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Advantages of oxide films as bases for aluminum pigmented surface coatings for aluminum alloys

Description: Both laboratory and weather-exposure corrosion tests showed conclusively that the protection afforded by aluminum pigmented spar varnish coatings applied to previously anodized aluminum surfaces was greatly superior to that afforded by the same coatings applied to surfaces which had simply been cleaned free from grease and not anodized.
Date: November 1931
Creator: Buzzard, R W & Mutchler, W H
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic characteristics of six commonly used Airfoils over a large range of positive and negative angles of attack

Description: This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were found to be approximately half the positive; but for the M-6 and the CYH, which have less effective values were, respectively, 0.8 and 0.6 of the positive values.
Date: November 1931
Creator: Anderson, Raymond F
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic characteristics of three tapered airfoils tested in the variable density wind tunnel

Description: This report contains the lift, drag, and moment characteristics of tapered Clark Y, Gottingen 393, and USA 45 airfoils as obtained from tests made in the Variable Density Wind Tunnel of the NACA. The results are given at both low and high Reynolds Numbers to show scale effect and to provide data for use in airplane design.
Date: February 1931
Creator: Anderson, Raymond F
Item Type: Report
Partner: UNT Libraries Government Documents Department

Basic requirements of fuel-injection nozzles for quiescent combustion chambers

Description: This report presents test results obtained during an investigation of the performance of a single-cylinder, high-speed, compression-ignition test engine when using multiple-orifice fuel-injection valve nozzles in which the number and the direction of the orifices were varied independently.
Date: June 1, 1931
Creator: Spanogle, J A & Foster, H H
Item Type: Report
Partner: UNT Libraries Government Documents Department

A comparison of the aerodynamic characteristics of the normal and three reflexed airfoils in the variable density wind tunnel

Description: An investigation was made of the aerodynamic effects of reflexing the trailing edge of three commonly used airfoils. Six airfoils were used in the investigation: three having the normal profiles of the Navy 60, the Boeing 106, and the Gottingen 398, and three having these profiles modified to obtain a reflexed trailing edge with the mean camber line changed to give Cmc/4=0. The tests were conducted at a value of the Reynolds Number of approximately 3,100,000 in the variable density wind tunnel of the National Advisory Committee for Aeronautics. Measurements of lift, drag, and pitching moment were made on each of the six airfoils. The expected reduction of the center of pressure travel was obtained. The maximum lift was reduced approximately 12 per cent and the minimum profile drag approximately 4 per cent.
Date: August 1, 1931
Creator: Defoe, George L
Item Type: Report
Partner: UNT Libraries Government Documents Department

Comparison of weights of 17ST and steel tubular structural members used in aircraft construction

Description: Although the strong aluminum alloys have proved themselves to be very efficient in aircraft construction there is a growing competition from the high-strength steels for certain parts, especially for tubular members. This tendency is being reflected in research work carried on at the Bureau of Standards. This study will be based largely on data given in Technical Note No. 307 of the NACA.
Date: May 1, 1931
Creator: Hartmann, E C
Item Type: Report
Partner: UNT Libraries Government Documents Department

Development of an impinging-jet fuel-injection valve nozzle

Description: During an investigation to determine the possibilities and limitations of a two-stroke-cycle engine and ignition, it was necessary to develop a fuel injection valve nozzle to produce a disk-shaped, well dispersed spray. Preliminary tests showed that two smooth jets impinging upon each other at an angle of 74 degrees gave a spray with the desired characteristics. Nozzles were built on this basis and, when used in fuel-injection valves, produced a spray that fulfilled the original requirements. The spray is so well dispersed that it can be carried along with an air stream of comparatively low velocity or entrained with the fuel jet from a round-hole orifice. The characteristics of the spray from an impinging-jet nozzle limits its application to situations where wide dispersion is required by the conditions in the engine cylinder and the combustion chamber.
Date: April 1, 1931
Creator: Spanogle, J A & Hemmeter, G H
Item Type: Report
Partner: UNT Libraries Government Documents Department

Effect of high air velocities on the distribution and penetration of a fuel spray

Description: By means of the NACA Spray Photography Equipment high speed moving pictures were taken of the formation and development of fuel sprays from an automatic injection valve. The sprays were injected normal to and counter to air at velocities from 0 to 800 feet per second. The air was at atmosphere temperature and pressure. The results show that high air velocities are an effective means of mixing the fuel spray with the air during injection.
Date: May 1, 1931
Creator: Rothrock, A. M.
Item Type: Report
Partner: UNT Libraries Government Documents Department

