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The Knock-Limited Performance of Fuel Blends Containing Spiropentane, Methylenecyclobutane, Di-Tert-Butyl Ether, Methyl Tert-Butyl Ether, and Triptane

Description: Tests show that at inlet-air temperatures of 250 deg F and 100 deg F the knock-limited performance of the base fuel of blends, leaded with 4 ml TEL per gallon and containing 20 percent spiropentane, was reduced at fuel/air ratios below 0.085. The 20 percent methylenecyclobutane reduced the knock-limited power of the base fuel at fuel/air ratios below 0.112. Di-tert-butyl ether, methyl-tert-butyl ether, and triptane increased the knock-limited power of the base fuel at all fuel/air ratios and at both temperatures.
Date: May 1, 1946
Creator: Meyer, Carl L.
Partner: UNT Libraries Government Documents Department

Effects of fuel-vapor loss on knock-limited performance and inspection properties of aviation fuels

Description: Report discussing the results of testing to discover the effects of fuel-vapor loss on F-3 and F-4 knock-limited performance ratings and inspection properties of two aviation fuels, 28-R and 33-R. The percentage of loss at several temperatures, ability to meet Army-Navy fuel specifications, and antiknock rating change is described.
Date: March 1946
Creator: Barnett, Henry C. & Marsh, Edred T.
Partner: UNT Libraries Government Documents Department

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
Partner: UNT Libraries Government Documents Department

An analysis of the fatigue life of an airplane wing structure under overload conditions

Description: From Introduction: "Fatigue life expectancy in normal transport operations was investigated in reference 1 and was found to be of equal importance with single-gust life. The effect of overload operation of transport airplanes on the probability of encountering single critical gusts was investigated in reference 2 and the frequency of critical gusts was found to increase rapidly with overload. The effect of overload operation on fatigue strength, however, has not heretofore been evaluated, hence the investigations of references 1 and 2 are combined herein to permit such evaluation and to determine the relative importance of fatigue and single-gust failures under conditions of overload operation."
Date: February 1946
Creator: Reisert, Thomas D
Partner: UNT Libraries Government Documents Department

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.
Partner: UNT Libraries Government Documents Department

Static-pressure error of an airspeed installation on an airplane in high-speed dives and pullouts

Description: From Summary: "Tests were made in high-speed dives and pull-outs to determine, by combined radar-optical tracking equipment, the static-pressure error of an airspeed-head installation on a P-51B airplane." The equipment used and testing procedure are described. The variation of static-pressure error is provided for several ranges of airplane lift coefficient.
Date: February 1946
Creator: Zalovcik, John A. & Wood, Clotaire
Partner: UNT Libraries Government Documents Department

Variation of hydrodynamic impact loads with flight-path angle for a prismatic float at 6 degrees and 9 degrees trim and a 22-1/2 degree angle of dead rise

Description: Report discusses the results of testing "to determine the relationship between impact normal acceleration and flight-path angle for seaplanes landing in smooth water" (from Summary). The tests were done at high and low forward speeds and trims at 6 degrees and 9 degrees, a 22.5 degree angle of dead rise, and a gross weight of 1100 pounds. Information about the forces acting on the aircraft and maximum depth of immersion and trim is provided.
Date: February 1946
Creator: Batterson, Sidney A. & Stewart, Thelma
Partner: UNT Libraries Government Documents Department

Variation of hydrodynamic impact loads with flight-path angle for a prismatic float at 12 degree trim and with a 22-1/2 degree angle of dead rise

Description: Report discusses the results of testing "to determine the relationship between impact normal acceleration and flight-path angle for seaplanes landing on smooth water" (from Summary). The tests were performed at 12 degrees trim, 22.5 degree angle of dead rise, and a total weight of 1100 pounds. The effect on the maximum impact normal acceleration and the effects of immersion on acceleration are described.
Date: February 1946
Creator: Batterson, Sidney A.
Partner: UNT Libraries Government Documents Department

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.
Partner: UNT Libraries Government Documents Department

The knock-limited performance of S reference fuel plus 2 milliliters of triethylthallium per gallon

Description: Report discusses the results of testing of thallium as an antiknock agent in an internal-combustion engine. From Introduction: "On a weight basis, the thallium vapors were found to have several times the antiknock value of tetraethyl lead, which was added to the fuel. The amount of thallium vapor necessary to raise the antiknock properties of a gasoline up to exact equivalence with a benzol-gasoline mixture was determined in these engine tests."
Date: November 1945
Creator: Meyer, Carl L.
Partner: UNT Libraries Government Documents Department

Use of variable-ratio geared tabs to improve stick-force characteristics in turning flight

Description: Report discussing the use of variable-ratio geared tabs with an experimental elevator to improve stick-force characteristics in turning flight. The stick forces with the tabs were found to be satisfactory for a variety of center-of-gravity ranges. The ability of pilots to use the controls is also described.
Date: October 1945
Creator: Kleckner, Harold F.
Partner: UNT Libraries Government Documents Department

An approximate determination of the power required to move control surfaces as related to control-booster design

