National Advisory Committee for Aeronautics (NACA) - 1,263 Matching Results

Search Results

Cylinder-Head Cooling by Means of a Shield in the Exhaust Passage
"Tests were run on a single-cylinder, air-cooled engine with a Wright C9GC cylinder to determine the improvement in cylinder-head cooling that can be obtained by building into the exhaust passage an insulating shield designed to protect the valve-guide boss and the exhaust-passage walls from the exhaust gas. The test results showed an appreciable improvement in cooling of the exhaust-valve-guide boss, of the guide bushing, and of the valve seat" (p. 1).
Cylinder Temperatures of Two Liquid-Cooled Aircraft Cylinders for Various Engine and Coolant Conditions
Report presenting tests conducted with two liquid-cooled cylinders in order to isolate the effects of the various engine and coolant variables on cylinder temperatures and to obtain engine-cooling data required for a fundamental study of the heat-transfer processes in liquid-cooled engines. Cylinder temperatures were obtained for a large range of engine speeds, manifold pressures, carburetor-air temperatures, fuel-air ratios, spark advances, coolant-flow rates, average coolant temperatures, and coolant pressures with water and AN-E-2 ethylene glycol and other ethylene glycol-water mixtures as coolants.
Data for Design of Entrance Vanes from Two-Dimensional Tests of Airfoils in Cascade
"As a part of a program of the NACA directed toward increasing the efficiency of compressors and turbines, data were obtained for application to the design of entrance vanes for axial-flow compressors or turbines. A series of blower-blade sections with relatively high critical speeds have been developed for turning air efficiently from 0 deg to 80 deg starting with an axial direction. Tests were made of five NACA 65-series blower blades (modified NACA 65(216)-010 airfoils) and of four experimentally designed blower blades in a stationary cascade at low Mach numbers" (p. 1).
Data on buckling strength of curved sheet in compression
Report presenting tests of curved panels of four different thicknesses and with radius-thickness ratios varying from about 150 to infinity. Results are also included from some previous testing.
Derivation of charts for determining the horizontal tail load variation with any elevator motion
Report presenting equations relating the wing and tail loads are derived for a unit elevator displacement. The equations are converted into a nondimensoinal form and charts are given that can be used to predict wing- and tail-load-increment variation for any type of elevator motion and for degrees of airplane stability.
A Description of the Ju 88 Airplane Anti-Icing Equipment
Bulletin presenting an examination of a part of the anti-icing equipment for a Ju 88 airplane, including exhaust-air heat exchangers, control valves, air duct system, and air-heated wing panels. Testing was performed on the components and indicated that the thermal ice-prevention equipment can maintain the outer-wing panel free from ice.
Design charts for cross-flow tubular intercoolers charge-across-tube type
Report presenting equations relating the various dimensions, air mass flow, and performance of a cross-flow tubular intercooler in which the charge flows across and the cooling air through the tubes. Design charts are presented from which the intercooler design characteristics and performance can be quickly determined.
Design charts for cross-flow tubular intercoolers charge-through-tube type
Report presenting equations relating the various dimensions, air weight flow, and performance of a cross-flow tubular intercooler in which the charge flows through and the cooling air across the tubes. A method of determining and presenting the performance of a given intercooler at various operating conditions is indicated. Results regarding the cooling effectiveness equation, effect of primary intercooler variables, design charts, effect of tube arrangement on intercooler characteristics, and performance charts are provided.
Design criterions for the dimensions of the forebody of a long-range flying boat
Report presenting a correlation of the gross-load coefficient and the forebody length-beam ratio for a limited number of present-day multiengine long-range flying boats for which the spray characteristics are known. Results indicate that the gross-load coefficient for comparable spray characteristics varies as the square of the forebody length-beam ratio.
The Design of Cooling Ducts With Special Reference to the Boundary Layer at the Inlet
"A study has been made of underslung cooling ducts with special references to the problems presented by the boundary layer on the fuselage skin. It was found that good flow can be obtained in such ducts by (1) making the inlet opening of such size that the mean inlet velocity is about 0.6 the free-stream velocity and (2) providing vanes behind as well as ahead of the radiator. Tables to facilitate design are included, together with an example " (p. 1).
Design of Nozzles for the Individual Cylinder Exhaust Jet Propulsion System
Report presenting an examination of the design of exhaust-stack nozzles for individual cylinder exhaust-gas jet propulsion and the results of tests on the effect of nozzle area on jet thrust and engine power. A satisfactory method of correlatig the test data for various engine-operating conditions is developed.
Design of power-plant installations pressure-loss characteristics of duct components
"A correlation of what are believed to be the most reliable data available on duct components of aircraft power-plant installations is presented. The information is given in a convenient form and is offered as an aid in designing duct systems and, subject to certain qualifications, as a guide in estimating their performance. The design and performance data include those for straight ducts; simple bends of square, circular, and elliptical cross sections; compound bends; diverging and converging bends; vaned bends; diffusers; branch ducts; internal inlets; and an angular placement of heat exchangers" (p. 1).
