UNT Libraries Government Documents Department - 1,264 Matching Results

Search Results

Flight Investigation of Boundary-Layer and Profile-Drag Characteristics of Smooth Wing Sections of a P-47D Airplane
Report presenting a flight investigation made of boundary-layer and profile-drag characteristics of smooth wing sections of a P-47D airplane. Measurements were made at three stations on the wing: boundary-layer measurements, pressure-distribution measurements, and wake surveys. The results indicated that a minimum profile-drag coefficient of 0.0062 for the smooth section at 63 percent semispan was obtained.
Investigation of Effects of Various Camouflage Paints and Painting Procedures on the Drag Characteristics of an NACA 65(Sub 421)-420, a = 1.0 Airfoil Section
Bulletin presenting an investigation of the effects of various camouflage paints and painting procedures on the drag characteristics of a 60-inch-chord low-drag airfoil in the NACA two-dimensional low-turbulence pressure tunnel.
Tests of a Heated Low-Drag Airfoil
Report discusses the results of an experimental investigation into the NACA 65,2-016 heated wing. Information about the effect of heating on the drag coefficients, Reynolds numbers, and stability of the laminar boundary layer.
High-Altitude Cooling 3: Radiators
Report details the methods of determining the heat-transfer rate, pressure drop, and drag power of high-altitude radiators. Performance charts are provided for a wide range of design variables.
Aerodynamic Factors Affecting the Ability of a Pilot to Return an Airplane to Level From a Banked Attitude by Use of the Rudder Alone and Without Change of Heading
Report presenting a study of the aerodynamic factors upon which the ability to perform the maneuver depends in an attempt to obtain a better understanding of the conditions involved and, if possible, to evolve criterions that may be used during design.
Airfoil Section Data From Tests of 10 Practical-Construction Sections of Helicopter Rotor Blades Submitted by the Sikorsky Aircraft Division, United Aircraft Corporation
Report presenting 10 practical-construction models of sections of helicopter rotor blades tested in the NACA two-dimensional low-turbulence pressure tunnel at atmospheric pressure. Lift, drag, and pitching-moment characteristics of blades representing the present method of construction of the YR-4A helicopter were determined.
High-Altitude Cooling 6: Axial-Flow Fans and Cooling Power
Report presenting the theory, design, and effect on cooling of the constant-velocity axial-flow fan as related to the problem of high-altitude aircraft engine cooling. The existing theory of the axial-flow fan, including a discussion of the fan losses, is summarized.
The Oxidation of Exhaust Gases at Room Temperature
Report presenting an investigation made to determine the effectiveness of various oxides and oxide mixtures in oxidizing at room temperature the exhaust gases from an internal-combustion engine for the determination of fuel-air ratio. The oxides of silver, copper, manganese, cobalt, nickel, iron, cerium, lead, bismuth, and mercury were tested individually and in various combinations.
Measurements of Friction Coefficients in a Pipe for Subsonic and Supersonic Flow of Air
Report presenting tests of the flow of air through brass tubes with the friction coefficient and incompressible flow relation as the main focus. The analytical relation between friction coefficient, tube length, and Mach number is shown for flow without shock and the conditions for flow with and without shock are delimited.
A Method for the Rapid Estimation of Turbulent Boundary-Layer Thickness for Calculating Profile Drag
"An analysis is developed that makes it possible to integrate von Kármán's boundary-layer momentum equation directly. For this purpose, the skin friction coefficient is expressed as a function of the Reynolds number based on the boundary-layer momentum thickness and the boundary-layer shape is assumed to be constant. The integrated equation permits the boundary-layer momentum thickness at the airfoil trailing edge to be rapidly determined for the estimation of airfoil profile-drag coefficients" (p .1).
A Method of Calculating Bending Stresses Due to Torsion
Report presenting a method for analyzing bending stresses due to torsion in a box with variable cross section and loading by means of a recurrence formula leading to a set of equations identical in form with the well-known three-moment equations. An approximate form of the general method of analysis is presented that eliminates the need of solving a system of equations.
A Method for Welding Sheet Aluminum to SAE 4140 Steel
Report presenting an investigation of a large variety of different metals used as an intermediate metal between aluminum and steel for the purpose of securing a good bond both from the viewpoint of strength and thermal conductivity. The principal result was that it was found possible to secure a satisfactory bond between aluminum and steel by electroplating the steel with a layer of silver of proper thickness.
