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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Year: 1933
 Serial/Series Title: NACA Technical Notes
 Collection: Technical Report Archive and Image Library
The aerodynamic characteristics of airfoils as affected by surface roughness

The aerodynamic characteristics of airfoils as affected by surface roughness

Date: April 1, 1933
Creator: HOCKER RAY W
Description: The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated at high values of the Reynolds number in a variable density wind tunnel. Tests were made on a number of National Advisory Committee for Aeronautics (NACA) 0012 airfoil models on which the nature of the surface was varied from a rough to a very smooth finish. The effect on the airfoil characteristics of varying the location of a rough area in the region of the leading edge was also investigated. Airfoils with surfaces simulating lap joints were also tested. Measurable adverse effects were found to be caused by small irregularities in airfoil surfaces which might ordinarily be overlooked. The flow is sensitive to small irregularities of approximately 0.0002c in depth near the leading edge. The tests made on the surfaces simulating lap joints indicated that such surfaces cause small adverse effects. Additional data from earlier tests of another symmetrical airfoil are also included to indicate the variation of the maximum lift coefficient with the Reynolds number for an airfoil with a polished surface and with a very rough one.
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The aerodynamic effect of a retractable landing gear

The aerodynamic effect of a retractable landing gear

Date: March 1, 1933
Creator: Defrance, Smith J
Description: Tests were conducted in the N.A.C.A. full scale wind tunnel at the request of the Army Air Corps to determine the effect of retractable landing gear openings in the bottom surface of a wing upon the characteristics of a Lockheed Altair airplane. The tests were extended to include the determination of the lift and drag characteristics throughout the angle-of-attack range with the landing gear both retracted and extended. Covering the wheel openings in the wing with sheet metal when the wheels were extended reduced the drag only 2 percent at a lift coefficient of 1.0, which was assumed for the take-off condition. Therefore, the wheel openings in the bottom side of the wing have a negligible effect upon the take-off of the airplane. Retracting the landing gear reduced the minimum drag of the complete airplane 50 percent.
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Aerodynamic tests of a low aspect ratio tapered wing with an auxiliary airfoil for use on tailless airplanes

Aerodynamic tests of a low aspect ratio tapered wing with an auxiliary airfoil for use on tailless airplanes

Date: November 1, 1933
Creator: Sanders, Robert
Description: None
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Aerodynamic tests of a low aspect ratio tapered wing with various flaps, for use on tailless airplanes

Aerodynamic tests of a low aspect ratio tapered wing with various flaps, for use on tailless airplanes

Date: June 1, 1933
Creator: Weick, Fred E & Sanders, Robert
Description: Wind tunnel tests were made of a model wing having an aspect ratio of 3 and a tapered plan form with a straight trailing edge. The model had the Clark Y airfoil section throughout it's entire span and had no washout, depending on a trailing-edge flap for longitudinal balance and control. The flap had a constant chord and was divided into four equal portions along the span. The tests were made with the entire flap deflected to obtain longitudinal control and balance, and also with the inner portions deflected alone, and with the outer portions deflected alone. It was found that the simple wing with no washout or change of basic section along the span has aerodynamic characteristics well suited for use on tailless airplanes. A higher lift coefficient was obtained with the full-span flap deflected as a unit to give longitudinal balance than was obtained with either the inner or the outer portions of the flap deflected.
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Charts for determining the pitching moment of tapered wings with sweepback and twist

Charts for determining the pitching moment of tapered wings with sweepback and twist

Date: December 1, 1933
Creator: Anderson, Raymond F
Description: This report presents a convenient method for calculating the pitching-moment characteristics of tapered wings with sweepback and twist. The method is based on the fact that the pitching-moment characteristics of a wing may be specified by giving the value of the pitching moment at zero lift and the location of the axis about which the axis is constant. Data for calculating these characteristics are presented by curves which apply to wings having a linear distribution of twist along the span and which cover a large range of aspect ratios. The curves are given for wings having straight taper and distorted elliptical plan forms. The characteristics of wings of other shapes may be determined by interpolation.
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Comparison of three methods for calculating the compressive strength of flat and slightly curved sheet and stiffener combinations

Comparison of three methods for calculating the compressive strength of flat and slightly curved sheet and stiffener combinations