The design of the optimum hull for a large long-range flying boat
Report presenting some principles for designing the optimum hull for a large long-range flying boat in order to suit the requirements of minimum drag, seaworthiness, and ability to take off and land at all operational gross weights. The principles include the use of moderate gross-load coefficients, ample forebody lengths, and deep steps and the close adherence of the form to that of a streamline body of revolution with a moderate fineness ratio.
Design, selection, and installation of aircraft heat exchangers
Report presenting a survey of aircraft heat exchangers in three parts: design, selection, and installation. Appendices give the physical properties of air, properties of standard atmosphere as defined by the Navy, Army, and NACA, and an impact-pressure chart.
Determination From Flight Tests of Thrust Coefficients for 10 Full-Scale Airplanes in the Gliding Condition With Engine Idling
"Typical thrust and torque coefficients and increments, due to the propeller, in the ratio of the dynamic pressure at the tail to the free-stream dynamic pressure are presented for 10 full-scale airplanes. Calculations indicate that an error of about 2 percent mean aerodynamic chord appears possible in determining the neutral point from wind-tunnel tests or a model in the gliding condition if the propeller is operated at zero thrust rather than at the values of thrust coefficient indicated by the flight tests" (p. 1).
Determination of Air-Consumption Parameters for Two Radial Aircraft Engines
"Air-consumption data from calibrations of two radial aircraft engines were analyzed to show the relation of engine air consumption to its primary influencing factors: intake-manifold pressure, exhaust back pressure, intake-manifold temperature, and engine speed. The analysis of the test data from these two engines led to the establishment of a relation of variables upon which the design of automatic metering controls can be based. The data obtained from one engine indicate that the air-consumption correlation obtained for this engine is accurate within 2 percent except under certain conditions that are well outside current engine-operation limits" (p. 1).
Determination of desirable lengths of Z- and channel-section columns for local-instability tests
From Summary: "Local-instability tests of 24S-T aluminum-alloy formed Z- and channel-section columns were made in order to determine a length of test specimen that would avoid the increased strength associated with short lengths and also permit the occurrence of a convenient buckling pattern. The effect of column length on the critical compressive stress, on the average stress at maximum load, and on the number of half-waves of the buckling pattern is shown."
The determination of effective column length from strain measurements
From Summary: "A method is presented for the experimental determination of the effective length of a column for which the end conditions are unknown by establishing the points of zero curvature from readings of strain gages distributed along the length of the column. Tests of four columns of different cross sections indicated that the proposed method gives satisfactory results even when there is considerable scatter in the strain-gage readings."
Determination of Gas Temperatures from the Frequency of Knock-Induced Gas Vibrations in an Internal-Combustion Engine
Report of a study to develop a method of obtaining gas temperatures from the frequency of knock-induced gas vibrations in an internal-combustion engine cylinder. Temperatures calculated from frequency data were in agreement with temperatures measured by the spectral line-reversal method in previous investigations and were about 700 degrees Fahrenheit lower than temperatures obtained from thermodynamic charts.
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.
Determination of Induced Velocity in Front of an Inclined Propeller by a Magnetic-Analogy Method
Report presenting the horizontal and vertical components of the induced velocity in front of an inclined propeller in a horizontal stream obtained by a magnetic-analogy method. The problem was formulated in terms of the linear theory of the acceleration potential of an incompressible nonviscous fluid.
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 Jet-Boundary Corrections to Cowling-Flap-Outlet Pressures by an Electrical Analogy Method
Report presenting corrections to the velocities near a cowling-flap tip in order to determine jet-boundary corrections to cowling-flap-outlet pressures. The presence of the low-energy air leaving the flap opening was taken into account by so shaping the nacelle model that its outer surface represented the stream surface leaving the flap tip. Copper was found unsatisfactory for use as electrode material.
The Determination of Span Load Distribution at High Speeds by Use of High-Speed Wind-Tunnel Section Data
Report presenting a tabular method for determining the span load distribution at high Mach numbers by utilizing high-speed airfoil section data. This method, which is also called the generalized method, is an easily applied process of successive approximations by which a general application of the lifting-line theory may be used to determine the span load distribution for wings composed of sections with arbitrary lift curves. An example is provided to show how the method is used.
Determination of the damping moment in yawing for tapered wings with partial-span flaps
Report presenting a method for determining the damping moment in yawing for tapered wings with partial-span flaps. Charts are given for untwisted wings with various taper ratios, aspect ratios, and center-span flaps. Theoretical and experimental results are provided.
