National Advisory Committee for Aeronautics (NACA) - 423 Matching Results
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- Experimental Studies of the Knock-Limited Blending Characteristics of Aviation Fuels 1: Preliminary Tests in an Air-Cooled Cylinder
- Report presenting an investigation of the relation between the knock limit and the blend composition of aviation fuels when tested under supercharged conditions in an air-cooled aircraft-engine cylinder. Results regarding the blending characteristics of two gasolines, paraffinic fuels, olefinic fuel, naphthenic fuel, aromatic fuels, when xylidines are present in the fuel components, and fuel components containing unequal concentrations of tetraethyl lead are provided.
- Experimental Study of the Coating Formed on Nitrided-Steel Piston Rings During Operation in Nitrided-Steel Cylinders
- Report presenting a study of nitrided-steel piston rings in nitrided-steel cylinder barrels, which showed material of high reflectivity on their running faces. The structure of the material could not be resolved at a magnification of 1500 diameters. Results regarding the occurrence of coating, thickness of coating, height of coating above the nominal surface, chemical characteristics, physical characteristics, metallurgical change, and additional tests are provided.
- Experimental Study of the Coating Found on Scuffed Cast-Iron Piston Rings During Operation in Nitrided-Steel Cylinders
- Report presenting cast-iron piston rings that were run in nitrided-steel cylinder barrels under scuffing conditions and showed a coating material on the scuffed areas. Only a few of the 14 etching reagents that were tried attacked the coating chemically, indicating good corrosion resistance. Results regarding the occurrence of coating, metallurgical characteristics, and chemical characteristics are provided.
- Experimental verification of a simplified vee-tail theory and analysis of available data on complete models with vee tails
- An analysis has been made of available data on vee tail surfaces. Previously published theoretical studies of vee tails have been extended to include the control effectiveness and control forces in addition to the stability. Tests of two isolated tail surfaces with various amounts of dihedral provided a check of the theory. Methods for designing vee tails were also developed and are given in the present paper.
- Experimental Verification of the Rudder-Free Stability Theory for an Airplane Model Equipped with Rudders Having Negative Floating Tendency and Negligible Friction
- "An investigation has been made in the Langley free-flight tunnel to obtain an experimental verification of the theoretical rudder-free stability characteristics of an airplane model equipped with conventional rudders having negative floating tendencies and negligible friction. The model used in the tests was equipped with a conventional single vertical tail having rudder area 40 percent of the vertical tail area. The model was tested both in free flight and mounted on a strut that allowed freedom only in yaw" (p. 1).
- Experiments on Drag of Revolving Disks, Cylinders and Streamline Rods at High Speeds
- Report presenting an experimental investigation concerned primarily with the extension of test data on the drag of revolving disks, cylinders, and streamline rods to high Mach numbers and Reynolds numbers. The tests generally confirm earlier theories and add in some new results. One of the primary findings of interest is that skin friction does not depend on Mach number.
- Experiments on Drag of Revolving Disks, Cylinders, and Streamline Rods at High Speeds
- An experimental investigation concerned primarily with the extension of test data on the drag of revolving disks, cylinders, and streamline rods to high Mach numbers and Reynolds numbers is presented. A Mach number of 2.7 was reached for revolving rods with Freon 113 as the medium. The tests on disks extended to a Reynolds number of 7,000,000" (p. 367).
- Extended Tables of Stiffness and Carry-Over Factor for Structural Members Under Axial Load
- Report presenting an extension of tables of stiffness and carry-over factor to include the stiffness of a member with the far end subjected to a moment equal and opposite to the moment applied at the near end. The formulas used in calculation to determine the values are also provided.
- Extension of Useful Operating Range of Axial-Flow Compressors by Use of Adjustable Stator Blades
- "A theory has been developed for resetting the blade angles of an axial-flow compressor in order to improve the performance at speeds and flows other than the design and thus extend the useful operating range of the compressor. The theory is readily applicable to the resetting of both rotor and stator blades or to the resetting of only the stator blades and is based on adjustment of the blade angles to obtain lift coefficients at which the blades will operate efficiently. Calculations were made for resetting the stator blades of the NACA eight-stage axial-flow compressor for 75 percent of design speed and a series of load coefficients ranging from 0.28 to 0.70 with rotor blades left at the design setting" (p. 425).
- F-3 and F-4 Engine Tests of Several High-Antiknock Components of Aviation Fuel
- Report discussing testing on triptane, hot-acid octane, diisopropyl, neohexane, mixed xylenes, cumene, benzene, toluene, and methyl tert-butyl ether in several blends to determine their knock-limited performance data in F-3 and F-4 engines at standard operating conditions. All of the blending agents examined were found to be usable, with concentrations varying depending on various thermodynamic properties.
