Search Results

open access

Investigations Relating to the Extension of Laminar Flow by Means of Boundary-Layer Suction Through Slots

Description: Note presenting experimental investigations of boundary-layer suction through slots as a means of increasing the extent of laminar flow on airfoil sections. The results show that, with the use of suitable slots, substantial increases in the extent of laminar flow can be achieved by boundary-layer control with only a small expenditure of power. Results regarding slot geometry and arrangement, suction slots in an unfavorable pressure gradient, suction slots in a favorable pressure gradient, and d… more
Date: October 1949
Creator: Loftin, Laurence K., Jr. & Burrows, Dale L.
Partner: UNT Libraries Government Documents Department
open access

An Investigation Utilizing an Electrical Analogue of Cyclic Deicing of Hollow Steel Propellers with Internal Electric Heaters

Description: "A study has been made of the heating requirements for the cyclic de-icing of hollow steel propellers fitted with two types of internal electric heaters. Solutions to the transient-heat-flow equations depicting the cyclic de-icing of propellers were obtained by use of an electrical analogy. The study showed the impracticability of using an internal tubular heater and illustrated the advantages of employing an internal shoe-type heater, which distributes the heat more evenly to the blade surface… more
Date: October 1953
Creator: Neel, Carr B., Jr.
Partner: UNT Libraries Government Documents Department
open access

The Effect of Ice Formations on Propeller Performance

Description: "Measurements of propeller efficiency loss due to ice formation are supplemented by an analysis to establish the magnitude of efficiency losses to be anticipated during flight in icing conditions. The measurements were made during flight in natural icing conditions; whereas the analysis consisted of an investigation of changes in blade-section aerodynamic characteristics caused by ice formation and the resulting propeller efficiency changes. Agreement in the order of magnitude of efficiency los… more
Date: October 1950
Creator: Neel, Carr B., Jr. & Bright, Loren G.
Partner: UNT Libraries Government Documents Department
open access

X-Ray Diffraction Study of the Internal Structure of Supercooled Water

Description: From Summary: "A Bragg X-ray spectrometer equipped with a volume-sensitive Geiger counter and Soller slits and employing filtered molybdenum Ka radiation was used to obtain a set of diffracted intensity curves as a Punction of angle for supercooled water. Diffracted intensity curves in the temperature region of 21 to -16 C were obtained. The minimum between the two main diffraction peaks deepened continuously with lowering temperature, indicating a gradual change in the internal structure of th… more
Date: October 1951
Creator: Dorsch, Robert G. & Boyd, Bemrose
Partner: UNT Libraries Government Documents Department
open access

Experimental Study of the Effects of Finite Surface Disturbances and Angle of Attack on the Laminar Boundary Layer of an NACA 64A010 Airfoil With Area Suction

Description: Note presenting a low-turbulence wind-tunnel investigation of an NACA 64A010 airfoil section with continuous suction through its porous surfaces to determine its ability to maintain extensive laminar flow behind finite surface disturbances and at angles of attack other than 0 degrees. Generally, application of area suction permitted only a small increase in the size of a finite disturbance required to cause premature boundary-layer transition as compared with the nonsuction airfoil.
Date: October 1952
Creator: Schwartzberg, Milton A. & Braslow, Albert L.
Partner: UNT Libraries Government Documents Department
open access

Effects of Extreme Surface Cooling on Boundary-Layer Transition

Description: Note presenting an investigation to determine the combined effects of surface cooling, pressure gradients, nose blunting, and surface finish on boundary-layer transition. Data were obtained for various body shapes at a Mach number of 3.12 and Reynolds numbers per foot as high as 15 x 10(exp 6). Results regarding the effect of extreme cooling, effect of pressure gradient, effect of blunting, effect of surface roughness, and roughness as cause of transition reversal are provided.
Date: October 1957
Creator: Jack, John R.; Wisniewski, Richard J. & Diaconis, N. S.
Partner: UNT Libraries Government Documents Department
open access