Date: March 1, 1933
Creator: Lundquist, Eugene E
Description: This report gives a comparison of the accuracy of the three methods for calculating the compressive strength of flat sheet and stiffener combinations such as occur in stressed-skin or monocoque structures for aircraft. Of the three methods based upon various assumptions with regard to the interaction of sheet and stiffener, the method based upon mutual action of the stiffener and an effective width as a column gave the best agreement with the results of the tests. An investigation of the effect of small curvature resulted in the conclusion that the compressive strength of the curved panels is, for all practical purposes, equal to the strength of flat panels except for thick sheet where non-uniform curvature throughout the length may cause the strength of the curved panel to be 10 to 15 percent less than that of a corresponding flat panel.
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A complete tank test of a model of a flying-boat hull-N.A.C.A. Model No.11

A complete tank test of a model of a flying-boat hull-N.A.C.A. Model No.11

Date: July 1, 1933
Creator: Shoemaker, James M & Parkinson, John B
Description: This note discusses the limitations of the conventional tank test of a seaplane model. The advantages of a complete test, giving the characteristics of the model at all speeds, loads, and trim angles in the useful range are pointed out. The data on N.A.C.A. Model No.11, obtained from a complete test, are presented and discussed. The results are analyzed to determine the best trim angle for each speed and load. The data for the best angles are reduced to non-dimensional form for ease of comparison and application. A practical problem using the characteristics of model no.11 is presented to show the method of calculating the take-off time and run of a seaplane from these data.
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A Complete Tank Test of a Model of a Flying-Boat Hull - N.A.C.A. Model No.11

A Complete Tank Test of a Model of a Flying-Boat Hull - N.A.C.A. Model No.11

Date: July 1, 1933
Creator: Shoemaker, James M. & Parkinson, John B.
Description: This note discusses the limitations of the conventional tank test of a seaplane model. The advantages of a complete test, giving the characteristics of the model at all speeds, loads, and trim angles in the useful range are pointed out. The data on N.A.C.A. Model No.11, obtained from a complete test, are presented and discussed. The results are analyzed to determine the best trim angle for each speed and load. The data for the best angles are reduced to non-dimensional form for ease of comparison and application. A practical problem using the characteristics of model no.11 is presented to show the method of calculating the take-off time and run of a seaplane from these data.
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A complete tank test of a model of a flying-boat Hull - N.A.C.A. model no.11-A

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

Date: September 1, 1933
Creator: Parkinson, John B
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.
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A complete tank test of a model of flying-boat Hull - N.A.C.A. Model 16

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

Date: September 1, 1933
Creator: Shoemaker, James H
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.
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The drag of streamline wires

The drag of streamline wires

Date: December 1, 1933
Creator: Jacobs, Eastman N
Description: Preliminary results are given of drag tests of streamline wires. Full-size wires were tested over a wide range of speeds in the N.A.C.A. high speed tunnel. The results are thus directly applicable to full-scale problems and include any compressibility effects encountered at the higher speeds. The results show how protuberances may be employed on conventional streamline wires to reduce the drag, and also show how the conventional wires compare with others having sections more like strut or symmetrical airfoil sections. Because the new wire sections developed are markedly superior aerodynamically to conventional wires, it is recommended that some of them be tested in service in order to investigate their relative susceptibility to vibration and to fatigue failure.
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Effect of aileron displacement on wing characteristics

Effect of aileron displacement on wing characteristics

Date: February 1, 1933
Creator: Heald, R H
Description: The effect of aileron displacement on wing characteristics has been investigated for the Clark Y and the U.S.A. 27 wing sections equipped with rectangular ailerons. The airfoils, rectangular in plan, and having a 10 inch chord and 60 inch span, were mounted on a model fuselage.
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The effect of partial-span split flaps on the aerodynamic characteristics of a Clark Y wing

The effect of partial-span split flaps on the aerodynamic characteristics of a Clark Y wing

Date: September 1, 1933
Creator: Wenzinger, Carl J
Description: Aerodynamic force tests were made in the N.A.C.A. 7 by 10 foot wind tunnel on a model Clark Y wing with a 20 percent chord split flap deflected 60 degrees downward. The tests were made to determine the effect of partial-span split flaps, located at various positions along the wing span on the aerodynamic characteristics of the wing-and-flap combination. The different lengths and locations of the flaps were obtained by cutting off portions of a full-span flap, first from the tips and then from the center. The results are given in the form of curves of lift, drag, and center of pressure. They show that with partial-span split flaps both the lift and drag are less than with full-span flaps; that the lift for a given length of flap is somewhat greater when the partial span is located at the center of the wing than when it is located at the tip portion, and that the drag for a given length of flap is the same regardless of the location over the flap with respect to the wing span.
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The effect of rivet heads on the characteristics of a 6 by 36 foot Clark Y metal airfoil

The effect of rivet heads on the characteristics of a 6 by 36 foot Clark Y metal airfoil