Description: From Summary: "As a part of a general investigation of control boosters, preliminary calculations were made to indicate the sizes of control boosters necessary to move the controls of airplanes of various sizes. The analysis was based on the assumption that the controls were moved with a rapidity and amplitude equal to that measured with a fighter airplane in simulated combat. A corollary purpose consisted in determining the effect on reducing booster-power unit size of incorporating an energy accumulator in the booster system."
Date: September 1945
Creator: Johnson, Harold I.
Partner: UNT Libraries Government Documents Department

Comparative fatigue tests of riveted joints of Alclad 24S-T, Alclad 24S-T81, Alclad 24S-RT, Alclad 24S-T86 and Alclad 75S-T sheet

Description: Report discusses testing performed to determine the fatigue strength of various types of riveted and spot-welded joints in the following aluminum alloys: Alclad 24S-T, 24S-RT, 758-T, 24S-T81, and 24S-T86. Details of the experiment, tensile properties, and information about failure are provided.
Date: August 1945
Creator: Moore, R. L. & Hill, H. N.
Partner: UNT Libraries Government Documents Department

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
Partner: UNT Libraries Government Documents Department

Effect of variation in diameter and pitch of rivets on compressive strength of panels with Z-section stiffeners: 1: panels with close stiffener spacing that fail by local buckling

Description: From Summary: "An experimental investigation is being conducted to determine the effect of varying the rivet diameter and pitch on the compressive strength of 24S-T aluminum-alloy panels with longitudinal Z-section stiffeners." The average stress at failing load for each rivet diameter, depth of countersink, and pitch of rivet is provided.
Date: August 1945
Creator: Dow, Norris F. & Hickman, William A.
Partner: UNT Libraries Government Documents Department

Comparison of structural efficiencies of diagonal-tension webs and truss webs of 24S-T aluminum alloy

Description: From Summary: "A comparison is made of the structural efficiencies of truss webs of 24S-T aluminum alloy with previously published values of the structural efficiencies of diagonal-tension webs of 24S-T aluminum alloy on the basis of identical allowable stresses. It is concluded that the diagonal-tension beam (web and flanges) can usually be built to be a more efficient beam than the truss beam, even though over a small range the web of a Warren truss beam is slightly more efficient than the web of a diagonal-tension beam."
Date: July 1945
Creator: Ochiltree, David W.
Partner: UNT Libraries Government Documents Department

Pressure lag in tubing used in flight research

Description: From Introduction: "Tests described in this report were undertaken to obtain a quantitative measure of the pressure lag in typical pressure-tubing systems used by the Ames Aeronautical Laboratory in flight research investigations. Lag measurements were made with both single-direction and oscillating pressure changes. Single-direction pressure changes were investigated to determine if the lag in orifice-pressure lines and in the research airspeed and altitude measuring systems of pursuit-type airplane undergoing flight tests was sufficient to cause an appreciable error in the record of a sudden pressure change. Oscillating pressure changes were investigated with particular reference to the accuracy of pressure peaks in pressure-distribution measurements during the time of buffeting conditions as found in stalls."
Date: July 1945
Creator: Turner, Howard L. & Rathert, George A., Jr.
Partner: UNT Libraries Government Documents Department

Tables and charts for the evaluation of profile drag from wake surveys at high subsonic speeds

Description: Report presents tables and charts for the evaluation of profile drag from wake surveys at high supersonic speeds. Two methods of evaluation are presented: an exact method that can be used on a wake of any shape and a simple approximate method that can be used when the variation of total-pressure loss across the wave has a typical form.
Date: July 1945
Creator: Block, Myron J. & Katzoff, S.
Partner: UNT Libraries Government Documents Department

Theoretical and experimental dynamic loads for a prismatic float having an angle of dead rise of 22-1/2 degrees

Description: Report discusses the maximum load, time to reach maximum load, and variation of load with time for prismatic floats in order to improve understanding of hydrodynamic theory for the landing impact of seaplane floats. Comparison of theoretical and experimental results and their applicability to flight impact are provided.
Date: July 1945
Creator: Mayo, Wilbur L.
Partner: UNT Libraries Government Documents Department

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.
Partner: UNT Libraries Government Documents Department

Fuel-evaporation loss as determined by the change in the specific gravity of the fuel in an aircraft fuel tank

Description: Report discusses the results of an investigation to determine the feasibility of using the change in the specific gravity of fuels in aircraft fuel tanks to measure fuel-vaporization loss. Six fuels were tested via fuel-distillation tests and simulated-flight tests. An equation based on the specific gravity of the fuel is also described.
Date: May 1945
Creator: Stone, Charles S. & Kramer, Walter E.
Partner: UNT Libraries Government Documents Department

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.
Partner: UNT Libraries Government Documents Department

Effects of compressibility and large angles of yaw on pressure indicated by a total-pressure tube

Description: Report discusses the effects of compressibility and angle of yaw on the pressure measured by a round-nose and a flat-nose total-pressure tube. The error incurred in the pressure measurements and factors affecting the total-pressure area are described.
Date: April 1945
Creator: Humphreys, Milton D.
Partner: UNT Libraries Government Documents Department