Technical Report Archive & Image Library (TRAIL) - 98 Matching Results
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- The Aerodynamic Tests of Three Edo Floats for the SB2U-3, 0S2U-2, and XSB2C-2 Seaplanes - NACA Models 106-K, 107-K, and 125-AH
- Report presenting aerodynamic testing of scale models of the Edo seaplane floats for the SB2U-3, OS2U-2, and XSB2C-2 seaplanes. Various coefficients, pitching moment, yawing moment, and drag coefficients are provided.
- Air-flow surveys in the region of the tail surfaces of a single-engine airplane equipped with dual-rotating propellers
- From Summary: "Surveys of the air flow in the region of the tail surfaces of a single-engine pursuit-type airplane equipped with dual-rotating propellers are presented."
- Analysis of Effect of Rolling Pull-Outs on Wing and Aileron Loads of a Fighter Airplane
- An analysis was made to determine the effect of rolling pull-out maneuvers on the wing and aileron loads of a typical fighter airplane, the P-47B. The results obtained indicate that higher loads are imposed upon wings and ailerons because of the rolling pull-out maneuver, than would be obtained by application of the loading requirements to which the airplane was designed. An increase of 102 lb or 15 percent of wing weight would be required if the wing were designed for rolling pull-out maneuver. It was also determined that the requirements by which the aileron was originally designed were inadequate.
- Application of a numerical procedure to stress analysis of stringer-reinforced panels
- From Introduction: "In the present paper a numerical procedure for the stress analysis of flat-sheet and stringer combinations of arbitrary construction and loading is presented and applied to axially loaded panels and to the reinforced covers of box beams."
- Approximate Formulas for the Computation of Turbulent Boundary-Layer Momentum Thicknesses in Compressible Flows
- Report presenting approximate formulas for the computation of the momentum thickness of turbulent boundary layers on two-dimensional bodies, on bodies of revolution at zero angle of attack, and on the inner surfaces of round channels all in compressible flow given in the form of integrals that can be conveniently computed. Results for skin-friction formulas, laminar boundary layers, and full thickness of boundary layer are provided.
- Artificial Running-in of Piston Rings
- Report presenting a consideration of the performance of sliding surfaces, such as piston rings, cylinders, journals, and bearings in aircraft engines with reference to the surface characteristics that they possess before and after running-in, prior to service operation. The phenomena accompanying the running-in process are analyzed.
- Characteristics of plain and balanced elevators on a typical pursuit fuselage at attitudes simulating normal-flight and spin conditions
- Report presenting lift and elevator hinge-moment characteristics of a horizontal tail with various plain and balanced elevators and mounted on a typical pursuit fuselage as measured in the 7- by 10-foot wind tunnel at attitudes simulating normal-flight and spin conditions. The lift effectiveness of the elevator was practically independent of the size of the aerodynamic balance. Results regarding the fuselage alone and fuselage interference, lift characteristics of fuselage-tail combinations, lift effectiveness of the tab, elevator hinge moments, parameters, effect of yaw on elevator hinge moments, effect of tab on elevator hinge moments, drag, and comparison with two-dimensional data are provided.
- Characteristics of Several Single- and Dual-Rotating Propellers in Negative Thrust
- Report discusses the thrust and power characteristics of several single- and dual-rotating propellers with differing blade width and number of blades for negative-thrust operation from -45 degrees to 145 degrees blade angle. From Summary: "The tests indicate that it is possible to predict for a given propeller design characteristics in the negative-thrust range from known characteristics at a different activity factor. Adequate negative thrusts were indicated for extremely high positive as well as negative blade angles."
- Charts for Critical Combinations of Longitudinal and Transverse Direct Stress for Flat Rectangular Plates
- Report presenting the use of the energy method to derive interaction equations that define the critical combinations of longitudinal and transverse direct stress for isotropic flat rectangular plates with four different edge conditions. Charts based on the interaction equations are presented for the four cases.
- Comparison of Tail and Wing-Tip Spin-Recovery Parachutes as Determined by Tests in the Langley 20-Foot Free-Spinning Tunnel
- Report presenting tests of spin-recovery parachutes on six models of typical fighter and trainer airplanes conducted in the 20-foot free-spinning tunnel to obtain data for correlating model and full-scale results. Parachutes attached to the tail of the models, to the outer wing tip, to the inner wing tip, and to both wing tips were tested. Results regarding parachute construction, loading variations, effect of test altitude, and action of spin-recovery parachutes are provided.
