National Advisory Committee for Aeronautics (NACA) - 1,126 Matching Results
Search Results
- The Theory of a Free Jet of a Compressible Gas
- "In the present report the theory of free turbulence propagation and the boundary layer theory are developed for a plane-parallel free stream of a compressible fluid. In constructing the theory use was made of the turbulence hypothesis by Taylor (transport of vorticity) which gives best agreement with test results for problems involving heat transfer in free jets" (p. 1).
- Variation in the Number of Revolutions of Air Propellers
- Note describing the variation in the number of revolutions per minute and provides simple formulas that allow for advanced calculation to be made of the variation of propeller speed with variation of one or more dimensions of the propeller and allow the necessary corrections to be applied.
- Theoretical study of the lateral frequency response to gusts of a fighter airplane, both with controls fixed and with several types of autopilots
- Report presenting a theoretical approach to determine the lateral frequency response of a fighter airplane to side gusts and rolling gusts at a Mach number of 0.7 and an altitude of 30,000 feet. Frequency response and power spectral density were determined with the controls fixed and in combination with three different basic types of attitude autopilots.
- Strain-Gage Measurements of Buffeting Loads on a Jet-Powered Bomber Airplane
- Buffet boundaries, buffeting-load increments for the stabilizers and elevators, and buffeting bending-moment increments for the stabilizers and wings as measured in gradual maneuvers for a jet-powered bomber airplane are presented. The buffeting-load increments were determined from strain-gage measurements at the roots or hinge supports of the various surfaces considered. The Mach numbers of the tests ranged from 0.19 to 0.78 at altitudes close to 30,000 feet. The predominant buffet frequencies were close to the natural frequencies of the structural components. The buffeting-load data, when extrapolated to low-altitude conditions, indicated loads on the elevators and stabilizers near the design limit loads. When the airplane was held in buffeting, the load increments were larger than when recovery was made immediately.
- Drag Measurements of Symmetrical Circular-Arc and NACA 65-009 Rectangular Airfoils Having an Aspect Ratio of 2.7 as Determined by Flight Tests at Supersonic Speeds
- Report discussing testing to determine the drag characteristics at zero lift of a wing with a circular-arc airfoil section with a maximum thickness of 9 percent chord. The results were compared to previous testing on an NACA 65-009 airfoil. It was found that the NACA airfoil had lower drag coefficients than the circular-arc airfoil tested in this experiment.
- Experimental Static Aerodynamic Forces and Moments at High Subsonic Speeds on a Missile Model During Simulated Launching From Unswept-, Sweptback-, and Modified-Delta-Wing-Fuselage Combinations at Zero Sideslip
- Report presenting an investigation in the high-speed tunnel to determine the static aerodynamic forces and moments on a missile model during simulated launching from midsemispan locations of various types of wings. The purpose of the investigation is to determine the nature and origin of the mutual interference experienced by various combinations of wing-fuselage models and externally carried missiles. Results regarding isolated missile characteristics, the effect of varying chordwise position, effects of angle of attack and Mach number, effect of airplane wing geometric characteristics, effect of missile spanwise location, and comparison of wing-fuselage and fuselage effects on the missile forces and moments are provided.
- The asymmetric adjustable supersonic nozzle for wind-tunnel application
- Report presenting the development of an asymmetric type of adjustable supersonic nozzle suitable for application to wind tunnels. This type of nozzle permits continuous adjustment of the test-section Mach number without the requirement of flexible walls.
- Problems of performance and heating of hypersonic vehicles
- Report presenting a comparison of three hypervelocity vehicles: a ballistic rocket, a skip rocket, and a rocket glider. Range efficiency, automatic heating, and problems of glide rockets are explored.
- Characteristics of flow over inclined bodies of revolution
- From Summary: "Experimental force, moment, and center-of-pressure variations for a large number of bodies of revolution have been compared with the calculated characteristics based on the approximate theory developed in NACA-RM-A9I26. The bodies varied in fineness ratio from 4.5 to 21.1, from blunt unboattailed bodies to airship hulls, and the experimental results are given for widely varying Mach number ranges of angle of attack. It is shown that the lift and drag characteristics are fairly accurately predicted by the theory but that the actual center of pressure is more rearward than the theory indicates."
