National Advisory Committee for Aeronautics (NACA) - 39 Matching Results

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On the flying qualities of helicopters

Description: Report presenting the flying qualities problems of current helicopters, including instability with angle of attack in forward flight, control sensitivity in hovering, and control forces following control movement in maneuvers. Some possible solutions to these issues are presented.
Date: January 27, 1949
Creator: Reeder, John P. & Gustafson, F. B.
Partner: UNT Libraries Government Documents Department

High-speed aerodynamic characteristics of horn and overhang balances on a full-scale elevator

Description: Report presenting high-speed wind tunnel testing of horn- and overhang-balance elevators on a full-scale, semispan, horizontal tail. The effects of unshielding the horn and unsealing the overhang were investigated. Results regarding aerodynamic characteristics, distortions of the tail, and critical Mach numbers are provided.
Date: February 27, 1948
Creator: Cleary, Joseph W. & Krumm, Walter J.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of several NACA airfoil sections at seven Reynolds numbers from 0.7 x 10(exp 6) to 9.0 x 10(exp 6)

Description: Report presenting an investigation of the two-dimensional aerodynamic characteristics of several NACA airfoil sections at four Reynolds numbers. Results regarding the minimum drag, maximum lift, lift-curve slope, and angle of zero lift and pitching moment are provided.
Date: May 27, 1948
Creator: Loftin, Laurence K., Jr. & Poteat, M. Irene
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of horizontal tails. 5: 45 degree swept-back plan form of aspect ratio 2

Description: Report presenting the results of a wind-tunnel investigation of the low-speed aerodynamic characteristics of a 45 degree sweptback horizontal-tail model of aspect ratio 2 and a comparison of these results with results for a model of the same aspect ratio with an unswept hinge line. Results regarding the lift and hinge-moment parameters, static longitudinal stability, effect of Reynolds number, effect of standard roughness, effect of removing elevator nose seal, and visualization of the air flow are provided.
Date: September 27, 1949
Creator: Dods, Jules B., Jr.
Partner: UNT Libraries Government Documents Department

Experimental pressure distributions over wing tips at Mach number 1.9 I :wing tip with subsonic leading edge

Description: An investigation was conducted at a Mach number of 1.91 to determine spanwise pressure distribution over a wing tip in a region influenced by a sharp subsonic leading edge swept back at 70 degrees. Except for pressure distribution on the top surface in the immediate vicinity of the subsonic leading edge, the maximum difference between linearized theory and experimental data was 2 1/2 percent (of free-stream dynamic pressure) for angles of attack up to 4 degrees and 7 percent for angles of attack up to 8 degrees. Pressures on the top surface nearest the subsonic edge indicated local expansions beyond values predicted by linearized theory.
Date: January 27, 1949
Creator: Jagger, James M. & Mirels, Harold
Partner: UNT Libraries Government Documents Department

Flight investigation from high subsonic to supersonic speeds to determine the zero-lift drag of a transonic research vehicle having wings of 45 degree sweepback, aspect ratio 4, taper ratio 0.6, and NACA 65A006 airfoil sections

Description: Report presenting rocket-powered flight tests from high subsonic to supersonic speeds and at high Reynolds numbers to determine the zero-lift drag of a transonic wing-body and body-alone configuration. The configuration tested featured a wing of 45 degree sweepback, aspect ratio 4, taper ratio 0.6, and an NACA 65A006 airfoil section, and a body of fineness ratio of 10 and a frontal area equal to 6.06 percent of the wing-plan-form area.
Date: October 27, 1949
Creator: Katz, Ellis
Partner: UNT Libraries Government Documents Department

Investigations of Tumbling Characteristics of a 1/20-Scale Model of the Northrop N-9M Airplane

Description: From Summary: "The tumbling characteristics of a 1/20-scale model of the Northrop N-9M airplane have been determined in the Langley 20-foot free-spinning tunnel for various configurations and loading conditions of the model. The investigation included tests to determine whether recovery from a tumble could be effected by the use of parachutes. An estimation of the forces due to acceleration acting on the pilot during a tumble was made. The tests were performed at an equivalent test altitude of 15,000 feet."
Date: January 27, 1947
Creator: MacDougall, George F., Jr.
Partner: UNT Libraries Government Documents Department

