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Pressure lag in tubing used in flight research

Description: Tests described in this report were undertaken to obtain a quantitative measure of the pressure lag in typical pressure-tubing systems used by the Ames Aeronautical Laboratory in flight research investigations. Lag measurements were made with both single-direction and oscillating pressure changes. Single-direction pressure changes were investigated to determine if the lag in orifice-pressure lines and in the research airspeed and altitude measuring systems of pursuit-type airplane undergoing flight tests was sufficient to cause an appreciable error in the record of a sudden pressure change. Oscillating pressure changes were investigated with particular reference to the accuracy of pressure peaks in pressure-distribution measurements during the time of buffeting conditions as found in stalls. (author).
Date: January 1, 1945
Creator: Turner, Howard L. & Rathert, George A., Jr.
Partner: UNT Libraries Government Documents Department

Analysis of V-G Records from the SNB-1 Airplane

Description: Availability data obtained on SNB-1 trainer-class airplanes were analyzed and results presented as flight envelopes which predict occurrences of large values of air speed and acceleration. Comparison is made with SNJ-4 trainer-class airplane data analyzed by the same method. It is concluded that flight envelopes are satisfactory; that the two types show large differences in flight loads and speeds experience; and that SNB-1 will seldom, if ever, exceed design limit load factor and restricted speed, which SNJ-4 can be expected to exceed design-limit load factor and restricted speed in a very small number of flight hours.
Date: July 1946
Creator: Meadows, May T. & Walker, Walter G.
Partner: UNT Libraries Government Documents Department

Performance Characteristics of an Aircraft Engine with Exhaust Turbine Supercharger, Special Report

Description: The Pratt and Whitney Aircraft company and the Naval Aircraft Factory of the United States Navy cooperated in a laboratory and flight program of tests on an exhaust turbine supercharger. Two series of dynamometer tests of the engine super-charger combination were completed under simulated altitude conditions. One series of hot gas-chamber tests was conducted by the manufacturer of the supercharger. Flight demonstrations of the supercharger installed in a twin-engine flying boat were terminated by failure of the turbine wheels. The analysis of the results indicated that a two-stage supercharger with the first-stage exhaust turbine driven will deliver rated power for a given indicated power to a higher altitude, will operate more efficiently, and will require simpler controls than a similar engine with the first stage of the supercharger driven from the crankshaft through multispeed gears.
Date: May 1, 1941
Creator: Lester, E. M. & Paulson, V. A.
Partner: UNT Libraries Government Documents Department

The Effect of Surface Irregularities on Wing Drag. IV - Manufacturing Irregularities, 5, Manufacturing Irregularities

Description: Tests were made in the NACA 8-foot high speed wind tunnel of a metal-covered, riveted, 'service' wing of average workmanship to determine the aerodynamic effects of the manufacturing irregularities incident to shop fabrication. The wing was of 5-foot chord and of NACA 23012 section and was tested in the low-lift range at speeds from 90 to 450 miles per hour corresponding to Reynolds numbers from 4,000,000 to 18,000,000. At a cruising condition the drag of the service wing was 46% higher than the drag of a smooth airfoil, whereas the drag of an accurately constructed airfoil having the same arrangement of 3/32-inch brazier-head rivets and lap joints showed a 29% increase. The difference, or 17% of the smooth-wing drag, is apparently the drag caused by the manufacturing irregularities: sheet waviness, departures from true profile, and imperfect laps. the service wing, for one condition at least, showed a drag increase due to compressibility at a lower air speed than did the more accurate airfoil.
Date: February 1, 1938
Creator: Robinson, Russell G.
Partner: UNT Libraries Government Documents Department

The Effect of Various Wing-Gun Installations on the Aerodynamic Characteristics of an Airplane Model Equipped with an NACA Low-Drag Wing, Special Report

Description: An investigation was made in the NACA 19-foot pressure wind tunnel to determine the effect of various win-gun installation on the aerodynamic characteristics of a model with an NACA low-drag wing. Measurements were made of lift and drag over an angle-of-attack range and for several values of dynamic pressure on a four-tenths scale model of a high-speed airplane equipped with the low-drag wing and with various wing-gun installations. Two installations were tested: one in which the blast tube and part of the gun barrel protrude ahead of the wing and another in which the guns is mounted wholly within the wing. Two types of openings for the latter installation were tested. For each installation three simulated guns were mounted in each wing. The results are given in the form of nondimensional coefficients. The installations tested appear to have little effect on the maximum-lift coefficient of the model. However, the drag coefficient shows a definite change. The least adverse effect was obtained with the completely internal mounting and small nose entrance. The results indicate that a properly designed wing-gun installation will have very little adverse effect on the aerodynamic characteristics of the low-drag wing.
Date: July 1, 1941
Creator: Muse, Thomas C.
Partner: UNT Libraries Government Documents Department

