Cooperative Measurements of Radio Fading in 1925 (open access)

Cooperative Measurements of Radio Fading in 1925

Scientific paper issued by the Bureau of Standards over studies conducted on radio fading. As stated in the abstract, "the series of measurements on fading were devoted to studies of fading effects during the sunset period, effects during the solar eclipse of January 24, the fading variations throughout a 24-hour day, and the effects of high transmitting power on fading" (p. 419). This paper includes tables, maps, illustrations, and photographs.
Date: August 17, 1927
Creator: Dellinger, J. H.; Jolliffe, C. B. & Parkinson, T.
System: The UNT Digital Library
Drag and Cooling With Various Forms of Cowling for A "Whirlwind" Radial Air-Cooled Engine - 2 (open access)

Drag and Cooling With Various Forms of Cowling for A "Whirlwind" Radial Air-Cooled Engine - 2

"This report gives the results of the second portion of an investigation in the twenty-foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics, on the cowling and cooling of a "Whirlwind" J-5 radial air-cooled engine. The first portion pertains to tests with a cabin fuselage. This report covers tests with several forms of cowling, including conventional types, individual fairings behind the cylinders, individual hoods over the over the cylinders, and the new N. A. C. A. complete cowling, all on an open cockpit fuselage. Drag tests were also made with a conventional engine nacelle, and with a nacelle having the new complete cowling" (p. 191).
Date: December 17, 1928
Creator: Weick, Fred E.
System: The UNT Digital Library
Tables for pressure of air on coming to rest from various speeds (open access)

Tables for pressure of air on coming to rest from various speeds

From Summary: "In Technical Report no. 247 of the National Advisory Committee for Aeronautics theoretical formulas are given from which was computed a table for the pressure of air on coming to rest from various speeds, such as those of aircraft and propeller blades. In that report, the table gave incompressible and adiabatic stop pressures of air for even-speed intervals in miles per hour and for some even-speed intervals in knots per hour. Table II of the present report extends the above-mentioned table by including the stop pressures of air for even-speed intervals in miles per hour, feet per-second, knots per hour, kilometers per hour, and meters per second."
Date: December 17, 1928
Creator: Zahm, A. F. & Louden, F. A.
System: The UNT Digital Library
Flow and Force Equations for a Body Revolving in a Fluid (open access)

Flow and Force Equations for a Body Revolving in a Fluid

Part I gives a general method for finding the steady-flow velocity relative to a body in plane curvilinear motion, whence the pressure is found by Bernoulli's energy principle. Integration of the pressure supplies basic formulas for the zonal forces and moments on the revolving body. Part II, applying this steady-flow method, finds the velocity and pressure at all points of the flow inside and outside an ellipsoid and some of its limiting forms, and graphs those quantities for the latter forms. Part III finds the pressure, and thence the zonal force and moment, on hulls in plane curvilinear flight. Part IV derives general equations for the resultant fluid forces and moments on trisymmetrical bodies moving through a perfect fluid, and in some cases compares the moment values with those found for bodies moving in air. Part V furnishes ready formulas for potential coefficients and inertia coefficients for an ellipsoid and its limiting forms. Thence are derived tables giving numerical values of those coefficients for a comprehensive range of shapes.
Date: December 17, 1928
Creator: Zahm, A. F.
System: The UNT Digital Library
Full-scale turning characteristics of the U.S.S. Los Angeles (open access)

Full-scale turning characteristics of the U.S.S. Los Angeles

This paper present a description of the method employed and results obtained in full-scale turning trials on the rigid airship U. S. S. "Los Angeles". The results of this investigation are not sufficiently comprehensive to permit definite conclusions as to the variation of turning characteristics with changes in speed and rudder angle. They indicate however, that the turning radius compares favorably with that for other large airships, that the radius is independent of the speed, that the position of the point of zero yaw is nearly independent of the rudder angle and air speed, and that a theoretical relation between radius and angle of yaw in a turn gives a close approximation to actuality.
Date: April 17, 1929
Creator: Thompson, F. L.
System: The UNT Digital Library