Stick-Fixed Stability and Control Characteristics of the Consolidated Vultee Model 240 Airplane as Estimated from Tests of a 0.092-Scale Powered Model

Description: From Summary: "Estimates of the static stick-fixed stability and control characteristics of the Consolidated Vultee model 240 airplane are presented in this report. The estimates are based on tests of a 0.092-scale powered model in the 10-foot wind tunnel of the Guggenheim Aeronautical Laboratory of the California Institute of Technology. Results of the analysis are evaluated in terms of the Army specifications for stability and control characteristics which are more specific and, in general, equal to or more rigid than the Civil Aeronautics Administration requirements."
Date: June 27, 1947
Creator: McCullough, George B.; Weiberg, James A. & Gault, Donald E.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of a new type of supersonic inlet

Description: A supersonic inlet with supersonic deceleration of the flow entirely outside of the inlet is considered. A particular arrangement with fixed geometry having a central body with a circular annular intake is analyzed, and it is shown theoretically that this arrangement gives high pressure recovery for a large range of Mach number and mass flow and therefore is practical for use on supersonic airplanes and missiles. For some Mach numbers the drag coefficient for this type of inlet is larger than the drag coefficient for the type of inlet with supersonic compression entirely inside, but the pressure recovery is larger for all flight conditions. The differences in drag can be eliminated for the design Mach number. Experimental results confirm the results of the theoretical analysis and show that pressure recoveries of 95 percent for Mach numbers of 1.33 and 1.52, 92 percent for a Mach number of 1.72, and 86 percent for a Mach number oof 2.10 are possible with the configurations considered. If the mass flow decreases, the total drag coefficient increases gradually and the pressure recovery does not change appreciably.
Date: November 27, 1946
Creator: Ferri, Antonio & Nucci, Louis M
Partner: UNT Libraries Government Documents Department

Aerodynamic Characteristics of Four Republic Airfoil Sections from Tests in Langley Two-Dimensional Low-Turbulence Tunnels

Description: Four airfoils sections, designed by the Republic Aviation Corporation for the root and tip sections of the XF-12 airplane, were tested in the Langley two-dimensional low-turbulence tunnels to obtain their aerodynamic characteristics. Lift characteristics were obtained at Reynolds numbers of 3,000,000, 6,000,000, 9,000,000, and 14,000,000, whereas drag characteristics were obtained at Reynolds numbers of 3,000,000, 6,000,000, and 9,000,000. Pressure distributions were obtained for one of the root sections for several angles of attack at a Reynolds number of 2,600,000. Comparison of the root section that appeared best from the tests with the corresponding NACA 65-series section shows the Republic section has a higher maximum lift and higher calculated critical speeds, but a higher minimum drag. In addition, with standard roughness applied to the leading edge, the maximum lift of the Republic airfoil is lower than that of the NACA airfoil. Comparison of the Republic tip section with the corresponding NACA 65-series section shows the Republic airfoil has a lower maximum lift and a higher minimum drag than the NACA airfoil. The calculated critical speeds of the Republic section are slightly higher than those of the NACA section.
Date: September 27, 1945
Creator: Klein, Milton M.
Partner: UNT Libraries Government Documents Department

Bending and shear stresses developed by the instantaneous arrest of the root of a moving cantilever beam

Description: A theoretical and experimental investigation has been made of the behavior of a cantilever beam in transverse motion when its root is suddenly brought to rest. Equations are given for determining the stresses, the deflections, and the accelerations that arise in the beam as a result of the impact. The theoretical equations, which have been confirmed experimentally, reveal that, at a given percentage of the distance from root to tip, the bending stresses for a particular mode are independent of the length of the beam, whereas the shear stresses vary inversely with the length.
Date: September 27, 1944
Creator: Stowell, Elbridge Z.; Schwartz, Edward B. & Houbolt, John C.
Partner: UNT Libraries Government Documents Department

