Search Results

Effect of Inlet-Guide-Vane Angle on Blade Vibration and Rotating Stall of 13-Stage Axial-Flow Compressor in Turbojet Engine
Report presenting a blade-vibration and rotating-stall survey on a modified version of a production turbojet engine with a 13-stage axial-flow compressor with a design pressure ratio of 7 and an air flow of 120 pounds per second. This testing was carried out due to the problems rotating stall can cause with both experimental and production axial-flow compressors. Results regarding the rotating-stall patterns, rotor-blade vibrations, radial and axial strength of rotating stall, and maximum rotating-stall speed are provided.
Flight investigation of pentaborane fuel in 9.75-inch-diameter ram-jet engine with downstream fuel injection
Report presenting a flight test of pentaborane fuel in an air-launched ramjet engine with a design free-stream Mach number of 1.8. The ramjet used in the investigation had a revised spray bar-flameholder configuration. Results regarding propulsive thrust and propulsive-thrust specific fuel consumption are provided.
Calculations of Laminar Heat Transfer Around Cylinders of Arbitrary Cross Section and Transpiration-Cooled Walls With Application to Turbine Blade Cooling
"An approximate method for the development of flow and thermal boundary layers in the laminar region on cylinders with arbitrary cross section and transpiration-cooled walls is obtained by the use of Karman's integrated momentum equation and an analogous heat-flow equation. Incompressible flow with constant property values throughout the boundary layer is assumed. The velocity and temperature profiles within the boundary layer are approximated by expressions composed of trigonometric functions" (p. 339).
Axially Symmetric Shapes With Minimum Wave Drag
"The external wave drag of bodies of revolution moving at supersonic speeds can be expressed either in terms of the geometry of the body, or in terms of the body-simulating axial source distribution. For purposes of deriving optimum bodies under various given conditions, it is found that the second of the methods mentioned is the more tractable. By use of a quasi-cylindrical theory, that is, the boundary conditions are applied on the surface of a cylinder rather than on the body itself, the variational problems of the optimum bodies having prescribed volume or caliber are solved" (p. 131).
Combustion of gaseous hydrogen at low pressures in a 35 degree sector of a 28-inch-diameter ramjet combustor
Report presenting testing of gaseous hydrogen fuel burned in a connected-pipe combustor with a cross section equal to 35 degrees sector of a 28-inch diameter. Eleven shrouded fuel-injector configurations were used to obtain combustion data at specified high-altitude ramjet combustor conditions. Results regarding shroud air blockage, mixing tabs, higher equivalence-ratio burning, injector size, flameholder durability, burner length, combustion efficiency, and temperature profile are provided.
Comparison of Several Methods of Cyclic De-Icing of a Gas-Heated Airfoil
"Several methods of cyclic de-icing of a gas-heated airfoil were investigated to determine ice-removal characteristics and heating requirements. The cyclic de-icing system with a spanwise ice-free parting strip in the stagnation region and a constant-temperature gas-supply duct gave the quickest and most reliable ice removal. Heating requirements for the several methods of cyclic de-icing are compared, and the savings over continuous ice prevention are shown. Data are presented to show the relation of surface temperature, rate of surface heating, and heating time to the removal of ice" (p. 1).
Effect of Design Variables on Performance of Mach 4.0 Hydrogen Expansion Engines
Memorandum presenting performance calculations for hypothetical hydrogen expansion engines in which only a small part of the engine airflow passes through the heat exchanger. The flight path was representative of those for long-range, high-speed aircraft. Results regarding the off-design operation and engine performance are provided.
Performance of Five Short Multielement Turbojet Combustors for Hydrogen Fuel in Quarter-Annulus Duct
Report described five short multielement turbojet combustors for use with hydrogen fuel and their performance. Information about the combustion efficiency, temperature profiles, pressure loss, durability, and comparison with previous short combustors is included.
