National Advisory Committee for Aeronautics (NACA) - 38 Matching Results

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Flight and test-stand investigation of high-performance fuels in double-row radial air-cooled engines 1: determination of cooling characteristics of flight engine

Description: Report discussing the cooling characteristics of a 14-cylinder double-row radial air-cooled engine in a four-engine airplane. The effects of charge-air flow, cooling-air pressure drop, and fuel-air ratio on the cooling characteristics were measured separately. The cooling equation, rear middle-barrel temperature, cooling-limited manifold pressure, and maximum cruising power versus temperature-limited power are described.
Date: December 20, 1944
Creator: Blackman, Calvin C.; White, H. Jack & Pragliola, Philip C.
Partner: UNT Libraries Government Documents Department

The effect of modified baffles and auxiliary-cooling ducts on the cooling of a double-row radial engine

Description: Report discussing testing to determine the cooling effect of modified baffles and auxiliary-cooling ducts on the rear-row cylinders of a double-row radial engine. The modified baffles were found to reduce the temperatures of the exhaust-valve seats, but did not have an effect on the valve-guide temperatures. The auxiliary-cooling ducts reduced temperatures of the exhaust-valve seats and rear spark plug gaskets.
Date: March 20, 1945
Creator: Gendler, Stanley L. & Geisenheyner, Robert M.
Partner: UNT Libraries Government Documents Department

Suitability of 18 aromatic amines for overwater storage when blended with aviation gasoline

Description: Report discussing testing of aromatic amines as antiknock additives, and more specifically the suitability of overwater storage for these fuel blends. 12 aromatic amines of three different concentrations at two temperatures were measured. The chemical properties of the most promising fuel blends are described in more detail and correlations were noted.
Date: June 20, 1945
Creator: Goodman, Irving A. & Howard, J. Nelson
Partner: UNT Libraries Government Documents Department

Analysis and modification of theory for impact of seaplanes on water

Description: From Summary: "An analysis of available theory on seaplane impact and a proposed modification thereto are presented. In previous methods the overall momentum of the float and virtual mass has been assumed to remain constant during the impact but the present analysis shows that this assumption is rigorously correct only when the resultant velocity of the float is normal to the keel."
Date: August 20, 1945
Creator: Mayo, Wilbur L.
Partner: UNT Libraries Government Documents Department

Cooling of Gas Turbines, 2, Effectiveness of Rim Cooling of Blades

Description: An analysis of rim cooling, which cools the blade by condition alone, was conducted. Gas temperatures ranged from 1300 degrees to 1900 degrees F and rim temperatures from 0 degrees to 1000 degrees F below gas temperatures. Results show that gas temperature increases up to 200 degrees F are permissible provided that the blades are cooled by 400 degrees to 500 degrees F below the gas temperature. Relatively small amounts of blade cooling, at constant gas temperature, give large increases in blade life. Dependence of rim cooling on heat-transfer coefficient, blade dimensions, and thermal conductivity is determined by a single parameter.
Date: September 20, 1945
Creator: Wolfenstein, Lincoln; Meyer, Gene L. & McCarthy, John S.
Partner: UNT Libraries Government Documents Department

An Analytical Investigation of the Heat Losses from a U.S. Navy K-Type Airship

Description: The heat losses from the envelope surface of a U.S. Navy K-type airship are evaluated to determine if the use of heat is a feasible means of preventing ice and snow accumulations on lighter-than-air craft during flight and when moored uncovered. Consideration is given to heat losses in clear air (no liquid water present in the atmosphere) and in probable conditions of icing and snow. The results of the analysis indicate that the amount of heat required in flight to raise the surface temperature of the entire envelope to the extent considered adequate for ice protection, based on experience with tests of heavier-than-air craft, is very large. Existing types of heating equipment which could be used to supply this quantity of heat would probably be too bulky and heavy to provide a practical flight installation. The heat requirements to provide protection for the nose and stern regions in assumed mild to moderate icing conditions appear to be within the range of the capacity of current types of heating equipment suitable for flight use. The amount of heat necessary to prevent snow accumulations on the upper surface of the airship envelope when moored uncovered under all conditions appear to be excessive for the heating equipment presently available for flight use, but could possibly be achieved with auxiliary ground heating equipment.
Date: December 20, 1946
Creator: Hillendahl, Wesley H. & George, Ralph E.
Partner: UNT Libraries Government Documents Department

Performance of the Modified V-1710-93 Engine-Stage Supercharger with a Constant-Area Vaneless Diffuser

