UNT Libraries Government Documents Department - 116 Matching Results

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Flight investigation at high Mach numbers of several methods of measuring static pressure on an airplane wing

Description: Report discusses an investigation into static pressures in subsonic and supersonic flow over an airplane wing as measured by static-pressure tubes, a static-pressure belt, and orifices flush with the wing surface. The results obtained from the three types of measuring devices and a comparison to theoretical calculations are presented.
Date: November 1944
Creator: Zalovcik, John A. & Daum, Fred L.

Flight tests of a glider model towed by twin parallel towlines

Description: From Summary: "The stability characteristics of a glider towed by twin parallel towlines have been studied in the NACA free-flight tunnel. A preliminary theoretical analysis of the stability of a glider restrained from yawing was followed by an experimental investigation of the stability of a model towed from fixed tunnel points in such a way as to simulate tow in level flight. The results of the tests confirm the theoretical analysis and indicate that a pilotless, stable, towed-glider system is possible when twin parallel towcables are used."
Date: April 1943
Creator: Pitkin, Marvin & McKinney, Marion O., Jr.

Investigation of methods of supporting single-thickness specimens in a fixture for determination of compressive stress-strain curves

Description: From Summary: "An investigation was made of the methods of supporting single-thickness specimens of aluminum-alloy sheet material in a fixture for determination of compressive stress-strain curves. The specimens were supported in the fixture by rollers, offset-grooved plates, opposite-grooved plates, flat brass plates, or flat wooden plates. The investigation also showed that the compression fixture, the specimen support, and the single-thickness specimens must be accurately made in order to obtain accurate stress-strain curves consistently."
Date: May 1945
Creator: Kotanchik, Joseph N.; Woods, Walter & Weinberger, Robert A.

A method for the determination of aromatics in hydrocarbon mixtures

Description: Bulletin discusses a method to estimate aromatic hydrocarbons in hydrocarbon mixtures, which is important for determining the percentage of aromatics in fuel blends. The method was tested with nine base stocks at several levels of aromatics concentration and the maximum level of error was found to be about 0.5 percent. The speed and simplicity of the testing is emphasized.
Date: December 1945
Creator: Hipsher, Harold F.

NACA procedure for flight tests of aileron characteristics of airplanes

Description: Report describes the standard procedure that NACA used for evaluating the aileron characteristics of airplanes. The variables measured in the testing are rolling velocity, aileron positions, aileron stick forces or tangential wheel force, indicated airspeed, altitude, free-air temperature, and rudder position. The step-by-step flight procedure is described and information regarding evaluation of the control data and general suggestions is included.
Date: July 1943
Creator: Johnson, Harold I.

A preliminary study of machine-countersunk flush rivets subjected to a combined static and alternating shear load

Description: Report discusses the results of an investigation to study the effect of the height of a rivet head on the number of cycles required to cause failure of a machine-countersunk flush-riveted joint under a combined static and alternating shear load. A tight joint and a loose joint were tested and the number of cycles to failure and location of fatigue failure were compared.
Date: December 1943
Creator: Crate, Harold

Preliminary tank experiments with a hydrofoil on a planing-tail seaplane hull

Description: Report describes exploratory testing to determine the feasibility of using a hydrofoil with a type of flying boat afterbody called a planing tail. Several hydrofoil locations were examined, including no hydrofoil, and the effects of resistance characteristics were charted. The researchers concluded that it is possible to add a single hydrofoil to that type of afterbody to provide additional hydrodynamic lift without introducing instability.
Date: March 1944
Creator: Wadlin, Kenneth L.

Preliminary tests to determine the dynamic stability characteristics of various hydrofoil systems for seaplanes and surface boats

Description: Report discusses the results of testing on the dynamic stability characteristics of various hydrofoil systems for seaplanes, including a flat-hydrofoil tandem system, a 20 degree V-hydrofoil tandem system, a curved-hydrofoil tandem system, a flat-hydrofoil ladder system, a Guidoni S.V.A.-type hydrofoil on a streamline spindle, and several self-propelled models, including the Tietjens hydrofoil system. The instability and spray were compared for the different systems.
Date: November 1943
Creator: Benson, James M. & King, Douglas A.

Landing characteristics of a model of a flying boat with the depth of step reduced to zero by means of a retractable planing flap

Description: From Conclusion: "A model of a flying boat was tested to determine the landing characteristics when the depth of the step was reduced to zero by means of a retractable planing flap on the forebody." The results of stability and resistance testing are presented.
Date: February 1944
Creator: Benson, James M. & Freihofner, Anton

The landing stability of a powered dynamic model of a flying boat with a 30 degree v-step and with two depths of transverse step

Description: Report discusses tests conducted using a model of a four-engine long-range flying boat with a 30 degree V-step and two different transverse steps of comparable positions and depths. The limits of stability, landing speed, and landing characteristics of the different models are presented.
Date: February 1944
Creator: Parkinson, John B. & Land, Norman S.

Lead susceptibility of several fuels as determined in an air-cooled aircraft-engine cylinder

Description: From Report: "In order to determine the lead susceptibility of several fuels, leaded and unleaded fuels from the same stock were blended and tested in a full-scale air-cooled aircraft-engine cylinder. The fuels were S-4 reference fuel, virgin-base stock, aviation alkylate, neohexane, and blends of 25-percent benzene with 75-percent virgin-base stock and 25-percent toluene with 75-percent virgin-base stock."
Date: February 1946
Creator: Stricker, Edward G. & Hensley, Reece V.

