National Advisory Committee for Aeronautics (NACA) - 13,806 Matching Results

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A Photographic Study of Freezing of Water Droplets Falling Freely in Air

Description: From Summary: "A photographic technique for investigating water droplets of diameter less than 200 microns falling freely in air at temperatures between 0 C and -50 C has been devised and used to determine: (1) The shape of frozen droplets, (2) The occurrence of collisions of partly frozen or of frozen and liquid droplets, and (3) The statistics on the freezing temperatures of individual free-falling droplets."
Date: February 25, 1952
Creator: Dorsch, Robert G. & Levine, Joseph
Partner: UNT Libraries Government Documents Department

Experimental investigation of effects of simulated nacelles and wing-root freedoms on supersonic flutter characteristics of a cambered, modified, swept, tapered wing

Description: Report presenting an investigation to determine the effects of simulated engine nacelles and wing-root freedoms on the flutter characteristics of a cambered, modified, swept, tapered, semispan wing through a range of Mach numbers. Wings were tested with and without nacelles and with the model restrained, free to roll, and free to translate in the vertical direction. Results regarding the effect of nacelles, flutter boundary, and effect of wing-mount freedom are provided.
Date: October 16, 1957
Creator: Hanson, Perry W.
Partner: UNT Libraries Government Documents Department

An instrument for recording the position of airplane control surfaces

Description: N.A.C.A. has developed an instrument which makes a continuous record of the angular position of the control surfaces of an airplane, not only in steady flight but during acrobatics as well. It has proven useful in researches into stability and controllability, and from records obtained from it many otherwise obscure details of piloting technique have been available for the instruction of pilots, from novices to seasoned experts.
Date: August 1923
Creator: Ronan, K. M.
Partner: UNT Libraries Government Documents Department

Experimental Investigation of Flutter and Divergence Characteristics of the Rocket-Motor Fin of the ASROC Missile

Description: Report presenting testing of models of rocket-motor fins of the ASROC missile for flutter and divergence in the supersonic flutter tunnel for a range of Mach numbers. Results indicate that both divergence of the overhung leading edge and flutter occur within the sea-level operating conditions of the missile at Mach numbers above 1.0. Results regarding the flutter boundary, type of flutter encountered, possible solutions to flutter problems, and possible effects of nondestructive type of flutter are provided.
Date: July 31, 1958
Creator: Levey, Gilbert M. & Hanson, Perry W.
Partner: UNT Libraries Government Documents Department

Investigation of Wingless Missile Configurations with Folding Controls and Low-Aspect-Ratio Stabilizing Surfaces

Description: Results regarding a wind-tunnel investigation of wingless missile configurations with cylindrical bodies and conical or hemispherical noses, extensible control surfaces aft of the nose, and tails consisting of eight low-aspect-ratio triangular or rectangular fins. Normal-force, axial-force, and pitching-moment coefficients were obtained for several control deflections for Mach numbers 1.2 and 1.9.
Date: September 17, 1958
Creator: Lazzeroni, Frank A.
Partner: UNT Libraries Government Documents Department

A Method for Prevention of Screaming in Rocket Engines

Description: From Summary: "Lateral and longitudinal combustion-pressure oscillations that occurred in screaming combustion of a 1000-pound-thrust rocket engine using white fuming nitric acid and JP-4 fuel as propellants were successfully prevented by means of longitudinal fins in the combustion chamber. Fin position was critical, and complete attenuation was achieved only when the fins were located in a zone approximately 8 to 16 inches from the injector. Fins located in other zones, that is, near the injector or far downstream from the injector, did not stop the oscillations."
Date: August 19, 1954
Creator: Male, Theodore & Kerslake, William R.
Partner: UNT Libraries Government Documents Department

A Body Modification to Reduce Drag Due to Wedge Angle of Wing with Unswept Trailing Edge

Description: From Summary: "Ward's slender-body-theory formula for zero-lift drag contains three integrals plus a base-drag term. Two of these integral terms depend only upon the cross-sectional area distribution of the body. The third integral term depends only upon the body shape and axial slopes at the base of the body. This term is neglected in the transonic area rule because in many cases it is zero; however, there are also many cases in which it is not zero. This paper examines the term for the possibility of drag reduction for a particular case."
Date: July 1958
Creator: Pitts, William C. & Nielsen, Jack Norman
Partner: UNT Libraries Government Documents Department

The Interference Effects of a Body on the Spanwise Load Distributions of Two 45 Degree Sweptback Wings of Aspect Ratio 8.02 from Low-Speed Tests