Flight Investigation of Pentaborane Fuel in 9.75-inch-diameter Ram-jet Engine With Downstream Fuel Injection
Flight investigation of pentaborane fuel in 9.75- inch-diameter ramjet engine with downstream fuel injection.
Performance of a Double-Ramp Side Inlet With Combinations of Fuselage, Ramp, and Throat Boundary-Layer Removal, Mach Number Range, 1.5 to 2.0
Double-ramp side inlet with combinations of fuselage, ramp, and throat boundary layer removal.
The Effect of Compressor-Inlet Water Injection on Engine and Afterburner Performance
"A turbojet engine incorporating a conventional-type afterburner was operated over a range of afterburner pressure levels from 1000 to 2000 pounds per square foot absolute and a range of engine-inlet water-air ratios from 0 to 0.08. At each pressure level and water-air ratio, the afterburner fuel flow was varied from lean blowout to maximum burner-outlet temperature" (p. 1).
Methods of analyzing wind-tunnel data for dynamic flight conditions
The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area. Solutions of the lateral equations of motion are given in a form suitable for direct computations. An approximate formula is developed that permits the rapid estimation of the accelerations produced during pull-up maneuvers involving abrupt elevator deflections.
Examination of Recent Lateral-Stability-Derivative Data
"In the present paper attention is directed to the aerodynamic parameters, the so-called stability derivatives, that affect the lateral behavior of airplanes and missiles. The discussion is centered on three important quantities, the effective-dihedral derivative, the directional-stability derivative, and the damping-in-roll derivative. These quantities are considered for a large angle-of-attack range at subsonic speeds" (p. 1).
An Investigation of the Downwash at the Probable Tail Location Behind a High-Aspect-Ratio Wing in the Langley 8-Foot High-Speed Tunnel
Report presenting measurements downwash angles behind a model of a high-aspect-ratio wing at points near the probable tail location at Mach numbers up to 0.89 in the high-speed tunnel. The model has an NACA 65-210 section, an aspect ratio of 9.0, a taper ratio of 2.5:1, no twist, dihedral, or sweepback. Results regarding experimental data and comparison of experimental and calculated results are provided.
Tests of a triangular wing of aspect ratio 2 in the Ames 12-foot pressure wind tunnel. 1: the effect of Reynolds number and Mach number on the aerodynamic characteristics of the wing with flap undeflected
Report presenting testing of a semispan model of a wing of triangular plan form and aspect ratio 2 in the 12-foot pressure tunnel to determine the aerodynamic characteristics of the wing as influenced by the independent effects of Reynolds number and Mach number up to Mach numbers approaching unity. Results regarding the effect of body and effect of wing-profile modification are also provided.
Pressure Distributions on the Blade Sections of the NACA 10-(3)(090)-03 Propeller Under Operating Conditions
The third report in a series of five that present unanalyzed pressure data obtained in tests of five full-scale propellers with NACA 16-series blade sections. Pressure distributions on the blade sections were measured under operating conditions to determine the aerodynamic characteristics of each blade section. This particular report presents information for nine radial stations of the NACA 10-(3)(090)-03 propeller.
Investigation of stage performance of X24C-2 ten-stage axial-flow compressor at design speed
The stage performance of the X24C-2 axial-flow compressor, as determined from radial distributions of total pressure and temperature measured in each stator-blade row, was investigated at design speed at weight flows corresponding to those of the maximum weight-flow, peak-efficiency, and surge points. The stage performance is presented as the measured stage pressure ratios and the calculated velocity diagrams. The average stage total-pressure ratio at the surge operating condition in the first stage was approximately 1.10; in the second stage, approximately 1.13; and in all remaining stages, approximately constant at a value of 1.15. Regions of inefficient flow are discussed so as to point out the reasons for the poor flow conditions.
