# National Advisory Committee for Aeronautics (NACA) - Browse

- Some Recent Contributions to the Study of Transition and Turbulent Boundary Layers
- No Description Available.
- Considerations of the Total Drag of Supersonic Airfoil Sections
- The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.
- Performance of B. M. W. 185-Horsepower Airplane Engine
- No Description Available.
- Tables and Charts of Flow Parameters Across Oblique Shocks
- Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.
- Two-Dimensional Subsonic Compressible Flows Past Arbitrary Bodies by the Variational Method
- Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.
- Summary of 65-Series Compressor-Blade Low-Speed Cascade Data by Use of the Carpet-Plotting Technique
- Carpet plots included permit the selection of the blade camber and the design angle of attack required to fulfill a design vector diagram. Other carpet plots provide means for the prediction of off-design turning angles.
- Tables for the Computation of Wave Drag of Arrow Wings of Arbitrary Airfoil Section
- Tables and computing instructions for the rapid evaluation of the wave drag of delta wings and of arrow wings having a ration of the tangent of the trailing-edge sweep angle to the tangent of the leading-edge sweep angle in the range from -1.0 to 0.8. The tables cover a range of both subsonic and supersonic leading edges.
- Two-Dimensional Irrotational Transonic Flows of a Compressible Fluid
- The methods of NACA TN No. 995 have been slightly modified and extended in include flows with circulation by considering the alteration of the singularities of the incompressible solution due to the presence of the hypergeometric functions in the analytic continuation of the solution. It was found that for finite Mach numbers the only case in which the nature of the singularity can remain unchanged is for a ratio of specific heats equal to -1. From a study of two particular flows it seems that the effect of geometry cannot be neglected, and the conventional "pressure-correction" formulas are not valid, even in the subsonic region if the body is thick, especially if there is a supersonic region in the flow.
- Charts for the Computation of Equilibrium Composition of Chemical Reactions in the Carbon-Hydrogen-Nitrogen System at Temperatures from 2000 to 5000 Degrees K
- Charts are provided for the estimation and progressive adjustment of two independent variables on which the calculations are based. Additional charts are provided for the graphical calculation of the composition.
- Aerodynamic Investigation of a Cup Anemometer
- Results of an investigation wherein the change of the normal force coefficient with Reynolds Number was obtained statically for a 15.5-centimeter hemispherical cup.
- Average Outside-Surface Heat-Transfer Coefficients and Velocity Distributions for Heated and Cooled Impulse Turbine Blades in Static Cascades
- Heat-transfer investigation conducted on cooled as well heated impulse-type turbine blades in a static cascade to determine the effect of direction of heat flow on convective heat-transfer coefficients.
- Bending Tests of Metal Monocoque Fuselage Construction
- Study of the bending stress in smooth skin, aluminum alloy, true monocoque fuselage sections of varying ratio of diameter to thickness.
- A Comparison of Theory and Experiment for High-Speed Free-Molecule Flow
- Comparison of free-molecule-flow theory with the results of wind-tunnel tests performed to determine the drag and temperature-rise characteristics of a transverse circular cylinder.
- Emergency measures for increasing the range of fighter airplanes
- No Description Available.
- Fuel-evaporation loss as determined by the change in the specific gravity of the fuel in an aircraft fuel tank
- No Description Available.
- Thermodynamic design of double-panel, air-heated windshields for ice prevention
- No Description Available.
- The use of geared spring tabs for elevator control
- No Description Available.
- The knock-limited performance of S reference fuel plus 2 milliliters of triethylthallium per gallon
- No Description Available.
- Annual report of the National Advisory Committee for Aeronautics (42nd). administrative report including Technical Report nos. 1254 to 1295
- Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.
- Effect of the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger for thermal ice prevention
- No Description Available.
- Investigation of the aerodynamic characteristics of the NACA RM-10 missile (with fins) at a Mach number of 1.62 in the Langley 9-inch supersonic tunnel
- No Description Available.
- The calculation of span LCAD distributions of swept-back wings
- Span load distributions of swept-back wings have been calculated. The method used was to replace the wing with a bound vortex at the quarter-chord line and to calculate the downwash due to the system of bound and trailing vortices to conform at the three-quarter-chord line to the slope of the flat-plate wing surface. Results are given for constant-chord and 5:1 tapered plan forms, for sweep-back angles of 0 degrees, 30 degrees, and 45 degrees, and for aspect ratios of 3, 6, and 9. Some comments on the stalling of swept-back wings are included.