Description: From Summary: "Tests of two wing-body combinations have been conducted in the Langley 19-foot pressure tunnel at a Reynolds number of 4 x 10(exp 6) and a Mach number of 0.19 to determine the effects of the bodies on the wing span load distributions. The wings had 45 degrees sweepback of the quarter-chord line, aspect ratio 8.02, taper ratio 0.45, and incorporated 12-percent-thick airfoil sections streamwise. One wing was untwisted and uncambered whereas the second wing incorporated both twist and camber. Identical bodies of revolution, of 10:1 fineness ratio, having diameter-to-span ratios of 0.10, were mounted in mid-high-wing arrangements."
Date: April 1956
Creator: Martina, Albert P.
Partner: UNT Libraries Government Documents Department

Performance of an All-internal Conical Compression Inlet With Annular Throat Bleed at Mach Number 5.0

Description: Report presenting an investigation of an all-internal conical compression inlet with annular bleed at the throat at Mach number 5.0 and zero angle of attack. Results regarding the performance of the diffuser alone, a Pitot-pressure survey of the flow leaving the diffuser, total-pressure distribution, and inlet efficiencies are provided.
Date: August 6, 1958
Creator: Stitt, Leonard E. & Obery, Leonard J.
Partner: UNT Libraries Government Documents Department

Performance of an Inlet Having a Variable-angle Two-dimensional Compression Surface and a Fixed-geometry Subsonic Diffuser for Application to Reduced Engine Rotative Speeds- Mach Numbers 0.66, 1.5, 1.7, and 2.0

Description: Report presenting the performance of a two-dimensional side inlet with a technique of varying compression-surface angle while retaining a fixed-geometry diffuser at several Mach numbers and zero angle of attack. A 12 degree compression ramp was faired into the diffuser contour in this conventional manner. Results regarding the inlet flow field, application to reduced engine speeds, and a inlet performance with a sudden expansion in the diffuser are provided.
Date: January 30, 1958
Creator: Allen, John L.
Partner: UNT Libraries Government Documents Department

A load factor formula

Description: The ultimate test of a load factor formula is experience. The chief advantages of a semi rational formula over arbitrary factors are that it fairs in between points of experience and it differentiates according to variables within a type. Structural failure of an airplane apparently safe according to the formula would call for a specific change in the formula. The best class of airplanes with which to check a load factor formula seems to be those which have experienced structural failure. Table I comprises a list of the airplanes which have experienced failure in flight traceable to the wing structure. The load factor by formula is observed to be greater than the designed strength in each case, without a single exception. Table II comprises the load factor by formula with the designed strength of a number of well-known service types. The formula indicates that by far the majority of these have ample structural strength. One case considered here in deriving a suitable formula is that of a heavy load carrier of large size and practically no reserve power.
Date: August 1927
Creator: Miller, Roy G.
Partner: UNT Libraries Government Documents Department

Variation of Local Liquid-Water Concentration About and Ellipsoid of Fineness Ratio 5 Moving in a Droplet Field

Description: From Summary: "Trajectories of water droplets about an ellipsoid of revolution with a fineness ratio of 5 (which often approximates the shape of an aircraft fuselage or missile) were computed with the aid of a differential analyzer. Analyses of these trajectories indicate that the local concentration of liquid water at various points about an ellipsoid in flight through a droplet field varies considerably and under some conditions may be several times the free-stream concentration."
Date: July 1954
Creator: Dorsch, Robert G. & Brun, Rinaldo J.
Partner: UNT Libraries Government Documents Department

Variation of Local Liquid-Water Concentration About an Ellipsoid of Fineness Ratio 10 Moving in a Droplet Field

Description: From Summary: "Trajectories of water droplets about an ellipsoid of revolution with a fineness ratio of 10 (10 percent thick) in flight through a droplet field were computed with the aid of a differential analyzer. Analyses of these trajectories indicate that the local concentration of liquid water at various points about an ellipsoid varies considerably and under some conditions may be several times the free-stream concentration. Curves of the local concentration factor as a function of spatial position were obtained and are presented in terms of dimensionless parameters that describe flight and atmospheric conditions."
Date: April 1955
Creator: Brun, Rinaldo J. & Dorsch, Robert G.
Partner: UNT Libraries Government Documents Department

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 the water. No discontinuity in this trend was noted at the melting point. The internal structure of supercooled water was concluded to become progressively more ice-like as the temperature is lowered."
Date: October 1951
Creator: Dorsch, Robert G. & Boyd, Bemrose
Partner: UNT Libraries Government Documents Department