- Fairing Compositions for Aircraft Surfaces
- Note presenting fairing compositions applied to aircraft surfaces, welds and junctions of metal plates, and rivet depressions to improve the aerodynamic efficiency of the airplane at high speeds. A method is described for formulating fairing compositions which have, within limits, desired coefficients of thermal expansion. Results regarding water-immersion tests, thermal expansion and softening temperature, temperature-cycle tests, and density are provided.
- Fatigue Strength and Related Characteristics of Aircraft Joints 1: Comparison of Spot-Weld and Rivet Patterns in 24S-T Alclad and 75S-T Alclad
- Report contains detailed results of a number of fatigue tests on spot-welded joints in aluminum alloys. The tests described include: (1) fatigue tests on spot-welded lap joints in sheets of unequal thickness of alclad 24s-t. These tests indicate that the fatigue strength of a spot-welded joint in sheets of two different gages is slightly higher than that of a similar joint in two sheets of the thinner gage but definitely lower than that of a similar joint in two sheets of the thicker gage. (2) Fatigue tests on spot-welded alclad 75s-t spot-welded lap-joint specimens of alclad 75s-t were not any stronger in fatigue than similar specimens of alclad 24s-t. (3) Fatigue tests on lap-joint specimens spot -welded after various surface preparations--these included ac welding wire-brushed surfaces, dc welding wire-brushed surfaces, and dc welding chemically cleaned surfaces. While the ac welds were strongest statically, the dc welds on wire-brushed surfaces were strongest in fatigue. Specimens prepared in this way were very nearly as strong as the best riveted specimens tested for comparison. (4) Fatigue tests on specimens spot-welded with varying voltage so as to include a wide range of static spot-weld strengths. The fatigue strengths were in the same order as the static strengths but showed less range. (author).
- Fatigue strength and related characteristics of joints in 24S-T Alclad sheet
- Report includes tension fatigue test results on the following types of samples of 0.040-inch alclad 24s-t: (1) monoblock sheet samples as received and after a post-aging heat treatment, (2) "sheet efficiency" samples (two equally stressed sheets joined by a single transverse row of spot welds) both as received and after post-aging, (3) spot-welded lap-joint samples as received and after post-aging, and (4) roll-welded lap-joint samples. (author).
- Fatigue Tests of Riveted Joints : Progress Report of Tests of 17S-T and 53S-T Joints
- Report presenting the fatigue data obtained at the Aluminum Research Laboratories from tests of various types of 17S-T and 53S-T specimens. The specimens were large enough to represent actual service conditions, but the repetition of loading was more rapid than would occur in ordinary service.
- Flame-visibility tests with individual exhaust stacks
- Report presenting testing made on a Wright 1820-G single-cylinder engine to determine the effect of operating variables and the effect of shape and size of the exhaust stack on the visibility of exhaust gases for individual-stack installations. Flame damping was improved by decrease in nozzle-exit area, increase in stack length, and reduction in hydraulic diameter of the exhaust jets. Results regarding the characteristics of exhaust flames and damping of exhaust flames are provided.
- Flight and Test-Stand Investigation of High-Performance Fuels in Double-Row Radial Air-Cooled Engines 1: Determination of Cooling Characteristics of Flight Engine
- Report discussing the cooling characteristics of a 14-cylinder double-row radial air-cooled engine in a four-engine airplane. The effects of charge-air flow, cooling-air pressure drop, and fuel-air ratio on the cooling characteristics were measured separately. The cooling equation, rear middle-barrel temperature, cooling-limited manifold pressure, and maximum cruising power versus temperature-limited power are described.
- Flight and Test-Stand Investigation of High-Performance Fuels in Double-Row Radial Air-Cooled Engines 2: Flight Knock Data and Comparison of Fuel Knock Limits With Engine Cooling Limits in Flight
- Report discussing a comparison of the antiknock characteristics of triptane with a temperature-sensitive blending agent and of the fuel knock limits with engine cooling limits. Estimates were also made of temperature-limited engine performance at several flight and engine conditions.
- Flight Investigation at High Mach Numbers of Several Methods of Measuring Static Pressure on an Airplane Wing
- Report discusses an investigation into static pressures in subsonic and supersonic flow over an airplane wing as measured by static-pressure tubes, a static-pressure belt, and orifices flush with the wing surface. The results obtained from the three types of measuring devices and a comparison to theoretical calculations are presented.