- Comparison of Wind-Tunnel and Flight Measurements of Stability and Control Characteristics of a Douglas A-26 Airplane
- Tests in Langley pressure tunnel of model XA-26 bomber were compared with those of A-26B (twin-engine attack bomber) and showed that static longitudinal stability, indicated by elevator-fixed neutral points, and variation of elevator deflection in straight and turning flight were good. Airplane possessed improved stability at low speeds which was attributed to pronounced stalling at root of production wing. At rudder-force reversal at speeds higher than those in flight tests, agreement in rudder-fixed and rudder-free static directional stability was good. Hinge moment obtained at zero sideslip was satisfactory for determining aileron forces in sideslip.
- A Correlation of the Dimensions, Proportions, and Loadings of Existing Seaplane Floats and Flying Boat Hulls
- Report presenting a study to determine what loadings and proportions have been chosen by designers of seaplanes and flying boats and what, if any, interrelations exist between the loadings and proportions. The characteristics considered include the beam, getaway speed, forebody length, afterbody length, hull length, center of gravity, and brake horsepower necessary.
- 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.
- Determination of Iron Contamination of Used Lubricating Oil for Use in Measuring Rates of Wear in Aircraft Engines
- Report discusses methods of determining the iron contamination of used lubricating oil in order to study wear rates of piston rings and cylinder barrels of aircraft engines. Two methods of separating iron from used lubricating oil are presented. The results of the analyses of the oil are presented and the methods are evaluated.
- Determination of Towline Tension and Stability of Spin-Recovery Parachutes
- Report presenting testing of a number of spin-recovery parachutes varying in size in order to determine the force exerted by the parachutes on the towline and the stability of the parachutes. The effects of modifications to the parachutes regarding towline tension and stability are also provided. Results regarding the parachute motions, air forces on parachutes, shock loads, and effects of modifications to line length and canopy vent are provided.
- Development of Wing Inlets
- Lift, drag, internal flow, and pressure distribution measurements were made on a low-drag airfoil incorporating various air inlet designs. Two leading-edge air inlets are developed which feature higher lift coefficients and critical Mach than the basic airfoil. Higher lift coefficients and critical speeds are obtained for leading half of these inlet sections but because of high suction pressures near exist, slightly lower critical speeds are obtained for the entire inlet section than the basic airfoil.
- Effect in Flight of the Propeller Cuffs and Spinner on Pressure Recovery in Front of a Double-Row Radial Aircraft Engine in a Twin-Engine Airplane
- Report presenting an investigation conducted with the propeller cuffs and spinner removed to determine their effect in flight on the pressure recovery of the cooling-air flow. Curves are presented to compare the pressure and temperature distribution over the front row of cylinders for flights with and without cuffs and spinner.
- The effect of altitude on cooling
- Report presenting variables that control the cooling of liquid-cooled and air-cooled engines and then to show by illustrations how either engine may be cooled at any desired altitude. Cooling was found to not be the limiting factor in the design of high-altitude airplanes and was also not found to be a valid reason for selecting either liquid- or air-cooled engines for high-altitude operation.
- Effect of Carburetor-Mixture-Control and Supercharger Characteristics on Fuel Knock Under Simulated Sea-Level Flight Conditions
- Report presenting knock-limit data recorded for a current 100-octane-number aviation gasoline in a full-scale single-cylinder test engine. Inlet-air temperatures were the temperatures estimated from a consideration of the temperature increase through an aircraft-engine supercharger. The data indicate that the relation of the carburetor-mixture-control characteristics to the knock characteristics of the fuel is an important factor in determining knock-free operation.
- The Effect of Compression Ratio, Cooled Exhaust Gas Mixed With Inlet Air, and Inlet-Air Temperature on the Knock-Limited Performance of a Full-Scale Single-Cylinder Engine
- Report presenting a study to determine the effect on the knock-limited permissible power output on the indicated specific fuel consumption and on the cylinder temperatures of exhaust-gas dilution of the inlet-air charge, inlet-air temperature without exhaust-gas dilation, and of compressible ratio.
- The Effect of Continuous Knock on the Endurance of an Aircraft Engine Cylinder
- Report presenting an investigation to determine any injurious effects of knock on engine parts. Endurance tests were run on a single-cylinder engine to compare the conditions of cylinders operated with and without knock. Results regarding the history of the tests, conditions of pistons and cylinders, absence of surface ignition, and effect of knock on cylinder temperatures are provided.
- The Effect of Modified Baffles and Auxiliary-Cooling Ducts on the Cooling of a Double-Row Radial Engine
- Report discussing testing to determine the cooling effect of modified baffles and auxiliary-cooling ducts on the rear-row cylinders of a double-row radial engine. The modified baffles were found to reduce the temperatures of the exhaust-valve seats, but did not have an effect on the valve-guide temperatures. The auxiliary-cooling ducts reduced temperatures of the exhaust-valve seats and rear spark plug gaskets.
