Memorandum presenting a study of an acceleration-limiting control on a turbojet engine in order to determine its feasibility as an acceleration control. A proportional-plus-integral type of controller was used in the investigation. Results regarding the one-loop control and two-loop control are provided.
Memorandum presenting an acceleration-limiting control used on a turbojet engine to study the feasibility of its use as an acceleration control. A proportional-plus-integral type of controller was used in this investigation. Results regarding one-loop control and two-loop control are provided.
The adhesive and protective characteristics of National Bureau of Standards Coating A-417 were investigated, as well as the effect of the coating on the life of forged Refractaloy 26 and cast Stellite 21 turbine blades. Coated and uncoated blades were run in a full-scale J33-9 engine and were subjected to simulated service operations consisting of consecutive 20-minute cycles (15 min at rated speed and approximately 5 min at idle). The ceramic coating adhered well to Refractaloy 26 and Stellite 21 turbine blades operated at 1500 degrees F. The coating also prevented corrosion of the Refractaloy 26, a corrosion-sensitive nickel-base alloy, and of the Stellite 21, a relatively corrosion-resistant cobalt-base alloy. Although the coating prevented corrosion of both alloys, it had no apparent effect on blade life.
Report presenting an investigation to determine the aerodynamic characteristics of a cruciform 70 degree delta-wing missile configuration with 70 degree delta canard control surfaces at M = 1.41 in the 4- by 4-foot supersonic pressure tunnel. Modifications to the configuration included variation of the body length and canard area and the substitution of a series of very small span wings for the cruciform delta wings and canard controls.
Report presenting an analysis of the force distribution on a slender pointed body of revolution at angle of attack utilizing pressure-distribution data and balance measurements. The data were obtained in the supersonic tunnel at a variety of Mach numbers and angles of attack. Results regarding normal forces and axial force are provided.
Report presenting an investigation at two Mach numbers to examine the flow, force, and moment characteristics associated with spoilers mounted on a flat plate at a range of sweep angles. Pressure measurements were obtained over the plate and spoiler faces. The pressures were integrated to determine the spoiler lift, pitching-moment, drag, and hinge-moment characteristics.
From Introduction: "The data obtained for each configuration are presented in a manner to show the effects of fuel distribution and flame-holder design on net thrust, specific fuel consumption, exhaust-gas temperature, combustion efficiency, operable range of tail-pipe-burner fuel-air ratios, and maximum altitude limit."
From Introduction: "The investigation reported herein, which was conducted in an NACA Lewis altitude test chamber, covered a range of altitudes from 30,000 to 50,000 feet at a flight Mach number of 0.8."
From Introduction: "Reported herein are the over-all engine performance and the starting and windmilling characteristics. Data are presented in the form of performance maps at each flight condition to show the effects of altitude and flight Mach number on various engine-performance variables. The effect of engine deterioration with operating time on performance is also discussed."
From Introduction: "The purpose of the present report is to present a comprehensive summary of theoretical investigations of comprehensible laminar boundary layers which have been carried out since 1949 at the Polytechnic Institute of Brooklyn under the sponsorship and with the financial assistance of the National Advisory Committee for Aeronautics. The results of these investigations are contained primarily in references 1 to 7."
"With the use of Karman's integrated momentum equation for the boundary layer and data on the wall-shearing stress and heat transfer in forced-convection flow, a calculation was carried out for the flow and heat transfer in the turbulent free-convection boundary layer on a vertical flat plate. The calculation is for a fluid with a Prandtl number that is close to 1. A formula was derived for the heat-transfer coefficient that was in good agreement with experimental data in the range of Grashof numbers from 10sup10 to 10sup12" (p. 1).
From Introduction: "This report extends the short-bearing pressure-distribution function of Michell and Cardullo to give equations for the various bearing characteristics. This short-bearing approximation makes available formulas relating eccentricity ratio to applied load, attitude angle, angular position of peak film pressure to unit pressure on projected area."
From Introduction: "An extension of the work presented in reference 2, the method was applied to six swept-wing airplanes for which the pilot opinion was well documented. The analytical results obtained are used herein to illustrate how wind-tunnel data may be used to predict the pitching motions and the comparative pitch-up behavior of new airplane designs or to assess the effects of modifications on existing airplanes."
