659,957 Matching Results

Search Results

Experimental determination of the lateral stability of a glider towed by a single towline and correlation with an approximate theory

Description: Report presenting an investigation to determine the effects of various design parameters on the lateral-stability characteristics of a glider towed by a single towline. The investigation showed that it is possible to obtain inherent lateral stability with a single towline system.
Date: November 12, 1948
Creator: Maggin, Bernard & Shanks, Robert E.
Partner: UNT Libraries Government Documents Department

Characteristics of Clark Y airfoils of small aspect ratios

Description: This report presents the results of a series of wind tunnel tests showing the force, moment, and autorotational characteristics of Clark Y airfoils having aspect ratios varying from 0.5 to 3. An airfoil of rectangular plan form was tested with rectangular tips, flared tips, and semicircular tips. Tests were also made on one airfoil of circular plan form and two airfoils of elliptical plan form. The tests revealed a marked delay of the stall and a decided increase in values of maximum lift coefficient and maximum resultant force coefficient for aspect ratios of the order of 1 as compared with values for aspect ratios of 2 and 3.
Date: May 5, 1932
Creator: Zimmerman, C. H.
Partner: UNT Libraries Government Documents Department

The measurement of fluctuations of air speed by the hot-wire anemometer

Description: "The hot-wire anemometer suggests itself as a promising method for measuring the fluctuating air velocities found in turbulent flow. The only obstacle is the presence of a lag due to the limited energy input which makes even a fairly small wire incapable of following rapid fluctuations with accuracy. This paper gives the theory of the lag and describes an experimental arrangement for compensating for the lag for frequencies up to 100 or more per second when the amplitude of the fluctuation is not too great. An experimental test of the accuracy of compensation and some results obtained with the apparatus in a wind-tunnel air stream are described. While the apparatus is very bulky in its present form, it is believed possible to develop a more portable arrangement" (p. 359).
Date: January 8, 1929
Creator: Dryden, H. L. & Kuethe, A. M.
Partner: UNT Libraries Government Documents Department

The effect of turbulence on the drag of flat plates

Description: "In determining the effect of turbulence on the forces exerted on bodies in the air stream of a wind tunnel, it is commonly assumed that the indications of the standard Pitot-static tube used to determine the air speed are not dependent on the turbulence. To investigate the truth of this assumption, the drag of a normally exposed flat plate, the difference in pressure between the front and rear of a thin circular disk, the rate of rotation of a vane anemometer, and the pressure developed by a standard Pitot-static tube were measured in an air stream for several conditions of turbulence. The results may be interpreted as indicating that there is no appreciable effect of turbulence on the vane anemometer and the standard pitot-static tube, but that there is small effect on the drag of a flat plate and the pressure difference between front and rear of a disk" (p. 129).
Date: June 22, 1935
Creator: Schubauer, G. B. & Dryden, H. L.
Partner: UNT Libraries Government Documents Department

Impingement of water droplets on wedges and double-wedge airfoils at supersonic speeds

Description: "An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves" (p. 85).
Date: April 21, 1953
Creator: Serafini, John S.
Partner: UNT Libraries Government Documents Department

The effect of the propeller slipstream on the characteristics of submerged inlets

Description: Report presenting a wind-tunnel investigation to determine the effect of propeller operation on the characteristics of submerged inlets. The tests were performed with a model of a hypothetical fighter airplane powered by a turbine-propeller unit. The propeller had eight blades with thin airfoil shanks and dual rotation and the submerged inlets were placed in the fuselage behind the propeller and forward of the wing.
Date: September 9, 1949
Creator: Delany, Noel K.
Partner: UNT Libraries Government Documents Department

Effect of turbulence in wind-tunnel measurements

Description: This paper gives some quantitative measurements of wind tunnel turbulence and its effect on the air resistance of spheres and airship models, measurements made possible by the hot wire anemometer and associated apparatus in its original form was described in Technical Report no. 320 and some modifications are presented in an appendix to the present paper. One important result of the investigation is a curve by means of which measurements of the air resistance of spheres can be interpreted to give the turbulence quantitatively. Another is the definite proof that the discrepancies in the results on the N. P. L. Standard airship models are due mainly to differences in the turbulences of the wind tunnels in which the tests were made.
Date: August 20, 1929
Creator: Dryden, H. L. & Kuethe, A. M.
Partner: UNT Libraries Government Documents Department

A theoretical and experimental study of boric oxide deposition on a surface immersed in an exhaust gas stream from a jet-engine combustor, including a method of calculating deposition rates on surfaces

Description: Report presenting the deposition rate of boric oxide from a stream containing submicron particles, which was found experimentally to fit a molecular diffusion equation. Results regarding boundary-layer studies, deposition studies, deposition tests, and turbojet engine performance are provided.
Date: October 8, 1957
Creator: Setze, Paul C.
Partner: UNT Libraries Government Documents Department

A preliminary study of fuel injection and compression ignition as applied to an aircraft engine cylinder