- An Experimental Investigation of Several Low-Drag Wing-Nacelle Combinations with Internal Air Flow
- From Summary: "The results of an experimental investigation of several low-drag wing-nacelle combinations, incorporating internal air-flow systems, are presented. The external-drag increments due to these nacelles are between one-half and two-thirds of those of conventional nacelle forms. This improvement is accomplished with only minor effects on the lift and moment characteristics of the wing. The procedure employed to determine the external shape of such low-drag nacelles is considered in detail. The design of an efficient internal-flow system with or without a blower or throttle, presents no serious problems. The energy losses in the expansion before the engine and the contraction thereafter can be kept small. It is believed that these nacelles have a wide application in housing engine pusher-propeller units and, with some alteration, jet-propulsion devices. It is probable that the low external drags may not be realized if such nacelles are used with a tractor propeller because of the high level of turbulence in the propeller slipstream."
- A method for the analysis of compounds containing boron, carbon, and hydrogen
- Report presenting a method for analyzing each of the elements, boron, carbon, and hydrogen from the quantitative analysis of a single sample of an organoboron compound. The method is helpful for the analysis of volatile hydrocarbons and polynuclear aromatic compounds.
- Force and pressure recovery characteristics at supersonic speeds of a conical spike inlet with a bypass discharging from the top or bottom of the diffuser in an axial direction
- Force and pressure-recovery characteristics of a nacelle-type conical-spike inlet with a fixed-area bypass located in the top or bottom of the diffuser are presented for flight Mach numbers of 1.6, 1.8, and 2.0 for angles of attack from 0 degrees to 9 degrees. Top or bottom location of the bypass did not have significant effects on diffuser pressure-recovery, bypass mass-flow ratio, or drag coefficient over the range of angles of attack, flight Mach numbers, and stable engine mass-flow ratios investigated. A larger stable subcritical operating range was obtained with the bypass on the bottom at angles of attack from 3 degrees to 9 degrees at a flight Mach number of 2.0. At a flight Mach number of 2.0, the discharge of 14 percent of the critical mass flow of the inlet by means of a bypass increased the drag only one-fifth of the additive drag that would result for equivalent spillage behind an inlet normal shock without significant reductions in diffuser pressure recovery.
- Tank Tests of Model 36 Flying Boat Hull
- "N.A.C.A. Model 36, a hull form with parallel middle body for half the length of the forebody and designed particularly for use with stub wings, was tested according to the general fixed-trim method over the range of practical loads, trims, and speeds. It was also tested free to trim with the center of gravity at two different positions. The results are given in the form of nondimensional coefficients. The resistance at the hump was exceptionally low but, at high planing speeds, afterbody interference made the performance only mediocre" (p. 1).
- Charts for estimation of longitudinal-stability derivatives for a helicopter rotor in forward flight
- Report presenting charts to provide a convenient means for obtaining the derivatives of rotor resultant force, rotor pitching amount about the helicopter center of gravity, and rotor torque with respect to rotor angle of attack, forward speed, rotor speed, and collective pitch.
- Maximum Lift Coefficients of Airplanes Based on Sum of Wing and Tail Areas
- Report discusses the maximum lift coefficients for conventional and tailless airplanes in the gliding and landing conditions. Three areas are used to calculate the coefficients: wing area alone, wing area plus horizontal-tail area, and wing area plus horizontal- and vertical-tail areas.
- Some Measurements of Flying Qualities of a Douglas D-558-II Research Airplane During Flights to Supersonic Speeds
- Report presenting some measurements of the dynamic lateral stability and lateral and longitudinal trim of a Douglas D-558-II in flights up to a Mach number of 1.87 and an altitude of about 67,000 feet. Testing indicated that the airplane flying in low density air at supersonic speeds had poor dynamic lateral stability, which worsened as the Mach number was increased to 1.85.
- Formation of a Vortex at the Edge of a Plate
- The flow about the plate of infinite width may be represented as a potential flow with discontinuity surfaces which extend from the plate edges. On the basis of a similitude requirement one succeeds in finding a solution of this problem for the plate of infinite width which is correct for the very beginning of the motion of the fluid. Starting from this solution, the further development of the vortex distribution and shape of the surface are observed in the case of a plate of finite width.
- Some approximate methods for estimating the effects of aeroelastic bending of rocket-propelled model-booster combinations
- Report presenting methods for estimating the aeroelastic effects and structural requirements of rocket-propelled model-booster combinations that are nearly symmetrical. The methods differ principally in the manner in which booster stiffness, reference axis, and inertia loading are considered. Special conditions and accuracy for each of the three models are provided.
- Some Principles Governing the Establishment of Meteorological Stations Along Air Routes
- The organization of a meteorological service for an air route involves the solution of two distinct problems: distribution and grouping of meteorological stations and communications. Experience gained in the establishment of two lines, Paris-Warsaw and Constantinople-Bucharest enables us to establish certain principles, which may be of interest to note here.
