National Advisory Committee for Aeronautics (NACA) - 31 Matching Results

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Determination of rate, area, and distribution of impingement of waterdrops on various airfoils from trajectories obtained on the differential analyzer

Description: From Summary: "The trajectories of waterdrops in air flowing over airfoils are determined for three airfoil - angle-of-attack combinations using the differential analyzer to solve the differential equations of motion of the waterdrops. From these trajectories the rate of water impingement, the area of impingement, and the distribution of impingement are determined as functions of two dimensionless moduli. Comparisons are made of the rate of water impingement on these airfoils and the rate of water impingement on cylinders."
Date: February 16, 1949
Creator: Guibert, A. G.; Janssen, E. & Robbins, W. M.
Partner: UNT Libraries Government Documents Department

A device for measuring sonic velocity and compressor Mach number

Description: A device has been developed which measures the velocity of sound in fluids at stagnation and is especially adaptable to turbine and compressor testing for which the constituency of the working fluid may be in doubt. By utilizing the shaft frequency of a rotary compressor, the instrument can also be used to provide a direct measurement of the compressor Mach number (ratio of blade-tip velocity to inlet velocity of sound at stagnation). A Helmholtz resonator is employed in the measurement of the sound velocity. Viscous effects in the orifice of the Helmholtz resonator are shown to be important and can be taken into account with the help of a parameter obtained from Stokes solution of the flow near an oscillating wall. This parameter includes the kinematic viscosity of the fluid and the frequency of sound in the resonator. When these effects are recognized, the resonator can be calibrated to measure velocity of sound or compressor Mach number to an accuracy of better than 0.5 percent.
Date: January 16, 1947
Creator: Huber, Paul W & Kantrowitz, Arthur
Partner: UNT Libraries Government Documents Department

Preliminary results of a flight investigation to determine the effect of negative flap deflection on high-speed longitudinal-control characteristics

Description: Report presenting flight testing on two propeller-driven airplanes with wings of NACA 66-series and NACA 230-series airfoil sections to determine the effect of deflecting the landing flaps upward on the high-speed longitudinal-control characteristics.
Date: December 16, 1947
Creator: White, Maurice D.; Sadoff, Melvin; Clousing, Lawrence A. & Cooper, George E.
Partner: UNT Libraries Government Documents Department

Flight investigation of flutter models with 1/10-scale Douglas D-558-2 wing panels

Description: Report presenting testing of three rocket-powered models with Douglas D-558-2 wings as horizontal fins with scaled structural parameters to determine whether the possibility of wing flutter due to torsion and bending exists in full-scale airplanes at transonic speeds. No wing flutter was present in the models tested, but pitching oscillation developed as it passed into the transonic range.
Date: February 16, 1949
Creator: Teitelbaum, Jerome M.
Partner: UNT Libraries Government Documents Department

An NACA Vane-Type Angle-of-Attack Indicator for use at Subsonic and Supersonic Speeds

Description: A vane-type angle-of-attack indicator suitable for measurements at both subsonic and supersonic speeds has been developed by the National Advisory Committee for Aeronautics. A brief history is given of the development, and a wind-tunnel calibration of the indicator is presented, together with a discussion of the corrections to be applied to the indicated readings.
Date: August 16, 1949
Creator: Mitchell, Jesse L. & Peck, Robert F.
Partner: UNT Libraries Government Documents Department

Effect of Length-Beam Ratio on the Aerodynamic Characteristics of Flying-Boat Hulls without Wing Interference

Description: Contains experimental results of an investigation of the aerodynamic characteristics of a family of flying boat hulls of length beam ratios 6, 9, 12, and 15 without wing interference. The results are compared with those taken on the same family of hulls in the presence of a wing.
Date: January 16, 1948
Creator: Lowry, John G. & Riebe, John M.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Tests of a 1/4-Scale Model of the Naval Aircraft Factory Float-Wing Convoy Interceptor, TED No. NACA 2314