Wind-Tunnel Investigation of Horizontal Tails 1: Unswept and 35 Degrees Swept-Back Plan Forms of Aspect Ratio 3
Memorandum presenting the results of a wind-tunnel investigation of the low-speed characteristics of horizontal tails of aspect ratio 3 with unswept and swept-back plan forms. Two models were tested which had identical areas, aspect ratio, taper ratio, and airfoil section, differing only in the angle of sweepback and elevator area ratios. The major effect of sweepback was to increase the rate of change of hinge-moment coefficient with angle of attack, to reduce the rate of change with elevator deflection, and to reduce the elevator effectiveness.
Preliminary Tank Investigation of the Use of Single Monoplane Hydrofoils for High-Speed Airplanes
Report presenting an investigation of the hydrodynamic take-off and landing characteristics of a model of a hypothetical jet- and rocket-propelled high-speed airplane fitted with various designs of a single monoplane hydrofoil mounted near the center of gravity. This testing is performed to determine the feasibility of the water-based operation of high-speed airplanes. Results regarding the general hydrodynamic characteristics, development of hydrofoils, and effects of some hydrofoil parameters are provided.
Effects of Some Airfoil-Section Variations on Wing-Aileron Rolling Effectiveness and Drag as Determined in Free Flight at Transonic and Supersonic Speeds
Report presenting an investigation in free flight of the rolling effectiveness of plain ailerons in conjunction with wings having 0 and 45 degrees sweepback with several airfoil sections. Results regarding the rolling characteristics of rectangular and sweptback-wing configurations and drag measurements are provided.
Investigation of High-Temperature Operation of Liquid-Cooled Gas Turbines 1: Turbine Wheel of Aluminum Alloy, a High-Conductivity Nonstrategic Material
Report presenting an investigation of turbine operating temperatures as affected by liquid cooling, especially if materials of high conductivity are used, at gas temperatures up to 1925 degrees Fahrenheit. Results regarding the statio heat-transfer rig and turbine rig are provided. The investigation showed that nonstrategic material such as aluminum alloy can be used in liquid-cooled turbine wheels at high gas temperatures.
Altitude-wind-tunnel investigation of compressor performance on J47 turbojet engine
From Introduction: "The effects of variations in altitude, flight Mach number, and exhaust-nozzle-outlet area on the compressor performance characteristics are graphically presented. A complete tabulation of the compressor performance data is also presented."
Drag characteristics of rectangular and swept-back NACA 65-009 airfoils having various aspect ratios as determined by flight tests at supersonic speeds
Report presenting tests to determine the effect of sweepback angle and aspect ratio on the drag at supersonic speeds of wings of NACA 65-009 airfoil section. The current report is part of a bigger investigation and includes results for aspect ratios of 3.8 and 5.0. Results regarding the drag coefficient and general effect of aspect ratio are provided.
An Evaluation of Air-Borne Radar as a Means of Avoiding Atmospheric Turbulence
"Gust-velocity measurements and air-borne-radar observations obtained during a transcontinental flight in July 1947 have been analyzed as part of a general investigation of the uses of air-borne radar. The analysis indicates that some reduction in turbulence and a consequent reduction in the risk of encountering the larger gust velocities may be obtained by avoiding portions of clouds giving a radar echo" (p. 1).
Comparison of National Bureau of Standards ceramic coatings L-7C and A-417 on turbine blades in a turbojet engine
Report presenting an investigation to determine which of two ceramic coatings, L-7C and A-417, developed by the National Bureau of Standards is more suitable as a protective coating for turbine blades in a turbojet engine. Four cast Vitallium turbine blades, two coated with each of the ceramics, were installed in a turbine wheel of a turbojet engine and subjected to accelerated cyclic life tests.
Effect of Inlet-Air Parameters on Combustion Limit and Flame Length in 8-Inch-Diameter Ram-Jet Combustion Chamber
Report presenting an investigation with a ram-jet combustion chamber to determine the effect of fuel-air ratio and the inlet-air parameters of pressure, temperature, and velocity on combustion limit, combustion efficiency, and flame length.