- Flight Investigation of Boundary-Layer Control by Suction Slots on an NACA 35-215 Low-Drag Airfoil at High Reynolds Numbers
- Report presenting an investigation of the effectiveness of suction slots as a means of extending the laminar boundary layer in flight at high Reynolds numbers on an NACA 35-215 airfoil. The results showed that, with a slot spacing of about 5 percent of the chord, the laminar boundary layer could be maintained to or slightly beyond 45 percent of the chord.
- Flight investigation of boundary-layer control by suction slots on an NACA 35-215 low-drag airfoil at high Reynolds numbers
- Report presenting an investigation of the effectiveness of suction slots a a means of extending the laminar boundary layer in flight at high Reynolds numbers using an NACA 35-215 airfoil. Tests were made over a range of indicated airspeeds, lift coefficients, and Reynolds numbers. Results regarding boundary-layer control, air-intake distributions, character of the boundary layer, total-intake rate, and profile-drag coefficient are provided.
- A Flight Investigation of the Effect of Surface Roughness on Wing Profile Drag With Transition Fixed
- Report presenting a flight investigation made on a wing section of a P-47D airplane to determine the effect of roughness on wing profile drag with transition fixed far forward. Surveys of the wake were made for two surface conditions with transition fixed by a thread at 5 percent chord back of the leading edge on the upper and lower surfaces. Below the Mach number at which shock occurred, variations in Mach number of as much as 0.16 appeared to have no appreciable effect on the section profile-drag coefficients of either the smooth or roughened surfaces with transition fixed.
- Flight measurements of horizontal tail loads on a typical propeller-driven pursuit airplane during stalled pull-outs at high speed
- Report presenting flight measurements of the pressures on the horizontal tail surfaces of a typical propeller-driven pursuit airplane during stalled pull-outs at high Mach number. Unit loads measured on the stabilizer at safe maneuvering limits were not only considerably in excess of the design unit loads, but also occurred in a direction opposite to the design loads. Revision of the tail-load design requirements and manner of specifying safe maneuverability limits to pilots appears necessary.
- Flight Studies of the Horizontal-Tail Loads Experienced by a Fighter Airplane in Abrupt Maneuvers
- Report presenting flight measurements made on a modern pursuit airplane to determine the approximate magnitude of the horizontal tail loads in accelerated flight. Pressures at a few points were used as an index of the tail loads by correlating these pressures with complete pressure-distribution data obtained in the NACA full-scale tunnel.
- Flight Studies of the Horizontal-Tail Loads Experienced by a Fighter Airplane in Abrupt Maneuvers
- Field measurements were made on a fighter airplane to determine the approximate magnitude of the horizontal tail loads in accelerated flight. In these flight measurements, pressures at a few points were used as an index of the tail loads by correlating these pressures with complete pressure-distribution data obtained in the NACA full-scale tunnel. In addition, strain gages and motion pictures of tail deflections were used to explore the general nature and order of magnitude of fluctuating tail loads in accelerated stalls.
- Flight Studies of the Horizontal-Tail Loads Experienced by a Fighter Airplane in Abrupt Maneuvers
- "Field measurements were made on a fighter airplane to determine the approximate magnitude of the horizontal tail loads in accelerated flight. In these flight measurements, pressures at a few points were used as an index of the tail loads by correlating these pressures with complete pressure-distribution data obtained in the NACA full-scale tunnel. In addition, strain gages and motion pictures of tail deflections were used to explore the general nature and order of magnitude of fluctuating tail loads in accelerated stalls" (p. 351).
- Flight tests of a pursuit airplane fitted with an experimental bellows-type bob weight
- Report presenting flight tests to determine the longitudinal stability characteristics of a pursuit airplane when flown with and without an experimental bellows-type bob weight. When the weight was installed, the stick-free static stability remained approximately constant irrespective of the shift in center of gravity resulting from a change in fuel quantity in the auxiliary fuselage fuel tank. Although the weight functioned satisfactorily, the performance could have been enhanced by the reduction of the friction in the mechanism.
- Flight tests of several exhaust-gas-to-air heat exchangers
- Report presenting an investigation of thirteen exhaust-gas-to-air heat exchangers to determine the practicability of the use of such heat exchangers in the thermal ice-prevention systems on aircraft. The results show that the exchangers constitute an excellent source of heated air for aircraft ice prevention and can be constructed to resist thermal and vibrational stresses.
