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An Investigation of the Effect of the WADC 30,000-Horsepower Whirl Rig Upon the Static Characteristics of a Propeller

Description: Tests have been made at the Langley Aeronautical Laboratory on a 6000-horsepower propeller dynamometer installed at a ground test facility to determine the effect of a half-scale model of the Wright Aeronautical Development Center 30,000-horsepower whirl rig upon the aerodynamic characteristics of a three-blade NACA 10-(3)(062)-045 propeller. The model of the whirl rig was mounted in front of the 6000-horsepower propeller dynamometer. Static propeller tests were made for 0deg, 5deg, 10deg, 15deg, and 20deg blade angles over a range of rotational speeds from 600 to 2200 rpm in 100-rpm increments. Measurements were made of propeller thrust and torque, stresses in the propeller blades, and static and total pressures over the surface of the model. Propeller thrust and torque were increased up to 33 percent by the presence of the model of the whirl rig, but the average increase was from 5 to 10 percent. Blade vibratory stresses were small.
Date: July 2, 1952
Creator: Salters, Leland B., Jr. & Norton, Harry T., Jr.
Partner: UNT Libraries Government Documents Department

Planing-surface tests at large Froude numbers - airfoil comparison

Description: The take-off capacity of a flying boat depends upon the design of the hull bottom ahead as well as aft of the step. Systematic tests - largely made by industry itself - had proved the benefit accruing from a well designed hull bottom long before theoretical insight into the flow phenomena involved had been obtained. The theoretical framing of the problem was beset with serious difficulties and, though restricted to the processes within range of the planing bottom ahead of the step, the solutions do not yet afford a comprehensive survey.
Date: February 1, 1938
Creator: Sambraus, A
Partner: UNT Libraries Government Documents Department

Hydrology of the Newberry Volcano Caldera, Oregon

Description: From abstract: Precipitation in the Newberry caldera is nearly in balance with evaporation, evapotranspiration, and and streamflow. A small surplus of water, estimated to be in the range 2,500 to 6,500 acre-feet, is available annually for recharge to deep aquifers beneath the caldera floor.
Date: 1983
Creator: Sammel, Edward A. & Craig, Robert W.
Partner: UNT Libraries Government Documents Department

Experimental Investigation of Average Heat-Transfer and Friction Coefficients for Air Flowing in Circular Tubes Having Square-Thread-Type Roughness

Description: An investigation of forced-convection heat transfer and associated pressure drops was conducted with air flowing through electrically heated Inconel tubes having various degrees of square-thread-type roughness, an inside diameter of 1/2 inch, and a length of 24 inches. were obtained for tubes having conventional roughness ratios (height of thread/radius of tube) of 0 (smooth tube), 0.016, 0.025, and 0.037 over ranges of bulk Reynolds numbers up to 350,000, average inside-tube-wall temperatures up to 1950deg R, and heat-flux densities up to 115,000 Btu per hour per square foot. Data The experimental data showed that both heat transfer and friction increased with increase in surface roughness, becoming more pronounced with increase in Reynolds number; for a given roughness, both heat transfer and friction were also influenced by the tube wall-to-bulk temperature ratio. Good correlation of the heat-transfer data for all the tubes investigated was obtained by use of a modification of the conventional Nusselt correlation parameters wherein the mass velocity in the Reynolds number was replaced by the product of air density evaluated at the average film temperature and the so-called friction velocity; in addition, the physical properties of air were evaluated at the average film temperature. The isothermal friction data for the rough tubes, when plotted in the conventional manner, resulted in curves similar to those obtained by other investigators; that is, the curve for a given roughness breaks away from the Blasius line (representing turbulent flow in smooth tubes) at some value of Reynolds number, which decreases with increase in surface roughness, and then becomes a horizontal line (friction coefficient independent of Reynolds number). A comparison of the friction data for the rough tubes used herein indicated that the conventional roughness ratio is not an adequate measure of relative roughness for tubes having a square-thread-type element. The present data, as ...
Date: June 27, 1952
Creator: Sams, E. W.
Partner: UNT Libraries Government Documents Department