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Wind-tunnel tests of single- and dual-rotating pusher propellers having from three to eight blades

Description: Report presenting tests of 10-foot-diameter, single- and dual-rotating pusher propellers with three to eight blades that were conducted in the 20-foot propeller research tunnel as a continuation of previous investigations of tractor propellers. The propellers were mounted at the rear end of a streamline body in spinners that covered the hubs and part of the shanks. The effects as compared to previous testing differed only in degree of effect size.
Date: February 1942
Creator: Gray, W. H.
Partner: UNT Libraries Government Documents Department

Flight Measurements to Determine Effect of a Spring-Loaded Tab on Longitudinal Stability of an Airplane

Description: In conjunction with a program of research on the general problem of stability of airplanes in the climbing condition, tests have been made of a spring-loaded tb which. is referred to as a ?springy tab,? installed on the elevator of a low-wing scout bomber. The tab was arranged to deflect upward with decrease in speed which caused an increase in the pull force required to trim at low speeds and thereby increased the stick-free static longitudinal stability of the airplane. It was found that the springy tab would increase the stick-free stability in all flight conditions, would reduce the danger of inadvertent stalling because of the definite pull force required to stall the airplane with power on, would reduce the effect of center-of-gravity position on stick-free static stability, and would have little effect on the elevator stick forces in accelerated f11ght. Another advantage of the springy tab is that it might be used to provide almost any desired variation of elevator stick force with speed by adjusting the tab hinge-moment characteristics and the variation of spring moment with tab deflection. Unlike the bungee and the bobweight, the springy tab would provide stick-free static stability without requiring a pull force to hold the stick back while taxying. A device similar to the springy tab may be used on the rudder or ailerons to eliminate undesirable trim-force variations with speed.
Date: February 1, 1946
Creator: Hunter, Paul A. & Reeder, John P.
Partner: UNT Libraries Government Documents Department

High-altitude cooling. 3 : Radiators

Description: Report details the methods of determining the heat-transfer rate, pressure drop, and drag power of high-altitude radiators. Performance charts are provided for a wide range of design variables.
Date: September 1944
Creator: Nielsen, Jack Norman
Partner: UNT Libraries Government Documents Department

An investigation of aircraft heaters 17: experimental inquiry into steady state unidirectional heat-meter corrections

Description: Report divided into two sections. One discusses a correction that must be applied to a heat meter when it is used at temperatures other than temperatures at which it was calibrated. The other section contains the results of an application of the two methods of correcting the heat-transfer rates for contact and heat-meter resistance to experimental data.
Date: August 1944
Creator: Boelter, L. M. K.; Poppendiek, H. F. & Gier, J. T.
Partner: UNT Libraries Government Documents Department

An investigation of a thermal ice-prevention system for a C-46 cargo airplane III: description of thermal ice-prevention equipment for wings, empennage, and windshield

Description: Report presenting an investigation of a thermal ice-prevention system for a Curtiss-Wright C-46 airplane, including the equipment for the wings, empennage, and windshield. The report is the third in a series and focuses on the revisions to the components for thermal ice prevention, the temperature- and pressure-measurement equipment installed in the airplane to determine the performance of the system, and the results of static-load structural tests of a specimen of the wing outer-panel leading edge.
Date: February 1945
Creator: Jones, Alun R. & Spies, Ray J., Jr.
Partner: UNT Libraries Government Documents Department

An investigation of aircraft heaters 15: the emissivity of several materials

Description: Report presenting a determination of the mean effective emissivity as a function of temperature for the surfaces of several metals and insulating materials. A description and discussion of the measuring technique is presented. The results are plotted on a variety of graphs.
Date: January 1944
Creator: Boelter, L. M. K.; Bromberg, R. & Gier, J. T.
Partner: UNT Libraries Government Documents Department

Investigation of air flow in right-angle elbows in a rectangular duct

Description: Report presenting testing on elbow shapes in airplane carburetor air intake ducts with low losses and good velocity distribution without the use of turning vanes. Results regarding the flow coefficient, velocity distribution, and comparison of a variety of elbow ducts are provided.
Date: October 1941
Creator: McLellan, Charles H. & Bartlett, Walter A., Jr.
Partner: UNT Libraries Government Documents Department

An investigation of aircraft heaters 14: an air and heat flow analysis of a ram-operated heater and duct system

Description: Report presenting a method of graphical analysis that allows for the prediction of the thermal and aerodynamic performance of a ram-operated heater and duct system, for cabin heating or wing de-icing, at any altitude and airplane speed. Performance can be predicted from the isothermal total pressure drop across the components of the duct system at several ventilating air rates and the thermal output of the heater at various air and exhaust gas rates.
Date: March 1944
Creator: Boelter, L. M. K.; Morrin, E. H.; Martinelli, R. C. & Poppendiek, H. F.
Partner: UNT Libraries Government Documents Department

