UNT Libraries Government Documents Department - 1,263 Matching Results

Search Results

Analysis of Wind-Tunnel Stability and Control Tests in Terms of Flying Qualities in Full-Scale Airplanes
From Summary: "The analysis of results of wind-tunnel stability and control tests of powered airplane models in terms of the flying qualities of full-scale airplanes is advocated. In order to indicate the topics upon which comments are considered desirable in the report of a wind-tunnel stability and control investigation and to demonstrate the nature of the suggested analysis, the present NACA flying-qualities requirements are discussed in relation to wind-tunnel tests. General procedures for the estimation of flying qualities from wind-tunnel tests are outlined."
Compressibility and Heating Effects on Pressure Loss and Cooling of a Baffled Cylinder Barrel
Report presenting testing to obtain experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. Testing occurred over a wide range of air flows and density altitudes.
The Knock-Limited Performance of S Reference Fuel Plus 2 Milliliters of Triethylthallium Per Gallon
Report discusses the results of testing of thallium as an antiknock agent in an internal-combustion engine. From Introduction: "On a weight basis, the thallium vapors were found to have several times the antiknock value of tetraethyl lead, which was added to the fuel. The amount of thallium vapor necessary to raise the antiknock properties of a gasoline up to exact equivalence with a benzol-gasoline mixture was determined in these engine tests."
A method for studying the hunting oscillations of and airplane with a simple type of automatic control
Report presenting a method for predicting the amplitude and frequency, under certain simplifying conditions, of the hunting oscillations of an automatically controlled aircraft with lag in the control system or in response of the aircraft to the controls. Formulas are given expressing the response to a variation of signal in terms of response to a unit signal.
Intercooler cooling-air weight flow and pressure drop for minimum drag loss
Report presenting an analysis of the power losses in airplane flight of cross-flow plate and tubular intercoolers to determine the cooling-air weight flow and pressure drop that give minimum total power loss for any given cooling effectiveness. The investigation covers a range of flight conditions of altitude, airspeed, lift-drag ratio, supercharger-pressure ratio, and adiabatic efficiency.
Correlation of exhaust-valve temperatures with engine operating conditions and valve design
Report presenting a theory regarding engine-cooling variables from a previous report, which was used as a basis for the development of a semi-empirical equation to correlate exhaust-valve temperature with engine conditions. Results regarding the determination of constants, influences of operating variables on mean effective gas temperatures, thermal-resistance factor, and accuracy of correlating equation are provided.
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.
The effect of compressibility on two-dimensional tunnel-wall interference for a symmetrical airfoil
Summary: The effective change in the velocity of flow past a wing section, caused by the presence of wind-tunnel walls, is known for potential flow. This theory is extended by investigation of the two-dimensional compressible flow past a thin Rankine Oval. It is shown that for a symmetrical section at zero angle of attack the velocity increment due to the tunnel walls in the incompressible case must be multiplied by the factor 1/1-M^2 to take account of compressibility effects. The Mach number, M, corresponds to conditions in the wind-tunnel test section with the model removed (p. 1.).
A method for determining the rate of heat transfer from a wing or streamline body
From Summary: "A method for calculating the rate of heat transfer from the surface of an airfoil or streamline body is presented. A comparison with the results of an experimental investigation indicates that the accuracy of the method is good. This method may be used to calculate the heat supply necessary for heat de-icing or in ascertaining the heat loss from the fuselage of an aircraft operating at great altitude, for example."
Emergency Measures for Increasing the Range of Fighter Airplanes
"An analysis was made to show the relative effectiveness of streamline external fuel tanks, a fuel tank in the form of a wing mounted in a biplane position, and auxiliary wing panels attached at the wing tips to increase the span as temporary means for increasing the range of a fighter-type airplane. Figures and charts for the various devices considered show the results of calculations of range, duration of flight, and take-off distance for both land-base and carrier operation. The results indicated that the wing-tip extensions were the most promising of the devices considered" (p. 1).
Review of Flight Tests of NACA C and D Cowlings on the XP-42 Airplane
Report presenting the results of flight tests of the performance and cooling characteristics of three NACA D cowlings and of a conventional NACA C cowling on the XP-42 airplane. The D cowling is, generally, characterized by the use of an annular inlet and diffuser section for the engine-cooling air. An increase in maximum speed was noted in the XP-42 airplane due to the change from a C cowling to a D cowling.