An investigation was conducted to determine the behavior of recently produced, forged S-816 turbine blades in a full-scale turbojet engine, and in particular, the scatter in performance of the alloy. The turbine blades were operated as continuously as possible at a temperature of 1500 degrees F and a centrifugal stress of 21,500 pounds per square inch. The operating lives of the turbine blades varied from 181 to 539 hours, a range of 358 hours. Stress-rupture properties of specimens cut from blade airfoils also varied considerably, as much as 1257 hours at 20,000 pounds per square inch and 1500 degrees F. Since the variability of scatter of stress-rupture data is greater than that of blade performance, the scatter is probably caused by variations in the properties of the forged blades rather than by variations caused by engine operation or installation of the blades. Metallographic examinations were made to determine possible causes of the scatter and although numerous differences in microstructures of blades were found, no consistent tendencies were observed and the findings did not permit an explanation of the scatter of blade performance. The results of the metallographic examinations and of the physical tests indirectly indicated variables in the fabricating method caused the scatter in properties.
From Summary: "Tests and calibrations of an AWS instrument shelter were made in the Langley 300 MPH 7- by 10-foot tunnel for the Signal Corps, U.S. Army. The behavior of the wind vane, the 3-cup anemometer, and the shelter cover was determined in wind speeds up to 150 miles per hour. It was discovered that the rotational speed of the anenometer was greatly influenced by the location, with respect to the wind direction, of three spacer posts that held two upper bays of instruments above the anenometer."
"A general method has been developed for calibrating strain-gage installations in aircraft structures, which permits the measurement in flight of the shear or lift, the bending moment, and the torque or pitching moment on the principal lifting or control surfaces. Although the stress in structural members may not be a simple function of the three loads of interest, a straightforward procedure is given for numerically combining the outputs of several bridges in such a way that the loads may be obtained. Extensions of the basic procedure by means of electrical combination of the strain-gage bridges are described which permit compromises between strain-gage installation time, availability of recording instruments, and data reduction time" (p. 1).
Report presenting an experimental investigation of the cooling characteristics of a small air-cooled turbine blade for use in a turboprop engine in a static cascade facility. Three test blades of the same size and chord were tested at several different combustion-gas temperatures. Results regarding the gas-flow conditions in cascade test section, correlation of temperature data and application of correlated data to typical engine are provided.
Memorandum presenting an experimental investigation of the cooling characteristics of a small air-cooled turbine blade for use in a turboprop engine in a static cascade facility. Three test blades were studiued at three combustion-gas temperatures. Results regarding gas-flow conditions in cascade test section, correlation of temperature data, and application of correlated data to the typical engine are provided.
Report presenting a wind-tunnel investigation of two semispan wing models with 45 degrees of sweepback, an aspect ratio of 5, and a taper ratio of 0.565. One wing had no camber or twist while the other was cambered for a design lift coefficient of 0.4 and twisted to relieve loading at the tip. Results regarding the plane wing, cambered and twisted wing, wing-body combinations, effect of camber and twist, effect of fences, effect of surface roughness, and lift-drag ratio are provided.
Report presenting testing of three scale models and a full-scale configuration of systems for ducting cooling air through a turbojet engine tail cone to a cooled turbine rotor in order to determine pressure-loss characteristics.
A comparison is made of free-molecule-flow theory with the results of wind-tunnel tests performed to determine the drag and temperature-rise characteristics of a transverse circular cylinder. The measured values of the cylinder center-point temperature confirmed the salient point of the heat-transfer analysis which was the prediction that an insulated cylinder would attain a temperature higher than the stagnation temperature of the stream. Good agreement was obtained between the theoretical and the experimental values for the drag coefficient.
Report presenting a survey of various types of catapults in connection with the problem of accelerating a large car along a track to a speed of 150 miles per hour. A hydraulic jet catapult seems to be the best-suited for the purpose, and various types of design problems are examined.
"Strain-gages were used to measure blade vibrations causing failures in the third stage of a production 11-stage axial-flow compressor. After the serious third-stage vibration was detected, a series of investigations were conducted with second-stage vane assemblies of varying angles of incidence. Curves presented herein show the effect of varying the angle of incidence of second-stage vane assembly on third-stage rotor-blade vibration amplitude and engine performance" (p. 1).
Report presenting zero-lift drag data for a flare-stabilized bluff body of fineness ratio 4.4 alone and with conical and flat windshields at a range of Mach and Reynolds numbers. The model with the flat windshield was found to have the lowest drag at Mach numbers up to 1.05, but there was little difference in drag among the models above 1.05.
Report presenting an investigation into the effect of end plates and end-mounted struts on the lift-drag ratios of a hydrofoil at several speeds and Reynolds numbers that were all above the limiting speed of wave propagation. Information about the lift-drag ratio, effective aspect ratio, and comparison of the results versus theoretical calculations is included.