- Flight Tests of Several Exhaust-Gas-to-Air Heat Exchangers in the B-17F Airplane
- Report presenting flight testing of seven exhaust-gas-to-air heat exchangers on a B-17F airplane to determine their performance characteristics and to investigate their flame-suppression qualities. Testing was conducted to secure performance data of heat exchangers which might be suitable for use in the thermal ice-prevention and cabin-heating system of the heavy bomber-type airplanes.
- Flight Tests of the High-Speed Performance of a P-51B Airplane (AAF No. 43-12105)
- Report discussing testing to check the improvement of 3 or 4 miles per hour in the maximum speed of the P-51B airplane as a result of sealing the wing-gun access doors and flap-spar lightening holes. Large variations in speed were observed during testing, so additional testing and analysis was carried out to determine the effects of various factors that were suspected of contributing to the inconsistency of the plane's performance.
- Flight tests of the thermal ice-prevention equipment on the B-17F airplane
- Report presenting performance tests of the thermal ice-prevention equipment developed for the B-17F airplane at the NACA Ice Research Project. Temperatures of the heated surfaces, structure, and circulating air and the air-flow rate and quantity of heat through the system were obtained during flights in dry air and in natural icing conditions. Results regarding the wing outer panel, wing tip, wing inner panel, carburetor and intercooler inlets, horizontal stabilizer, vertical stabilizer, windshield, windows, and engine cowls are provided.
- Flight tests of various tail modifications on the Brewster XSBA-1 airplane 3: measurements of flying qualities with tail configuration 3
- Report presenting a series of tests on the Brewster XSBA-1 airplane to determine the effects of various tail modifications. Some of the modifications include variations of the chord of the elevator and rudder while the span and total area of the surfaces are kept constant and variations of the total area of the vertical tail surface. Results regarding the longitudinal stability and control and lateral stability and control are provided.
- Flight Variables Affecting Fuel-Vapor Loss From a Fuel Tank
- "Tests were conducted to determine the effect of several flight variables and several types of fuel agitation on fuel-vapor loss from a fuel tank during flight. Data were obtained from simulated-flight tests, in which the effects of rate of climb, altitude, initial fuel temperature, weathering of fuel, and fuel agitation were investigated; and a correlation between the simulated-flight and actual-flight data was established" (p. 1).
- The Flow of a Compressible Fluid Past a Circular Arc Profile
- Report presenting the use of the Ackeret iteration process to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient.
- The Flow of a Compressible Fluid Past a Circular Arc Profile
- "The Ackeret iteration process is utilized to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient. The first two terms of the development correspond to the Prandtl-Glauert approximation and yield the well-known correction to the circulation about the profile" (p. 385).
- Fluid de-icing tests on a Chandler-Evans 1900 CPB-3 carburetor mounted on a Pratt & Whitney R-1830-C4 intermediate rear engine section
- Report presenting an investigation of the icing and de-icing characteristics of a Pratt & Whitney R-1830 engine induction system. The current report covers a program to determine the most effective rate and method of injection of de-icing fluid to remove a heavy ice formation from the induction system. Results regarding the flow rates, recovery times, de-icing portions of the runs, and ice formation characteristics are provided.
- Flutter tests of B-34 fin-rudder-tab system
- From Summary: "Tests on the B-34 fin-rudder-tab assembly were performed in the NACA 8-foot high-speed tunnel. Two cases of tab flutter were studied. It was shown conclusively that the frequency of the original or heavy tab was too low and caused coupling with one of the lower bending frequencies. A general conclusion was made that the tab frequency should be considerably higher than the lower modes of the fin-rudder assembly because there is generally a weaker coupling between the tab and the higher mode responses."
- Flying Qualities of a High-Speed Bomber With a Dual Pusher Propeller Aft of the Empennage as Estimated From Wind-Tunnel Tests of a 1/8-Scale Powered Model
- Report discussing the flying qualities of a high-speed bomber with a dual pusher propeller aft of the empennage. The airplane was found to have satisfactory flying qualities except for stability issues with aft center of gravity, high elevator control forces in landing, insufficient elevator control in take-off, and low rudder-free directional stability.
- Foaming of Aircraft-Engine Oils as a Problem in Colloid Chemistry - 1
- Report presenting an investigation conducted on the foaming characteristics of representative aircraft-engine lubricants in order to arrive at an adequate theory of the foaming of such oils. Methods of measuring foaming are compared and analyzed for their significant factors.