Fuel-Evaporation Loss as Determined by the Change in the Specific Gravity of the Fuel in an Aircraft Fuel Tank
Report discusses the results of an investigation to determine the feasibility of using the change in the specific gravity of fuels in aircraft fuel tanks to measure fuel-vaporization loss. Six fuels were tested via fuel-distillation tests and simulated-flight tests. An equation based on the specific gravity of the fuel is also described.
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.
Flight tests of thermal ice-prevention equipment in the XB-24F airplane
Report presenting performance tests of thermal ice-prevention equipment designed and installed in the XB-24F airplane in icing and non-icing conditions. The recorded temperature and air-flow data, and the calculated quantities of heat flow throughout the system are presented in tabular form.
Flight Tests of Modifications to Improve the Aileron Control Characteristics of a North American XP-51 Airplane (AC No. 41-38)
Investigations were undertaken to improve the ailerons of a P-51 fighter so as to obtain greater effectiveness without increasing the stick forces. Modifications consisted of increasing the deflection range of the aileron to 70 percent and changing the original concave section to a thick section with beveled trailing edge. Results of the modified ailerons showed an increase in effectiveness over the original aileron of 70 percent at low speed and 55 percent at high speeds.
Ultraviolet spectrochemical analysis for aromatics in aircraft fuels
Report presenting tests to verify and extend ultraviolet spectroscopic techniques for applications to the analysis of aviation fuels for their aromatic constituents. Results regarding photographic absorption spectra, spectrophotometric absorption spectra, and spectrophotometric analyses are provided.
On the plane potential flow past a symmetrical lattice of arbitrary airfoils
Report presenting a theoretical investigation of the two-dimensional, incompressible potential flow past a symmetrical lattice of airfoils of arbitrary shape. Expressions are given for evaluation of the velocity and pressure distribution at the airfoil boundary.
Visual Studies of Cylinder Lubrication [Part] 1: The Lubrication of the Piston Skirt
Report describes the lubrication characteristics of an aircraft-type piston as visually studied in a V-type engine with a glass cylinder. Information about the movement of the piston, the piston rings, and the oil-control rings and their effect on lubrication is included.
Tests of a Thermal Ice-Prevention System for a Wing Leading-Edge Landing-Light Installation
Report discussing the creation of a thermal ice-prevention system of a bomber-type airplane to provide protection against ice and fog formations on the transparent fairing over the landing light in the wing leading edge. A comparison between the design performance and actual performance showed that the outer-surface heat-transfer coefficient was correctly predicted, but the inner-surface heat-transfer coefficient was four times as large, leading to failure of the plastic fairing.
Critical combinations of shear and transverse direct stress for an infinitely long flat plate with edges elastically restrained against rotation
Report presenting an exact solution and a closely concurring approximate energy solution for the buckling of an infinitely long flat plate under combined shear and transverse direct stress with edges elastically restrained against rotation. An appreciable fraction of the critical stress in pure shear may be applied to the plate without any reduction in the transverse compressive stress necessary to produce buckling.
NACA Mach number indicator for use in high-speed tunnels
Report presenting a description of a device for indicating stream Mach number in a high-speed tunnel. It consists of a mechanism for determining the pressure ratio that Mach number is a function of. The instrument is in service in the 8-foot high-speed tunnel and its accuracy has been found adequate for wind-tunnel requirements.
On a New Method for Calculating the Potential Flow Past a Body of Revolution
Report presenting a new method for obtaining the velocity potential of the flow about a solid of revolution moving uniformly in the direction of its axis of symmetry in a fluid otherwise at rest. The method is based essentially on the fact that the form of the differential equation for the velocity potential is invariant with regard to conformal transformations in a meridian plane. The general results are applied to a body of revolution obtained by revolving a symmetrical Joukowski profile about its axis of symmetry.
Ditching Tests With 1/10-Size Model of the Army a-20a Airplane 1: Calm-Water Tests in NACA Tank No.2
Report presenting tests to determine the behavior of landplanes when they are forced to land on the water. The report is incomplete.
The development and application of high-critical-speed nose inlets
From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was undertaken in the Langley 8-foot high-speed tunnel to establish the effects of nose-inlet proportions on critical Mach number and to develop a rational method for the design of high-critical-speed nose inlets to meet desired requirements."