The Effect of Injection-Valve Opening Pressure on Spray-Tip Penetration

Description: The effect of various injection-valve opening pressures on the spray-tip penetration was determined for several injection pressure. A common-rail fuel injection system was used. For a given injection pressure a maximum rate of penetration was obtained with an injection-valve opening pressure equal to the injection pressure. As the excess of the injection pressure over the injection-valve opening pressure was increased for a given injection pressure, the effect of the injection-valve opening pressure on the spray-tip penetration was increased.
Date: July 1, 1931
Creator: Rothrock, A. M. & Marsh, E. T.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Effect of nose shape on the characteristics of symmetrical airfoils

Description: Tests of nine symmetrical airfoils, having different leading-edge radii, were made in the variable density wind tunnel. Three symmetrical NACA airfoils having maximum thickness-to-chord ratio of 0.06, 0.012, and 0.018 were used as basic (or normal) sections; and for each of these thicknesses one thinner and one blunter nose section were developed. Although the slope of the lift curve varies with thickness, these tests show that for any given thickness the slope is independent of nose radius.
Date: August 1, 1931
Creator: Pinkerton, Robert M
Item Type: Report
Partner: UNT Libraries Government Documents Department

Effect of orifice length-diameter ratio on the coefficient of discharge of fuel-injection nozzles

Description: The variation of the coefficient of discharge with the length-diameter ratio of the orifice was determined for nozzles having single orifice 0.008 and 0.020 inch in diameter. Ratios from 0.5 to 10 were investigated at injection pressures from 500 to 5,000 pounds per square inch. The tests showed that, within the error of the observation, the coefficients were the same whether the nozzles were assembled at the end of a constant tube or in an automatic injection valve having a plain stem.
Date: March 1, 1931
Creator: Gelalles, A G & March, E T
Item Type: Report
Partner: UNT Libraries Government Documents Department

The effect of slots and flaps on the lift and drag of the McDonnell Airplanes determined in flight

Description: This note contains the results of flight test conducted by the National Advisory Committee for Aeronautics on a low-wing monoplane equipped with leading-edge slots extending over the entire wing and flaps extending only to the ailerons, to find their effect on the lift and drag characteristics of the airplane. Curves are given showing the lift and drag characteristics of the airplane for the following conditions of the slots and flaps neutral; slots closed and flaps down; and slots open and flaps down. In addition, the high and low speed in level flight and the climbing characteristics are given. The results show that the slots used alone increase the maximum lift coefficient 54 per cent; the flaps alone increase it 38 per cent; and the slots and flaps in combination decrease the landing speed from 60 to 43 m.p.h.; increase the speed range of the airplane 40 per cent; and increase the glide angle at landing speed 4.2 degrees.
Date: November 1, 1931
Creator: Soule, Hartley A
Item Type: Report
Partner: UNT Libraries Government Documents Department

The effect of small variations in profile of airfoils

Description: This report deals with the effect of small variations in ordinates specified by different laboratories for the airfoil section. This study was made in connection with a more general investigation of the effect of small irregularities of the airfoil surface on the aerodynamic characteristics of an airfoil. These tests show that small changes in airfoil contours, resulting from variations in the specified ordinates, have a sufficiently large effect upon the airfoil characteristics to justify the taking of great care in the specification of ordinates for the construction of models.
Date: January 1, 1931
Creator: Ward, Kenneth E
Item Type: Report
Partner: UNT Libraries Government Documents Department

The effectiveness of a double-stem injection valve in controlling combustion in a compression-ignition engine

Description: An investigation was made to determine to what extent the rates of combustion in a compression-ignition engine can be controlled by varying the rates of fuel injection. The tests showed that the double-stem valve operated satisfactorily under all normal injection conditions; the rate of injection has a definite effect on the rate of combustion; the engine performance with the double-stem valve was inferior to that obtained with a single-stem valve; and the control of injection rates permitted by an injection valve of two stages of discharge is not sufficient to effect the desired rates of combustion.
Date: December 1, 1931
Creator: Spanogle, J A & Whitney, E G
Item Type: Report
Partner: UNT Libraries Government Documents Department

Endurance and other properties at low temperatures of some alloys for aircraft use

Description: The low temperature endurance properties of materials for aircraft construction are not well known. In order to determine them, apparatus for testing endurance at -40 C has been devised. The endurance properties of monel metal, low-carbon stainless steel, "18 and *, " 3 1/2% Ni steel and chromium-molybdenum steel have been determined at -40 C and at room temperature about +20 C. Tensile, impact and hardness tests of these materials have also been made at various temperatures. The results show an increase in endurance limit, tensile strength, and hardness with decreased temperature. Impact strength is, in general, decreased, but of all the alloys tested, only one, low-carbon stainless steel, gives less than 15 ft. lb. Chrpay impact test at -40 C.
Date: June 1, 1931
Creator: Russell, H W & Welcker, W A , Jr
Item Type: Report
Partner: UNT Libraries Government Documents Department