The Effects of Aerodynamic Heating on Ice Formations on Airplane Propellers

Description: An investigation has been made of the effect of aerodynamic heating on propeller-blade temperatures. The blade temperature rise resulting from aerodynamic heating was measured and the relation between the resulting blade temperatures and the outer limit of the iced-over region was examined. It was found that the outermost station at which ice formed on a propeller blade was determined by the blade temperature rise resulting from the aerodynamic heating at that point.
Date: August 1, 1940
Creator: Rodert, Lewis A.
Partner: UNT Libraries Government Documents Department

Effects of Direction of Propeller Rotation on the Longitudinal Stability of the 1/10-Scale Model of the North American XB-28 Airplane with Flaps Neutral, Special Report

Description: The effects of direction of propeller rotation on factors affecting the longitudinal stability of the XB-28 airplane were measured on a 1/10-scale model in the 7- by 10-foot tunnel of the Ames Aeronautical Laboratory. The main effect observed was that caused by regions of high downwash behind the nacelles (power off as well as power on with flaps neutral). The optimum direction of propeller rotation, both propellers rotating up toward the fuselage, shifted this region off the horizontal tail and thus removed its destabilizing effect. Rotating both propellers downward toward the fuselage moved it inboard on the tail and accentuated the effect, while rotating both propellers right hand had an intermediate result. Comparisons are made of the tail effects as measured by force tests with those predicted from the point-by-point downwash and velocity surveys in the region of the tail. These surveys in turn are compared with the results predicted from available theory.
Date: June 1, 1942
Creator: Delany, Noel K.
Partner: UNT Libraries Government Documents Department

An Electrical-Type Indicating Fuel Flowmeter

Description: An electrical-type meter has been developed for measuring mass rates of flow of gasoline or other nonconducting fluids. Its temperature dependence is small over a large range and it has no known vibrational or viscosity errors. The maximum temperature rise is less than 5 C. The rates of flow, measurable within 1% with the present instrument, are approximately 100 to 1,000 or more pounds of gasoline per hour when a potentiometer is used, or 100 to 300 pounds per hour when a deflection-type meter is used.
Date: September 1, 1939
Creator: Tozier, Robert E.
Partner: UNT Libraries Government Documents Department

Drag and Propulsive Characteristics of Air-Cooled Engine-Nacelle Installations for Large Airplanes, Special Report

Description: An investigation is in progress in the NACA full-scale wind tunnel to determine the drag and propulsive efficiency of nacelle sizes. In contrast with the usual tests with a single nacelle, these tests were conducted with nacelle-propeller installations on a large model of a 4-engine airplane. Data are presented on the first part of the investigation, covering seven nacelle arrangements with nacelle diameters from 0.53 to 1.5 times the wing thickness. These ratios are similar to those occurring on airplane weighing from about 20 to 100 tons. The results show that the drag, the propulsive efficiency, and the overall efficiency of the various nacelle arrangements as functions of the nacelle size, the propeller position, and the airplane lift coefficient. The effect of the nacelles on the aerodynamic characteristics of the model are shown for both propeller-removed and propeller-operating conditions.
Date: August 1, 1939
Creator: Silverstein, Abe & Wilson, Herbert A., Jr.
Partner: UNT Libraries Government Documents Department

Drag of Several Gunner's Enclosures at High Speeds, Special Report

Description: The drag of several types of gunner's turrets, windshields, blisters, and other protuberances, including projecting guns, was investigated at speeds from 75 to 440 miles per hour in the NACA 8-foot high-speed wind tunnel. The various gunner's enclosures were represented by 1/10 and 1/7 full-size models on a midwing-fuselage combination representative of bomber types. Most of the usual types of retractable turrets are very poor aerodynamically; they caused wind drag increments, dependent upon the size of the turret relative to the fuselage and upon the speed, up to twice the drag of the fuselage alone. A large streamline blister sufficient to enclose completely one type of rotating cylindrical turret caused a drag increment of approximately one-half that of the turret and at the same time provided space adequate for two gunners rather than for one gunner. A large portion of the drag increments for some types of turret appeared to be due to adverse effects on the fuselage flow caused by the turret rather than by the direct drag of the turret.
Date: July 1, 1941
Creator: Stack, John & Moberg, Richard J.
Partner: UNT Libraries Government Documents Department

The Effect of Compressibility on the Growth of the Laminar Boundary Layer on Low-Drag Wings and Bodies

Description: The development of the laminar boundary layer in a compressible fluid is considered. Formulas are given for determining the boundary-layer thickness and the ratio of the boundary-layer Reynolds number to the body Reynolds number for airfoils and bodies of revolution. It i s shown that the effect of compressibility will profoundly alter the Reynolds number corresponding to the upper limit of the range of the low-drag coefficients . The available data indicate that for low-drag and high critical compressibility speed airfoils and bodies of revolution, this effect is favorable.
Date: January 1, 1943
Creator: Allen, H. Julian & Nitzberg, Gerald E.
Partner: UNT Libraries Government Documents Department

The Effect of Initial Displacement of the Center Support on the Buckling of a Column Continuous over Three Supports