- High Speed Stability and Control Characteristics of a 0.17-Scale Model of the McDonnell XF2H-1 Airplane (TED No. NACA DE 318)
- "High-speed wind-tunnel tests were conducted of two versions of a 0.17-scale model of the McDonnell XF2H-1 airplane to ascertain the high-speed stability and control characteristics and to study means for raising the high-speed buffet limit of the airplane, The results for the revised model, employing a thinner wing and tail than the original model, revealed a mild diving tendency from 0.75 to 0.80 Mach number, followed by a marked climbing tendency from 0.80 to 0.875 Mach number. The high-speed climbing tendency was caused principally by the pitching-moment characteristics of the wing" (p. 1).
- Investigation of a Slat in Several Different Positions on an NACA 64A010 Airfoil for a Wide Range of Subsonic Mach Numbers
- Report presenting the two-dimensional aerodynamic characteristics of an NACA 64A010 airfoil with a slat at a range of Mach numbers. Two types of slat positions were investigated, one with the slat leading edge extended forward along the airfoil chord line and one with the slat extended forward and displaced below the chord line. Results regarding lift, drag, pitching moment, and pressure distribution are provided.
- A simplified chart for determining Mach number and true airspeed from airspeed-indicator readings
- "The determination of flight Mach number from measurements of indicated airspeed and pressure altitude is shown to be relatively simple and leads to direct and accurate computation of true airspeed. A simplified chart is presented for determining flight Mach number and true airspeed for a range of values of indicated airspeed, pressure altitude, and air temperature. A table of standard atmospheric values is included" (p. 1).
- The "Universal Propeller": Built by Paragon Engineers, Inc., Baltimore, MD.
- At the request of the N.A.C.A. the "Universal Propeller" was operated and explained by the inventor, Mr. Spencer Heath, for the purpose of demonstrating the following features of design: 1) Elimination of continuously running gears, collars or bearings in the pitch control mechanism; 2) The use of engine power in place of manual labor in changing blade angle; 3) The absence of any structural limitation to the range of blade angles available and the possibility of limiting the blade travel between any two predetermined extreme positions; 4) Continuous indication on the instrument board of the blade position; 5) Automatic throttling of the engine while the propeller is passing through the position of neutral pitch.
- A simplified theoretical method of determining the characteristics of a lifting rotor in forward flight
- Theoretical derived expressions for the flapping, the thrust, the torque, and the profile drag-lift ratio of nonfeathering rotor with hinged, rectangular, linearly twisted blades are given as simple functions of the inflow velocity and the blade pitch. Representative values of the coefficients of each of the terms in these expressions are tabulated for a series of specified values of the tip-speed ratio. Analysis indicates that the tabulated values can be used to calculate, with reasonable accuracy, the characteristics of any rotor of conventional design.
- An Estimate of the Effect of Engine Supercharging on the Take-Off Thrust of a Typical Helicopter at Different Altitudes and Temperatures
- Report discussing the effects of supercharging on the take-off thrust and useful load for a typical helicopter. Performance of the engine with the supercharger and on the rotor thrust is detailed.
- Evolution of the Helicopter
- Report presenting an investigation of problems related to helicopters. Also included are the history of the evolution of the helicopter and a series of propeller experiments.
- Atmospheric Waves and Their Utilization in Soaring Flight
- In soaring flight, ascending air currents are utilized and the interesting question is raised whether there are such currents which extend to any considerable distance and which can be utilized practically.
- Aerodynamic Rolling and Yawing Moments Produced by Floating Wing-Tip Ailerons, as Measured by Spinning Balance
- From Summary: "The investigation described in this report was made to determine the effectiveness of floating wing-tip ailerons as an airplane control in the spin. In these tests the ailerons, not being balanced, were set parallel to the axis of rotation, which is probably very nearly the attitude that balanced floating ailerons would assume in a spin. Rolling - and yawing moment coefficients are given as measured for the model with and without the ailerons, and computed values are given for the ailerons alone."
- The Effects of Horizontal-Tail Height and a Partial-Span Leading-Edge Extension on the Static Longitudinal Stability of a Wing-Fuselage-Tail Combination Having a Sweptback Wing
- Memorandum presenting an investigation made to valuate the effects of vertical height of the horizontal tail on the static longitudinal stability of a model with a wing with 35 degrees of sweepback, an aspect ratio of 4.5, a taper ratio of 0.5, and NACA 64A010 sections. The investigation also included the effects of adding a partial-span, leading-edge chord extension to the outer portions of the wing. Results regarding the effect of tail height, wing-wake and local downwash measurements, and effect of a leading-edge extension are provided.