Description: A 1/4 - scale model of the Naval Aircraft Factory float-wing convoy interceptor was tested in the Langley 7-by 10-foot tunnel to determine the longitudinal and lateral stability characteristics. The model was tested in the presence of a ground board to determine the effect of simulating the ground on the longitudinal characteristics.
Date: January 16, 1947
Creator: Wells, Evalyn G. & McKinney, Elizabeth G.
Partner: UNT Libraries Government Documents Department

Flight Tests of a Curtiss No. 838-1C2-18 Three-Blade Propeller Having Trailing-Edge Extensions

Description: Flight tests to determine propeller performance have been made of a Curtiss No. 838-102-18 three-blade propeller having trailing-edge extensions on a Republic P-47D-28 airplane in climb and high speed. These tests are a part of a general propeller flight-test program at the Langley Laboratory of the National Advisory Committee for Aeronautics. Results of climb tests indicate that when power is changed from approximately 1475 horsepower at 2550 rpm (roughly normal power) to 2400 horsepower at 2700 rpm (approximately military power) there is a loss in propeller efficiency of 3 percent at an altitude of 7000 feet, and 4 percent at 21,000 feet. At an airplane Mach number of 0.7 there is a gain of 9 percent in propeller efficiency when the power coefficient per blade is increased from 0.06 to 0.09. Optimum power coefficient per blade at this Mach number is estimated to be approximately 0.12. An analysis to determine the effect of the addition of extensions on the performance of the basic propeller blades indicates that climb performance was increased but high-speed performance was reduced. Both effects, however, were small.
Date: July 16, 1947
Creator: Gardner, John J.
Partner: UNT Libraries Government Documents Department

Tests of a 1/7-Scale Semispan Model of the XB-35 Airplane in the Langley 19-Foot Pressure Tunnel

Description: A 1/7 scale semispan model of the XB-35 airplane was tested in the Langley 10 foot pressure tunnel, primarily for the purpose of investigating the effectiveness of a leading-edge slot for alleviation of stick-fixed longitudinal instability at high angles of attack caused by early tip stalling and a device for relief of stick-free instability caused by elevon up-floating tendencies at high angles of attack. Results indicated that the slot was not adequate to provide the desired improvement in stick-fixed stability. The tab-flipper device provided improvement in stick-free stability abd two of the linkage combinations tested gave satisfactory variations of control force with airspeed for all conditions except that in which the wing-tip "pitch-control" flap was fully deflected. However, the improvement in control force characteristics was accompanied by a detrimental effect on stick-fixed stability because of the pitching moments produced by the elevon tab deflection.
Date: January 16, 1946
Creator: Teplitz, Jerome; Kayten, Gerald G. & Cancro, Patrick A.
Partner: UNT Libraries Government Documents Department

Hydrodynamic Characteristics of an Aerodynamically Refined Planing-Tail Hull

Description: The hydrodynamic characteristics of an aerodynamically refined planing-tail hull were determined from dynamic model tests in Langley tank no. 2. Stable take-off could be made for a wide range of locations of the center of gravity. The lower porpoising limit peak was high, but no upper limit was encountered. Resistance was high, being about the same as that of float seaplanes. A reasonable range of trims for stable landings was available only in the aft range of center-of-gravity locations.
Date: July 16, 1948
Creator: McKann, Robert & Suydam, Henry B.
Partner: UNT Libraries Government Documents Department

Altitude-wind-tunnel investigation of various can-type burners in Bumblebee 18-inch ram jet

