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

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

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

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

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

The Effect of High Solidity on Propeller Characteristics at High Forward Speeds from Wind-Tunnel Tests of the NACA 4-(3)(06.3)-06 and NACA 4-(3)(06.4)-09 Two-Blade Propellers

Description: Tests of two-blade propellers having the NACA 4-(3)(06.3)-06 and NACA 4-(3)(06.4)-09 blade designs (blade activity factors of 179 and 263, respectively) have been made in the Langley 8-foot high-speed tunnel through a range of blade angle from 20 degrees to 70 degrees for free-stream Mach numbers from 0.165 to 0.725 to determine the effects of high solidity and compressibility on propeller characteristics. The tests are part of a general investigation of propellers at high forward speeds. Results previously reported for similar tests of two-blade propellers having the NACA 4-308-03 and NACA 4-308-045 blade designs (blade activity factors of 87 and 133, respectively) are included for comparison. The results showed that the 0.06- and 0.09-solidity blades, although producing efficiencies of the order of 90 percent, were less efficient than blades of conventional solidity. The variation in average blade lift coefficient with solidity at a constant blade angle and advance-diameter ratio through the speed range of these tests was found to be analogous to the variation of wing lift coefficient with aspect ratio, indicating that high-solidity blades may be desirable at very high speeds. Because of power limitations of the test equipment, conclusive evidence of the possible favorable effects of increased blade solidity at high speeds was not obtained. Further tests are desirable.
Date: February 27, 1947
Creator: Delano, James B.
Partner: UNT Libraries Government Documents Department

Theoretical Comparison of Several Methods of Thrust Augmentation for Turbojet Engines

Description: A theoretical investigation has been made of various methods of thrust augmentation for turbojet engines. The method investigated were tail-pipe burning, water injection at the compressor inlet, a combination of tail-pipe burning and water injection, bleedoff in conjunction with water injection at the compressor inlet, and rocket assist. The effect of ratio of augmented-to-normal total liquid consumption, flight conditions, and design compressor pressure ratio on the augmentation produced by each method were determined. A comparison was also made for a given time of operation of the weight of an augmented engine plus fuel and additional liquids to the weight of a standard engine plus fuel producing the same thrust.
Date: October 27, 1948
Creator: Hall, Eldon W. & Wilcox, E. Clinton
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

Lateral Stability Characteristics of a 1/8.33-Scale Powered Model of the Republic XF-12 Airplane

Description: The XF-12 airplane is a high-performance photo-reconnaissance aircraft designed for the Army Air Forces by the Republic Aviation Corporation. An investigation of a 1/8.33 - scale powered model was made in the Langley l9-foot pressure tunnel to obtain information relative to the aerodynamic design of the airplane. The model was tested with and without the original vertical tail. and with two revised tails. For the revised tail no. 1, the span of the original vertical .tail was increased about 15 percent and the portion of the vertical tail between the stabilizer and fuselage behind the rudder hinge line was allowed to deflect simultaneously with the main rudder. Revision no. 2 incorporated the increased span, but the lower rudder was locked in the neutral position. For all the tail arrangements investigated it was indicated that the airplane will possess positive effective dihedral and will be directionally stable regardless of flap or power condition. The rudder effectiveness is greater for the revised tails than for the original tail, but this is offset by the increase in directional stability caused by the revised tail. All the rudder arrangements appear inadequate in trimming out the resultant yawing moments at zero yaw in a take - off condition with the left-hand outboard propeller windmilling and the remaining engines developing take-off power.
Date: February 27, 1947
Creator: Pepper, Edward & Foster, Gerald V.
Partner: UNT Libraries Government Documents Department

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

Description: 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. The jet-survey data presented extend the work previously done with low-velocity and low-temperature jets to the region of high velocities and high temperatures. The results obtained agree with previously determined experimental data and with predicted theoretical expressions for the dimensionless transverse velocity and temperature profiles across a jet. The spread of both the temperature and the velocity profiles was very nearly linear. Dimensionless plots of temperature and velocity along the axis of a heated jet agree with experimental results of tests with a cold jet.
Date: December 27, 1946
Creator: Fleming, William A.
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

F-3 and F-4 engine tests of several high-antiknock components of aviation fuel

Description: Report discussing testing on triptane, hot-acid octane, diisopropyl, neohexane, mixed xylenes, cumene, benzene, toluene, and methyl tert-butyl ether in several blends to determine their knock-limited performance data in F-3 and F-4 engines at standard operating conditions. All of the blending agents examined were found to be usable, with concentrations varying depending on various thermodynamic properties.
Date: November 27, 1944
Creator: Imming, Harry S.; Barnett, Henry C. & Genco, Russell S.
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

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

Method of estimating the minimum size of a tail or wing-tip parachute for emergency spin recovery of an airplane

Description: Report presenting a method for estimating the size of a tail or wing-tip parachute required for satisfactory emergency recovery of airplanes during spin demonstrations. A comparison of the parachute sizes estimated by the method versus information obtained during experimentation indicated satisfactory agreement. Information about the calculations for a conventional and a tailless airplane is provided.
Date: October 27, 1948
Creator: Malvestuto, Frank S., Jr.
Partner: UNT Libraries Government Documents Department