Method of Calculating Performance of Dual-Rotating Propellers From Airfoil Characteristics
"A method is developed for calculating the performance of a dual-rotating propeller from the section characteristics of the blade elements. The method is applied to an eight-blade dual-rotating propeller and the computed results are compared with low-speed wind-tunnel tests of the same propeller in both the tractor and pusher positions. The computations are found to agree within the experimental accuracy of the measurements" (p. 1).
Measurements of the Flying Qualities of a Hawker Hurricane Airplane
Report presenting an investigation of the flying qualities of a Hawker Hurricane airplane. Thirteen flights and approximately 17 hours of flying time were required to complete the tests, which included extensive measurements of stability, controllability, and stalling characteristics. The results were similar to the flying qualities of other previously studied pursuit airplanes.
A Method for Making Quantitative Studies of the Main Spray Characteristics of Flying-Boat Hull Models
Report presenting a method and apparatus for making quantitative tests of the spray characteristics of flying-boat-hull models. The method is applied to three related models of flying-boat hulls which differed in one major characteristic of shape: the overall dead rise.
A Method for Studying the Longitudinal Dynamic Stability of Flying-Boat-Hull Models at High Planing Speeds and During Landing
Report presenting an investigation of a method of studying the longitudinal dynamic stability of flying-boat-hull models, as instability may be encountered when flying a flying boat on the water at high speeds and high trim angles, especially upper-limit porpoising and skipping. A method is described for carrying out generalized experimental studies of the longitudinal dynamic stability of flying-boat-hull models.
Preliminary Vibration and Flutter Studies on P-47 Tail
Report presenting a report illustrated by photographs and vibration records on the failure of the P-47 rudder in the high-speed tunnel at a true speed of 468 miles per hour and a density corresponding to 9000 feet altitude. The fin-rudder unit was tested as being at least representative of the tail design of the P-47 airplane.
Procedure Used at Aluminum Research Laboratories for Determining Type of Attack in Some Aluminum Alloys
Report presenting samples of 17S-T and 24S-T aluminum alloys subjected to accelerated corrosion tests in which the corrosion period was established at 6 hours for samples that had been etched to produce a uniform surface. The results indicate the types of corrosion attack, which are described in standard terminology, and may form a basis for estimating the resistance of the material to corrosion by a comparison of the relative depth and frequency of the corrosive attacks.
Preliminary Drag Tests in Flight of Low-Drag Wing on the Curtiss XP-60 Airplane
"The following preliminary drag results obtained in flight on the low-drag wing of the Curtiss XP-60 airplane are given herewith in compliance with the request of the Army Air Corps" (p. 1).
Preliminary Report on the Characteristics of the N.A.C.A. 4400R Series Airfoils
Report presenting tests made in the variable-density wind tunnel of airfoils of the NACA 4400 series modified by reflex at the trailing edge designed to reduce the pitching moment to the value of -0.03. The modified airfoils are designated the NACA 4400R series.
Preliminary Tank Tests With Planing-Tail Seaplane Hulls
Report presenting testing made with simplified models of two types of hulls that differ considerably from conventional types. Both have a single main planing surface that is combined with after-planing surfaces placed directly below the aerodynamic tail surfaces. Results regarding an investigation of twin planing tails, a single-planing tail, and potentialities indicated by tests are provided.
The Preparation of 2, 2, 4, 4-Tetramethylpentane
Report presenting seven distinct operations in the preparation of 2,2,4,4-tetramethylpentane, including the preparation of di-isobutylene hydrochloride, preparation of dimethylzinc, reaction of dimethylzinc in dry benzene with di-isobutylene hydrochloride, preliminary distillation of the reaction products, treatment of the first distillate with sodium and alcohol, final distillation after appropriate washing of the products, and recovery of the iodine in the zinc residues of II as methyl iodide.
A Procedure for the Shear-Lag Analysis of Box Beams
Report presenting a procedure for the shear-lag analysis of box beams, such as wing structures. It is based off of a previous method but allows for the separation of the most essential part of the shear-lag analysis.
Preliminary Data on Buckling Strength of Curved Sheet Panels in Compression
Report presenting the results obtained in compression tests of eight stiffened panels. The radius-thickness ratio of the skin between stiffeners varied from 400 to infinity.