- Force Test of a 1/5-Scale Model of the Type GB-5 Controllable Glide Bomb
- Report presenting information regarding the development of a type GB-5 controllable glide bomb equipped with a target-seeking device. The model was tested on the six-component balance in order to measure the stability and control characteristics of the bomb in its original condition and with various modifications. Results regarding the effect of end plates on dihedral parameter, effect of vertical-tail arrangement on directional stability, aileron tests, and glide-path control are provided.
- Frequency of Occurrence of Atmospheric Gusts and of Related Loads on Airplane Structures
- Report presenting an evaluation of a number of samples of flight acceleration data under a variety of operating conditions to determine the total frequencies and the frequency distribution of atmospheric gusts. The samples include 1748 hours of operation by several airplanes of the domestic airlines of the United States, a Martin M-130 airplane, and a Boeing B-15 airplane. The results indicated that the distribution of gusts within turbulent regions of the earth's atmosphere follows a substantially fixed pattern regardless of the source of the turbine.
- The Frictional Force with Respect to the Actual Contact Surface
- "Hardy's statement that the frictional force is largely adhesion, and to a lesser extent, deformation energy is proved by a simple experiment. The actual contact surface of sliding contacts and hence the friction per unit of contact surface was determined in several cases. It was found for contacts in normal atmosphere to be about one-third t-one-half as high as the macroscopic tearing strength of the softest contact link, while contacts annealed in vacuum and then tested, disclosed frictional forces which are greater than the macroscopic strength" (p. 1).
- Full-Scale Wind-Tunnel Investigation of Forward Underslung Cooling-Air Ducts
- Report presenting an investigation of underslung cooling-air ducts in various locations on a model of a typical single-engine tractor airplane in the full-scale tunnel. The report contains the results of tests of two forward underslung ducts. Results regarding pressure recoveries at the radiator, pressures behind the radiator, drag and duct efficiency, and critical speeds are provided.
- Gas Jets
- "A brief summary of the contents of this paper is presented here. In part I the differential equations of the problem of a gas flow in two dimensions is derived and the particular integrals by which the problem on jets is solved are given. Use is made of the same independent variables as Molenbroek used, but it is found to be more suitable to consider other functions. The stream function and velocity potential corresponding to the problem are given in the form of series" (p. 1).
- Gasoline-water distribution coefficients of 27 aromatic amines
- Report presenting an investigation of the suitability of 27 aromatic amines for overwater storage of their gasoline blends. The program is also meant to determine the antiknock effectiveness and low-temperature solubility in gasoline.
- General resistance tests on flying-boat hull models
- Report re-examining known procedures for handling general resistance testing on flying-boat hull models, with particular attention paid to saving test time and improving the usefulness of the results to designers. While specific testing will likely always be needed, the procedures given in the report for condensing resistance data should make data analysis easier to apply to design.
- General tank tests on the hydrodynamic characteristics of four flying-boat hull models of differing length-beam ratio
- Report presenting the results of general tests on the hydrodynamic characteristics of four related flying-boat hull models of differing length-beam ratio. Five different characteristics were investigated in an effort to gain perspective and determine which characteristics were most important: resistance, porpoising, main forebody spray blister, bow spray in rough water, and yawing stability near hump speeds.
- Guides for preventing buckling in axial fatigue tests of thin sheet-metal specimens
- From Summary: "Guide fixtures are described by means of which axial fatigue loads including compression may be applied to a thin sheet-metal specimen. Tests indicate that the guides prevented buckling without bypassing the load or injuring the specimen."
- Heat-Capacity Lag in Turbine-Working Fluids
- Report discusses measurements of the relaxation time of steam and nitrogen due to their importance as turbine-working fluids. Additional calculations regarding different nozzle lengths are included.
- Heat Transfer in a Turbulent Liquid or Gas Stream
- "The theory of heat.transfer from a solid body to a liquid stream could he presented previously only with limiting assumptions about the movement of the fluid (potential flow, laminar frictional flow). (See references 1, 2, and 3). For turbulent flow, the most important practical case, the previous theoretical considerations did not go beyond dimensionless formulas and certain conclusions as to the analogy between the friction factor and the unit thermal conductance, (See references 4, 5, 6, and 7,) In order to obtain numerical results, an experimental treatment of the problem was resorted to, which gave rise to numerous investigations because of the importance of this problem in many branches of technology" (p. 1).
- High-Altitude Cooling 1: Resume of the Cooling Problem
- Report presenting a paper in a series about the cooling of aircraft-engine installations with special reference to the difficulties of cooling at high altitudes. This particular paper discusses the properties of NACA standard air and Army summer air, with corresponding stagnation conditions for a range of flight speed, as summarized in tables and figures.