Experiments with an airfoil model on which the boundary layers are controlled without the use of supplementary equipment

Description: This report describes test made in the Variable Density Wind Tunnel of the NACA to determine the possibility of controlling the boundary layer on the upper surface of an airfoil by use of the low pressure existing near the leading edge. The low pressure was used to induce flow through slots in the upper surface of the wing. The tests showed that the angle of attack for maximum lift was increased at the expense of a reduction in the maximum lift coefficient and an increase in the drag coefficient.
Date: April 1, 1931
Creator: Abbott, I H
Item Type: Report
Partner: UNT Libraries Government Documents Department

Interference effects and drag of struts on a monoplane wing

Description: Tests were conducted in the Variable Density Wind Tunnel of the NACA to determine the importance of the interference effects and drag of struts on a monoplane. Inclined struts were placed upon a Gottingen 387 airfoil in the lower surface positions and in two upper surface positions. Tests were made at values of Reynolds Number comparable with those obtained in flight. It was found that the interference drag of struts may be as great as the drag of the struts alone.
Date: February 1, 1931
Creator: Ward, Kenneth E
Item Type: Report
Partner: UNT Libraries Government Documents Department

The interference effects on an airfoil of a flat plate at mid-span position

Description: This report gives the results of an investigation of the mutual interference of an airfoil and a flat plate inserted at mid-span position. The tests were conducted in the Variable-Density Wind Tunnel of the National Advisory Committee for Aeronautics at a high value of the Reynolds Number. The interference effects of this combination were found to be small. Supplementary tests indicated that the use of fillets decreases both the lift and drag slightly. A bibliography of publication dealing with interference between wings and bodies, and with the effects of cut-outs and fillets is included.
Date: December 1, 1931
Creator: Ward, Kenneth E
Item Type: Report
Partner: UNT Libraries Government Documents Department

An investigation of cotton for parachute cloth

Description: This is a resume of the work of the Bureau of Standards on a cotton parachute cloth for use as a substitute for silk in the event of an emergency curtailing the supply. Cotton yarn of high strength in proportion to its weight and otherwise specially suitable for parachute cloth was developed. Cloth woven from this yarn in the bureau mill was equal or superior to parachute silk in strength and tear resistance, met the requirements with respect to air permeability, and weighed only a few tenths of an ounce per square yard more than the silk cloth. Practical trials of cotton parachutes carried out by the Navy Department clearly indicate that the cotton parachute closely approaches the silk parachute in performance as to rate of descent, opening time, strength and ability to function when stored in the pack for sixty days. The increase in weight of the equipment resulting from the use of cotton cloth instead of silk is considered to be well within practicable limits. A specification for cotton parachute cloth and the way in which the requirements of the specification have been met are given. Cotton yarns suitable for parachute cloth are now being woven commercially in the United States.
Date: September 1, 1931
Creator: Appel, Wm D & Worner, R K
Item Type: Report
Partner: UNT Libraries Government Documents Department

Investigation of the discharge rate of a fuel-injection system

Description: In connection with the development of a method for analyzing indicator cards taken from high-speed compression-ignition engines, this investigation was undertaken to determine the average quantity of fuel discharged during each crank degree of injection period.
Date: April 1, 1931
Creator: Gerrish, Harold C & Voss, Fred
Item Type: Report
Partner: UNT Libraries Government Documents Department

Lift and drag characteristics of a cabin monoplane

Description: The results of flight tests conducted by the NACA to determine the lift and drag characteristics of a full-scale airplane are given herein. A Fairchild FC-2W2 cabin monoplane having a Gottingen 387 wing section was used for the tests. The maximum lift coefficient for the airplane is compared with that obtained for the Gottingen 387 airfoil in recent tests in the Variable Density Tunnel. The maximum lift coefficient for the airplane was found to be 1.50 and that for the airfoil 1.56. Although the flight tests were confined chiefly to glides with the propeller locked horizontally, data obtained with the propeller operating at zero thrust for a few angles of attack are also included.
Date: January 1, 1931
Creator: Thompson, F L & Keister, P H
Item Type: Report
Partner: UNT Libraries Government Documents Department

Metal-truss wing spars

Description: The purpose of the study was to develop improvements in the current methods for the calculation of the loads in members of metal truss wing spars which are subjected to combined bending and compression. The theory developed here has two important practical applications. One is the calculation of the effective moment of inertia of a truss spar from the geometry of the spar and the loads to which the spar is to be subjected. The second is the determination of the most economical location of metal for stiffening a truss spar which has too much deflection.
Date: July 1, 1931
Creator: Swickard, Andrew E
Item Type: Report
Partner: UNT Libraries Government Documents Department