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ABOUT BROWSE FEED
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.
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 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.
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.
Effect of the performance of a turbosupercharged engine of an exhaust-gas-to-air heat exchanger for thermal ice prevention
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.
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.
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.
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.
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.
Air-consumption parameters for automatic mixture control of aircraft engines
No Description Available.
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.).
Correlation of exhaust-valve temperatures with engine operating conditions and valve design
No Description Available.
An investigation of aircraft heaters XVIII : a design manual for exhaust gas and air heat exchangers
No Description Available.
Ultraviolet spectrochemical analysis for aromatics in aircraft fuels
No Description Available.
Single-cylinder oil-control tests of porous chrome plated cylinder barrels for radial air-cooled engines
No Description Available.
Wall interference in a two-dimensional-flow wind tunnel with consideration of the effect of compressibility
No Description Available.
Derivation of charts for determining the horizontal tail load variation with any elevator motion
No Description Available.
Spin tests of two models of a low-wing monoplane to investigate scale effect in the model test range
No Description Available.
The effect of increased cooling surface on performance of aircraft-engine cylinders as shown by tests of the NACA cylinder
No Description Available.
Compressibility and heating effects on pressure loss and cooling of a baffled cylinder barrel
No Description Available.
The problem of longitudinal stability and control at high speeds
No Description Available.
A method for calculating heat transfer in the laminar flow region of bodies
No Description Available.
Flight measurements of the effect of various amounts of aileron droop on the low-speed lateral-control characteristics of an observation airplane
No Description Available.
Flight tests of several exhaust-gas-to-air heat exchangers in the B-17F airplane
No Description Available.
Flight tests of thermal ice-prevention equipment in the XB-24F airplane
No Description Available.
A method for determining the rate of heat transfer from a wing or streamline body
No Description Available.
Laminar-boundary-layer oscillations and transition on a flat plate
No Description Available.
An investigation of aircraft heaters IX : measured and predicted performance of two exhaust gas-air heat exchangers and an apparatus for evaluating exhaust gas-air heat exchangers
No Description Available.
Icing tests of aircraft-engine induction systems
No Description Available.
Review of flight tests of NACA C and D cowlings on the XP-42 airplane
No Description Available.
The effect of altitude on cooling
No Description Available.