An investigation of aircraft heaters 24: the heat meter in the transient state for unidirectional heat transfer

Description: Report describing the behavior of the heat meter when it is used in thermal circuits which are under the influence of transient potentials. Three scenarios are considered: a heat meter suddenly placed on a hot surface, a heat meter mounted on the interior surface of the cabin wall of an uninsulated airplane climbing through air of decreasing temperature, and a heat meter mounted on the interior surface of the composite cabin wall of an airplane climbing through air of decreasing temperature.
Date: September 1944
Creator: Boelter, L. M. K.; Poppendiek, H. F.; Dunkle, R. V. & Gier, J. T.
Partner: UNT Libraries Government Documents Department

Measurements in flight of the pressure distribution on the right wing of a P-39N-1 airplane at several values of Mach number

Description: Report presenting pressure-distribution measurements made on the right wing of a P-39N-1 airplane at values of Mach number up to 0.80. A considerable portion of the lift was carried by components of the airplane other than the wings, and the proportion carried by the wing varies considerably with Mach number. Results regarding the variation of wing loads and moments with Mach number, internal wing pressure, and airplane lift-curve slope are provided.
Date: April 1945
Creator: Clousing, Lawrence A.; Turner, William N. & Rolls, L. Stewart
Partner: UNT Libraries Government Documents Department

Wind-tunnel tests of four full-scale seaplane floats

Description: Report presenting wind tunnel testing of four full-scale seaplane floats to determine the aerodynamic characteristics of the floats and to evaluate several drag-reducing refinements. Four floats were investigated; two differed only in external details like flush rivets, while one was the type used on twin-float installations. The variation of lift, drag, and pitching moment with pitch angle are presented for each float.
Date: July 1943
Creator: Conway, Robert N. & Maynard, Julian D.
Partner: UNT Libraries Government Documents Department

Quantitative analysis for aromatic amines in aviation fuels by ultraviolet spectrophotometry

Description: From Summary: "A method of quantitative analysis for individual aromatic amines or mixtures of aromatic amines in hydrocarbon fuel blends by spectrophotometric measurement of ultraviolet-light absorption is presented. The effect of the precision of the spectrophotometric measurements, the purity of the aromatic amine, photochemical decomposition of the amine, and the composition of the fuel on the accuracy of the analysis is discussed and the results of tests of the precision of the procedure are given."
Date: November 1945
Creator: Tischler, Adelbert O.
Partner: UNT Libraries Government Documents Department

Performance tests of NACA type A finned-tube exhaust heat exchanger

Description: Report presenting tests to determine the thermal and pressure-drop performance and durability of a cross-flow, internally finned, tubular exhaust-heat exchanger. The test covered a range of exhaust-gas flows, cooling-air flows, and exhaust-gas temperatures.
Date: August 1944
Creator: Reuter, J. George & Manson, S. V.
Partner: UNT Libraries Government Documents Department

Wind-tunnel vibration tests of dual-rotating propellers

Description: Report presenting vibration tests of six- and eight-blade tractor and seven- and eight-blade pusher dual-rotating propellers conducted in the 16-foot high-speed tunnel to determine the severity of vibrations excited by blade passages. Measurements of vibratory stresses were made for engine-speed ranges at low, intermediate, and high engine powers. Few vibrations caused by blade passages were detected, and those vibrations were not serious.
Date: September 1943
Creator: Miller, Mason F.
Partner: UNT Libraries Government Documents Department

Wind-tunnel vibration tests of a four-blade single rotating pusher propeller

Description: Report presenting vibration tests of a four-blade single-rotating propeller operating in a simulated pusher condition performed because the combination of wake and downwash behind a wing might provide serious excitation for reactionless vibrations of propellers with four or more blades. Measurements of propeller vibratory stress were made for various airspeeds, engine speeds, and engine powers.
Date: June 1943
Creator: Miller, Mason F.
Partner: UNT Libraries Government Documents Department

Preliminary report on flight tests of an airplane having exhaust-heated wings

Description: Report presenting testing of an airplane in icing conditions to determine the effect of exhaust heat applied to the wings as a means of preventing ice formations. Other ice-prevention equipment, including an exhaust gas-heated pitot-static head, hot-air-heated windshield, and an inflatable de-icer were also tested.
Date: April 1941
Creator: Rodert, Lewis A.; McAvoy, William H. & Clousing, Lawrence A.
Partner: UNT Libraries Government Documents Department

Principles of moment distribution applied to stability of structures composed of bars or plates