Take-off Stability Characteristics of a 1/13-scale Model of the Consolidated Vultee Skate 7 Seaplane (TED No. NACA DE 338)

Description: The take-off stability characteristics of a Consolidated Vultee Aircraft Corporation Skate 7 seaplane were determined in the Langley tank no. 2. Trim limits of stability, trim tracks, and elevator limits of stability are presented.
Date: April 27, 1949
Creator: McKann, Robert; Coffee, Claude W. & Abrabian, Donald D.
Partner: UNT Libraries Government Documents Department

Effect of Maximum Cruise-Power Operation at Ultra-Lean Mixture and Increased Spark Advance on the Mechanical Condition of Cylinder Components

Description: A continuous 50-hour test was conducted to determine the effect of maximum cruise-power operation at ultra-lean fuel-air mixture and increased spark advance on the mechanical conditions of cylinder components. The test was conducted on a nine-cylinder air-cooled radial engine at the following conditions:brake horsepower, 750; engine speed, 1900 rpm; brake mean effective pressure, 172 pounds per square inch; fuel-air ratio, 0.052; spark advance, 30 deg B.T.C.; and maximum rear-spark-plug-bushing temperature, 400 F. In addition to the data on corrosion and wear, data are presented and briefly discussed on the effect of engine operation at the conditions of this test on economy, knock, preignition, and mixture distribution. Cylinder, piston, and piston-ring wear was small and all cylinder component were in good condition at the conclusion of the 50-hour test except that all exhaust-valve guides were bellmouthed beyond the Army's specified limit and one exhaust-valve face was lightly burned. It is improbable that the light burning in one spot of the valve face would have progressed further because the burn was filled with a hard deposit so that the valve face formed an unbroken seal and the mating seat showed no evidence of burning. The bellmouthing of the exhaust-valve guides is believed to have been a result of the heavy carbon and lead-oxide deposits, which were present on the head end of the guided length of the exhaust-valve stem. Engine operational the conditions of this test was shown to result In a fuel saving of 16.8 percent on a cooled-power basis as compared with operation at the conditions recommended for this engine by the Army Air Forces for the same power.
Date: September 27, 1945
Creator: Harris, Herbert B.; Duffy, Robert T. & Erwin, Robert D., Jr.
Partner: UNT Libraries Government Documents Department

An Investigation of the McDonnell XP-85 Airplane in the Ames 40- by 80-foot Wind Tunnel. Force and Moment Tests

Description: Wind-tunnel tests of the McDonnell XP-85 airplane were conducted to determine its longitudinal, lateral, and directional stability and the characteristics of the aileron, the ruddervator, the leading-edge droop nose flap, and the stall control vanes. The directional stability of the airplane with numerous skyhook modifications and with a ventral fin was also investigated. The results of the tests showed that the effectiveness of the droop nose flaps and the stall control vanes was negligible with regard to either the maximum lift or longitudinal stability of the airplane. Contrary to any previous small-scale results, extension of the skyhook caused a 75-percent reduction in the directional stability of the airplane for both low and high values of lift coefficient. The simplest solution to the problem short of a major redesign of the skyhook appears to be the adoption of a ventral fin.
Date: September 27, 1948
Creator: Hunton, Lynn W. & James, Harry A.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Investigation of a 1/5-Scale Model of the Ryan XF2R Airplane

Description: Wind-tunnel tests on a 1/5-scale model of the Ryan XF2R airplane were conducted to determine the aerodynamic characteristics of the air intake for the front power plant, a General Electric TG-100 gas turbine, and to determine the stability and control characteristics of the airplane. The results indicated low-dynamic-pressure recover3- for the air intake to the TG-100 gas turbine ~rith the standard propeller in operation. Propeller cuffs were designed and tested for the purpose of imp~oving the dynamic-pressure recovery. Data obtained with the cuffs installed and the gap between the spinner an& the cuff sealed indicated a substantial gain in dynamic pressure recovery over that obtained with the standard propeller and with the cuffed propeller unsealed. Stability and control tests were conducted with the sealed cuffs installed on the propeller. The data from these tests indicated the following unsatisfactory characteristics for the airplane: 1. Marginal static longitudinal stability. 2. Inadequate directional stability and control. 3. Rudder-pedal-force reversal in the climb condition. 4. Negative dihedral effect in the power-on approach and wave-off conditions.
Date: June 27, 1947
Creator: Wong, Park Y.
Partner: UNT Libraries Government Documents Department