Determination of the Effect of Horizontal-Tail Flexibility on Longitudinal Control Characteristics
Report presenting an iteration method for determining the longitudinal control characteristics of a flexible horizontal tail. The method permits factors such as the actual spanwise variation of elasticity and the aerodynamic induction effects due to three-dimensional flow to be accounted for to any degree of accuracy needed. An analysis is also included of the effects of horizontal-tail flexibility on the tail effectiveness, the hinge-moment characteristics, and the control-force gradients in a dive recovery for two modern fighter airplanes.
Determination of the Effect of Wing Flexibility on Lateral Maneuverability and a Comparison of Calculated Rolling Effectiveness With Flight Results
Report presenting an analysis which shows that, when account is taken of sideslip and wing flexibility, the calculated rolling maneuverability of an airplane is in good agreement with the results obtained from flight tests. The method used avoids the complications of successive approximations but is nevertheless believed to be more nearly accurate than other methods based on semirigid-wing assumptions. The method is applied to a wing of tubular shell construction and the procedure is illustrated for a modern pursuit airplane.
Determination of the Stability and Control Characteristics of a Straight-Wing, Tailless Fighter-Airplane Model in the Langley Free-Flight Tunnel
Report presenting an investigation to determine the stability and control characteristics of a straight-wing, tailless fighter model with a pusher propeller in the free-flight tunnel. The investigation consisted principally of force and flight tests of a powered dynamic model. Results regarding longitudinal stability, longitudinal control, trim at high angles of attack, lateral stability, and lateral control are provided.
Determination of the Stability and Control Characteristics of a Tailless All-Wing Airplane Model with Sweepback in the Langley Free-Flight Tunnel
Force and flight tests were performance on an all-wing model with windmilling propellers. Tests were conducted with deflected and retracted flaps, with and without auxiliary vertical tail surfaces, and with different centers of gravity and trim coefficients. Results indicate serious reduction of stick-fixed longitudinal stability because of wing-tip stalling at high lift coefficient. Directional stability without vertical tail is undesirably low. Low effective dihedral should be maintained. Elevator and rudder control system is satisfactory.
Determination of the Stability and Control Characteristics of Airplanes from Tests of Powered Models
Report presenting a technique of testing wind tunnel powered models developed as a result of experience gained in the investigation of the static longitudinal and lateral staiblity and control characteristics of several powered models in the 7- by 10-foot wind tunnel. A discussion of the conditions to be investigated, methods of presenting and interpreting the data, and a suggested operating technique are given.
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.
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."
Development of Cowling for Long-Nose Air-Cooled Engine in the NACA Full-Scale Wind Tunnel
"An investigation of cowlings for long-nose radial engines was made on the Curtiss XP-42 fighter in the NACA full-scale wind tunnel. The unsatisfactory aerodynamic characteristics of all the cowlings with scoop inlets tested led to the development of the annular high-velocity inlet cowlings. Tests showed that ratio of cooling-air velocity at cowling inlet to stream velocity should not be less than 0.5 for this type of cowling and that critical compressibility speed can be extended to more than 500 mph at 20,000 ft altitude" (p. 1).
The Development of Satisfactory Flying Qualities on the Douglas Dive Bomber, Model SBD-1 Through Flight Testing Successive Modifications in Control-Surface Area, Hinge-Line Location, and Aerodynamic-Balance Nose Shape
Report presenting flight-test data contributing to the development of the present SBD-1 flying qualities based on the interest expressed in the methods used to obtain control-force characteristics on the Douglas Model SBD-1 by minor relocation of control-surface hinge line in combination with modifications in the aerodynamic balance nose shape. Results regarding the stalling characteristics, lateral-directional stability and control, longitudinal stability and control, and design recommendations are provided.
Development of thermal ice-prevention equipment for the B-17F airplane
Report presenting a thermal ice-prevention system for the B-17F airplane. The report includes a description of the design, an outline of the design, analysis, and a presentation and discussion of flight-test thermal data secured under non-icing conditions. The basic idea of the design was to raise the temperature of the surfaces to be protected from ice formations by subjecting the inner faces to a stream of heated air.
Development of thermal ice-prevention equipment for the B-24D airplane
Report presenting a thermal ice-prevention system for the B-24D airplane. The report includes a description of the design and an outline of the method of design analysis. Results of performance tests of the installation will be presented in a supplementary report.
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.
Dilution of Exhaust-Gas Samples From a Multicylinder Engine Equipped With an Exhaust-Gas Collector
Report discusses the results of an investigation to determine the effect of a collector ring on exhaust-gas sampling. The results of tests to determine the percentage by volume of exhaust gas from the collector ring are presented for several engine powers and speeds. The danger of air dilution from the breathing action of the engine is almost entirely eliminated by the use of a collector ring.