- Initial Flight Tests of the NACA FR-2, a High-Velocity Rocket-Propelled Vehicle for Transonic Flutter Research
- Report presenting initial flight tests of two simplified flutter vehicles. Test results were in agreement with the results of the freely-falling-body test in that the wing failures in the transonic range occurred at velocities greater than the flutter velocity calculated from the two-dimensional theory.
- An Evaluation of the Knock-Limited Performance of Triptane
- Report discussing an investigation of the knock-limited performance of triptane in F-3 and F-4 rating engines, two full-scale air-cooled aircraft cylinders, and flight tests on a full-scale multicylinder engine. Information about the lead susceptibility and effect of engine operating conditions is also provided.
- Effects of Fuel-Vapor Loss on Knock-Limited Performance and Inspection Properties of Aviation Fuels
- Report discussing the results of testing to discover the effects of fuel-vapor loss on F-3 and F-4 knock-limited performance ratings and inspection properties of two aviation fuels, 28-R and 33-R. The percentage of loss at several temperatures, ability to meet Army-Navy fuel specifications, and antiknock rating change is described.
- Flight Test of an End-Burning Solid-Fuel Ramjet
- Report presenting a flight investigation of a rocket-launched ram-jet engine incorporating an end-burning solid fuel. Results regarding acceleration, altitude, booster separation, survival time of booster adapter, and air specific impulse are provided.
- Wind-Tunnel Investigation of Wing Inlets for a Four-Engine Airplane
- Report presenting an investigation in the propeller-research tunnel to develop wing-leading-edge inlets for locations between the inboard and outboard nacelles on each wing of a four-engine airplane. Testing was performed on the basic wing and original inlet as well as NACA-developed inlets for two versions of the airplane.
- Temperature Drops Through Liquid-Cooled Turbine Blades With Various Cooling-Passage Geometries
- Memorandum presenting the effects of variations in cooling-passage geometry on the relations between heat flow and temperature drops within liquid-cooled turbine blades. Wall thicknesses, blade section depths, and cooling-passage sizes, shapes, and spacings were varied experimentally on a simple electric analog on which are simulated rectangular sections of blades. Results are presented in terms of temperature differences between the cooled-surface temperature and average heated-surface temperature, minimum heated-surface temperature, maximum heated-surface temperature, and maximum temperature at the centerline of the turbine blades.
- Thermal Conductance of Contacts in Aircraft Joints
- Note presenting tests conducted to determine the factors influencing the thermal conductance across the interference between 75S-T6 aluminum-alloy and AISI Type 416 stainless-steel structural joints. The type of joints investigated included: bare metal-to-metal contact, contact surfaces coated with zinc-chromate primer, contact surfaces separated by thin foils of good conductors, contact surfaces separated by thin sheets of insulation, contact surfaces joined by strength-giving bonds, and riveted joints. The factors investigated were heat flow, temperature drop, temperature level, and surface condition.
- A Simplified Method of Elastic-Stability Analysis for Thin Cylindrical Shells
- "This paper develops a new method for determining the buckling stresses of cylindrical shells under various loading conditions. In part I, the equation for the equilibrium of cylindrical shells introduced by Donnell in NACA report no. 479 to find the critical stresses of cylinders in torsion is applied to find critical stresses for cylinders with simply supported edges under other loading conditions. In part II, a modified form of Donnell's equation for the equilibrium of thin cylindrical shells is derived which is equivalent to Donnell's equation but has certain advantages in physical interpretation and in ease of solution, particularly in the case of shells having clamped edges" (p. 285).
- Critical Combinations of Shear and Direct Stress for Simply Supported Rectangular Flat Plates
- Note presenting an investigation of the buckling of a simply supported rectangular flat plate under combinations of shear and direct stress by means of an energy method. The critical combinations of stress for several length-width ratios were determined to an accuracy of about 1 percent in conjunction with a modified matrix iteration method. Results regarding the shear and longitudinal stress and shear and transverse stress are provided.
- Critical Stress of Thin-Walled Cylinders in Axial Compression
- Empirical design curves are presented for the critical stress of thin-wall cylinders loaded in axial compression. These curves are plotted in terms of the nondimensional parameters of small-deflection theory and are compared with theoretical curves derived for the buckling of cylinders with simply supported and clamped edges. An empirical equation is given for the buckling of cylinders having a length-radius ratio greater than about 0.75.
- Critical Combinations of Longitudinal and Transverse Direct Stress for an Infinitely Long Flat Plate With Edges Elastically Restrained Against Rotation
- Report presenting a theoretical investigation of the buckling of an infinitely long flat plate with edges elastically restrained against rotation under combinations of longitudinal and transverse direct stress. Interaction curves are presented that give the critical combinations of stress for several different degrees of elastic edge restraint, including simple support and complete fixity.
