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  Partner: UNT Libraries Government Documents Department
 Collection: National Advisory Committee for Aeronautics Collection
Comparison of Three Multicylinder Icing Meters and Critique of Multicylinder Method

Comparison of Three Multicylinder Icing Meters and Critique of Multicylinder Method

Date: June 1, 1952
Creator: Howell, Wallace E.
Description: Three multicylinder cloud meters, fundamentally similar but differing in important details, were compared in use at the Mount Washington Observatory. Determinations of liquid water content were found to agree within the limits of the probable error, but the two instruments designed by the National Advisory Committee for Aeronautics indicated larger drop sizes than did the Observatory's instrument, apparently because of spurious ice catch on the rather rough surface of the larger cylinders. Comparisons of drop-size distribution were largely indeterminate., In a critique of the method, the probable error of determination of liquid water content was found to be +/-8 percent; of drop size, +/-6 percent; and of drop-size distribution, about +/-0.7 unit of the modulus of distribution. Of the systematic errors, run-off of unfrozen water is most important, blow-off and erosion seldom being hampering. Revision of collection-efficiency computations for cylinders in clouds with distributed drop sizes was found necessary and also revision of one of the correction-factor graphs heretofore used. The assumption of constant ice density in deriving cylinder size was found to be permissible for cylinders 1 inch or more in diameter.
Contributing Partner: UNT Libraries Government Documents Department
A probability analysis of the meteorological factors conducive to aircraft icing in the United States

A probability analysis of the meteorological factors conducive to aircraft icing in the United States

Date: July 1, 1952
Creator: Lewis, W. & Bergrun, N. R.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Experimental Droplet Impingement on Four Bodies of Revolution

Experimental Droplet Impingement on Four Bodies of Revolution

Date: December 1, 1957
Creator: Lewis, James P. & Ruggeri, Robert S.
Description: The rate and. area of cloud droplet impingement on four bodies of revolution were obtained experimentally in the NACA Lewis icing tunnel with a dye-tracer technique. The study included spheres, ellipsoidal forebodies of fineness ratios of 2.5 and 3.0, and a conical forebody of 300 included angle and covered a range of angles of attack from 0? to 60 and rotational speeds up to 1200 rpm. The data were obtained at an airspeed of 157 knots and are correlated by dimensionless impingement parameters. In general, the experimental data show that the local and total impingement rates and impingement limits of bodies of revolution are primarily functions of the modified inertia parameters, the body shape, and fineness ratio. Both the local impingement rate and impingement limits depend upon the angle of attack. Rotation of the bodies had a negligible effect on the impingement characteristics except for an averaging effect at angle of attack. For comparable diameters the bluffer bodies had the largest total impingement efficiency, but the finer and sharper bodies had the largest values of maximum local impingement efficiency and, in most cases, the largest limits of impingement. In most cases, the impingement characteristics were less than those calculated from ...
Contributing Partner: UNT Libraries Government Documents Department
Experimental Droplet Impingement on Several Two-Dimensional Airfoils with Thickness Ratios of 6 to 16 Percent

Experimental Droplet Impingement on Several Two-Dimensional Airfoils with Thickness Ratios of 6 to 16 Percent

Date: December 1, 1956
Creator: Gelder, Thomas F.; Smyers, William H., Jr. & VonGlahn, Uwe
Description: The rate and area of cloud droplet impingement on several two-dimensional swept and unswept airfoils were obtained experimentally in the NACA Lewis icing tunnel with a dye-tracer technique. Airfoil thickness ratios of 6 to 16 percent; angles of attack from 0 deg to 12 deg, and chord sizes from 13 to 96 inches were included in the study. The data were obtained at 152 knots and are extended to other conditions by dimensionless impingement parameters. In general, the data show that the total and local collection efficiencies and impingement limits are primary functions of the modified inertia parameter (in which airspeed, droplet size, and body size are the most significant variables) and the airfoil thickness ratio. Local collection efficiencies and impingement limits also depend on angle of attack. Secondary factors affecting impingement characteristics are airfoil shape, camber, and sweep angle. The impingement characteristics obtained experimentally for the airfoils were within +/-10 percent on the average of the characteristics calculated from theoretical trajectories. Over the range of conditions studied, the experimental data demonstrate that a specific method can be used to predict the impingement characteristics of swept airfoils with large aspect ratios from the data for unswept airfoils of the same ...
Contributing Partner: UNT Libraries Government Documents Department
An Electric Thrust Meter Suitable for Flight Investigation of Propellers

An Electric Thrust Meter Suitable for Flight Investigation of Propellers

Date: May 9, 1949
Creator: Perkins, Porter J., Jr. & Millenson, Morton B.
Description: A lightweight instrument that utilizes resistance-wire electric strain gases to measure propeller-shaft thrust has been developed. A wind-tunnel investigation on a propeller installed, on a single-engine pursuit airplane showed that the instrument gave a reliable indication of propeller-shaft thrust to an accuracy of +/-2 percent within its calibrated range. No attempt was made to determine the relation of indicated shaft thrust to net propeller thrust.
Contributing Partner: UNT Libraries Government Documents Department
A review of instruments developed for the measurement of the meteorological factors conductive to aircraft icing

A review of instruments developed for the measurement of the meteorological factors conductive to aircraft icing

Date: April 26, 1949
Creator: Jones, A. R. & Lewis, W.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
A heated-wire liquid-water-content instrument and results of initial flight tests in icing conditions

A heated-wire liquid-water-content instrument and results of initial flight tests in icing conditions

Date: January 20, 1955
Creator: Neel, C. B.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Measurement of distortion in second experimental control rod for argonne naval reactor with constant transverse temperature gradient and uniform longitudinal temperature distribution

Measurement of distortion in second experimental control rod for argonne naval reactor with constant transverse temperature gradient and uniform longitudinal temperature distribution

Date: September 26, 1951
Creator: Lietzke, A. F. & Nagey, T. F.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Model tests of a wing-duct system for auxiliary air supply

Model tests of a wing-duct system for auxiliary air supply

Date: January 1, 1941
Creator: Bierman, D. & Corson, B. W., Jr.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Low-speed wind-tunnel tests of a 1/8-scale model of the bell d-188a vtol airplane

Low-speed wind-tunnel tests of a 1/8-scale model of the bell d-188a vtol airplane

Date: August 25, 1958
Creator: Mc Kinney, M. O. & Smith, C. C., Jr.
Description: None
Contributing Partner: UNT Libraries Government Documents Department