- Effect of normal pressure on the critical compressive and shear stress of curved sheet
- Results are presented of tests of two sets of 20 curved-sheet specimens to determine the effect of normal pressure on the critical compressive and shear stress of curved sheets. It was found that normal pressure raised the critical compressive and shear stress of curved sheets except when outward bulging occurred in compression, in which case the critical stress was lowered by normal pressure. (author).
- Effect of Rotor-Tip Speed on Helicopter Hovering Performance and Maximum Forward Speed
- Report presenting a study of several sample helicopters in order to evaluate the effect of rotor-tip speed on hovering performance and limiting forward speed. The main purpose of the study was to determine whether hovering performance could be increased by the use of lower tip speeds without undue sacrifice in maximum forward speed. Results regarding typical helicopters, low-solidity helicopters, and high-speed helicopters are provided.
- 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).
- 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.
- An Electron and X-Ray Diffraction Investigation of Surface Changes on Nitrided-Steel Piston Rings During Engine Operation in Nitrided-Steel Cylinders Barrels
- Report presenting an examination of new and used nitrided-steel piston rings by electron and X-ray diffraction in a study of the surface changes produced during engine operation. Both new and used rings, examined after degreasing, gave an electron-diffraction pattern consisting of diffuse bands: those from used rings fell at the usual positions of the bands from polished metal surfaces.
- 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.
- Estimation of Critical Speeds of Airfoils and Streamline Bodies
- Report presenting methods and charts for estimating the critical compressibility speeds of a large number of airfoils and streamline bodies. The systematic effects of thickness, thickness distribution, camber, camber location, leading-edge radius, and lift coefficient are considered. The results indicate that with a given lift coefficient, the thickness of the airfoil or of the body is the primary factor controlling its critical speed.
- Estimation of stick-fixed neutral points of airplanes
- Report presenting a method for calculating the stick-fixed neutral point of an airplane with the propeller windmilling, the flaps neutral, and landing gear retracted. The methods used in this report should be useful in estimating the stick-fixed neutral points of new designs for all flight conditions.
- 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.
- An Experimental Investigation of Flow Across Tube Banks
- Flow across tube banks was investigated by surveys of total dynamic and static pressure by visualization of the flow through the use of titanium tetrachloride smoke, by thermocouple surveys of heated tubes, and by hot-wire surveys of both heated and unheated tubes. It was found that turbulence increased as the depth of the bank increased and that the broad wake behind each tube affected flow over the succeeding tubes.
- 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.
- Flight Investigation at High Speeds of Profile Drag of Wing of a P-47D Airplane Having Production Surfaces Covered with Camouflage Paint
- Wing section outboard of flap was tested by wake surveys in Mach range of 0.25 - 0.78 and lift coefficient range 0.06 - 0.69. Results indicated that minimum profile-drag coefficient of 0.0097 was attained for lift coefficients from 0.16 to 0.25 at Mach less than 0.67. Below Mach number at which compressibility shock occurred, variations in Mach of 0.2 had negligible effect on profile drag coefficient. Shock was not evident until critical Mach was exceeded by 0.025.
- Flight tests of a P-63-1 airplane with an electric torquemeter
- Report presenting an electric torquemeter that was used to measure the power of an Allison V-1710-93 engine installed in a Bell P-63A-1 airplane. Results of maximum-available-power tests in flight at a range of density altitudes showed good agreement between the measured maximum power output and the maximum power shown on the engine manufacturer's calibration chart.
- Flight Tests of a Rudder With a Spring Tab on an F6F-3 Airplane (BuAer No.04776)
- Report discussing testing on an F6F-3 with a spring-tab rudder to determine the directional stability and control characteristics. Using the spring-tab rudder was found to result in lower trim-force change with speed and lower pedal forces in sideslips than the original rudder. Pilots were found to prefer the maneuverability of this configuration.
- 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 the Sikorsky HNS-1 (Army YR-4B) Helicopter 1: Experimental Data on Level-Flight Performance With Original Rotor Blades
- "Results of performance measurements made in level fight with the HNS-1 (Army YR-4B) helicopter are presented. These data include torquemeter measurements of shaft power for both the main rotor and the tail rotor. The power data, in conjunction with full-scale-tunnel date on the lift and drag of the fuselage, are used to calculate the drag-lift ratio for the main rotor" (p. 1).
- 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 critical gust loads on overloaded airplanes
- Report presenting statistical gust-frequency data used to determine the effect of overloading an airplane on the frequency of occurrence of gust loads that stress the airplane to or above its design applied bending moment. The analysis was made for three transport-type airplanes operating at cruising power with overloads varying from 0 to 50 percent of the design gross weight. The probability of structural failure was found to increase rapidly with overload.