Report presenting an investigation to determine the effect of frequency of sideslipping motion on the lateral stability derivatives of a 60-degree delta-wing airplane configuration. Results regarding the steady-state tests, oscillation-in-sidestep tests, comparison of oscillation data for delta wings with a round edge versus a sharp edge, and effect of sideslip oscillatory derivatives are provided.
Memorandum presenting an investigation to study the effect of ground proximity on the aerodynamic characteristics of two jet vertical-take-off-and-landing airplane models in which the fuselage remains in a horizontal attitude for the take-off and landing. Results regarding the flow surveys and force tests are provided.
Memorandum presenting a determination of the effect of nose shape on the normal-force, pitching-moment, and axial-force coefficients of a body of revolution with a fineness ratio of 10.94 as determined at subsonic speeds. Six nose shapes were investigated, which included flat-faced noses with various corner radii, a hemispherical nose, and two ogival noses.
Memorandum presenting an investigation in the 7- by 10-foot tunnel to determine the effect of wing-root leading-edge and scoop-type jet-engine air-inlet configurations on the static longitudinal stability characteristics and the duct-flow characteristics of a scale model of the MX-1764 airplane. The addition of the inlet configurations to the model generally resulted in slight reductions in longitudinal stability and increases of maximum lift coefficient.
Report presenting an investigation in the 300 mph 7- by 10-foot tunnel to determine the effect of wing-root leading-edge and scoop-type jet-engine air-inlet configurations on the static longitudinal stability characteristics and the duct-flow characteristics of a model of the MX-1764 airplane. The inlet configurations generally resulted in slight reductions in longitudinal stability and increases of maximum lift coefficient.
A longitudinal stability and control characteristics of a Boeing B-29 airplane have been measured with a booster incorporated in the elevator-control system. Tests were made to determine the effects on the handling qualities of the test airplane of variations in the pilot's control-force gradients as well as the effects of variations in the maximum rate of control motion supplied by the booster. The results of the control-rate investigation indicate that large airplanes may have satisfactory handling qualities with the booster adjusted to give much lower rates of control motion than those normally used by pilots.
Report presenting the results of an investigation to determine the effects of a small jet of air exhausting from the nose of an elliptical body of revolution upon boundary-layer transition and the viscous, pressure, and total drag of the forebody at three body stations at Mach number 1.62. The jet effects on body pressure, pressure variations, boundary-layer transition, and total drag are provided.
Report presenting an investigation of three phases: an experimental investigation of a thin airfoil with blowing over a trailing-edge flap, a comparison of the results of the experimental investigation with the results of other similar investigations, and a theoretical study of the relationships among the air-flow and power parameters for the general blowing case. The investigation utilized a two-dimensional model of the NACA 0006 airfoil equipped with a nose flap and six alternate trailing-edge flaps.
The magnitude and the effects of boundary-layer separation on normal-force-curve slopes, centers of pressure, pressure distributions, and lift and drag coefficients were determined for various bodies of revolution with conical tail flares at Mach numbers from 3.0 to 6.3. Some of the experimental results are compared to theoretical predictions of the aerodynamic characteristics of the bodies.
Report presenting an experimental investigation in a simulated afterburner test rig to determine the effects of some configuration variations on afterburner combustion performance. Results regarding the reduced-diameter flameholder, inclined radial-gutter flameholder, tapered-shell afterburner, and turbulence generators are provided.
Memorandum presenting an experimental investigation conducted in a 25.75-inch-diameter simulated-afterburner test rig to determine the effects of some configuration variations on afterburner combustion performance. The variations included a V-gutter flameholder with the maximum gutter-ring diameter reduced from 20 to 17 inches, but with equal projected blockage; an inclined radial-gutter flameholder; a tapered-shell afterburner; and a V-gutter flameholder with turbulence generators added.
Tests have been made in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 2.01 to determine the effects of the addition of four small fuselage-mounted cruciform fins on the directional characteristics of a 45 deg swept-wing airplane model at angles of attack up to 15.3 deg and angles of sideslip up to about 16 deg. The results showed that the addition of the four cruciform fins to the model increased the directional stability substantially at the highest angle of attack and, at the same time, caused relatively small changes in drag.
Report presenting an investigation to determine the static characteristics of a two-blade NACA 10-(3)(062)-045 propeller. Experimental data were obtained for a blade-angle range from -5 degrees to 40 degrees measured at the 0.75 radial station and for tip Mach numbers up to 1.0.