Description: Principles of the cross method of moment distribution, which have previously been applied to the stability of structures composed of bars under axial load, are applied to the stability of structures composed of long plates under longitudinal load.
Date: January 1, 1943
Creator: Lundquist, Eugene E.; Stowell, Elbridge Z. & Schuette, Evan H.
Partner: UNT Libraries Government Documents Department

Preliminary flight research on an all-movable horizontal tail as a longitudinal control for flight at high Mach numbers

Description: Report presenting flight tests of an all-movable horizontal tail installed on a Curtiss XP-42 airplane due to its possible advantages as a longitudinal control at high Mach numbers. The elevator control was found to be unsatisfactory with the control arrangements tested.
Date: March 1945
Creator: Kleckner, Harold F.
Partner: UNT Libraries Government Documents Department

The Longitudinal Stability of Flying Boats as Determined by Tests of Models in the NACA Tank II : Effect of Variations in Form of Hull on Longitudinal Stability

Description: Data taken from tests at constant speed to establish trim limits of stability, tests at accelerated speeds to determine stable limits of center of gravity shift, and tests at decelerated speeds to obtain landing characteristics of several model hull forms were used to establish hull design effect on longitudinal stability of porpoising. Results show a reduction of dead rise angle as being the only investigated factor reducing low trim limit. Various methods of reducing afterbody interference increased upper trim limit.
Date: November 1, 1942
Creator: Olson, Roland E. & Truscott, Starr
Partner: UNT Libraries Government Documents Department

The Measurement of Fuel-Air Ratio by Analysis of the Oxidized Exhaust Gas

Description: An investigation was made to determine a method of measuring fuel-air ratio that could be used for test purposes in flight and for checking conventional equipment in the laboratory. Two single-cylinder test engines equipped with typical commercial engine cylinders were used. The fuel-air ratio of the mixture delivered to the engines was determined by direct measurement of the quantity of air and of fuel supplied and also by analysis of the oxidized exhaust gas and of the normal exhaust gas. Five fuels were used: gasoline that complied with Army-Navy Fuel Specification, No. AN-VV-F-781 and four mixtures of this gasoline with toluene, benzene, and xylene. The method of determining the fuel-air ratio described in this report involves the measurement of the carbon-dioxide content of the oxidized exhaust gas and the use of graphs or the presented equation. This method is considered useful in aircraft, in the field, or in the laboratory for a range of fuel-air ratios from 0.047 to 0.124.
Date: October 1, 1943
Creator: Memm, J. Lawrence, Jr.
Partner: UNT Libraries Government Documents Department

Flame-visibility tests with individual exhaust stacks

Description: Report presenting testing made on a Wright 1820-G single-cylinder engine to determine the effect of operating variables and the effect of shape and size of the exhaust stack on the visibility of exhaust gases for individual-stack installations. Flame damping was improved by decrease in nozzle-exit area, increase in stack length, and reduction in hydraulic diameter of the exhaust jets. Results regarding the characteristics of exhaust flames and damping of exhaust flames are provided.
Date: February 1944
Creator: Turner, L. Richard & Humble, Leroy V.
Partner: UNT Libraries Government Documents Department

Flight Tests of the Lateral Control Characteristics of an F6F-3 Airplane Equipped with Spring-Tab Ailerons

Description: Tests were made to determine whether spring-tab ailerons tended to oscillate or flutter in speed ranges up to 400 mph. Flight tests showed spring-tab ailerons had desirable light stick forces and no tendency to overbalance. No flutter tendencies were indicated up to 400 mph, and any oscillations following abrupt control deflections were heavily damped. Recommendations were made for modifications to increase aileron effectiveness at low speeds without affecting lateral control at high speeds by increasing available deflection and modifying spring-tab arrangement.
Date: April 1, 1945
Creator: Williams, Walter C.
Partner: UNT Libraries Government Documents Department

Wind tunnel investigation of control surface characteristics 9: some analytical considerations and experimental test results for an internally balanced flap

Description: Report presenting an analysis of the probable aerodynamic section characteristics of a plain flap with various arrangements of internal balance. The results of the calculations previously obtained were found to be in agreement with the experiment. Some possible applications of the data to balancing tabs are also provided.
Date: July 1942
Creator: Sears, Richard I.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of control-surface characteristics 1: effect of gap on the aerodynamic characteristics of an NACA 0009 airfoil with a 30-percent-chord plain flap

Description: From Summary: "Tests have been made to determine the effect of a gap at the flap nose upon the aerodynamic section characteristics of an NACA 0009 airfoil with a plain flap and tab. The results are presented in the form of airfoil and flap section characteristics for several flap deflections, tab deflections, and for four sizes of gap."
Date: June 1941
Creator: Sears, Richard I.
Partner: UNT Libraries Government Documents Department