Description: As part of an investigation to increase the power output of the V-1710-93 engine at altitude, the engine-stage supercharger was combined with a constant-area vaneless diffuser designed to improve the performance of the engine-stage supercharger at the rated engine operating point. The performance of the modified supercharger was investigated in a variable-component supercharger test rig and compared with that of the standard supercharger with an 8-vaned diffuser. A separate evaluation of the component efficiencies and a study of the flow characteristics of the modified supercharger was made possible by internal diffuser instrumentation. At the volume flow required by the engine for rated operating conditions, the modified supercharger increased the over-all adiabatic efficiency 0.05 and the over-all pressure coefficient 0.035. Furthermore, the capacity of the engine-stage supercharger was increased by replacing the standard 8-vaned diffuser with the vaneless diffuser. The peak over-all adiabatic efficiency for the modified supercharger, however, was 0.05 to 0.07 lower than that of the standard unit over the range of tip speeds investigated. The improved performance of the modified supercharger at rated engine operating conditions resulted from a shift of the point of peak adiabatic efficiency and pressure coefficient of the standard supercharger to a higher flow. The energy loss through the vaneless diffuser was found to be small. Because of the restricted diffuser diameter, however, diffusion was inadequate, which resulted in a relatively small static-pressure rise through the diffuser, high diffuser-exit velocities, and excessive collector-case losses.
Date: December 20, 1946
Creator: Douglas, John E. & Schwartz, Irving R.
Partner: UNT Libraries Government Documents Department

Effect of Exhaust Pressure on the Cooling Characteristics of a Liquid-Cooled Engine

Description: Data for a liquid-cooled engine with a displacement volume of 1710 cubic inches were analyzed to determine the effect of exhaust pressure on the engine cooling characteristics. The data covered a range of exhaust pressures from 7 to 62 inches of mercury absolute, inlet-manifold pressures from 30 to 50 inches of mercury absolute, engine speeds from 1600 to 3000 rpm, and fuel-air ratios from 0.063 to 0.100. The effect of exhaust pressure on engine cooling was satisfactorily incorporated in the NACA cooling-correlation method as a variation in effective gas temperature with exhaust pressure. Large variations of cylinder-head temperature with exhaust pressure were obtained for operation at constant charge flow. At a constant charge flow of 2 pounds per second (approximately 1000 bhp) and a fuel-air ratio of 0.085, an increase in exhaust pressure from 10 to 60 inches of mercury absolute resulted in an increase of 40 F in average cylinder-head temperature. For operation at constant engine speed and inlet-manifold pressure and variable exhaust pressure (variable charge flow), however, the effect of exhaust pressure on cylinder-head temperature is small. For example, at an inlet-manifold pressure of 40 inches of mercury absolute, an engine speed of 2400 rpm.- and a fuel-air ratio of 0.085, the average cylinder-head temperature was about the same at exhaust pressures of 10 and 60 inches of,mercury absolute; a rise and a subsequent decrease of about 70 occurred between these extremes.
Date: January 20, 1947
Creator: Doyle, Ronald B. & Desmon, Leland G.
Partner: UNT Libraries Government Documents Department

Effects of Induction-System Icing on Aircraft-Engine Operating Characteristics

Description: An investigation was conducted on a multicylinder aircraft engine on a dynamometer stand to determine the effect of induction-system icing on engine operating characteristics and to compare the results with those of a previous laboratory investigation in which only the carburetor and the engine-stage supercharger assembly from the engine were used. The experiments were conducted at simulated glide power, low cruise power, and normal rated power through a range of humidity ratios and air temperatures at approximately sea-level pressure. Induction-system icing was found to occur within approximately the same limits as those established by the previous laboratory investigation after making suitable allowances for the difference in fuel volatility and throttle angles. Rough operation of the engine was experienced when ice caused a marked reduction in the air flow. Photographs of typical ice formations from this investigation indicate close similarity to icing previously observed in the laboratory.
Date: January 20, 1947
Creator: Stevens, Howard C., Jr.
Partner: UNT Libraries Government Documents Department