Memorandum presenting a determination of the static lateral stability of six delta wings at subsonic speeds. In addition, two of the wings with 82.5 degree and 75 degree sweep of the leading edge were oscillated in yaw about the 50-percent point of the root chord in order to determine the effects of frequency and amplitude on the combination lateral stability derivatives resulting from the motion. Results regarding the static characteristics and oscillatory characteristics are provided.
Memorandum presenting a thermodynamic method of determining the work input to a centrifugal compressor operating with water injection. The method was used to compute the work input to a double-entry centrifugal compressor, which was operated at a design equivalent impeller speed over a range of inlet-water ratios and varying weight flow.
Memorandum presenting oscillatory hinge-moment characteristics obtained from free-flight tests of two rocket-powered models equipped with a 60 degree sweptback clipped delta wing featuring an unbalanced, constant-chord, full-span trailing-edge control. One aircraft had a control with a sharp trailing edge, and the other had a trailing-edge thickness equal to 1/2 the thickness at the hinge line. Results regarding control pulsing systems, control damping, and control restoring moments are provided.
"An experimental investigation was conducted to determine the cooling effectiveness of a wide variety of air-cooled turbine-blade configurations. The blades, which were tested in the turbine of a - commercial turbojet engine that was modified for this investigation by replacing two of the original blades with air-cooled blades located diametrically opposite each other, are untwisted, have no aerodynamic taper, and have essentially the same external profile. The cooling-passage configuration is different for each blade, however" (p. 1).
"An experimental investigation of a 0.8 hub-tip radius ratio, nontwisted-rotor-blade turbine designed for a stagnation-pressure ratio of 2.5 and an equivalent mean blade speed of 643 feet per second was made in a cold-air turbine with (a) nontwisted stator blades, and (b) twisted stator blades designed to maintain zero rotor-inlet incidence angles. Turbine efficiencies of the order of 0.85 at the design point were obtained with a nontwisted-rotor-blade turbine with a hub-tip radius ratio of 0.80. The turbine with the twisted stator blades gave higher efficiencies at the design point (of the order of 1.5 percentage points) than the turbine with the nontwisted stator blades" (p. 1).
The flow fields near a 45 degree swept-wing-fuselage combination at moderate angles of sideslip (plus-or-minus 8 degrees), as determined experimentally at low speed, are presented as variations with chordwise distance for various spanwise and vertical locations and angles of attack. The results indicated that for positions close to the fuselage (on and near the plane of symmetry) changes in the angle of sideslip caused large changes in the flow-field characteristics and particularly in the local angles of sideslip, which in some cases were nearly double the static angle of sideslip.
Report presenting an investigation in the flutter research tunnel to determine the oscillating forces and moments on a two-dimensional wing equipped with an oscillating circular-arc spoiler. The study indicated that force and moment coefficients and their phase angles are affected by Reynolds number, Mach number, and reduced frequency.
Report presenting a small-scale apparatus for simulating the motion and heating of ballistic missiles and its elements of design and operation. Experiments demonstrate that conditions for simulation are fulfilled according to theoretical requirements. Results regarding the application to full-scale missiles, shadowgraph observations, observations of recovered models, and spectroscopic observations are provided.
Memorandum presenting an investigation of the effect of skewed plain nose flaps on a thin, low-aspect-ratio triangular wing in combination with a high fineness-ratio fuselage conducted at low speeds and high Reynolds numbers. The plan form of the flaps was such that the flap chord varied from zero percent of the wing chord at the model center line to 100 percent at about 91-percent wing semispan. The results indicated that the nose flaps provided a significant delay in the occurrence of both the leading-edge type of separation and tip stalling.
"A general matrix method is developed for the solution of characteristic-value problems of the type arising in many physical applications. The scheme employed is essentially that of Gauss and Seidel with appropriate modifications needed to make it applicable to characteristic-value problems. An iterative procedure produces a sequence of estimates to the answer; and extrapolation techniques, based upon previous behavior of iterants, are utilized in speeding convergence. Theoretically sound limits are placed on the magnitude of the extrapolation that may be tolerated" (p. 747).
Report presenting an investigation of the section and panel characteristics and loads obtained from pressure measurements over a 35 degree sweptback wing at level-flight lifts for a range of Mach numbers. Section pressure distributions were taken at the root, midspan, and tip stations of a Douglas D-558-II airplane.
This report presents the results of flight measurements of longitudinal stability and control characteristics made on a swept-wing jet aircraft to determine the origin of the pitch-up encountered in maneuvering flight at transonic speeds. For this purpose measurements were made of elevator angle, tail angle of attack, and wing-fuselage pitching moments (obtained from measurements of the balancing tail loads).
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