Description: "This report summarizes some results obtained with a single cylinder test engine at the Langley Field Laboratory during a preliminary investigation of the problem of applying fuel injection and compression ignition to aircraft engines. For this work a standard Liberty Engine cylinder was fitted with a high compression, 11.4 : 1 compression ratio, piston, and equipped with an airless injection system, including a primary fuel pump, an injection pump, and an automatic injection valve. The results obtained during this investigation have indicated the possibility of applying airless injection and compression ignition to a cylinder of this size, 8-inch bore by 7-inch stroke, when operating at engine speeds as high as 1,850 R. P. M." (p. 313).
Date: 1927
Creator: Gardiner, Arthur W.
Partner: UNT Libraries Government Documents Department

The relative performance obtained with several methods of control of an overcompressed engine using gasoline

Description: "This report presents some results obtained during an investigation to determine the relative characteristics for several methods of control of an overcompressed engine using gasoline and operating under sea-level conditions. For this work, a special single cylinder test engine, 5-inch bore by 7-inch stroke, and designed for ready adjustment of compression ratio, valve timing and valve lift while running, was used. This engine has been fully described in NACA-TR-250. Tests were made at an engine speed of 1,400 R. P. M. for compression ratios ranging from 4.0 to 7.6" (p. 329).
Date: February 25, 1927
Creator: Gardiner, Arthur W. & Whedon, William E.
Partner: UNT Libraries Government Documents Department

The N.A.C.A. photographic apparatus for studying fuel sprays from oil engine injection valves and test results from several researches

Description: "Apparatus for recording photographically the start, growth, and cut-off of oil sprays from injection valves has been developed at the Langley Memorial Aeronautical Laboratory. The apparatus consists of a high-tension transformer by means of which a bank of condensers is charged to a high voltage. The controlled discharge of these condensers in sequence, at a rate of several thousand per second, produces electric sparks of sufficient intensity to illuminate the moving spray for photographing. The sprays are injected from various types of valves into a chamber containing gases at pressures up to 600 pounds per square inch" (p. 361).
Date: May 25, 1927
Creator: Beardsley, Edward G.
Partner: UNT Libraries Government Documents Department

Static-pressure error calibrations for nose-boom airspeed installations of 17 airplanes

Description: Report presenting a flight investigation to determine the static-pressure errors for nose-boom airspeed installations of 17 airplanes. Both research-type and service-type aircraft are covered in the investigation. Results indicated that the magnitude of static-pressure errors for the airspeed installations of all the airplanes is shown to vary with airplane geometric characteristics that include nose-boom length, fuselage diameter, and nose fineness ratio.
Date: March 13, 1957
Creator: Larson, Terry J.; Stillwell, Wendell H. & Armistead, Katharine H.
Partner: UNT Libraries Government Documents Department

The influence of inlet air temperature and jacket water temperature on initiating combustion in a high speed compression ignition engine

Description: Report presenting some tests to determine the influence on initiating combustion in a one-cylinder compression ignition engine of inlet air temperature and jacket water temperature. The results show that the engine is very sensitive to changes in final compression pressure, induced by a change in the initial compression pressure, and that some way of providing compensating means for conditions that tend to lower section pressure is necessary.
Date: March 1924
Creator: Matthews, Robertson & Gardiner, Arthur W.
Partner: UNT Libraries Government Documents Department

Analog computer study of some filtering, command-computer, and automatic-pilot problems connected with the attack phase of the automatically controlled supersonic interceptor

Description: From Summary: "Presented herein are the results of a study of some of the problems associated with the cross-roll filter, command computer, and g-limiter of an automatic interceptor system."
Date: October 3, 1957
Creator: Sherman, Windsor L.
Partner: UNT Libraries Government Documents Department

Performance evaluation of reduced-chord rotor blading as applied to J73 two-stage turbine 5: effect of inlet pressure on over-all performance at design speed and inlet temperature of 700 degrees R

Description: Report presenting an investigation of a reduced-chord multistage turbine at design speed and various turbine-inlet pressures from 12 to 40 inches of mercury absolute. At each inlet pressure, the turbine was operated over a range of overall turbine total-pressure ratios; turbine-inlet temperature was maintained at 700 degrees R. The results indicated that no appreciable effect on turbine overall performance was observed over the range of turbine-inlet total pressures investigated.
Date: July 5, 1957
Creator: Schum, Harold J.
Partner: UNT Libraries Government Documents Department

An investigation at low speed of a 51.3 degrees sweptback semispan wing with a raked tip and with 16.7-percent-chord ailerons having three spans and three trailing-edge angles

Description: Report presenting a wind-tunnel investigation at low speed to determine the aerodynamic characteristics of a 51.3 degree sweptback semispan wing with a raked tip and with 16.7-percent-chord sealed plain ailerons. Lift, drag, pitching-moment, and hinge-moment data were obtained for the wing with transition free and fixed with various spans of aileron deflected as lift flaps. The rolling moment, yawing moment, hinge moment, and aileron seal pressure characteristics were determined for each of the nine possible aileron-span and trailing-edge-angle combinations tested.
Date: July 21, 1948
Creator: Fischel, Jack & Schneiter, Leslie E.
Partner: UNT Libraries Government Documents Department