- Static stability of fuselages having a relatively flat cross section
- Report presenting an investigation in the free-flight tunnel to determine the static stability characteristics of several fuselages with a relatively flat cross section and a high fineness ratio. Results regarding the fuselages alone and fuselages with various vertical and horizontal surfaces are provided.
- Wind-tunnel investigation at Mach 1.9 of multijet-missile base pressures
- From Summary: "An experimental wind-tunnel investigation was conducted at Mach 1.9 to determine the pressures acting on the base of a multijet missile using unheated air and carbon dioxide as jet fluids. The variation of base pressure with jet static-pressure ratio was compared with results estimated for an axisymmetric single-jet model and some correlation was observed."
- Wind-Tunnel Data on the Longitudinal and Lateral-Directional Rotary Derivatives of a Straight-Wing, Research Airplane Configuration at Mach Numbers From 2.5 to 3.5
- Memorandum presenting the results of wind-tunnel oscillation tests to measure the rotary derivatives of a research airplane configuration at supersonic speeds. Measurements were made of the damping in yaw, pitch, and roll, the static longitudinal and directional stability derivatives, the effective-dihedral derivative, the rolling moment due to yawing, and the yawing moment due to rolling. The configuration was found to be statistically stable throughout the Mach number range, although its stability was becoming marginal at high angles of attack at Mach number 3.5.
- Low-Speed Cascade Tests of Two 45 Degree Swept Compressor Blades With Constant Spanwise Loading
- Report discussing an investigation of two 45 degree swept blades in low-speed cascade tunnels at a range of angles of attack and various combinations of inlet-air angle and solidity. The isolated wing method used to design the blade predicted the twist distribution and camber shape necessary to obtain an almost uniform spanwise loading.
- The Effect of Spinner-Body Gap on the Pressures Available for Cooling in the NACA E-Type Cowling
- "Tests of a 1/3-scale model of an NACA E-type cowling were made in the 8-foot high-speed tunnel for the purpose of determining the effect of the gap between the skirt of the hollow spinner and the cowling proper on the pressures available for cooling. It was found that even a large gap (0.096 in. on the model) had no appreciable effect on the available cooling pressures" (p. 1).
- Impact Waves and Detonation: Part 1
- "Among the numerous thermodynamic and kinetic problems that have arisen in the application of the gaseous explosive reaction as a source of power in the internal combustion engine, the problem of the mode or way by which the transformation proceeds and the rate at which the heat energy is delivered to the working fluid became very early in the engine's development a problem of prime importance. The work of Becker here given is a notable extension of earlier investigations, because it covers the entire range of the explosive reaction in gases - normal detonation and burning" (p. i).
- Impact Waves and Detonation: Part 2
- A continuation of a previous technical memorandum regarding impact waves and detonation. This particular report focuses on the applications to detonation under several different conditions, including variations in pressure.
- Performance of J-33-A-21 Turbojet-Engine Compressor I - Over-All Performance Characteristics at Equivalent Impeller Speeds from 6000 to 13,400 RPM
- "The NACA is investigating a series of J-33 turbojet-engine compressors to determine the over-all and component performances and to improve theories of flow through large centrifugal compressors, The production model J-33-A-21 was operated over a range of inlet temperatures from 80 to -40 F and inlet pressures from 14 to 5 inches mercury absolute for equivalent impeller speeds from 6000 to 13,400 rpm. At the equivalent design speed of 11,500 rpm, the compressor had a peak pressure ratio of 3.98 at an equivalent weight flow of 73.4 pounds per second and an adiabatic temperature-rise , efficiency of 0.701" (p. 1).
- Wake measurements behind a wing section of a fighter airplane in fast dives
- Report presenting wake measurements made in a vertical plane behind a wind section of a fighter airplane for a range of Mach numbers up to 0.78. The critical Mach number of each wing section was exceeded by 0.05 before large increases in the profile-drag coefficient occurred.
- Effect of Wall Cooling on Inlet Parameters of a Scoop Operating in a Turbulent Boundary Layer on a Flat or Conical Surface for Mach Numbers 2 to 10
- Note presenting analytical results obtained for boundary-layer mass flow, momentum, total-temperature, and total-pressure recovery ratios of a scoop inlet with a height equal to the boundary-layer thickness and operating in a turbulent boundary layer, for flat and conical surfaces with wall cooling. The results indicate that design of boundary-layer intake devices or diverters must reflect the effects of wall cooling by either variable or compromised size.