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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
The NACA high-speed wind tunnel and tests of six propeller sections

The NACA high-speed wind tunnel and tests of six propeller sections

Date: January 1, 1934
Creator: Stack, John
Description: This report gives a description of the high-speed wind tunnel of the National Advisory Committee for Aeronautics. The operation of the tunnel is also described and the method of presenting the data is given. An account of an investigation of the aerodynamic properties of six propeller sections is included.
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Performance of a fuel-injection spark-ignition engine using a hydrogenated safety fuel

Performance of a fuel-injection spark-ignition engine using a hydrogenated safety fuel

Date: January 1, 1934
Creator: Schey, Oscar W & Young, Alfred W
Description: This report presents the performance of a single-cylinder test engine using a hydrogenated safety fuel. The safety fuel has a flash point of 125 degrees f. (Cleveland open-dup method), which is high enough to remove most of the fire hazard, and an octane number of 95, which permits higher compression ratios to be used than are permissible with most undoped gasolines.
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The experimental determination of the moments of inertia of airplanes

The experimental determination of the moments of inertia of airplanes

Date: January 1, 1934
Creator: Soule, Hartley A & Miller, Marvel P
Description: The application of the pendulum method to the experimental determination of the moments of inertia of airplanes is discussed in this report. Particular reference is made to the effects of the air, in which the airplane is immersed, on the swinging tests and to the procedure by which these effects are taken into account. This procedure has been used for some time, and the data on several airplanes for which the moments of inertia have been found are included.
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Wind-tunnel tests on combinations of a wing with fixed auxiliary airfoils having various chords and profiles

Wind-tunnel tests on combinations of a wing with fixed auxiliary airfoils having various chords and profiles

Date: January 1, 1934
Creator: Weick, Fred E & Sanders, Robert
Description: This report presents the results of wind tunnel tests on various auxiliary airfoils having three different airfoil sections and several different chord lengths in combination with a Clark y model wing in a sufficient number of relative positions to determine the optimum with regard to certain criterions of aerodynamic performance. The airfoil sections included a symmetrical profile, one of medium camber, and a highly cambered one. The chord sizes of the auxiliary airfoils ranged from 7.5 to 25 percent of the chord of the main wing, and the span was equal to that of the main wing.
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Increasing the air charge and scavenging the clearance volume of a compression-ignition engine

Increasing the air charge and scavenging the clearance volume of a compression-ignition engine

Date: January 1, 1934
Creator: Spanogle, J A; Hicks, C W & Foster, H H
Description: The object of the investigation presented in this report was to determine the effects of increasing the air charge and scavenging the clearance volume of a 4-stroke-cycle compression-ignition engine having a vertical-disk form combustion chamber. Boosting the inlet-air pressure with normal valve timing increased the indicated engine power in proportion to the additional air inducted and resulted in smoother engine operation with less combustion shock. Scavenging the clearance volume by using a valve overlap of 145 degrees and an inlet-air boost pressure of approximately 2 1/2 inches of mercury produced a net increase in performance for clear exhaust operation of 33 percent over that obtained with normal valve timing and the same boost pressure. The improved combustion characteristics result in lower specific fuel consumption, and a clearer exhaust.
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Determination of the theoretical pressure distribution for twenty airfoils

Determination of the theoretical pressure distribution for twenty airfoils

Date: January 1, 1934
Creator: Garrick, I E
Description: This report gives the theoretical distribution of pressure at lift coefficients of 0, 0.5, 1.0, and 1.5 for 20 airfoils, calculated on the basis of a rigorous potential theory of arbitrary airfoils. It also provides tables from which the characteristics of the airfoils for any angle of attack in 2-dimensional potential flow are readily calculable. The theoretical values of the angles of zero lift, the lift and moment coefficients, and the ideal angles of attack are listed and some comparisons with experiment are indicated. The results presented may be of value in predicting structural loads and also in a correlation of theoretical pressure gradients with profile resistance.
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Mechanism of flutter.a theoretical and experimental investigation of the flutter problem

Mechanism of flutter.a theoretical and experimental investigation of the flutter problem

Date: January 1, 1940
Creator: Theodorsen, Theodore & Garrick, I E
Description: The results of the basic flutter theory originally devised in 1934 and published as NACA Technical Report no. 496 are presented in a simpler and more complete form convenient for further studies. The paper attempts to facilitate the judgement of flutter problems by a systematic survey of the theoretical effects of the various parameters. A large number of experiments were conducted on cantilever wings, with and without ailerons, in the NACA high-speed wind tunnel for the purpose of verifying the theory and to study its adaptability to three-dimensional problems. The experiments included studies on wing taper ratios, nacelles, attached floats, and external bracings. The essential effects in the transition to the three-dimensional problem have been established. Of particular interest is the existence of specific flutter modes as distinguished from ordinary vibration modes. It is shown that there exists a remarkable agreement between theoretical and experimental results.
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Flame speeds and energy considerations for explosions in a spherical bomb

Flame speeds and energy considerations for explosions in a spherical bomb

Date: January 1, 1940
Creator: Fiock, Ernest F; Marvin, Charles F , Jr; Caldwell, Frank R & Roeder, Carl H
Description: Simultaneous measurements were made of the speed of flame and the rise in pressure during explosions of mixtures of carbon monoxide, normal heptane, iso-octane, and benzene in a 10-inch spherical bomb with central ignition. From these records, fundamental properties of the explosive mixtures, which are independent of the apparatus, were computed. The transformation velocity, or speed at which flame advances into and transforms the explosive mixture, increases with both the temperature and the pressure of the unburned gas. The rise in pressure was correlated with the mass of charge inflamed to show the course of the energy developed.
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The unsteady lift of a wing of finite aspect ratio

The unsteady lift of a wing of finite aspect ratio

Date: January 1, 1940
Creator: Jones, Robert T
Description: Unsteady-lift functions for wings of finite aspect ratio have been calculated by correcting the aerodynamic inertia and the angle of attack of the infinite wing. The calculations are based on the operational method.
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Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Date: January 1, 1940
Creator: Stickle, George W; Naiman, Irven & Crigler, John L
Description: Report presents the results of an investigation of full-scale nose-slot cowlings conducted in the NACA 20-foot wind tunnel to furnish information on the pressure drop available for cooling. Engine conductances from 0 to 0.12 and exit-slot conductances from 0 to 0.30 were covered. Two basic nose shapes were tested to determine the effect of the radius of curvature of the nose contour; the nose shape with the smaller radius of curvature gave the higher pressure drop across the engine. The best axial location of the slot for low-speed operation was found to be in the region of maximum negative pressure for the basic shape for the particular operating condition. The effect of the pressure operating condition on the available cooling pressure is shown.
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