Date: May 1, 1933
Creator: Dearborn, Clinton H
Description: An investigation was conducted in the N.A.C.A. full-scale wind tunnel to determine the effects of exposed rivet heads on the aerodynamic characteristics of a metal-covered 6 by 36 foot Clasky airfoil. Lead punching simulating 1/8inch rivet heads were attached in full-span rows at a pitch of 1 inch at various chord positions. Tests were made at velocities varying from 40 to 120 miles per hour to investigate the scale effect. Rivets at the 5 percent chord position the upper surface of the airfoil produced the greatest increase in drag for a single row. Nine rows of rivets on both surfaces, simulating rivet spacing of multispan construction, increased the drag coefficients by a constant amount at velocities between 100 and 120 miles per hour. Accordingly, if rivets spaced the same as those on the test airfoil were used on a Clark Y wing of 300 square feet area and operated at 200 miles per hour, the drag would be increased over that for the smooth wing by 55 pounds and the power required would be increased by 29 horsepower.
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The effect of split trailing-edge wing flaps on the aerodynamic characteristics of a parasol monoplane

The effect of split trailing-edge wing flaps on the aerodynamic characteristics of a parasol monoplane

Date: November 1, 1933
Creator: Wallace, Rudolf, N
Description: This paper presents the results of tests conducted in the N.A.C.A. full-scale wind tunnel on a Fairchild F-22 airplane equipped with a special wing having split trailing-edge flaps. The flaps extended over the outer 90 percent of the wing span, and were of the fixed-hinge type having a width equal to 20 percent of the wing chord. The results show that with a flap setting of 59 degrees the maximum lift of the wing was increased 42 percent, and that the flaps increased the range of available gliding angles from 2.7 degrees to 7.0 degrees. Deflection of the split flaps did not increase the stalling angle or seriously affect the longitudinal balance of the airplane. With flaps down the landing speed of the airplane is decreased, but the calculated climb and level-flight performance is inferior to that with the normal wing. Calculations indicate that the take-off distance required to clear an obstacle 100 feet high is not affected by flap settings from 0 degrees to 20 degrees but is greatly increased by larger flap angles.
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The effect of spray strips on a model of the P3M-1 flying boat hull

The effect of spray strips on a model of the P3M-1 flying boat hull

Date: December 1, 1933
Creator: Dawson, John R
Description: This note presents the results of a series of tests made in the N.A.C.A. tank on a one-sixth full-size model of the hull and side floats of the Navy P3M-1 flying boat for the purpose of finding a method of reducing the amount of spray thrown into the propellers of this craft when taking off and landing. The model was tested without spray strips and with five different spray-strip arrangements. The best arrangement was an improvement over the bare hull with no spray strips, but the improvement was not sufficient to be satisfactory with the propellers in the designed position.
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Effect of stabilizer location upon pitching and yawing moments in spins as shown by tests with the spinning balance

Effect of stabilizer location upon pitching and yawing moments in spins as shown by tests with the spinning balance

Date: November 1, 1933
Creator: Bamber, M J & Zimmerman, C H
Description: Tests were made with the spinning balance in a 5-foot wind tunnel to study the effect of stabilizer location upon the pitching and yawing moments given by the tail surfaces in spinning attitudes. The tests revealed that the horizontal surfaces, when in a normal location, seriously reduced the effectiveness of the fin and rudder, particularly at angles of attack of 50 degrees or more. The tests also revealed that a more forward or more rearward location gave no consistent or decided improvement; that a lower location greatly increased the shielding so that the yawing moment from the combination was in general less than that given by the bare fuselage; and that a higher location decreased the shielding and gave a favorable interference effect, particularly at the high angles of attack. Additional results regarding the stabilizer and the elevator are given.
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The effect on engine performance of change in jacket-water outlet temperature

The effect on engine performance of change in jacket-water outlet temperature

Date: November 1, 1933
Creator: Garlock, E A & Ellis, Greer
Description: Tests made on a Curtiss D-12 engine in the Altitude Laboratory at the Bureau of Standards show the following effects on engine performance of change in jacket-water outlet temperature: 1) Friction at all altitudes is a linear function of the jacket-water temperature, decreasing with increasing temperature. 2) The brake horsepower below an altitude of about 9,000 feet decreases, and at higher altitudes increases, with jacket-water temperature. 3) The brake specific fuel consumption tends to decrease, at all altitudes, with increasing jacket-water temperature. 4) The percentage change in brake power output is roughly equal to the algebraic sum of the percentage change in volumetric efficiency and mechanical efficiency.
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The effect on lift, drag, and spinning characteristics of sharp leading edges on airplane wings

The effect on lift, drag, and spinning characteristics of sharp leading edges on airplane wings