Longitudinal Stability Characteristics of a 42 Degree Sweptback Wing and Tail Combination at a Reynolds Number of 6.8 X 10 (Exp 6)
Results of a wind-tunnel investigation at a Reynolds number of 6.8 x 10(exp 6) to determine the static longitudinal stability characteristics of a 42 degree sweptback wing and fuselage combination with a sweptback horizontal tail are provided. Included are the effects of vertical position of fuselage and tail with respect to wing for several combinations of high-lift and staff-control devices. Also included is the effect of a simulated ground.
Evaluation of Gust and Draft Velocities From Flights of an AT-6 Airplane Within Cumulus Clouds July 1, 1947 to July 22, 1947 at Clinton County Army Air Field, Ohio
Memorandum presenting measurements of gust and draft velocities within cumulus clouds at a certain army air field using an AT-6 airplane. The measurements were made to supplement the at a obtained with P-61C airplanes. The data are summarized in tables.
Experimental investigation at supersonic speeds of twin-scoop duct inlets of equal area 3: inlet enclosing 37.2 percent of the maximum circumference of the forebody
Report presenting testing of a twin-scoop duct inlet that enclosed 37.2 percent of the forebody circumference at Mach numbers between 1.36 and 2.01. The approach to each scoop consisted of a ramp that deflected the flow to create an oblique shock wave in front of the duct entrance. Results regarding the inlet proportions, ramp angle, slots, and angle of incidence are provided.
Stability Results Obtained With Douglas D-558-1 Airplane (BuAero No. 37971) in Flight Up to a Mach Number of 0.89
Memorandum presenting measurements of some of the high-speed characteristics of the D-558-1 airplane up to Mach number 0.89. The results of the tests showed that the stabilizer incidence drastically affected the longitudinal trim characteristics above a Mach number of 0.80.
Notes on the Application of Airfoil Studies to Helicopter Rotor Design
Report presenting a discussion of a number of the problems that most frequently arise with airfoils on helicopters. A reference list of published reports on airfoil section characteristics which are useful in regards to these helicopter problems is also included.
Vibration of turbine blades in a turbojet engine during operation
Report presenting an experimental investigation to determine the vibration phenomena that occur in turbine blades of a typical jet-propulsion engine during service operation; high-temperature strain gages were used to measure the turbine-blade vibrations. Results regarding modes of vibration, centrifugal stresses, and vibration of turbine blades during operation are provided.
Free-flight performance of 16-inch-diameter supersonic ram-jet units 1: four units designed for combustion-chamber-inlet Mach number of 0.12 at free-stream Mach number of 1.6 (units A-2, A-3, A-4, and A-5)
Report presenting free-flight investigations conducted on four 16-inch-diameter ramjet units to determine the performance at high subsonic and supersonic velocities. Data for evaluating the performance were obtained from radio-telemetering and radar-tracking equipment. Results regarding combustion performance, diffuser total-pressure recovery, thrust coefficient, and external drag coefficient are provided.
Tank spray tests of a jet-powered model fitted with NACA hydro-skis
Report presenting tank results for take-off tests with a powered dynamic model of a hypothetical jet-propelled high-speed airplane fitted with NACA hydro-skis and with flush turbojet intakes on the upper part of the fuselage near the nose. Some of the investigations included were the possibility of making take-offs without spray entering the intakes, the effect of turbojet air inflow on the tendency of spray to enter the intakes, and the effect of jet power on trim.
Experimental data concerning the effect of high heat-input rates on the pressure drop through radiator tubes
From Summary: "The pressure drops through electrically heated Inconel tubes with length-diameter ratios of 29.25, 58.50, 87.75, and 117.00 have been measured at entrance Mach numbers from approximately 0.12 to the value at which choking occurred. The heat-input rate was varied from zero to the highest values allowable without damaging the tubes. Experimental data and a number of computed variables are presented in tabular form."