- Full-scale wind-tunnel and flight tests of a Fairchild XR2K-1 airplane with a zap flap and upper-surface aileron-wing installation
- Report presenting testing of a Fairchild XR2K-1 airplane equipped with a wing having a full-span Zap flap and upper-surface ailerons in the full-scale wind tunnel and in flight to determine the characteristics of the flap and ailerons. Results regarding the lift, drag, and pitching-moment coefficients of the airplane and the aileron rolling, yawing, and hinge-moment coefficients were measured at various flap deflections are provided. Maximum rolling velocity and acceleration, yawing velocity, time lag in aileron response, and aileron control forces were also determined.
- High-Speed Photographs of a YR-4B Production Rotor Blade for Simulated Flight Conditions in the Langley Full-Scale Tunnel
- Report discussing tests of a Sikorsky YR-4B helicopter, including photography of a rotor blade in forward-flight conditions at several azimuth angles for several tip-speed ratios. Fabric deformation in the form of sagging and bulging was noted. A reversal in the bending curve near the blade tip was also noted, which was hypothesized to come from losses of lift and high centrifugal force.
- High Temperature Characteristics of 17 Alloys at 1200 and 1350 Degrees F
- Report presenting the results of a study of the rupture-test characteristics of 13 wrought and 4 cast alloys which were considered to have promise for service in exhaust gas turbines. The results are given in the forms of a table of information and data, a page of curves, and a page of photomicrographs.
- An Investigation of Aircraft Heaters 8: A Simplified Method for the Calculation of the Unit Thermal Conductance Over Wings
- Report presenting a simplified approximate method of calculating the unit thermal conductance along an airfoil as a function of distance from the leading edge, by use of heat transfer data for smooth cylinders and smooth flat plates. Several examples are used in order to show the effectiveness of the method.
- An Investigation of Aircraft Heaters 9: Measured and Predicted Performance of Two Exhaust Gas-Air Heat Exchangers and an Apparatus for Evaluating Exhaust Gas-Air Heat Exchangers
- Report presenting laboratory testing to determine the thermal output and pressure drop characteristics of the Airesearch and Solar fluted-type exhaust gas-air heat exchangers. The apparatus used in these tests consisted of a natural gas furnace of 3,000,000 Btu per hour thermal capacity, a centrifugal blower, and a system of ducting and various measuring devices. Results regarding the method of analysis, the Airesearch heat exchanger tests, the solar heat exchanger tests, and a comparison of the two heat exchangers are provided.
- An investigation of aircraft heaters 10: measured and predicted performance of a fluted-type exhaust gas and air heat exchanger
- Report presenting performance data on a small exhaust gas and air heat exchanger. The heat transfer rates were measured using about 8000 pounds per hour of exhaust gas and 4300 pounds per hour of ventilating air. The thermal performance of heater no. 2 can be estimated to 3 to 17 percent by use of the method described in the report.
- An investigation of aircraft heaters 14: an air and heat flow analysis of a ram-operated heater and duct system
- Report presenting a method of graphical analysis that allows for the prediction of the thermal and aerodynamic performance of a ram-operated heater and duct system, for cabin heating or wing de-icing, at any altitude and airplane speed. Performance can be predicted from the isothermal total pressure drop across the components of the duct system at several ventilating air rates and the thermal output of the heater at various air and exhaust gas rates.
- Investigation of Ice Formation in the Induction System of an Aircraft Engine 1: Ground Tests
- "Ground tests were conducted on a twin-engine fighter airplane to study icing of an induction system incorporating an exhaust-driven turbosupercharger. The ground tests were made to determine the disposition of free water in the induction system of the airplane, to determine the charge-air heat rise available from the turbosupercharger, and to correlate actual airplane-test results with those of laboratory tests" (p. 1).
- Investigation of Slipstream Effects on a Wing-Inlet Oil-Cooler Ducting System of a Twin-Engine Airplane in the Ames 40- by 80-Foot Wind Tunnel
- Report discussing an investigation of wing-inlet oil-cooler ducts on a twin-engine airplane to determine internal and external-flow characteristics of the ducting installation. Testing was also performed on revised inlets to attempt to develop a ducting system with low overall losses throughout the operating range.
- Investigation of the Longitudinal Stability at High Speeds of a 1/5-Scale Model of a Tailless Pursuit Airplane
- "Tests of a tailless pursuit airplane model at the Ames Aeronautical Laboratory have shown that in conditions corresponding to level flight at a Mach number less than 0.7 and at an altitude under 35,000 feet, no serious compressibility effects occurred and that no sudden adverse diving moments were encountered up to a Mach number of 0.74, the maximum speed of the tests. However, there were indications that the elevons might lose their effectiveness for longitudinal control during a pull-out from a steep dive" (p. 1).