Description: The test indicate that "an indiscriminate single application of the Southwell method (for analyzing Exp. Observations in problems of elastic stability)--can result in definite and measurable errors" The test also indicate "that the effect of curvature due to bending on the critical load for the compression flange material of a box beam is probably small and can be neglected." We have not found this to be true in our tests. It is believed that the effect of curvature, together with a small amount of fixity at the ribs, tends to force the stiffeners to bow in each bay thus effectively increasing their end fixity and thereby raising their allowable loads.
Date: November 1, 1940
Creator: Lunquist, Eugene E. & Kotanchik, Joseph N.
Partner: UNT Libraries Government Documents Department

The Effect of Lateral Inclination of the Thrust Axis and of Sweepback of the Leading Edge of the Wing on Propulsive and Net Efficiencies of a Wing-Nacelle-Propeller Combination

Description: This report describes and gives the results of tests made to determine the effect of lateral inclination of the propeller thrust axis to the direction of flight. A wing-nacelle-propeller combination with the nacelle axis located successively parallel to and at 15 degrees to the perpendicular to the leading edge of a wing was tested with the combination at several angles of yaw. Tests of the wing alone at the same angles of yaw were also made. The data are presented in the usual graphic form. An increase in propulsive efficiency with increase in angle of the thrust axis was found. The change in net efficiency, found by charging the whole nacelle drag to the power unit, was negligible, however, within the range of the tests.
Date: April 1, 1935
Creator: Wood, Donald H. & Windler, Ray
Partner: UNT Libraries Government Documents Department

The Effect of Streamlining the Afterbody of an N.A.C.A. Cowling

Description: The drag and the power cost associated with the changing of the nose of a nacelle from a streamline shape to a conventional N.A.C.A. cowling shape was investigated in the N.A.C.A. 20-foot tunnel. Full-scale propellers and nacelles were used. The increment of drag associated with the change of nose shapes was found to be critically dependent on the afterbody of the nacelle. Two streamline afterbodies were tested. The results fo the tests with the more streamlined afterbody showed that the added drag due to the open-nose cowling was only one-fourth of the drag increase obtained with the other afterbody. The results of this research indicate that the power cost, in excess of that with a streamline nose, of using an N.A.C.A. cowling in front of a well-designed afterbody to enclose a 1,500-horsepower engine in an airplane with a speed of 300 miles per hour amounts to 1.5 percent of the engine power. If the open-nose cowling is credited with 1 percent because it cools the front of the cylinders, the non-useful power cost amounts to only 0.5 percent of the engine power.
Date: December 1, 1939
Creator: Stickle, George W.; Crigler, John L. & Naiman, Irven
Partner: UNT Libraries Government Documents Department

The Effect of Surface Irregularities on Wing Drag, 3, Roughness

Description: Tests have been made in the N.A.C.A. 8-foot high-speed wind tunnel of the drag caused by roughness on the surface of an airfoil of N.A.C.A. 23012 section and 5-foot chord. The tests were made at speeds from 80 t o 500 miles per hour at lift coefficients from 0 to 0.30. For conditions corresponding to high-speed flight, the increase in the drag was 30 percent of the profile drag of the smooth airfoil for the roughness produced by spray painting and 63 percent for the roughness produced. by 0.0037-inch carborundum grains. About one-half the drag increase was caused by the roughness on the forward one-fourth of the airfoil. Sandpapering the painted surface with No. 400 sandpaper made it sufficiently smooth that the drag was no greater than when the surface was polished. In the lower part of the range investigated the drag due to roughness increased rapidly with Reynolds Number.
Date: February 1, 1938
Creator: Hood, Manley J.
Partner: UNT Libraries Government Documents Department

Characteristics of NACA 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps

Description: At the request of the Bureau of Aeronautics, Navy Department, tests were made in the variable-density wind tunnel of a tapered wing of 3-10-18 plan form and based on the NACA 4400R series sections. The wing was also tested with 0.2 chord spit flaps, deflected 60 deg span ratios of 0.3, 0.5, 0.7 and 1.0 respectively. In order to get data from which to calculate the characteristics of the flapped wing, the investigation was extended to include tests of the four rectangular airfoils of the NACA 4400R series (4409R, 4412R, 4415R, and 4418R) with full-span 0.2 chord, trailing edge split flaps deflected 60 deg.
Date: January 1941
Creator: Greenberg, Harry
Partner: UNT Libraries Government Documents Department

Comparison of Intercooler Characteristics

Description: A method is presented of comparing the performance, weight, and general dimensional characteristics of inter-coolers. The performance and dimensional characteristics covered in the comparisons are cooling effectiveness, pressure drops and weight flows of the charge and cooling air, power losses, volume, frontal area, and width. A method of presenting intercooler data is described in which two types of charts are plotted; (1) A performance chart setting forth all the important characteristics of a given intercooler and (2) a replot of these characteristics for a number of intercoolers intended to assist in making a selection to satisfy a given set of installation conditions. The characteristics of commercial intercoolers obtained from manufacturers' data and of some computed designs are presented on this basis. A standard test procedure and instrumentation are suggested whereby comparable data may be obtained by different testing organizations.
Date: May 1, 1941
Creator: Reuter, J. George & Valerino, Michael F.
Partner: UNT Libraries Government Documents Department