High-speed aerodynamic characteristics of a lateral-control model 3: section characteristics, fence studies, and tabulated pressure coefficients with modified NACA 0012-64 section, 26.6-percent-chord, plain aileron, 0 and 45 degree sweepback
Report presenting wind-tunnel measurements of the pressure distribution on a semispan wing with a modified NACA 0012-64 airfoil section and a plain trailing-edge aileron with the wing unswept and also swept back 45 degrees. Adverse changes in loading and loss of aileron effectiveness developed with the wing unswept as the Mach number was increased, but did not occur at Mach numbers up to 0.925 with the swept wing. Results regarding section characteristics and effect of fences are provided.
Effects of stabilizing fins and a rear-support sting on the base pressure of a body of revolution in free flight at Mach numbers from 0.7 to 1.3
From Summary: "Ogive-cylindrical fuselages of fineness ratio 11 have been flight-tested with and without stabilizing fins. Base-pressure measurements over a range of free-stream Mach numbers from 0.7 to 1.3 indicated that the fins reduced the base drag. A rear-support sting similar to those used in wind tunnels was tested with one of the fuselages and found to reduce base suction by 40 percent at subsonic speeds, but to have little effect at Mach numbers above 1.15."
Preliminary air-flow and thrust calibrations of several conical Cooling-air ejectors with a primary to secondary temperature ratio of 1.0 I :diameter ratios of 1.21 and 1.10
Report presenting an investigation of the performance of several conical cooling-air ejectors at primary jet pressure ratios from 1 to 10, secondary shroud pressure ratios from 0.60 to 4.00, and primary to secondary temperature ratio of 1.0. The investigation centered on primary air flow, secondary air flow, primary nozzle thrust, and gross ejector thrust.
Effect of water vapor on combustion of magnesium hydrocarbon slurry fuels in small-scale afterburner
Report presenting testing of JP-3 fuel and a slurry of 60 percent powdered magnesium in JP-3 fuel in a small-scale afterburner in the presence of large quantities of water vapor. The results indicated that total temperature, combustion efficiency, and air specific impulse were improved when the magnesium slurry was used, but the improvements came at the cost of increased liquid consumption.
A Preliminary Experimental and Analytical Evaluation of Diborane as a Ram-Jet Fuel
Report presenting an analytical and experimental evaluation of diborane as a ram-jet fuel, which seems to offer greater flight range, thrust, and combustion stability beyond what is attainable with petroleum fuels. Results regarding ideal thrust, stability, deposits, and flight range with several blends of diborane are provided.
Some Effects of Spanwise Aileron Location and Wing Structural Rigidity on the Rolling Effectiveness of 0.3-Chord Flap-Type Ailerons on a Tapered Wing Having 63 Degrees Sweepback at the Leading Edge and Naca 64A005 Airfoil Sections
Report presenting an investigation of some effects of aileron spanwise location and wing structural rigidity on the rolling power of 0.3-chord plain, flap-type ailerons on a wing with a taper ratio of 0.25, an aspect ratio of 3.5, and swept back 63 degrees at the leading edge. Results regarding the aeroelastic effects and aileron span and spanwise location are provided.
Dynamic Longitudinal Stability and Control of Tandem Coupled Bomber-Fighter Airplane Models With Rigid and Pitch-Free Couplings
Report presenting an investigation in the free-flight tunnel to determine the dynamic longitudinal stability and control characteristics of tandem-coupled bomber-fighter airplane models. Results regarding bomber alone tests, freely coupled combination, and rigidly coupled combination are provided.
Investigation of mechanisms of blade failure of forged Hastelloy B and cast Stellite 21 turbine blades in turbojet engine
An investigation was conducted to study the mechanisms of blade failure of forged Hastelloy B and cast Stellite 21. The blades were mounted in a 16-25-6 alloy rotor and subjected to 20-minute cycles consisting of 15 minutes at rated speed and approximately 5 minutes at idle. The first failures of the Hastelloy B and Stellite 21 blades were probably the result of excessive vibratory stresses and occurred after 14.25 and 16.75 hours, respectively. After 28.75 hours of operation, all but 3 of the original 25 Hastelloy B blades had either failed or contained stress-rupture-type cracks and four of the original 27 Stellite 21 blades contained stress-rupture-type cracks.
