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The calculated effect of trailing-edge flaps on the take-off of flying boats

Description: The results of take-off calculations are given for an application of simple trailing-edge flaps to two hypothetical flying boats, one having medium wing and power loading and consequently considerable excess of thrust over total resistance during the take-off run, the other having high wing and power loading and a very low excess thrust. For these seaplanes the effect of downward flap settings was: (1) to increase the total resistance below the stalling speed, (2) to decrease the get-away speed, (3) to improve the take-off performance of the seaplane having considerable excess thrust, and (4) to hinder the take-off of the seaplane having low excess thrust. It is indicated that flaps would allow a decrease in the high angles of wing setting necessary with most seaplanes, provided that the excess thrust is not too low.
Date: November 1, 1934
Creator: Parkinson, J E & Bell, J W

Calculated effect of various types of flap on take-off over obstacles

Description: In order to determine whether or not flaps could be expected to have any beneficial effect on take-off performance, the distances required to take off and climb to an altitude of 50 feet were calculated for hypothetical airplanes, corresponding to relatively high-speed types and equipped with several types of flap. The types considered are the Fowler wing, the Hall wing, the split flap, the balanced split flap, the plain flap, and the external-airfoil flap. The results indicate that substantial reductions in take-off distance are possible through the use of flaps, provided that the proper flap angle corresponding to a given set of conditions is used. The best flap angle for taking off varies inversely as power loading and, to a much smaller extent, varies inversely with wing loading. Apparently, the best take-off characteristics are provided by the type of device in which the flap forms an extension to the main wing as in the case of the Fowler wing and the external-airfoil flap.
Date: May 1, 1936
Creator: Wetmore, J W

Boosted performance of a compression-ignition engine with a displaced piston

Description: Performance tests were made using a rectangular displacer arranged so that the combustion air was forced through equal passages at either end of the displacer into the vertical-disk combustion chamber of a single-cylinder, four-stroke-cycle compression-ignition test engine. After making tests to determine optimum displacer height, shape, and fuel-spray arrangement, engine-performance tests were made at 1,500 and 2,000 r.p.m. for a range of boost pressures from 0 to 20 inches of mercury and for maximum cylinder pressures up to 1,150 pounds per square inch. The engine operation for boosted conditions was very smooth, there being no combustion shock even at the highest maximum cylinder pressures. Indicated mean effective pressures of 240 pounds per square inch for fuel consumptions of 0.39 pound per horsepower-hour have been readily reproduced during routine testing at 2,000 r.p.m. at a boost pressure of 20 inches of mercury.
Date: May 1, 1936
Creator: Moore, Charles S & Foster, Hampton H

Some effects of air and fuel oil temperatures on spray penetration and dispersion

Description: Presented here are experimental results obtained from a brief investigation of the appearance, penetration, and dispersion of oil sprays injected into a chamber of highly heated air at atmospheric pressure. The development of single sprays injected into a chamber containing air at room temperature and at high temperature was recorded by spray photography equipment. A comparison of spray records showed that with the air at the higher temperature, the spray assumed the appearance of thin, transparent cloud, the greatest part of which rapidly disappeared from view. With the chamber air at room temperature, a compact spray with an opaque core was obtained. Measurements of the records showed a decrease in penetration and an increase in the dispersion of the spray injected into the heated air. No ignition of the fuel injected was observed or recorded until the spray particles came in contact with the much hotter walls of the chamber about 0.3 second after the start of injection.
Date: May 1, 1930
Creator: Gelalles, A. G.

Some characteristics of fuel sprays at low-injection pressures

Description: This report presents the results of tests conducted at the Langley Memorial Aeronautical Laboratory, Langley Field, Va., to determine some of the characteristics of the fuel sprays obtained from an 0.008-inch and a 0.020-inch open nozzle when injection pressures from 100 to 500 pounds per square inch were used. Fuel oil and gasoline were injected into air at densities of atmospheric land 0.325 pound per cubic foot. It was found that the penetration rate at these low pressures was about the same as the rate obtained with higher pressures. Spray cone-angles were small and individual oil drops were visible in all the sprays. Gasoline and fuel oil sprays had similar characteristics.
Date: November 1, 1931
Creator: Rothrock, A. M. & Waldron, C. D.

