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Trends in surface-ignition temperatures

Description: Report discusses the variation of surface-ignition temperature with charge density, fuel-air ratio, and surface-ignition advance. Tests on several fuels were conducted on a supercharged CFR engine to determine surface-ignition temperature as a function of the three variables. It was concluded that surface-ignition temperature is not a satisfactory criterion for differentiating between preignition characteristics of different fuels.
Date: September 1944
Creator: Alquist, Henry E. & Male, Donald W.

Wind-tunnel tests of a dual-rotating propeller having one component locked or windmilling

Description: From Summary: "The effect on the propulsive efficiency of locking or windmilling one propeller of a six-blade dual-rotating propeller installation was determined in the Langley propeller-research tunnel. Tests were made of both pusher and tractor configurations, with the unpowered propeller both leading and following the powered propeller, which was set at a blade angle of 40 degrees. The maximum propulsive efficiency of the powered propeller in combination with the locked or windmilling propeller was, in all cases, lower than that of the powered propeller operating alone."
Date: January 1945
Creator: Bartlett, Walter A., Jr.

Tensile Tests of NACA and Conventional Machine- Countersunk Flush Rivets

Description: An investigation was conducted to determine and compare the tensile strength of NACA and conventional machine-countersunk flush rivets of several rivet-head angles and varying countersunk depth. The results of the investigation are presented in the form of curves that show the variation of the tensile strength of the rivet with the ratio of the sheet thickness to the rivet diameter. For the same rivet-head angle and for a given angle of c/d, the NACA rivets developed higher tensile strength than the conventional rivets.
Date: October 1, 1944
Creator: Bartone, Leonard M. & Mandel, Merven W.

The Porpoising Characteristics of a Planing Surface Representing the Forebody of a Flying-Boat Hull

Description: Porpoising characteristics were observed on V-body fitted with tail surfaces for different combinations of load, speed, moment of inertia, location of pivot, elevator setting, and tail area. A critical trim was found which was unaltered by elevator setting or tail area. Critical trim was lowered by moving pivot either forward or down or increasing radius or gyration. Increase in mass and moment of inertia increased amplitude of oscillations. Complete results are tabulated and shown graphically.
Date: May 1, 1942
Creator: Benson, James M.

Tank tests of a flying-boat model equipped with several types of fairing designed to reduce the air drag of the main step

Description: From Summary: "Tank tests were made of a flying-boat model having various types of fairing with and without ventilation ducts behind the main step to investigate the hydrodynamic characteristics of the model. All the types were designed to reduce significantly the air drag chargeable to the main step. The configuration that combined the best stability with a good aerodynamic form consisted of a shallow step and an adjoining ventilation aperture having an area about 7 percent of the square of the beam."
Date: April 1945
Creator: Benson, James M. & Havens, Robert F.

The use of a retractable planing flap instead of a fixed step on a seaplane

Description: Report presents and discusses the improvements in hydrodynamic and aerodynamic performance of a seaplane with a retractable planing flap instead of a conventional main step. A type of flap that could be used is described and tested for hydrodynamic stability. Results regarding the trim limits of stability, limiting positions of the center of gravity, and skipping are provided.
Date: May 1943
Creator: Benson, James M. & Lina, Lindsay J.

Heat-transfer tests of aqueous ethylene glycol solutions in an electrically heated tube

Description: As part of an investigation of the cooling characteristics of liquid-cooled engines, tests were conducted with an electrically heated single-tube heat exchanger to determine the heat-transfer characteristics of an-e-2 ethylene glycol and other ethylene glycol-water mixtures. Similar tests were conducted with water and commercial butanol (n-butyl alcohol) for check purposes. The results of tests conducted at an approximately constant liquid-flow rate of 0.67 pound per second (Reynolds number, 14,500 to 112,500) indicate that at an average liquid temperature 200 degrees f, the heat-transfer coefficients obtained using water, nominal (by volume) 30 percent-70 percent and 70 percent-30 percent glycol-water mixtures are approximately 3.8, 2.8, and 1.4 times higher, respectively, than the heat-transfer coefficients obtained using an-e-2 ethylene glycol.
Date: August 1, 1945
Creator: Bernardo, Everett & Eian, Carroll S