- Comparison of Vee-Type and Conventional Tail Surfaces in Combination with Fuselage and Wing in the Variable-Density Tunnel
- The pitching and the yawing moments of a vee-type and a conventional type of tail surface were measured. The tests were made in the presence of a fuselage and a wing-fuselage combination in such a way as to determine the moments contributed by the tail surfaces. The results showed that the vee-type tail tested, with a dihedral angle of 35.3 deg, was about 71 percent as effective in pitch as the conventional tail and had a yawing-moment to pitching-moment ratio of 0.3. The conventional tail, the panels of which were all congruent to those of the vee-type tail, had a yawing-moment to pitching-moment ratio of 0.48. These ratios are in fair agreement with values calculated by methods shown in this and previous reports. The values of the measured moments were reduced from 15 to 25 percent of the calculated value by fuselage interference.
- Methods of analyzing wind-tunnel data for dynamic flight conditions
- The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind-tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area. Solutions of the lateral equations of motion are given in a form suitable for direct computations. An approximate formula is developed that permits the rapid estimation of the accelerations produced during pull-up maneuvers involving abrupt elevator deflections.
- A low-speed experimental investigation of the effect of a sandpaper type of roughness on boundary-layer transition
- No Description Available.
- Further measurements of normal accelerations on racing airplanes
- The work of collecting acceleration data for racing airplanes during races, started in January 1934, has been continued by obtaining similar data in the airplanes winning first and second places in the 1935 Thompson Trophy Race. Records were taken in the Howard Racer "Mr. Mulligan" and in the Wittman D-12 Racer. The maximum positive accelerations were generally smaller than those recorded in other airplanes during earlier races; the maximum in the Howard Racer was 2.8 g, and one value of 4.25 g was obtained in the Wittman Racer. Minimum values were as low as -0.55 g in the Howard Racer and 0.3 g in the Wittman Racer.
- The variation in pressure in the cabin of an airplane in flight
- The pressure in the cabin of a Fairchild cabin monoplane wa surveyed in flight, and was found to decrease with increased air speed over the fuselage and to vary with the number and location of openings in the cabin. The maximum depression of 2.2 inches of water (equivalent pressure altitude at sea level of 152 feet) occurred at the high speed of the airplane in level flight with the cabin closed.
- The Unsteady Lift of a Finite Wing
- Unsteady lift function for wings of finite aspect ratio have been calculated by approximate methods involving corrections of the aerodynamic inertia and of the angle of the infinite wing. The starting lift of the finite wing is found to be only slightly less than that of the infinite wing; whereas the final lift may be considerably less. The calculations indicate that the distribution of lift near the start is similar to the final distribution. Both the indicia and the oscillating lift functions are given. Approximate operational equivalents of the functions have been devised to facilitate the calculation of lift under various conditions of motion.
- Analysis of circular shell-supported frames
- No Description Available.
- Effects of some present-day airplane design trends on requirements for lateral stability
- No Description Available.
- Preliminary report on the problem of the atmosphere in relation to aeronautics
- A report to the Weather Bureau, Washington DC, from the chairman of the Subcommittee on the Atmosphere in Relation to Aeronautics describing the activities accomplished and the proposal of work to be undertaken by the subcommittee.
- Stability of the parachute and helicopter
- This report deals with an extension of the theory of stability in oscillation to the case of aircraft following a vertical trajectory, and particularly to the oscillations of parachutes.
- The Kiln Drying of Wood for Airplanes
- This report is descriptive of various methods used in the kiln drying of woods for airplanes and gives the results of physical tests on different types of woods after being dried by the various kiln-drying methods.
- Supplies and production of aircraft woods
- The purpose of this report is to present in brief form such information as is available regarding the supplies of the kinds of wood that have been used or seem likely to become important in the construction of airplanes, and the amount of lumber of each species normally put on the market each year. A general statement is given of the uses to which each kind of wood is or may be put.
- The Lagrangian Multiplier Method of Finding Upper and Lower Limits to Critical Stresses of Clamped Plates
- The theory of Lagrangian multipliers is applied to the problem of finding both upper and lower limits to the true compressive buckling stress of a clamped rectangular plate. The upper and lower limits thus bracket the truss, which cannot be exactly found by the differential-equation approach. The procedure for obtaining the upper limit, which is believed to be new, presents certain advantages over the classical Raleigh-Rite method of finding upper limits. The theory of the lower-limit procedure has been given by Trefftz but, in the present application, the method differs from that of Trefftz in a way that makes it inherently more quickly convergent. It is expected that in other buckling problems and in some vibration problems problems the Lagrangian multiplier method finding upper and lower limits may be advantageously applied to the calculation of buckling stresses and natural frequencies.