The longitudinal shear strength required in double-angle columns of 24S-T aluminum alloy

Description: From Summary: "Tests were made of riveted double-angle columns to determine the total rivet strength that is required to make these built-up columns develop the strength predicted by the standard column formulas. Results of the tests led to the conclusion that the required rivet strength may be calculated by the beam method of design."
Date: May 1943
Creator: Kuhn, Paul & Moggio, Edwin M.

Determination of desirable lengths of Z- and channel-section columns for local-instability tests

Description: From Summary: "Local-instability tests of 24S-T aluminum-alloy formed Z- and channel-section columns were made in order to determine a length of test specimen that would avoid the increased strength associated with short lengths and also permit the occurrence of a convenient buckling pattern. The effect of column length on the critical compressive stress, on the average stress at maximum load, and on the number of half-waves of the buckling pattern is shown."
Date: October 1944
Creator: Heimerl, George J. & Roy, J. Albert

Determination of iron contamination of used lubricating oil for use in measuring rates of wear in aircraft engines

Description: Report discusses methods of determining the iron contamination of used lubricating oil in order to study wear rates of piston rings and cylinder barrels of aircraft engines. Two methods of separating iron from used lubricating oil are presented. The results of the analyses of the oil are presented and the methods are evaluated.
Date: March 1944
Creator: Tischler, Adelbert O.

Effect of Changes in Aileron Rigging on the Stick Forces of a High-Speed Fighter Airplane

Description: From Summary: "The effects of changes in aileron rigging between 2 deg up and 2 deg down on the stick forces were determined from wind-tunnel data for a finite-span wing model. These effects were investigated for ailerons deflecting equally in both directions and linearly with stick deflection. Data were analyzed for a Frise, a sealed internally balanced, and a beveled-trailing-edge aileron. The results of the analysis showed that only ailerons having linear hinge-moment characteristics are unaffected by changes in rigging and indicated that ailerons having decidedly nonlinear hinge-moment-coefficient curves, particularly for deflections near 0 deg, are very sensitive to changes in rigging."
Date: May 1944
Creator: Murray, Harry E. & Warren, S. Anne

Critical compressive stress for curved sheet supported along all edges and elastically restrained against rotation along the unloaded edges

Description: From Summary: "A formula is given for the critical compressive stress for slightly curved sheet with equal elastic restraints against rotation along the unloaded edges. The theory of small deflections is used and the formula reduces to that given by Timoshenko for the case of simply-supported edges. For larger curvatures, a modification of Redshaw's formula to include the effect of edge restraint is suggested."
Date: September 1943
Creator: Stowell, Elbridge Z.

Determination from flight tests of thrust coefficients for 10 full-scale airplanes in the gliding condition with engine idling

Description: From Summary: "Typical thrust and torque coefficients and increments, due to the propeller, in the ratio of the dynamic pressure at the tail to the free-stream dynamic pressure are presented for 10 full-scale airplanes. Calculations indicate that an error of about 2 percent mean aerodynamic chord appears possible in determining the neutral point from wind-tunnel tests or a model in the gliding condition if the propeller is operated at zero thrust rather than at the values of thrust coefficient indicated by the flight tests."
Date: June 1945
Creator: Talmage, Donald B.

Effect of powered propellers on the aerodynamic characteristics and the porpoising stability of a dynamic model of a long-range flying boat

Description: Report discusses the results of two tests: "1) aerodynamic tests to determine the effect of the slipstream and thrust from the powered propellers on the lift and trimming-moment characteristics, and 2) hydrodynamic tests to determine the effect of the powered propellers on the range of stable locations of the center of gravity (from Introduction)." Large differences in the stable range between half-thrust and full-thrust conditions were observed. Three effects of power were also involved in the location of the stable range of the center of gravity.
Date: May 1943
Creator: Land, Norman S.

Comparative tests of the strength and tightness of commercial flush rivets of one type and NACA flush rivets in machine-countersunk and counterpunched joints

Description: Report discusses an investigation that was conducted to compare the strength and tightness of machine-countersunk flush-riveted joints assembled with NACA flush rivets and a type of commercial flush rivet. A comparison was also generated between the strength and tightness of counterpunched flush-riveted joints assembled with the same types of rivet. NACA's flush-riveted joints tended to be stronger and tighter than the commercial joints.
Date: February 1, 1944
Creator: Mandel, Merven W.

Aerodynamic characteristics of four NACA airfoil sections designed for helicopter rotor blades

Description: From Introduction: "The purpose of the present work is to extend the previous investigation and to derive additional airfoil sections designed to minimize the undesirable characteristics of the previously tested airfoils. The tests of these additional airfoils were made in the Langley two-dimensional low-turbulence tunnel (LTT)."
Date: February 1946
Creator: Rice, Fred J., Jr.

Computation of the mean tangential velocity of the air leaving the blade tips of a centrifugal supercharger

Description: Report discusses the differences between the mean tangential velocity of the air leaving the blade tips of a centrifugal supercharger calculated by the conventional turbine equation and by an equation that uses the isentropic increase in total enthalpy. The velocities are compared to experimental values observed with three diffusers.
Date: August 1945
Creator: Brown, W. Byron

The effect of oil consumption and piston cooling on knock-limited aircraft-engine performance

Description: Report discusses the "effects of oil introduced into the combustion chamber and of oil-spray piston cooling on the knock-limited performance of aircraft engines" (from Summary). A CFR engine and Allison V-1710 cylinder were used to test the rate of oil consumption, knock, and knock-limited brake mean effective pressure.
Date: May 1944
Creator: Huppert, Mercle C.; Imming, Harry S. & Richard, Paul H.