Flight Investigation of the Effects of Ice on an I-16 Jet-Propulsion Engine

Description: A flight investigation of an I-16 jet propulsion engine installed in the waist compartment of a B-24M airplane was made to determine the effect of induction-system icing on the performance of the engine. Flights were made at inlet-air temperatures of 15 deg, 20 deg., and 25 F, an indicated airspeed of 180 miles per hour, jet-engine speeds of 13,000 and 15,000 rpm, liquid-water contents of approximately 0.3 to 0.5 gram per cubic meter, and an average water droplet size of approximately 50 microns. Under the most severe icing conditions obtained, ice formed on the screen over the front inlet to the compressor and obstructed about 70 percent of the front-inlet area. The thrust was thereby reduced 13.5 percent, the specific fuel consumption increased 17 percent, and the tail-pipe temperature increased 82 F. No icing of the rear compressor-inlet screen was encountered.
Date: January 20, 1947
Creator: Pragliola, Philip C. & Werner, Milton
Partner: UNT Libraries Government Documents Department

Preliminary Tests in the Supersonic Sphere

Description: This report presents preliminary data obtained in the Langley supersonic sphere. The supersonic sphere is essentially a whirling mechanism enclosed in a steel shell which can be filled with either air or Freon gas. The test models for two-dimensional study are of propeller form having the same plan form and diameter but varying only in the airfoil shape and thickness ratio. Torque coefficients for the 16-006, 65-110, and the 15 percent thick ellipse models are presented, as well as pressure distributions on a circular-arc supersonic airfoil section having a maximum thickness of 10 percent chord at the 1/3-chord position. Torque coefficients were measured in both Freon and air on the 15 percent thick ellipse, and the data obtained in air and Freon are found to be in close agreement. The torque coefficients for the three previously mentioned models showed large differences in magnitude at tip Mach numbers above 1, the model with the thickest airfoil section having the largest torque coefficient. Pressure distribution on the previously mentioned circular-arc airfoil section are presented at Mach numbers of 0.69, 1.26, and 1.42. At Mach numbers of 1.26 and 1.42 the test section is in the mixed flow region where both subsonic and supersonic speeds occur on the airfoil. No adequate theory has been developed for this condition of mixed flow, but the experimental data have been compared with values of pressure based on Ackeret's theory. The experimental data obtained at a Mach number of 1.26 on the rear portion of the airfoil section agree fairly well with the values calculated by Ackeret's theory. At a Mach number of 1.42 a larger percentage of the airfoil is in supersonic flow, and the experimental data for the entire airfoil agree fairly well with the values obtained using Ackeret's theory.
Date: January 20, 1947
Creator: Baker, John E.
Partner: UNT Libraries Government Documents Department

Two-Dimensional Wind-Tunnel Investigation of Modified NACA 65(sub 112)-111 Airfoil with 35-Percent-Chord Slotted Flap at Reynolds Numbers up to 25 Million

Description: From Summary: "An investigation has been made in the Langley two-dimensional low-turbulence tunnels to develop the optimum configuration of a .035-chord slotted flap on an NACA 65(sub(112)-111 airfoil section modified by removing the trailing-edge cusp. Included in the investigation were measurements to determine the scale effects on the section lift and drag characteristics of the airfoil with the flap retracted for Reynolds numbers ranging from 3.0 X 10(exp 6) to 2.5 X 10(exp 6). The scale effects on the lift characteristics were also determined for the same Reynolds numbers for the flap deflected in the rotation found to be optimum at a Reynolds number of 9.0 X 10(exp 6)."
Date: January 20, 1947
Creator: Racisz, Stanley F.
Partner: UNT Libraries Government Documents Department

Drag measurements of a 34 degree swept-forward and swept-back NACA 65-009 airfoil of aspect ratio 2.7 as determined by flight tests at supersonic speeds

Description: Report presenting the results of flight testing to determine the zero-lift drag of an NACA 65-009 airfoil at a specified aspect ratio. The results are compared to previous testing of unswept and swept-back arrangements. The swept-forward and swept-back airfoils were found to produce lower values of zero-drag lift than the unswept airfoil.
Date: February 20, 1947
Creator: Alexander, Sidney R.
Partner: UNT Libraries Government Documents Department

Measurements in Flight of the Flying Qualities of a Chance Vought F4U-4 Airplane: TED No. NACA 2388

Description: From Summary: "The results of flight tests to determine flying qualities of a Chance Vought F4U-4 airplane are presented and discussed herein. In addition to comprehensive measurements at low altitude (about 8000 ft), tests of limited scope were made at high altitude (about 25,000 ft)."
Date: March 20, 1947
Creator: Liddell, Charles J., Jr.; Reynolds, Robert M. & Christofferson, Frank E.
Partner: UNT Libraries Government Documents Department

Measurements of the effects of thickness ratio and aspect ratio on the drag of rectangular-plan-form airfoils at transonic speeds