An investigation at low speed of a 51.3 degree sweptback semispan wing equipped with 16.7-percent-chord plain flaps and ailerons having various spans and three trailing-edge angles

Description: Report presenting a wind-tunnel investigation performed at low speed to determine the aerodynamic characteristics of a 51.3 degree sweptback semispan wing equipped with 16.7-percent-chord plain flaps and ailerons with various spans and spanwise locations and one with span of aileron with trailing-edge angles of 6, 14, and 25 degrees. Results regarding the wing aerodynamic characteristics, aileron-control characteristics, spoiler control characteristics, and effect of wing-tip shape are provided.
Date: November 12, 1948
Creator: Fischel, Jack & Schneiter, Leslie E.
Partner: UNT Libraries Government Documents Department

The comparative performance of an aviation engine at normal and high inlet air temperatures

Description: "This report presents some results obtained during an investigation to determine the effect of high inlet air temperature on the performance of a Liberty 12 aviation engine. The purpose of this investigation was to ascertain, for normal service carburetor adjustments and a fixed ignition advance, the relation between power and temperature for the range of carburetor air temperatures that may be encountered when supercharging to sea level pressure at altitudes of over 20,000 feet and without intercooling when using plain aviation gasoline and mixtures of benzol and gasoline" (p. 409).
Date: February 11, 1927
Creator: Gardiner, Arthur W. & Schey, Oscar W.
Partner: UNT Libraries Government Documents Department

Spray penetration with a simple fuel injection nozzle

Description: The purpose of the tests covered by this report was to obtain specific information on the rate of penetration of the spray from a simple injection nozzle, having a single orifice with a diameter of 0.015 inch when injecting into compressed gases. The results have shown that the effects of both chamber and fuel pressures on penetration are so marked that the study of sprays by means of high-speed photography or its equivalent is necessary if the effects are to be appreciated sufficiently to enable rational analysis. It was found for these tests that the negative acceleration of the spray tip is approximately proportional to the 1.5 power of the instantaneous velocity of the spray tip.
Date: 1926
Creator: Miller, Harold E. & Beardsley, Edward G.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of short two-dimensional subsonic diffusers

Description: Report presenting several short two-dimensional subsonic diffusers over a range of throat Mach numbers from 0.3 to 0.9. The designs incorporated an effective diffusion angle of approximately 30 degrees and an area ratio of 3. At a throat Mach number of 0.7, the resulting profile distortion of the unmodified 30 degree diffuser was diminished from about 11 to approximately 4 percent by using any of the configurations.
Date: May 25, 1956
Creator: Woollett, Richard R.
Partner: UNT Libraries Government Documents Department

Thermodynamic study of a Roots compressor as a source of high-temperature air

Description: Report presenting an analysis to ascertain the feasibility of using the device to produce high-temperature air. The production of high temperature is associated with the leakage of the hot outlet air through the tip clearance to the inlet and the subsequent mixing with the supply air. The calculated performance of the unit is very sensitive to the assumed value of Stanton number.
Date: June 1957
Creator: Cohen, Clarence B.; Woollett, Richard R. & Weston, Kenneth C.
Partner: UNT Libraries Government Documents Department

Comparison of experimental with theoretical total-pressure loss in parallel-walled turbojet combustors

Description: "An experimental investigation of combustor total-pressure loss was undertaken to confirm previous theoretical analyses of effects of geometric and flow variables and of heat addition. The results indicate that a reasonable estimate of cold-flow total-pressure-loss coefficient may be obtained from the theoretical analyses. Calculated total-pressure loss due to heat addition agreed with experimental data only when there was no flame ejection from the liner at the upstream air-entry holes" (p. 1).
Date: January 9, 1957
Creator: Dittrich, Ralph T.
Partner: UNT Libraries Government Documents Department

Discharge coefficients for combustor-liner air-entry holes 2: flush rectangular holes, step louvers, and scoops

Description: Experimental discharge coefficients for various types of combustor-liner air-entry holes are presented as a function of a dimensionless flow parameter. In general, scoops and step louvers have higher discharge coefficients and wider flow ranges than flush holes. The effects of size or shape of a given type of hole are small. The proximity of multiple flush holes or the wall inclination of a convergent duct has a negligible effect on discharge coefficient.
Date: April 1958
Creator: Dittrich, Ralph T.
Partner: UNT Libraries Government Documents Department

Investigation of low-pressure performance of experimental tubular combustors differing in air-entry-hole geometry

Description: Report presenting an investigation to determine, by experiments within the scope of air-entry-hole geometry, design criteria for tubular combustors with good low-pressure performance. Combustion efficiency, operable fuel-air-ratio and pressure ranges, and minimum ignition pressures were determined for several combustor configurations at conditions simulating a 5.2-pressure-ratio turbojet engine operating at 85 percent of rated rotor speed, a flight Mach number of 0.6, and altitudes from 56,000 to 80,000 feet.
Date: September 4, 1953
Creator: Dittrich, Ralph T.
Partner: UNT Libraries Government Documents Department