Date: February 1, 1933
Creator: Weick, Fred E & Scudder, Nathan F
Description: An investigation with special reference to auto rotation and spinning was conducted in two wind tunnels and in flight to find the aerodynamic effects of adding a sharp leading edge to a wing sector.
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The effects of slots and flaps on lateral control of a low-wing monoplane as determined in flight

The effects of slots and flaps on lateral control of a low-wing monoplane as determined in flight

Date: November 1, 1933
Creator: Soule, Hartley A & Wetmore, J W
Description: This paper presents the results of flight tests made to determine the effect of slots and flaps on the lateral control of a low-wing monoplane. Maximum angular accelerations in roll and yaw produced by sudden application of the ailerons and maximum accelerations in yaw produced by sudden application of the rudder during gliding flight were recorded for the following wing arrangements: (a) no auxiliary device; (b) full-span slots; (c) plain flaps; (d) flaps and full-span slots; (e) wing-tip slots. Rolling- and yawing-moment coefficients were derived from the accelerations. The full span slots and the flaps each had about the same influence on the aileron rolling moments. At values of the lift coefficient obtainable with the plain wing, the effect of these devices was negligible. At the higher lift coefficients obtainable with these devices, the rolling-moment coefficients increased slightly but, despite this increase, the aileron effectiveness progressively decreased with increasing lift coefficient, owing to the corresponding reduction in air speed. In the range covered by the tests, the effectiveness of the controls was appreciably reduced by the wing-tip slots. The adverse yawing moment of the ailerons experienced at the large lift coefficients obtained with the flaps was appreciably less than at ...
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Engine performance with a hydrogenated safety fuel

Engine performance with a hydrogenated safety fuel

Date: July 1, 1933
Creator: Schey, Oscar W & Young, Alfred W
Description: This report presents the results of an investigation to determine the engine performance obtained with a hydrogenated safety fuel developed to eliminate fire hazard. The tests were made on a single-cylinder universal test engine at compression ratios of 5.0, 5.5, and 6.0. Most of the tests were made with a fuel-injection system, although one set of runs was made with a carburetor when using gasoline to establish comparative performance. The tests show that the b.m.e.p. obtained with safety fuel when using a fuel-injection system is slightly higher than that obtained with gasoline when using a carburetor, although the fuel consumption with safety fuel is higher. When the fuel-injection system is used with each fuel and with normal engine temperatures the b.m.e.p. with safety fuel is from 2 to 4 percent lower than with gasoline and the fuel consumption about 25 to 30 percent higher. However, a few tests at an engine coolant temperature of 250 F have shown a specific fuel consumption approximating that obtained with gasoline with only a slight reduction in power. The idling of the test engine was satisfactory with the safety fuel. Starting was difficult with a cold engine but could be readily accomplished when the ...
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Experiments with a counter-propeller

Experiments with a counter-propeller

Date: March 1, 1933
Creator: Lesley, E P
Description: This note describes tests made at Stanford University on a four-blade fixed counter-propeller in combination with a two-blade rotating propeller. It is shown that the efficiency of the normal form, well-designed air propeller can be increased about two percent over the full working range by the addition of fixed counter-propeller blades.
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Formulas for the stress analysis of circular rings in a monocoque fuselage

Formulas for the stress analysis of circular rings in a monocoque fuselage

Date: June 1, 1933
Creator: Miller, Roy A & Wood, Karl D
Description: The formulas given in this report provide a simplified method for the stress-analysis of fuselage bulkheads that are approximately circular rings of uniform cross section. Complicated load systems acting on a ring can usually be resolved into simplified load systems; and formulas for moment, axial force, and shear for such simplified load systems are given in this report. Illustrative examples showing the use of this method in practical stress-analysis work are also included.
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Full-scale wind-tunnel research on tail buffeting and wing-fuselage interference of a low-wing monoplane

Full-scale wind-tunnel research on tail buffeting and wing-fuselage interference of a low-wing monoplane

Date: May 1, 1933
Creator: Hood, Manley J & White, James A
Description: Some preliminary results of full scale wind tunnel testing to determine the best means of reducing the tail buffeting and wing-fuselage interference of a low-wing monoplane are given. Data indicating the effects of an engine cowling, fillets, auxiliary airfoils of short span, reflexes trailing edge, propeller slipstream, and various combinations of these features are included. The best all-round results were obtained by the use of fillets together with the National Advisory Committee for Aeronautics (NACA) cowling. This combination reduced the tail buffeting oscillations to one-fourth of their original amplitudes, increased the maximum lift 11 percent, decreased the minimum drag 9 percent, and increased the maximum ratio of lift to drag 19 percent.
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