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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
NASA NTRS1929

Wind tunnel pressure distribution tests on an airfoil with trailing edge flap

This report deals with pressure distribution tests on an airfoil with a conventional trailing edge flap. These tests were conducted in the Atmospheric Wind Tunnel of the National Advisory Committee for Aeronautics. Maximum chord loadings were obtained with the flap displaced downward and with the airfoil at large angles of attack. Greater changes were produced in the normal force and in the center of pressure travel by up-flap than by an equal down-flap displacement.

Wenzinger, Carl J↗
NASA NTRS1928

Preliminary biplane tests in the variable density wind tunnel

Biplane cellules using the N.A.C.A.-M6 airfoil section have been tested in the variable density wind tunnel of the National Advisory Committee for Aeronautics. Three cellules, differing only in the amount of stagger, were tested at two air densities, corresponding to pressures of one atmosphere and of twenty atmospheres. The range of angle of attack was from -2 degrees to +48 degrees. The effect of stagger on the lift and drag, and on the shielding effect of the upper wing by the lower at high angles of attack was determined.

Shoemaker, James M↗
NASA NTRS1931

The Interference Effects on an Airfoil of a Flat Plate at Mid-span Position

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.

Ward, Kenneth E↗
NASA NTRS1931

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

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.

AIRFOILS - GOETTINGER 398 - CHAR , C P & ORDINATES↗
NASA NTRS1931

The Effect of Slots and Flaps on the Lift and Drag of the Mcdonnell Airplanes Determined in Flight

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.

Soule, Hartley A↗
NASA NTRS1930

Full Scale Drag Tests on Various Parts of Fairchild (FC-2W2) Cabin Monoplane

The drag due to the various parts of a Fairchild (FC-2W2) cabin monoplane was measured at air speeds varying from 50 to 100 m.p.h., in the Twenty-Foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics. It was found that the largest drag was due to the radial air-cooled engine. The measured drag due to the landing gear was also large, being about 4/5 of that due to the engine. Substituting Musselman type wheels for the standard wheels caused no change in the drag due to the landing gear. A small decrease in drag was effected by adding a turtle back to the airplane fuselage.

ENGINES, RADIAL - DRAG↗
NASA NTRS1932

Methods of Visually Determining the Air Flow Around Airplanes

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.

Gough, Melvin N↗
NASA NTRS1936

Tank Tests of Models of Floats for Single-float Seaplanes First Series.

Large models of the Mark V and Mark VI floats used for single float seaplanes (National Advisory Committee for Aeronautics (NACA) models 41-A and 41-B, respectively) were tested in the NACA tank to provide general test data for typical single floats and a basis for possible improvements of their form. The resistance of model 41-B was greater than that of model 41-A, either when free to trim or at the best trim angle for each. The resistance of model 35-B (a pointed step hull tested free to trim) was less than either of the models at the hump speed, greater at intermediate planing speeds, and less at the speeds and loads near get-away, although the spray was generally worse owing to the absence of transverse flare. The results of the fixed-trim tests of model 41-A were cross plotted to obtain data at the angle for zero trimming moment and at the best trim angle. The trims assumed by models 41-A and 41-B, when tested free to trim, were found to be excessive at the hump speed. The corresponding trim of model 35-B was found to be approximately 3 degrees lower because of the lower angle of afterbody keel used in this model, and the maximum hump resistance was 15 percent lower.

Parkinson, J B↗
NASA NTRS1934

Landing characteristics of an autogiro

An investigation to determine the rate of descent, the horizontal velocity, and the attitude at contact of an autogiro in landings was made by the National Advisory Committee for Aeronautics at the request of the Bureau of Air Commerce, Department of Commerce. The investigation covered various types of landings. The results of the investigation disclosed that the maximum rate of descent at contact with the ground (10.6 feet per second) was less than the minimum rate of descent attainable in a steady glide (15.8 feet per second); that the rates of descent at contact were of the same order of magnitude as those experienced by conventional airplanes in landings; that flared landings resulted in very low horizontal velocities at contact. Also that unexpectedly high lift and drag force coefficients were developed in the latter stages of the flared landings.

Peck, William C↗
NASA NTRS1933

The Aerodynamic Characteristics of Airfoils as Affected by Surface Roughness

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.

HOCKER RAY W↗
NASA NTRS1933

Full-scale Wind-tunnel Research on Tail Buffeting and Wing-fuselage Interference of a Low-wing Monoplane

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.

Hood, Manley J↗
NASA NTRS1936

Tank Tests of Models of Flying Boat Hulls Having Longitudinal Steps

Four models with longitudinal steps on the forebody were developed by modification of a model of a conventional hull and were tested in the National Advisory Committee for Aeronautics (NACA) tank. Models with longitudinal steps were found to have smaller resistance at high speed and greater resistance at low speed than the parent model that had the same afterbody but a conventional V-section forebody. The models with a single longitudinal step had better performance at hump speed and as low high-speed resistance except at very light loads. Spray strips at angles from 0 degrees to 45 degrees to the horizontal were fitted at the longitudinal steps and at the chine on one of the two step models having two longitudinal steps. The resistance and the height of the spray were less with each of the spray strips than without; the most favorable angle was found to lie between 15 degrees and 30 degrees.