An Experimental Investigation of Rectangular Exhaust-Gas Ejectors Applicable for Engine Cooling
Report presenting an experimental investigation of rectangular exhaust-gas ejector pump to provide data that would serve as a guide to the design of ejector applications for aircraft engines with marginal cooling. With a decrease in the quantity of air pumped and an increase in the length of an ejector, the ejector pressure rise increases to optimum values. Results regarding straight ejectors, diffuser ejectors, curved ejectors, ejector aspect ratio, divided ejectors, multistage ejectors, and nozzle-exit effects are provided.
Wind-Tunnel Investigation of the Effects of Spoilers on the Characteristics of a Low-Drag Airfoil Equipped With a 0.25-Chord Slotted Flap
Report discussing the effects of circular-arc spoilers on the section characteristics of an NACA 66,2-216 airfoil with a 0.25-chord slotted flap. Spoilers were tested on the upper surface of the airfoil, on the lower surface, and on both simultaneously. Only the simultaneous placement of spoilers was found to provide satisfactory results as a lateral control device.
An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 5: Effect of Thermal System on Airplane Cruise Performance
Report presenting flight tests conducted to evaluate the effect of a thermal ice prevention system on the aerodynamic performance of a C-46 cargo airplane. The installation of the thermal ice-prevention system was found to reduce the indicated airspeed by about 6 miles per hour. Results regarding the overall performance change resulting from the installation of the thermal system, reduction of power attributed to heat-exchanger exhaust-gas back pressure, reduction of power attributed to the internal and external drag of the thermal system, and the additional airplane gross weight attributed to the thermal system are provided.
On the Flow of a Compressible Fluid by the Hodography Method 1: Unification and Extension of Present-Day Results
Report presenting elementary basic solutions of the equations of motion of a compressible fluid in the hodograph variables are developed and used to provide a basis for comparison in the form of velocity correction formulas, of corresponding compressible and incompressible flows.
An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 3: Description of Thermal Ice-Prevention Equipment for Wings, Empennage, and Windshield
Report presenting an investigation of a thermal ice-prevention system for a Curtiss-Wright C-46 airplane, including the equipment for the wings, empennage, and windshield. The report is the third in a series and focuses on the revisions to the components for thermal ice prevention, the temperature- and pressure-measurement equipment installed in the airplane to determine the performance of the system, and the results of static-load structural tests of a specimen of the wing outer-panel leading edge.
Flight Measurements of the Effect of Various Amounts of Aileron Droop on the Low-Speed Lateral-Control Characteristics of an Observation Airplane
Report presenting tests of the low-speed lateral-control characteristics of an observation airplane with ailerons and spoilers in combination and with the spoilers disconnected and the ailerons used alone with various amounts of droop. The results indicated that in unstalled flight at low speeds and with flaps deflected, little or no aerodynamic benefit was derived by changing the lateral-control system from the aileron and spoiler combination to a normal aileron installation either with or without aileron droop.
An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 4: Results of Flight Tests in Dry-Air and Natural-Icing Conditions
Report presenting an investigation of a thermal ice-prevention system for a C-46 cargo airplane, which involved flight tests in dry-air and natural-icing conditions at two different laboratories. The purpose of the investigation was to determine the effectiveness of the C-46 airplane ice-prevention system and to continue the develop of thermal ice-prevention equipment. Results regarding the wing outer panel, wing tips, wing center panel, horizontal stabilizers, vertical fin, windshields, ice-removal tests, unprotected surfaces, and heat exchangers are provided.
Determination of General Relations for the Behavior of Turbulent Boundary Layers
Report presenting an analysis of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. Results indicate that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter.
Analysis of Heat and Compressibility Effects in Internal Flow Systems and High-Speed Tests of a Ram-Jet System
Report presenting an analysis of the effects of heat and compressibility in the flow through the internal systems of aircraft. Equations and charts are developed whereby the flow characteristics at key stations in a typical internal system may be readily obtained.
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.
The Use of Geared Spring Tabs for Elevator Control
Report discussing the use of two types of geared spring tabs for elevator control: ordinary (or ungeared) spring tabs and geared spring tabs. Their use in airplanes of various sizes and in comparison to conventional control systems is described.