Investigation of Heat Transfer from a Stationary and Rotating Conical Forebody

Description: From Summary: "The convective heat transfer from the surface of a conical forebody having a hemispherical nose, an included angle of approximately 30 deg, and. a maximum diameter of 18.9 inches was investigated in a wind tunnel for both stationary and. rotating operation. The range of test conditions included free-stream velocities up to 400 feet per second, rotational speeds up to 1200 rpm, and. angles of attack of 0 deg and 6 deg. Both a uniform surface temperature and a uniform heater input … more
Date: October 1957
Creator: Ruggeri, Robert S. & Lewis, James P.
Partner: UNT Libraries Government Documents Department
open access

Simple Graphical Solution of Heat Transfer and Evaporation From Surface Heated to Prevent Icing

Description: "Equations expressing the heat transfer and evaporation from wetted surfaces during ice prevention have been simplified and regrouped to permit solutions by simple graphical means. Working charts for quick and accurate anti-icing calculations are also included" (p. 1).
Date: October 1952
Creator: Gray, Vernon H.
Partner: UNT Libraries Government Documents Department
open access

Experimental Values of the Surface Tension of Supercooled Water

Description: "The results of surface-tension measurements for supercooled water are presented. A total of 702 individual measurements of surface tension of triple-distilled water were made in the temperature range, 27 to -22.2 C, with 404 of these measurements at temperatures below 0 C. The increase in magnitude of surface tension with decreasing temperature, as indicated by measurements above 0 C, continues to -22.2 C. The inflection point in the surface-tension - temperature relation in the vicinity of 0 … more
Date: October 1951
Creator: Hacker, Paul T.
Partner: UNT Libraries Government Documents Department
open access

Impingement of Droplets in 60 Degree Elbows with Potential Flow

Description: Trajectories were determined for water droplets or other aerosol particles in air flowing through 600 elbows especially designed for two-dimensional potential motion. The elbows were established by selecting as walls of each elbow two streamlines of a flow field produced by a complex potential function that establishes a two-dimensional flow around. a 600 bend. An unlimited number of elbows with slightly different shapes can be established by selecting different pairs of streamlines as walls. S… more
Date: October 1956
Creator: Hacker, Paul T.; Saper, Paul G. & Kadow, Charles F.
Partner: UNT Libraries Government Documents Department
open access

Notes on Specifications for French Airplane Competitions

Description: Given here are the rules officially adopted by the Aeronautical Commission of the Aero Club of France for a flight competition to be held in France in 1920 at the Villacoublay Aerodrome. The prize will be awarded to the pilot who succeeds in obtaining the highest maximum and lowest minimum speeds, and in landing within the shortest distance.
Date: October 1920
Creator: Margoulis, W.
Partner: UNT Libraries Government Documents Department
open access

Tests of the Daimler D-IVa Engine at a High Altitude Test Bench

Description: Reports of tests of a Daimler IVa engine at the test-bench at Friedrichshafen, show that the decrease of power of that engine, at high altitudes, was established, and that the manner of its working when air is supplied at a certain pressure was explained. These tests were preparatory to the installation of compressors in giant aircraft for the purpose of maintaining constant power at high altitudes.
Date: October 1920
Creator: Noack, W. G.
Partner: UNT Libraries Government Documents Department
open access

Crippling Strength of Axially Loaded Rods

Description: A new empirical formula was developed that holds good for any length and any material of a rod, and agrees well with the results of extensive strength tests. To facilitate calculations, three tables are included, giving the crippling load for solid and hollow sectioned wooden rods of different thickness and length, as well as for steel tubes manufactured according to the standards of Army Air Services Inspection. Further, a graphical method of calculation of the breaking load is derived in whic… more
Date: October 1921
Creator: Natalis, F. & Pawlowski, F. W.
Partner: UNT Libraries Government Documents Department
open access