Full-scale, free-jet investigation of methods of improving outlet flow distribution in a side-inlet supersonic diffuser

Description: Report presenting a full-scale, free-jet investigation to determine the performance of a side-inlet supersonic diffuser designed for a flight Mach number of 2.75. Several internal modifications made to improve diffuser-outlet flow uniformity were also evaluated. Results regarding the general characteristics of the diffuser and effect of diffuser modifications on flow distribution are provided.
Date: March 28, 1955
Creator: Farley, John M. & Seashore, Ferris L.
Partner: UNT Libraries Government Documents Department

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. Some of these have a pocket on the outside wall. The elbows produced by the complex potential function are suitable for use in aircraft air-inlet ducts and have the following characteristics: (1) The resultant velocity at any point inside the elbow is always greater than zero but never exceeds the velocity at the entrance. (2) The air flow field at the entrance and exit is almost uniform and rectilinear. (3) The elbows are symmetrical with respect to the bisector of the angle of bend. These elbows should have lower pressure losses than bends of constant cross-sectional area.
Date: October 1956
Creator: Hacker, Paul T.; Saper, Paul G. & Kadow, Charles F.
Partner: UNT Libraries Government Documents Department

Impingement of Water Droplets on a Sphere

Description: Droplet trajectories about a sphere in ideal fluid flow were calculated. From the calculated droplet trajectories the droplet impingement characteristics of the sphere were determined. Impingement data and equations for determining the collection efficiency, the area, and the distribution of impingement are presented in terms of dimensionless parameters. The range of flight and atmospheric conditions covered in the calculations was extended considerably beyond the range covered by previously reported calculations for the sphere.
Date: November 1955
Creator: Dorsch, Robert G.; Saper, Paul G. & Kadow, Charles F.
Partner: UNT Libraries Government Documents Department

Determination of rate, area, and distribution of impingement of of waterdrops on various airfoils from trajectories obtained on the differential analyzer

Description: From Summary: "The trajectories of waterdrops in air flowing over airfoils are determined for three airfoil-angle-of-attack combinations using the differential analyzer to solve the differential equations of motion of the waterdrops. From these trajectories the rate of water impingement, the area of impingement, and the distribution of impingement are determined as functions of two dimensionless moduli. Comparisons are made of the rate of water impingement on these airfoils and the rate of water impingement on cylinders."
Date: February 16, 1949
Creator: Guibert, A. G.; Janssen, E. & Robbins, W. M.
Partner: UNT Libraries Government Documents Department

Design and performance of flight-type liquid-hydrogen heat exchanger

Description: Report presenting an investigation of a liquid-hydrogen fuel system developed to operate one of the turbojet engines in a twin-engine light bomber at an altitude of 50,000 feet and Mach number 0.75. The heat exchanger was evaluated in an altitude test chamber in conjunction with the complete aircraft fuel system. Results regarding calculated heat-exchanger performance, experimental heat-exchanger performance, and reliability are provided.
Date: August 19, 1957
Creator: Fenn, David B.; Braithwaite, Willis M. & Ordin, Paul M.
Partner: UNT Libraries Government Documents Department

Aerodynamic Effects Caused by Icing of an Unswept NACA 65A004 Airfoil

Description: From Summary: "The effects of ice formations on the section lift, drag, and pitching-moment coefficients of an unswept NACA 65A004 airfoil section of 6-foot chord were studied.. The magnitude of the aerodynamic penalties was primarily a function of the shape and size of the ice formation near the leading edge of the airfoil. The exact size and shape of the ice formations were determined photographically and found to be complex functions of the operating and icing conditions."
Date: February 1958
Creator: Gray, Vernon H. & von Glahn, Uwe H.
Partner: UNT Libraries Government Documents Department

Aerodynamic forces, moments, and stability derivatives for slender bodies of general cross section

Description: From Introduction: "The present paper employs an approach believed to be novel in slender-body theory and is concerned with developing formulas for the forces and moments as well as the stability derivatives for general slender wing-body combinations."
Date: November 1954
Creator: Sacks, Alvin H.
Partner: UNT Libraries Government Documents Department

Air force and three moments for F-5-L Seaplane

Description: From Introduction: "A model of the F-5-L seaplane was made, verified, and tested at 40 miles an hour in the 8' x 8' tunnel for lift and drag, also for pitching, yawing and rolling moments. Subsequently, the yawing moment test was repeated with a modified fin. The results are reported without VL scale correction."
Date: February 1922
Partner: UNT Libraries Government Documents Department