A general representation for axial-flow fans and turbines
From Summary: "A general representation of fan and turbine arrangements on a single classification chart is presented which is made possible by a particular definition of the stage of an axial-flow fan or turbine. Several unconventional fan and turbine arrangements are indicated and the applications of these arrangements are discussed."
An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 6: Dry-Air Performance of Thermal System at Several Twin- and Single-Engine Operating Conditions at Various Altitudes
Report presenting flight tests to establish the dry-air-performance characteristics of a thermal ice-prevention system at various operating conditions and altitudes. Results regarding twin-engine tests and single-engine tests of characteristics such as skin temperatures and location of heating are provided.
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.
Performance of an exhaust-gas "blowdown" turbine on a nine-cylinder radial engine
Report presenting tests on an exhaust-gas turbine with four separate nozzle boxes each covering a 90 degree arc of the nozzle diaphragm and each connected to a pair of adjacent cylinders in a Pratt & Whitney R-1340-12 nine-cylinder radial engine. Results regarding the power output of the engine and turbine, effect of the turbine on engine power, turbine power output and speed characteristics, mean turbine efficiency, effect of the blowdown turbine on exhaust-gas temperature, and condition of the blowdown turbine after tests are provided.
Thermodynamic Design of Double-Panel, Air-Heated Windshields for Ice Prevention
Report details the development of design equations for double-panel, air-heated windshields with ice prevention properties. The application of the equations and suggestions for experimental flight testing are described.
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.
Compressible potential flow with circulation about a circular cylinder
Report presenting the potential function for flow, with circulation, of a compressible fluid about a circular cylinder, which is obtained in series form including terms of the order of M(exp 4) where M is the Mach number of the free stream. The equations are used to obtain pressure coefficient as a function of Mach number at a point on the surface of the cylinder for different values of circulation.
An Investigation of a Thermal Ice-Prevention System for a C-46 Cargo Airplane 2: The Design, Construction, and Preliminary Tests of the Exhaust-Air Heat Exchanger
Report presenting an investigation of an exhaust-air heat exchanger, which has been designed, constructed, and flight-tested for a C-46 cargo airplane. The primary purpose of the investigation was to provide the C-46 airplane with a satisfactory source of heated air and to continue the development of the heat exchanger as a part of thermal ice-prevention equipment. Results indicated that the required thermal output and desired air-temperature rise have been achieved and that the exchanger is suitable for use in the C-46 airplane.
The Propeller and Cooling-Air-Flow Characteristics of a Twin-Engine Airplane Model Equipped With NACA D(Sub S)-Type Cowlings and With Propellers of NACA 16-Series Airfoil Sections
Report presenting an investigation in the 19-foot pressure tunnel to determine the nacelle drag, the cowling-air flow, and the propeller characteristics of a model of a high-performance military airplane. The model is fitted with NACA D(sub S)-type engine cowlings and with propellers embodying NACA 16-series airfoil sections. Results regarding the propeller characteristics, drag and cowling-air flow with the propeller removed, the effect of propeller on flow through cowling, and the influence of cooling requirements on airplane performance are provided.
Pressure drop in tank and float vent tubes on diving airplanes
Report presenting an experiment regarding tank and float venting conditions that exist on diving airplanes undergoing rapid changes in altitude. The results indicated that large pressure differences build up between the outside and inside of tanks and floats on diving airplanes unless the correct size of venting tube is used.
Application of Spring Tabs to Elevator Controls
Report presenting equations for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of the satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling, and to prevent flutter.
On the Flow of a Compressible Fluid by the Hodography Method 2: Fundamental Set of Particular Flow Solutions of the Chaplygin Differential Equation
Report presenting the utilization of the differential equation of Chaplygin's jet problem to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows.
NACA Investigation of a Jet-Propulsion System Applicable to Flight
"Following a brief history of the NACA investigation of jet-propulsion, a discussion is given of the general investigation and analyses leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight-performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made" (p. 1).
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.
The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system
Report presenting tests on a single-cylinder, air-cooled engine to determine the effect of several different exhaust-stack shapes on the design and performance of the individual cylinder exhaust-gas jet-propulsion systems. Results regarding the effect of nozzle area and stack shape on exhaust-gas jet thrust, effect of nozzle area and stack shape on overall performance for the S-shape, the 90 degree bend, and the 180 degree bend, the effect on the shape on engine power and volumetric efficiency, and the effect of a branched stack on engine power are provided.
Back to Top of Screen