Preliminary Investigation and Design of an Air-Heated Wing for Lockheed 12A Airplane
Report presenting a study of the design of an air-heated wing and the results of tests performed on a model air-heated leading edge, which were made to determine the validity of the proposed wing design.
Airfoil-Contour Modifications Based on (Epsilon)-Curve Method of Calculating Pressure Distribution
From Introduction: "Certain alternations of a qualitative nature may be performed in spite of the fact that a pressure change cannot be prescribed. It is the purpose of this paper to indicate a method by which qualitative alternation may be performed. It will be noted that the present method of contour modification will serve the intended purpose of the inverse method."
Stability and Control Tests of a 3/4-Scale Model of the XP-69 Airplane in the NACA Full-Scale Tunnel
Report presenting tests in the full-scale tunnel to determine the longitudinal- and lateral-stability and control characteristics of a scale model of the XP-69 airplane. The data include measurements of the forces and moments on the model at various angles of attack and angles of yaw. The effects of elevator, rudder, and aileron deflection on control-surface effectiveness and on hinge moments were determined.
An Investigation of Aircraft Heaters 5: Theory and Use of Heat Meters for the Measurement of Rates of Heat Transfer Which Are Independent of Time
Report presenting a description of a meter which will measure the heat flowing through surfaces. Its operation is based on the measurement of the temperature decrease through a fixed thermal resistance. Only the case of heat flow independent of time is discussed in this particular report.
Aerodynamic Characteristics of a 1/8-Scale Powered Model of a High-Speed Bomber With a Dual Pusher Propeller Aft of the Empennage
Report presenting wind-tunnel tests made to determine the aerodynamic characteristics of a scale model of a high-speed bomber with a dual pusher propeller aft of the empennage. Some of the results discussed include longitudinal, lateral, and directional stability and control, the empennage design, and ground effects on the aerodynamic characteristics. The results indicate that this particular airplane has several advantages with regard to stability and control over the conventional-type single-engine airplane configuration.
Investigation of Extreme Leading-Edge Roughness on Thick Low-Drag Airfoils to Indicate Those Critical to Separation
Bulletin presenting a study of several airfoils, including a conventional NACA 23021 and some low-drag airfoils for which the thickness had been increased, as smooth airfoils and after the application of a standard roughness. The results show some of the airfoils to be critical to separation resulting from such flow disturbances.
An Investigation of Aircraft Heaters 2: Properties of Gases
Report presenting the properties of some exhaust gases and air that are pertinent to airplane heat transfer calculations, including air, hydrogen, nitrogen, oxygen, carbon dioxide, and carbon monoxide. A bibliography related to gas properties is also provided.
Flight Measurements of the Elevator Deflections Used in Landings of Several Airplanes
"A collection of data on the elevator deflections used in landings of several airplanes is presented in tabular form. The physical characteristics of these airplanes are also given. The elevator deflections used in landing some airplanes was found to be as much as 14.4 degrees greater than that used to stall under the same flight and loading conditions" (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.
Fuel Consumption Corrected for Cooling Drag of an Air-Cooled Radial Aircraft Engine at Low Fuel-Air Ratios and With Variable Spark Advance
Report presenting results of tests conducted with an air-cooled, radial aircraft engine to determine the reduction in the brake specific fuel consumption that would result from operating with a very low fuel-air ratio and an increased spark advance. Computed values of the brake specific fuel consumption corrected for cooling-air drag are also given.
Flight and Test-Stand Investigation of High-Performance Fuels in Double-Row Radial Air-Cooled Engines 3: Comparison of Cooling Characteristics of Flight and Test-Stand Engines
Report presenting the cooling characteristics of a 14-cylinder double-row radial air-cooled engines in a test stand and in flight. Three types of cooling tests were made for both engines: variable charge-air flow, variable cooling-air pressure drop, and variable fuel-air ratio. For the same operating conditions, the test-stand engine was found to run consistently cooler than the flight engine.
Flight Measurements of the Rudder Control and Sideslip Characteristics of Four Vertical Tail Arrangements on the P-40 Series Airplanes
Report presenting an investigation of rudder trim force change with speed and power, rudder force reversals in sideslips, and rudder positions in sideslips and straight flight of a P-40E airplane. Quantitative measurements of the items were made on three other vertical arrangements.