Allison, John M↗
NASA NTRS1936

Mechanical Properties of Aluminum-alloy Rivets

The development of metal construction for aircraft has created a need for accurate and detailed information regarding the strength of riveted joints in aluminum-alloy structures. To obtain this information the National Bureau of Standards in cooperation with the National Advisory Committee for Aeronautics is investigating the strength of riveted joints in aluminum alloys. The strength of riveted joints may be influenced by the form of the head, the ratio of the rivet diameter to the sheet thickness, the driving stress, and other factors. This note gives the results of tests to develop the riveting technique for test specimens and to determine the effects of these factors.

Brueggeman, Wm C↗
NASA NTRS1937

Free-spinning Wind-tunnel Tests of a Low-wing Monoplane with Systemic Changes in Wings and Tails

A series of tests was made at the National Advisory Committee for Aeronautics (NACA) free-spinning tunnel to determine the effect of systematic changes in wing and tail arrangement upon steady-spinning and recovery characteristics of a conventional low-wing monoplane model for a basic loading condition. Eight wings and three tails, covering a wide range of aerodynamic characteristics, were independently ballasted so as to be interchangeable with no change in mass distribution. For each of the 24 wing-tail combinations, observations were made of steady spins for four control settings and of recoveries for five control manipulators. The results are presented in the form of charts comparing the spin characteristics. The results showed that, with a poor tail arrangement, wing plan form and tip shape had a considerable effect on the spinning characteristics.

Seidman, Oscar↗
NASA NTRS1934

Effect of retractable-spoiler location on rolling- and yawing-moment coefficients

In this report are presented the results of wind-tunnel tests of retractable spoilers on the upper surface of a Clark Y wing, which have been made as part of an investigation of lateral control devices being conducted by the National Advisory Committee for Aeronautics. Spoilers with chords up to 15.0 percent of the wing chord were tested in several locations on a plain rectangular wing and in two locations on the same wing equipped with a 20.0 percent chord split flap down 60 degrees. Charts are given for four representative angles of attack from which values of rolling- and yawing-moment coefficients may be obtained for spoilers up to 15.0 percent chord located on the upper surface of a Clark Y wing. The tests showed that at low angles of attack practically the same rolling moments can be obtained with a given spoiler at any location back of 30.0 percent of the wing chord, while at high angles of attack there is a definite advantage in locating the spoiler at least as far forward as 30.0 percent of the chord. The yawing moments accompanying a given rolling moment increase positively as the spoiler location is moved forward from the trailing edge of the wing. It is concluded that the 30.0 percent chord location is probably the optimum provided that instantaneous response of the airplane to a control movement can be obtained.

Shortal, J A↗
NASA NTRS1942

Strength tests of thin-walled elliptic duralumin cylinders in pure bending and in combined pure bending and torsion

An analysis is presented of the results of tests made by the Massachusetts Institute of Technology and by the National Advisory Committee for Aeronautics on an investigation of the strength of thin-walled circular and elliptic cylinders in pure bending and in combined torsion and bending. In each of the loading conditions, the bending moments were applied in the plane of the major axis of the ellipse.

Lundquist, Eugene E↗
NASA NTRS1940

A Flight Investigation of Exhaust-heat De-icing

The National Advisory Committee for Aeronautics conducted exhaust-heat de-icing tests in flight to provide data needed in the application of this method. The capacity to extract heat from the exhaust gas for de-icing purposes, the quantity of heat required, and other factors were examined. The results indicate that a wing-heating system employing a spanwise exhaust tube within the leading edge of the wing removed 30 to 35 percent of the heat from exhaust gas entering the wing. Data are given from which the heat required for ice prevention can be calculated. Sample calculations have been made on the basis of existing engine power/wing area ratios to show that sufficient heating can be obtained for ice protection on modern transportation airplanes, provided that uniform distribution of the heat can be secured.

Jones, Alun R↗
NASA NTRS1943

Some Investigations of the General Instability of Stiffened Metal Cylinders IV : Continuation of Tests of Sheet-covered Specimens and Studies of the Buckling Phenomena of Unstiffened Circular Cylinders

This is the fourth of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. The first five reports of this series cover investigations of the general instability problem under the loading conditions of pure bending and were prepared under the sponsorship of the Civil Aeronautics Administration. The succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory Committee for Aeronautics. This report is to deal primarily with the continuation of tests of sheet-covered specimens and studies of the buckling phenomena of unstiffened circular cylinders.

CYLINDERS, STEEL↗