Effects of Reynolds Number on the Aerodynamic Characteristics of a Delta Wing at Mach Number of 2.41
Memorandum presenting the results of an experimental investigation to determine the effects of Reynolds number on the flow characteristics over a delta wing at a Mach number 2.41. The wing streamwise airfoil sections are based on the NACA 00-thickness series with the maximum thickness varying from 4 percent at the root section to 6.24 percent at the 90-percent spanwise station. Results regarding force data and pressure-distribution data are provided.
Investigation of Low-Speed Lateral Control and Hinge-Moment Characteristics of a 20-Percent-Chord Plain Aileron on a 47.7 Degrees Sweptback Wing of Aspect Ratio 5.1 at a Reynolds Number of 6.0 X 10(Exp 6)
Report presenting the low-speed lateral control and hinge-moment characteristics of a 20-percent-chord plain aileron on a 47.7 degree sweptback wing of aspect ratio 5.1 in the pressure tunnel. The tests were performed with and without high-lift and stall-control devices. Results regarding the basic aileron data, rolling-moment characteristics, and pitching-moment characteristics are also provided.
Investigation of the Effects of Variations in the Reynolds Number Between 0.4 X 10(Exp 6) 3.0 X 10(Exp 6) on the Low-Speed Aerodynamic Characteristics of Three Low-Aspect-Ratio Symmetrical Wings With Rectangular Plan Forms
Report presenting an investigation of the effect of Reynolds number and the addition of leading-edge roughness on the aerodynamic characteristics of wings with aspect ratio 1, 2, and 3, a rectangular plan form, square-cut wing tips, and NACA 0012 airfoil sections. Results regarding lift and moment, lift-curve slope, and maximum lift are provided.
Summary of pitch-damping derivatives of complete airplane and missile configurations as measured in flight at transonic and supersonic speeds
Report presenting longitudinal-damping data in the form of the pitching-moment derivatives and summarized from flight tests of rocket-propelled models and full-scale airplanes. 22 models and 4 airplanes are examined in the study and the damping derivative results are generalized.
Investigation of Turbines for Driving Supersonic Compressors 2: Performance of First Configuration With 2.2 Percent Reduction in Nozzle Flow Area
"The experimental performance of a modified turbine for driving a supersonic compressor is presented and compared with the performance of the original configuration to illustrate the effect of small changes in the ratio of nozzle-throat area to rotor-throat area. Performance is based on the performance of turbines designed to operate with both blade rows close to choking. On the basis of the results of this investigation, the ratio of areas is concluded to become especially critical in the design of turbines such as those designed to drive high-speed, high-specific weight-flow compressors where the turbine nozzles and rotor are both very close to choking" (p. 1).
Aerodynamic characteristics of two 25-percent-area trailing-edge flaps on an aspect ratio 2 triangular wing at subsonic and supersonic speeds
Report presenting the results of an investigation of flap-type controls on a low-aspect-ratio triangular wing using NACA 0005-63 sections for a constant-chord and a constant-percent-chord control surface. Two flap profiles were investigated: one with a true contour and the other with a blunt trailing edge. Results regarding lift, drag, pitching moment, hinge moment, and rolling moments were obtained for several Mach numbers, a constant Reynolds number, and a range of angles of attack.
Influence of airfoil trailing-edge angle and trailing-edge-thickness variation on the effectiveness of a plain flap at high subsonic Mach numbers
Report presenting the effects of variation of trailing-edge angle and trailing-edge thickness on the lift characteristics of a 10-percent-chord thick symmetrical NACA airfoil section with a 25-percent-chord plain flap as determined from wind tunnel tests over a range of Mach numbers. Results regarding the section lift and pitching-moment characteristics, variation of lift coefficient with flap deflection, schileren photographs, and effect of angle of attack are provided.
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