lift curve slope.
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The N.A.C.A. apparatus for studying the formation and combustion of fuel sprays and the results from preliminary tests

The N.A.C.A. apparatus for studying the formation and combustion of fuel sprays and the results from preliminary tests

Date: September 1, 1931
Creator: Rothrock, A M
Description: Described here is an apparatus for studying the formation and combustion of fuel sprays under conditions closely simulating those in a high speed compression-ignition engine. The apparatus consists of a single-cylinder modified test engine, a fuel injection system so designed that a single charge of fuel can be injected into the combustion chamber, an electric driving motor, and a high-speed photographic apparatus. The cylinder head of the engine has a vertical disk form of combustion chamber whose sides are glass windows. When the fuel is injected into the combustion chamber, motion pictures at the rate of 2000 per second are taken of the spray formation by means of spark discharges. When combustion takes place, the light of combustion is recorded on the same photographic film as the spray photographs. Included here are the results of some tests to determine the effect of air temperature, air flow, and nozzle design on the spray formation. The results show that the compression temperature has little effect on the penetration of the fuel spray, but does not affect the dispersion, that air velocities of about 300 feet per second are necessary to destroy the core of the spray, and that the effect of air ...
Contributing Partner: UNT Libraries Government Documents Department
An accurate method of measuring the moments of inertia of airplanes

An accurate method of measuring the moments of inertia of airplanes

Date: October 1, 1930
Creator: Miller, M P
Description: This note contains a description of an improved apparatus and procedure used by the NACA for determining the moments of inertia of airplanes. The method used, based on the pendulum theory, is similar to that previously used, but a recent investigation of its accuracy has resulted in the improvements described herein. The error, when using the new apparatus and procedure, has been found to be of the order of 1 per cent.
Contributing Partner: UNT Libraries Government Documents Department
Methods for the identification of aircraft tubing of plain carbon steel and chromium-molybdenum steel

Methods for the identification of aircraft tubing of plain carbon steel and chromium-molybdenum steel

Date: October 1, 1930
Creator: Mutchler, W H & Buzzard, R W
Description: The survey of the possibilities for distinguishing between plain carbon and chromium-molybdenum steel tubing included the Herbert pendulum hardness, magnetic, sparks, and chemical tests. The Herbert pendulum test has the disadvantages of all hardness tests in being limited to factory use and being applicable only to scale-free, normalized material. The small difference in the range of hardness values between plain carbon and chromium-molybdenum steels is likewise a disadvantage. The Rockwell hardness test, at present used in the industry for this purpose, is much more reliable. It may be concluded on the basis of the experiments performed that of all methods surveyed, spark testing appears to be, at present, the most suitable for factory use from the standpoint of speed, accuracy, nondestructiveness and reliability. It is also applicable for field use.
Contributing Partner: UNT Libraries Government Documents Department
A method for reducing the temperature of exhaust manifolds

A method for reducing the temperature of exhaust manifolds

Date: September 1, 1931
Creator: Schey, Oscar W & Young, Alfred W
Description: This report describes tests conducted at the Langley Memorial Aeronautical Laboratory on an "air-inducting" exhaust manifold for aircraft engines. The exhaust gases from each cylinder port are discharged into the throat of an exhaust pipe which has a frontal bellmouth. Cooling air is drawn into the pipe, where it surrounds and mixes with the exhaust gases. Temperatures of the manifold shell and of the exhaust gases were obtained in flight for both a conventional manifold and the air-inducting manifold. The air-inducting manifold was installed on an engine which was placed on a test stand. Different fuels were sprayed on and into the manifold to determine whether the use of this manifold reduced the fire hazard. The flight tests showed reductions in manifold temperatures of several hundred degrees, to values below the ignition point of aviation gasoline. On the test stand when the engine was run at idling speeds fuels sprayed into the manifold ignited. It is believed that at low engine speeds the fuel remained in the manifold long enough to become thoroughly heated, and was then ignited by the exhaust gas which had not mixed with cooling air. The use of the air-inducting exhaust manifold must reduce the fire ...
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Effect of orifice length-diameter ratio on spray characteristics

Effect of orifice length-diameter ratio on spray characteristics

Date: October 1, 1930
Creator: Gellales, A G
Description: The effect of variations of orifice length to diameter ratio on spray characteristics was determined for a 0.014-inch and a 0.040-inch orifice for ratio of 0.5 to 4.0. The nozzles containing the orifices were mounted in an injection valve and tested with a plan stem and with a helically grooved stem. The injection pressure was varied from 4000 to 8000 pounds per square inch. The air density into which the fuel was sprayed was varied from the density obtained with a pressure of 60 pounds per square inch to the density obtained with a pressure of 250 pounds per square inch at room temperature. The tests showed that increasing the orifice length to diameter ratio with a plain stem in the injection valve causes the spray tip penetration first to decrease, reaching a minimum between a ratio of 1.5 and 2.5, and then to increase, reaching a maximum at a ratio greater than 3.5. The spray cone angle showed little change with variation of the ratio. With a helically grooved stem and small ratio of orifice area to groove area, the penetration at first shows little tendency towards a minimum; but as the time of injection is increased to 0.004 ...
Contributing Partner: UNT Libraries Government Documents Department
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