Description: An investigation on various can-type burners in a Bumblebee 18-inch ram jet under controlled conditions of pressure altitude and ram pressure ratio was conducted in the NACA Lewis altitude wind tunnel with kerosene as fuel. The performance of the following can-type burner configurations was better than that of the other burner configurations investigated: (1) a flame holder having a two-pitch alinement of perforations, 0.07-inch-wide cooling slots, and an arrangement of fuel nozzles located within an annulus having a mean radius of 7.24 inches; and (2) a flame holder having a zero-pitch alinement of perforations, 0.16-inch-wide cooling slots, and an annulus of fuel nozzles having a mean radius of 6.89 inches. The maximum net-thrust coefficient and minimum specific fuel consumption were obtained with the ram-jet configuration that consisted of the burner just described having a flame holder with a two-pitch alinement of perforations and a combustion-chamber outlet restricted by a 14-and-three-quarter-inch-diameter orifice plate. At a ram pressure ratio equivalent to a free-stream Mach number of 1.44 and a pressure altitude of 30,000 feet, the net-thrust coefficient was 0.68 and the reduced specific fuel consumption was 3.0 pounds of fuel per hour per pound of net thrust.
Date: March 16, 1949
Creator: Dupree, D T; Nussdorfer, T J & Sterbentz, W H
Partner: UNT Libraries Government Documents Department

Free-Spinning-Tunnel Tests of a 1/29-Scale Model of the Republic XP-91 Airplane with a Vee Tail Installed

Description: A spin investigation has been conducted in the Langley 20 -foot free-spinning tunnel on a 1/29 - scale model of the Republic XP-91 airplane with vee tail installed. The effects cf control settings and movements upon the effect spin and recovery characteristics of the model were determined for the clean condition (wing tanks removed, landing gear and flaps retracted). The tests were made at a loading simulating that following cruise at altitude and at a time when nearly all fuel was expended. The results indicated that the airplane might not spin at normal spinning-control configuration, but if a spin were obtained, recovery therefrom by full rudder reversal would be satisfactory. It was also indicated that aileron-against settings would lead to violent oscillatory motions and should be avoided.
Date: January 16, 1948
Creator: Snyder, Thomas L.
Partner: UNT Libraries Government Documents Department

Detail Calculations of the Estimated Shift in Stick-Fixed Neutral Point Due to the Windmilling Propeller and to the Fuselage of the Republic XF-12 Airplane

Description: Detail calculations are presented of the shifts in stick-fixed neutral point of the Republic XF-12 airplane due to the windmilling propellers and to the fuselage. The results of these calculations differ somewhat from those previously made for this airplane by Republic Aviation Corporation personnel under the direction of Langley flight division personnel. Due to these differences the neutral point for the airplane is predicted to be 37.8 percent mean aerodynamic chord, instead of 40.8 percent mean aerodynamic chord as previously reported.
Date: October 16, 1944
Creator: White, M. D.
Partner: UNT Libraries Government Documents Department

Tests of an adjustable-area exhaust nozzle for jet-propulsion engines

Description: Report discussing a comparison between a centrifugal-flow-type turbojet engine with an adjustable-area exhaust nozzle and with a series of fixed-area nozzles of various throat diameters. The adjustable-area nozzle was found to be as efficient as the fixed-area nozzles in testing. Information about the corrected static thrust, fuel flow, and tail-pipe gas temperature for both types of nozzles is provided.
Date: August 16, 1945
Creator: Wilcox, E. C.
Partner: UNT Libraries Government Documents Department

Effect of modifications to induction system on altitude performance of V-1710-93 engine III : use of parabolic rotating guide vanes and NACA designed auxiliary-stage inlet elbow and interstage duct

Description: Bench runs of a modified V-1710-93 engine equipped with a two-stage supercharger, interstage carburetor, aftercooler assembly, and backfire screens have been made at a simulated altitude of 29,000 feet to determine the effect of several induction-system modifications on the engine and supercharger performance. The standard guide vanes on the auxiliary- and engine-stage superchargers were replaced by rotating guide vanes with a parabolic blade profile. The auxiliary-stage inlet elbow and interstage duct were replaced with new units of NACA design. These modifications were made one at a time and data were obtained after each change to determine the effect of each modification. All runs were made at a constant engine speed of 3000 rpm at a simulated altitude of 29,000 feet and all changes in engine power were made by varying the speed of the auxiliary-stage supercharger.
Date: January 16, 1947
Creator: Standahar, Ray M. & Mccarty, James S.c
Partner: UNT Libraries Government Documents Department