Some characteristics of fuel sprays from open nozzles

Description: The penetration and cone-angle of fuel sprays from open nozzles were recorded with the NACA Spray Photography Equipment. The results show that for injection systems in which the rate of pressure rise at the discharge orifice is high, open nozzles give spray-tip velocities and penetrations which compare favorably with those of closed nozzles. The spray cone-angle was the same for all tests, although open nozzles having different orifice diameters were used, and one nozzle was used both as an open and as a closed nozzle. In designing a fuel system using open nozzles, particular care must be taken to avoid air pockets. The check valve should be placed close to the discharge orifice.
Date: November 1, 1930
Creator: Rothrock, A. M. & Lee, D. W.

Calibration and lag of a Friez type cup anemometer

Description: Tests on a Friez type cup anemometer have been made in the variable density wind tunnel of the Langley Memorial Aeronautical Laboratory to calibrate the instrument and to determine its suitability for velocity measurements of wind gusts. The instrument was calibrated against a Pitot-static tube placed directly above the anemometer at air densities corresponding to sea level, and to an altitude of approximately 6000 feet. Air-speed acceleration tests were made to determine the lag in the instrument reading. The calibration results indicate that there should be an altitude correction. It is concluded that the cup anemometer is too sluggish for velocity measurements of wind gusts.
Date: June 1, 1930
Creator: Pinkerton, Robert M

A complete tank test of a model of a flying-boat Hull - N.A.C.A. model no.11-A

Description: Model No. 11-A was designed as an improvement over N.A.C.A. Model No. 11, a complete test of which is described in N.A.C.A. Technical Note No. 464. In contrast with the longitudinal upward curvature in the planing bottom forward of the main step on Model 11-A was made as flat as practicable. Otherwise, the two models have very nearly the same form. The results of towing tests made on Model 11-A in the N.A.C.A. tank over a wide range of speed, load on the water, and trim angle are presented, both as original test data and as non dimensional coefficients. A comparison is made with similar results from the test of Model No. 11. The practical significance of the improvement obtained is demonstrated by applying the data from the new form to the illustrative design problem use in the note on Model NO. 11.
Date: September 1, 1933
Creator: Parkinson, John B

A complete tank test of a model of flying-boat Hull - N.A.C.A. Model 16

Description: A model of a 2-step flying-boat hull, of the type generally used in England, was tested according to the complete method described in the N.A.C.A. Technical Note No. 464. The lines of this model were taken from offsets given by Mr. William Munro in Flight, May 29, 1931. The data cover the range of loads, speeds, and trim angles that may be of use in applying the hull form to the design of any seaplane. The results are reduced to nondimensional form to aid application to design problems and facilitate comparison with the performance of other hulls. The water characteristics of Model 16 are compared with those of Model 11-A, which is representative of current American practice. The results show that when the two forms are applied to a given seaplane design under optimum conditions for each, the performance of Model 16 will be somewhat inferior to that of Model 11-A.
Date: September 1, 1933
Creator: Shoemaker, James H

A complete tank test of the hull of the Sikorsky S-40 flying boat - American Clipper Class

Description: The results of a complete test in the N.A.C.A. tank on a model of the hull of Sikorsky S-40 flying boat ('American Clipper') are reported. The test data are given in tables and curves. From these data non-dimensional coefficients are derived for use in take-off calculations and the take-off time and run for the S-40 are computed. The computed take-off time was obtained by the Sikorsky Aviation Corporation in performance tests of the actual craft.
Date: December 1, 1934
Creator: Dawson, John R

The effects of equal-pressure fixed slots on the characteristics of a Clark Y Airfoil

Description: A type of fixed open slot so arranged that no flow would pass through it at a lift coefficient corresponding to high-speed flight was investigated in the N.A.C.A. 7 by 10 foot wind tunnel to determine the possibilities of such a high-lift device for increasing the speed-range ratio of a wing. The condition of no through flow was achieved by locating the slot openings at points of equal static pressure at the design lift coefficient as determined from the pressure distribution about the plain wing. Two models of Clark Y wings with such equal-pressure slots were tested and the smoke-flow patterns about them observed. The results of this investigation show that the condition of no air flow through the slot at the desired lift coefficient is attainable. The surface discontinuities produced by the slot openings have, however, such a large effect on the drag that such slots show little promise. An appreciable increase is produced in the maximum lift and the speed-range can be as high as for the plain wing.
Date: October 1, 1934
Creator: Harris, Thomas A & Sherman, Albert

Methods of visually determining the air flow around airplanes

Description: This report describes methods used by the National Advisory Committee for Aeronautics to study visually the air flow around airplanes. The use of streamers, oil and exhaust gas streaks, lampblack and kerosene, powdered materials, and kerosene smoke is briefly described. The generation and distribution of smoke from candles and from titanium tetrachloride are described in greater detail because they appear most advantageous for general application. Examples are included showing results of the various methods.
Date: July 1, 1932
Creator: Gough, Melvin N & Johnson, Ernest