- A Theoretical Investigation of Longitudinal Stability of Airplanes with Free Controls Including Effect of Friction in Control System
- The relation between the elevator hinge moment parameters and the control forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. The stability of the short period oscillations is shown as a series of boundaries giving the limits of the stable regions in terms of the elevator hinge moment parameters. The effects of static stability, elevator moment of inertia, elevator mass unbalance, and airplane density are also considered. Dynamic instability is likely to occur if there is mass unbalance of the elevator control system combined with a small restoring tendency (high aerodynamic balance). This instability can be prevented by a rearrangement of the unbalancing weights which, however, involves an increase of the amount of weight necessary. It can also be prevented by the addition of viscous friction to the elevator control system provided the airplane center of gravity is not behind a certain critical position. For high values of the density parameter, which correspond to high altitudes of flight, the addition of moderate amounts of viscous friction may be destabilizing even when the airplane is statically stable. In this case, increasing the viscous friction makes the oscillation stable again. The condition in which viscous friction causes dynamic instability of a statically stable airplane is limited to a definite range of hinge moment parameters. It is shown that, when viscous friction causes increasing oscillations, solid friction will produce steady oscillations having an amplitude proportional to the amount of friction.
- Principal Effects of Axial Load on Moment-Distribution Analysis of Rigid Structures
- This thesis presents the method of moment distribution modified to include the effect of axial load upon the bending moments. This modification makes it possible to analyze accurately complex structures, such as rigid fuselage trusses, that heretofore had to be analyzed by approximate formulas and empirical rules. The method is simple enough to be practicable even for complex structures, and it gives a means of analysis for continuous beams that is simpler than the extended three-moment equation now in common use. When the effect of axial load is included, it is found that the basic principles of moment distribution remain unchanged, the only difference being that the factors used, instead of being constants for a given member, become functions of the axial load. Formulas have been developed for these factors, and curves plotted so that their applications requires no more work than moment distribution without axial load. Simple problems have been included to illustrate the use of the curves.
- Corrugated metal diaphragms for aircraft pressure-measuring instruments
- No Description Available.
- Intercooler cooling-air weight flow and pressure drop for minimum drag loss
- No Description Available.
- NACA Mach number indicator for use in high-speed tunnels
- No Description Available.
- On the flow of a compressible fluid by the hodography method I : unification and extension of present-day results
- No Description Available.
- On the flow of a compressible fluid by the hodography method II : fundamental set of particular flow solutions of the Chaplygin differential equation
- No Description Available.
- Performance of an exhaust-gas "blowdown" turbine on a nine-cylinder radial engine
- No Description Available.
- Experiments on drag of revolving disks, cylinders and streamline rods at high speeds
- No Description Available.
- 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
- No Description Available.
- Supplement to Comparison of automatic control systems
- This analysis deals with the indirect regulator, wherefrom the behavior of the direct regulator is deduced as a limiting case. The prime mover is looked upon as "independent of the load": a change in the adjusting power (to be applied) for the control link (as, for example, in relation to the adjusting path (eta) with pressure valves or the rudder of vessels) does not modify the actions of the prime mover. Mass forces and friction are discounted; "clearance" also is discounted in the transmission links of the regulator.
- The critical velocity of a body towed by a cable from an airplane
- It is sufficient to consider only the equations of motion of the towed body whereas those of the cable may be left out of consideration. The result obtained makes it possible to determine which factors affect the critical velocity and what modifications of the instrument are necessary for extending the upper limit of that velocity.
- The transformation of heat in an engine
- This report presents a thermodynamic basis for rating heat engines. The production of work by a heat engine rests on the operation of supplying heat, under favorable conditions, to a working fluid and then taking it away.
- On the plane potential flow past a symmetrical lattice of arbitrary airfoils
- No Description Available.
- 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. It was found that the main fire could be restricted to an intense, small, and short annular blue flame burning steadily and under control in the intended combustion space. With these readily obtainable combustion conditions, the combustion chamber the nozzle walls and the surrounding structure could be maintained at normal temperatures. The system investigated was found to be capable of burning one-half the intake air up the fuel rates of 3 pounds per second. Calculations were shown to agree well with experiment. It was concluded that the basic features of the jet-propulsion system investigation in the ground-test mock-up were sufficiently developed to be considered applicable to flight installation. Calculations indicated that an airplane utilizing this jet-propulsion system would have unusual capabilities in the high-speed range above the speeds of conventional aircraft and would, in addition, have moderately long cruising ranges if only the engine were used.