Flight Measurements of the Effects of a Wing Leading-Edge Slot and Other Modifications on the Stability, Maximum Lift, and High Speed of an Observation Airplane
Report presenting stability, maximum lift, and high-speed tests of an observation airplane fitted with Maxwell leading-edge slots. The static and dynamic longitudinal and lateral stability was generally satisfactory and not affected much by the slots.
High-Altitude Cooling 2: Air-Cooled Engines
Report presenting the heat-transfer theory for air-cooled engines and an analysis of the cooling pressure drop for the case in which the pressure drop is an appreciable fraction of the absolute pressure. A chart is given for the simple determination of the cooling pressure drop predicted on the basis of the usual type of sea-level cooling-correlation tests.
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.
High-Altitude Cooling 4: Intercoolers
"The variation of intercooling requirements with altitude is discussed and the corresponding effects on intercooler design are shown. A discussion is also given of the relations among the various design parameters and of the ranges of choice in design. The important effects of the various factors on intercooler proportions are illustrated with charts for the Harrison copper cross-flow intercooler" (p. 1).
An Investigation of Aircraft Heaters 1: Elementary Heat Transfer Considerations in an Airplane
Report presenting a report regarding the basic factors of heat transfer applied specifically to aircraft heating and to guide the experimenter in planning experiments to obtain further data.
Investigation of Means for Extending the Range of Several Bombers to 6000 Miles
Report presenting an investigation of means to increase the range of several airplanes to 6000 miles, including the B-17E, B-24D, B-26C, and B-25A. Tank-wing trailers and tank gliders were found to be the most practical ways of increasing range and calculations are provided for determining the proper loading and dimensions.
Measurements of the Flying Qualities of a Supermarine Spitfire VA Airplane
Report presenting the flying qualities of the Supermarine Spitfire airplane. A variety of information regarding the construction, installation, longitudinal stability and control, and lateral stability and control are provided.
Investigation of Methods of Reducing the Temperature Variation Among Cylinders on Air-Cooled Aircraft Engines
Report presenting testing to determine methods for reducing the temperatures of the hot cylinders on air-cooled aircraft engines. A Pratt & Whitney R-1830-43, 14-cylinder engine used for the tests. Results regarding the cooling-air ducts, mixture-enriching tests, additional cooling area, baffle modifications, and an application of the information are provided.
Investigation of the Variation of Lift Coefficient With Reynolds Number at a Moderate Angle of Attack on a Low-Drag Airfoil
Bulletin presenting an investigation of the boundary layer about the NACA 66,2-216, a = 0.6 airfoil section in the two-dimensional low-turbulence tunnel. The primary purpose was to find an explanation for the decreased slope of the lift curve observed for some of the low-drag sections outside the low-drag range at low Reynolds numbers.
An Investigation of Aircraft Heaters 4: Measured and Predicted Performance of Longitudinally Finned Tubes
Report presenting a study of two double tube, cylindrical, longitudinally finned heat exchangers in which hot exhaust gases pass through the annular space and ventilating air passes through the center tube in order to determine heat transfer and pressure drop performance.
An Investigation of Aircraft Heaters 7: Thermal Radiation From Athermanous Exhaust Gases
"Equations and necessary data for the calculation of the gaseous radiation from water vapor and carbon dioxide in an exhaust gas heat exchanger are presented. A typical calculation is included" (p. 1).
An Investigation of Aircraft Heaters 3: Measured and Predicted Performance of Double Tube Heat Exchangers
Report presenting a study of two double tube cylindrical heat exchangers, in which hot exhaust gases pass through the annular space and ventilating air passes through the center tube, to determine heat transfer performance and pressure drop. Tests were performed in order to establish a simple, accurate method of predicting the performance of the double tube heat exchanger, to compare the performance of the straight and dimpled tubes, and to determine the pressure drop across the units.
An Investigation of Aircraft Heaters 6: Heat Transfer Equations for the Single Pass Longitudinal Exchanger
Report presenting an analysis of parallel flow and contraflow single pass heat exchangers, together with charts which allow the direct evaluation of the thermal performance of the units without recourse to trail-and-error techniques. The use of equations and charts is illustrated by several examples.
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.