Langley Field wind tunnel apparatus

Description: From Summary: "The difficulties experienced in properly holding thin tipped or tapered airfoils while testing on an N.P.L. type aerodynamic balance even at low air speeds, and the impossibility of holding even solid metal models at the high speeds attainable at the National Advisory Committee's wind tunnel, necessitated the design of a balance which would hold model airfoils of any thickness and at speeds up to 150 m.p.h. In addition to mechanical strength and rigidity, it was highly desirable … more
Date: October 1921
Creator: Bacon, D. L.
Partner: UNT Libraries Government Documents Department
open access

The N.A.C.A. Three Component Accelerometer

Description: "A new instrument known as the NACA three component accelerometer is described in this note. This instrument was designed by the technical staff of the NACA for recording accelerations along three mutually perpendicular axes, and is of the same type as the NACA single component accelerometer with the addition of two springs and a few minor improvements such as a pump for filling the dash-pots and a convenient method for aligning the springs. This note includes a few records as well as photograp… more
Date: October 1922
Creator: Reid, H. J. E.
Partner: UNT Libraries Government Documents Department
open access

The effect of longitudinal moment of inertia upon dynamic stability

Description: "Free flight tests were carried out to show whether the longitudinal oscillations of a standard S.E.5A airplane are noticeably affected if its longitudinal moment of inertia is increased. These oscillations were taken by means of a self-recording instrument, the airplane having first its ordinary moment of inertia and then one increased by 14 percent. The period of oscillation was slightly longer after the increase of the moment of inertia, but the damping was not affected" (p. 1).
Date: October 1922
Creator: Norton, F. H. & Carroll, T.
Partner: UNT Libraries Government Documents Department
open access

Maximum Evaporation Rates of Water Droplets Approaching Obstacles in the Atmosphere Under Icing Conditions

Description: "When a closed body or a duct envelope moves through the atmosphere, air pressure and temperature rises occur ahead of the body or, under ram conditions, within the duct. If cloud water droplets are encountered, droplet evaporation will result because of the air-temperature rise and the relative velocity between the droplet and stagnating air. It is shown that the solution of the steady-state psychrometric equation provides evaporation rates which are the maximum possible when droplets are entr… more
Date: October 1953
Creator: Lowell, Herman H.
Partner: UNT Libraries Government Documents Department
open access

The Logarithmic Polar Curve - Its Theory and Application to the Predetermination of Airplane Performance

Description: "The logarithmic polar curve has for several years been used by the most prominent aerodynamical laboratories as well as by airplane manufacturers in Europe. To show more clearly the practical application of the polar curve, a series of examples are given with suggestions for solution. After a discussion of the theory and the practical application of the polar curve, the following problems are discussed: climbing flight, speed at various altitudes, and the characteristics of two seater observat… more
Date: October 1924
Creator: Cronstedt, Val
Partner: UNT Libraries Government Documents Department
open access

Fittings and Other Structural Parts of Airplanes

Description: "The strength and reliability of airplanes depend greatly on the careful design and manufacture of fittings, couplings, and other highly stressed parts. The more important parts of the airplane must be occasionally tested for increased loads and in order to avoid the possibility of defects creeping in during subsequent production. Strength tests are discussed for fittings for wing spar joints, fittings for strut connections, internal bracing, control gear, and landing gear" (p. 1).
Date: October 1923
Creator: Eydam, P.
Partner: UNT Libraries Government Documents Department
open access

The Arithmetic of Distribution in Multi-Cylinder Engines

Description: Note presenting a consideration of the effect on engine performance of a known inequality of distribution. A measure of perfect distribution is provided and some of the factors that influence the unequal distribution of power among cylinders.
Date: October 1923
Creator: Sparrow, Stanwood W.
Partner: UNT Libraries Government Documents Department
open access

Graphic Method for Calculating the Speed and Climbing Ability of Airplanes

Description: Note presenting a graphic method for calculating the speed and climbing ability of airplanes. This method starts from the actual power developed by the engine and makes it possible to determine all factors which together constitute what are known as flight performances for any combination of engine and airplane from the single graphic diagram given.
Date: October 1923
Creator: Rohrbach, Adolf & Lupberger, Edwin
Partner: UNT Libraries Government Documents Department
Back to Top of Screen