Description: Report presenting testing conducted on two airfoils from a series of rectangular-plan-form airfoils of aspect ratios 7.6 and 5.1 and with NACA 65-006, 65-009, and 65-012 sections using the free-fall method. Results regarding the time histories, ground-velocity data, airfoil drag measurements, and drag coefficients are provided.
Date: June 20, 1947
Creator: Thompson, Jim Rogers & Mathews, Charles W.
Partner: UNT Libraries Government Documents Department

Cooling of gas-turbines 7: effectiveness of air cooling of hollow turbine blades with inserts

Description: Report presenting an analytical investigation to determine primarily the reduction in cooling-air requirement and the increase in effective gas temperature for the same quantity of cooling air resulting from the use of an insert in the cooling-air passage of a hollow air-cooled turbine blade.
Date: October 20, 1947
Creator: Bressman, Joseph R. & Livingood, John N. B.
Partner: UNT Libraries Government Documents Department

Determination of coupled modes and frequencies of swept wings by use of power series

Description: From Summary: "A solution is presented for the coupled modes and frequencies of swept wings mounted on a fuselage. The energy method is used in conjunction with power series to obtain the characteristic equations for both symmetrical and asymmetrical vibration. A numerical example which is susceptible to exact solution is presented, and the results for the exact solution and the solution presented in this paper show excellent agreement."
Date: October 20, 1947
Creator: Anderson, Roger A.
Partner: UNT Libraries Government Documents Department

Effect of a pilot's canopy on the drag of an NACA RM-2 drag research model in flight at transonic and supersonic speeds

Description: Report presenting data from two experiments. One used the NACA RM-2 drag research model equipped with a pilot's canopy to determine the effect on aerodynamics. The other was conducted with the same configuration and returned similar results.
Date: April 20, 1948
Creator: Purser, Paul E.
Partner: UNT Libraries Government Documents Department

Calculated condenser performance for a steam turbine power plant for aircraft

Description: Report presenting calculations to determine the effect of several operating conditions on the performance of condensers for steam-turbine power plants. The analysis covered a range of turbine-inlet pressures and turbine-outlet pressures for various condenser cooling-air pressure drops, flight speeds, and altitudes. Results regarding steam-cycle performance, effect of turbine-outlet pressure on condenser performance, effect of cooling-air pressure drop on condenser performance, effect of turbine-inlet temperature on condenser performance, and power-plant-weight estimates are provided.
Date: May 20, 1948
Creator: Humble, Leroy V. & Doyle, Ronald B.
Partner: UNT Libraries Government Documents Department

Flight test of NACA FR-1-B, a low-acceleration rocket-propelled vehicle for transonic flutter research

Description: Report presenting testing of a low-acceleration transonic flutter test vehicle to obtain flutter data on two similar sweptback wings which indicated that wing flutter was symmetrical in mode. Results regarding flight and flutter characteristics for the FR-1-B are provided.
Date: July 20, 1948
Creator: Angle, Ellwyn E.; Clevenson, Sherman A. & Lundstrom, Reginald R.
Partner: UNT Libraries Government Documents Department

Longitudinal Trim and Tumble Characteristics of a 0.057-Scale Model of the Chance Vought XF7U-1 Airplane, TED NO. NACA DE311

Description: Based on results of longitudinal trim and tumble tests of a 0.057-scale model of the Chance Vought XF7U-1 airplane, the following conclusions regarding the trim and tumble characteristics of the airplane have been drawn: 1. The airplane will not trim at any unusual or uncontrolled angles of attack. 2. The airplane will not tumble with the center of gravity located forward of 24 percent of the mean aerodynamic chord. When the center of gravity is located at 24 percent of the mean aerodynamic chord and slats are extended and elevators are deflected full up, the airplane may tumble if given an external positive pitching moment. 3. The tumbling motion obtained will be readily terminated by deflecting the elevators full down so as to oppose the rotation. 4. The accelerations encountered during an established tumble may be dangerous to the pilot and, therefore, action should be taken to terminate a tumble immediately upon its inception. 5. Simultaneous opening of two wing-tip parachutes having diameters of 4 feet or larger and having drag coefficients of approximately 0.7 will effectively terminate the tumble. 6. Model results indicate that the pilot will not be struck by the airplane if it becomes necessary to leave the airplane during a tumble. The pilot may require aid from an ejection-seat arrangement.
Date: July 20, 1948
Creator: Bryant, Robert L.
Partner: UNT Libraries Government Documents Department