Ditching behavior of military airplanes as affected by ditching aids
Report presenting an investigation of planing devices like hydroflaps and hydrofoils on several dynamically scaled models of military airplanes and their effectiveness in improving ditching characteristics. The ditching aids were generally found to be of value. Results regarding the hydroflap test in the impact basin, dynamic model tests at the outdoor catapult, and effect of ditching aids on ditching performance and rough water are provided.
Ditching Tests of a 1/8-Scale Model of the Navy SB2c-1 Airplane (Army A-25) in Langley Tank Number 2 and on an Outdoor Catapult
Report presenting testing to determine the best way to land the SB2C-1 airplane in calm and rough water and to determine its probable ditching performance. The behavior of the model was determined by making visual observations and by recording the maximum longitudinal decelerations and by taking motion pictures of the ditchings. Results regarding the effect of flaps, attitude, weight, a wing-low landing, effect of simulated damage, effect of tail wheel, ditching aids, and seaway are provided.
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.
Ditching Tests With 1/16-Size Models of the Army B-17 Airplane in Langley Tank Number 2 and on an Outdoor Catapult
Report presenting tests with dynamically similar models made to study the behavior of the Army B-17F and B-17G when ditched and to determine the best way to land them in calm and rough water. Various landing attitudes, speeds, and conditions of damage were simulated. The ideal landing condition was found to be in a three-point landing attitude and with the flaps 45 degrees at the slowest possible speed.
Ditching tests with a 1/10-size model of the Army A-20A airplane in Langley tank no.2 and on an outdoor catapult
Testing of a dynamically similar model of an Army A-20A airplane to determine the best way to land the airplane in calm and rough water and to determine its probable ditching performance. Results regarding the effect of speed and attitude, effect of flap setting, effect of wind and seaway, effect of simulated damage, effect of sinking speed, effect of propellers, effect of gun blisters, and effect of weight are provided.
Ditching tests with a 1/11-size model of the Army B-25 airplane in NACA tank number 2 and on an outdoor catapult
Report presenting testing to determine the best way to land the B-25 airplane in calm and rough water and to determine its probable ditching performance. By landing with flaps down in a tail-down attitude at as slow a speed as possible, smooth straight landing runs will probably result in calm water. Results regarding the effect of attitude, effect of flap setting, effect of simulated damage, effect of propellers, and effect of seaway are provided.
Ditching Tests With a 1/12-Size Model of the Army B-26 Airplane in NACA Tank Number 2 and on an Outdoor Catapult
Report presenting tests made with a dynamic model of the Army B-26 airplane to determine its behavior when landed on water. Results regarding the general behavior, effect of flaps, effect of landing attitude and speed, tests with undamaged model, tests with simulated damage, tests with propellers, vertical decelerations, and effect of weight are provided.
Ditching tests with a 1/16-size dynamic model of the Army B-24 airplane in Langley tank number 2 and on an outdoor catapult
Testing conducted to determine the best way to ditch the Army B-24 airplane in calm and rough water and to determine its probable ditching performance. A dynamically similar model was ditched in calm water in tank no. 2 and calm and rough water from an outdoor catapult. Results regarding the effect of attitude and speed, effect of flap setting, effect of vertical velocity, effect of location of center of gravity, effect of simulated damage, effect of ditching aids, effect of fuselage length, effect of landing gear, effect of load, and effect of seaway are provided.
Drag Analysis of Single-Engine Military Airplanes Tested in the NACA Full-Scale Wind Tunnel
Report presenting tests in the full-scale wind tunnel on 11 single-engine military airplanes to investigate methods for increasing their high speed. Results regarding the power-plant installation, flow characteristics, wings, cockpit canopies, landing gear, and air leakage are provided.
Drag and propulsive characteristics of air-cooled engine-nacelle installations for two-engine airplanes
Report presenting a study on wing-nacelle propeller arrangements using a two-engine airplane with nacelles varying in diameter. Results regarding the power-off characteristics, propulsive and overall efficiencies, power-on characteristics, and pressure distributions are provided.
Drag measurements at high Reynolds numbers of a 100-inch-chord NACA 23016 practical construction wing section submitted by Chance Vought Aircraft Company
Report presenting drag measurements in the two-dimensional low-turbulence tunnel of an available 100-inch-chord model of the NACA 23016 wing section. Results regarding the curves of section drag coefficient plotted against Reynolds number for various surface conditions and lift coefficients, variation of drag coefficient with lift coefficient, and effects of skin friction are provided.
Drag Measurements of a Protruding 0.50-Caliber Machine Gun
Report presenting drag and cross-wind force measurements of a Browning 0.50-caliber M2 machine gun at a range of air speeds in the NACA wind tunnel. The gun protruded through the top of the tunnel wall into the air stream and tests were performed at a variety of angles in order to determine the power required to turn the gun against the aerodynamic forces and the horsepower absorbed in air drag by the protruding gun. Special attention is given to the jacket around the gun, which seems to provide the greatest amount of drag.
Back to Top of Screen