Calculated Condenser Performance for a Mercury-Turbine Power Plant for Aircraft

Description: As part of an investigation af the application of nuclear energy to various types of power plants for aircraft, calculations have been made to determine the effect of several operating conditions on the performance of condensers for mercury-turbine power plants. The analysis covered 8 range of turbine-outlet pressures from 1 to 200 pounds per square inch absolute, turbine-inlet pressures from 300 to 700 pounds per square inch absolute,and a range of condenser cooling-air pressure drops, airplane flight speeds, and altitudes. The maximum load-carrying capacity (available for the nuclear reactor, working fluid, and cargo) of a mercury-turbine powered aircraft would be about half the gross weight of the airplane at a flight speed of 509 miles per hour and an altitude of 30,000 feet. This maximum is obtained with specific condenser frontal areas of 0.0063 square foot per net thrust horsepower with the condenser in a nacelle and 0.0060 square foot per net thrust horsepower with the condenser submerged in the wings (no external condenser drag) for a turbine-inlet pressure of 500 pounds per square inch absolute, a turbine-outlet pressure of 10 pounds per square inch absolute, and 8 turbine-inlet temperature of 1600 F.
Date: August 27, 1948
Creator: Doyle, Ronald B.
Partner: UNT Libraries Government Documents Department

Measurements of the Lateral and Directional Stability and Control Characteristics of a P-51H Airplane (AAF No. 44-64164)

Description: From Summary: "Flight tests of a P-51H airplane with two different vertical-tail assemblies were made to determine lateral and directional stability and control characteristics. The airplane had satisfactory directional stability in the landing, approach, and wave-off conditions with either tail. In the power-on clean and glide conditions, however, the airplane had weak directional stability with the original tail. The production tail, which had a 7-inch fin extension and a shorter span rudder, improved the directional stability in the power-on clean and glide conditions, but the stability was still weak in the power-on clean condition."
Date: January 27, 1948
Creator: Kraft, Christopher C., Jr. & Reeder, J. P.
Partner: UNT Libraries Government Documents Department

Characteristics of a Hot Jet Discharged from a Jet-Propulsion Engine

Description: From Summary: "An investigation of a heated jet was conducted in conjunction with tests of an axial-flow jet-propulsion engine in the Cleveland altitude wind tunnel. Pressure and temperature surveys were made across the jet 10 and 15 feet behind the jet-nozzle outlet of the engine. Surveys were obtained at pressure altitudes of 10,000, 20,000, 30,000, and 40,000 feet with test-section velocities from 30 to 110 feet per second and test-section temperatures from 60 F to -50 F. From measurements taken throughout the operable range of engine speeds, tail-pipe outlet temperatures from 500 F to 1250 F and jet velocities from 400 to 2200 feet per second were obtained."
Date: December 27, 1946
Creator: Fleming, William A.
Partner: UNT Libraries Government Documents Department

Dynamics of a turbojet engine considered as a quasi-static system

Description: From Summary: "A determination of the dynamic characteristics of a typical turbojet engine with a centrifugal compressor, a sonic-flow turbine-nozzle diaphragm, and fixed area exhaust nozzle is presented. A generalized equation for transient behavior of the engine was developed; this equation was then verified by calculations using compressor and turbine performance charts extrapolated from equilibrium operating data and by experimental data obtained from an engine operated under transients in fuel flow."
Date: July 27, 1949
Creator: Otto, Edward W. & Taylor, Burt L., III
Partner: UNT Libraries Government Documents Department