A method of estimating the aerodynamic effects of ordinary and split flaps of airfoils similar to the Clark Y

Description: An empirical method is given for estimating the aerodynamic effect of ordinary and split flaps on airfoils similar to the Clark Y. The method is based on a series of charts that have been derived from an analysis of existing wind-tunnel data. Factors are included by which such variables as flap location, flap span, wing aspect ratio, and wing taper may be taken into account. A series of comparisons indicate that the method would be suitable for use in making preliminary performance calculations and in structural design.
Date: June 1, 1936
Creator: Pearson, H A

Moments of inertia of several airplanes

Description: This paper, which is the first of a series presenting the results of such measurements, gives the momental ellipsoids of ten army and naval biplanes and one commercial monoplane. The data were obtained by the use of a pendulum method, previously described. The moments of inertia are expressed in coefficient as well as in dimensional form, so that those for airplanes of widely different weights and dimensions can be compared.
Date: May 1, 1931
Creator: Miller, Marvel P & Soule, Hartley A

The N.A.C.A. combustion chamber gas-sampling valve and some preliminary test results

Description: A gas sampling valve of the inertia-operated type was designed for procuring samples of the gases in the combustion chamber of internal combustion engines at identical points in successive cycles so that the analysis of the gas samples thus procured may aid in the study of the process of combustion. The operation of the valve is described. The valve was used to investigate the CO2 content of gases taken from the quiescent combustion chamber of a high speed compression-ignition engine when operating with two different multiple-orifice fuel injection nozzles. An analysis of the gas samples thus obtained shows that the state of quiescence in the combustion chamber is maintained during the combustion of the fuel.
Date: March 1, 1933
Creator: Spanogle, J A & Buckley, E C

Full-scale wind-tunnel and flight test of a Fairchild 22 airplane equipped with a Zap flap and Zap ailerons

Description: A wing equipped with a Zap flap and Zap ailerons was tested on a Fairchild 22 airplane in the full-scale wind tunnel and in flight to determine the effect of the flaps and ailerons on the performance and the control characteristics of the airplane. The flaps were 0.30 of the wing chord and 0.83 of the wing span. Two sets of ailerons having equal areas but different proportions were tested, one set being 0.56 of the semispan and 0.18 of the chord and the other set being 0.46 of the semispan and 0.22 of the chord. The wind-tunnel tests showed that, when the ailerons and horizontal tail surfaces were removed, the flaps increased the maximum lift coefficient from 1.48 to 2.39. In flight, the fully deflected flaps decreased the minimum speed from 48.2 to 38.8 miles per hour. The take-off and landing distances were both reduced by the flaps. The wind-tunnel tests showed the ailerons to increase the drag coefficient, at a lift coefficient and Reynolds Number corresponding to the high speed of the airplane, from 0.0432 to 0.0498 and 0.0514, the 0.46 semispan ailerons giving the highest drag. In the flight tests both sets of ailerons were found to give satisfactory rolling action in the normal-flight range. They required relatively large stick forces for their operation, however, and the variation of the forces with aileron deflection was not linear.
Date: March 1, 1937
Creator: Dearborn, C H & Soule, H A

A general tank test of NACA model 11-C flying-boat hull, including the effect of changing the plan form of the step

Description: The results of a general tank test model 11-C, a conventional pointed afterbody type of flying-boat hull, are given in tables and curves. These results are compared with the results of tests on model 11-A, from which model 11-C was derived, and it is found that the resistance of model 11-C is somewhat greater. The effect of changing the plan form of the step on model 11-C is shown from the results of tests made with three swallow-tail and three pointed steps formed by altering the original step of the model. These results show only minor differences from the results obtained with the original model.
Date: August 1, 1935
Creator: Dawson, John R

Full-scale wind-tunnel to determine a satisfactory location for a service Pitot-static tube on a low-wing monoplane

Description: Surveys of the air flow over the upper surface of four different airfoils were made in the full-scale wind tunnel to determine a satisfactory location for a fixed Pitot-static tube on a low-wing monoplane. The selection was based on small interference errors, less than 5 percent, and on a consideration of structural and ground handling problems. The most satisfactory location on the airfoils without flaps that were investigated was 10 percent of the chord aft and 25 percent of the chord above the trailing edge of a section approximately 40 percent of the semispan inboard of the wing tip. No satisfactory location was found near the wing when the flaps were deflected.
Date: March 1, 1936
Creator: Parsons, John F.