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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

Aerodynamic characteristics of twenty-four airfoils at high speeds

Description: The aerodynamic characteristics of 24 airfoils are given for speeds of 0.5, 0.65, 0.8, 0.95, and 1.08 times the speed of sound, as measured in an open-jet air stream 2 inches in diameter, using models of 1-inch chord. The 24 airfoils belong to four general groups. The first is the standard R. A. F. family in general use by the Army and Navy for propeller design, the members of the family differing only in thickness. This family is represented by nine members ranging in thickness from 0.04 to 0.20 inch. The second group consists of five members of the Clark Y family, the members of the family again differing only in thickness. The third group, comprising six members, is a second R. A. F. Family in which the position of the maximum ordinate is varied. Combined with two members of the first R.A.F. family, this group represents a variation of maximum ordinate position from 30 to 60 percent of the chord in two camber ratios, 0.08 and 0.16. The fourth group consists of three geometrical forms, a flat plate, a wedge, and a segment of a right circular cylinder. In addition one section used in the reed metal propeller was included. These measurements form a part of a general program outlined at a Conference on Propeller Research organized by the National Advisory Committee for Aeronautics and the work was carried out with the financial assistance of the committee (author).
Date: 1930~
Creator: Brigg, L. J. & Dryden, H. L.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of wings with cambered external airfoil flaps, including lateral control, with a full-span flap

Description: The results of a wind-tunnel investigation of the NACA 23012, the NACA 23021, and the Clark Y airfoils, each equipped with a cambered external-airfoil flap, are presented in this report. The purpose of the research was to determine the relative merit of the various airfoils in combination with the cambered flap and to investigate the use of the flap as a combined lateral-control and high-lift device.
Date: 1935
Creator: Platt, Robert C
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic drag of five models of side floats N.A.C.A. Models 51-E, 51-F, 51-G, 51-H, 51-J

Description: The drag of five models of side floats was measured in the N.A.C.A. 7- by 10-foot wind tunnel. The most promising method of reducing the drag of floats indicated by these tests is lowering the angle at which the floats are rigged. The addition of a step to a float does not always increase the drag in the flying range, floats with steps sometimes having lower drag than similar floats without steps. Making the bow chine no higher than necessary might result in a reduction in air drag because of the lower angle of pitch of the chines. Since side floats are used formally to obtain lateral stability when the seaplane is operating on the water at slow speeds or at rest, greater consideration can be given to factors affecting aerodynamic drag than is possible for other types of floats and hulls.
Date: December 1938
Creator: House, R O
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic drag of flying-boat hull model as measured in the NACA 20-foot wind tunnel I.

Description: Measurements of aerodynamic drag were made in the 20-foot wind tunnel on a representative group of 11 flying-boat hull models. Four of the models were modified to investigate the effect of variations in over-all height, contours of deck, depth of step, angle of afterbody keel, and the addition of spray strips and windshields. The results of these tests, which cover a pitch-angle range from -5 to 10 degrees, are presented in a form suitable for use in performance calculations and for design purposes.
Date: April 1935
Creator: Hartman, Edwin P
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic effect of a retractable landing gear

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.
Date: March 1933
Creator: Defrance, Smith J
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic effects of a split flap on the spinning characteristics of a monoplane model

Description: The investigation described in this report was made to determine the change in aerodynamic forces and moments produced by split flaps in a steady spin. The test were made with the spinning balance in the NACA 5-foot vertical wind tunnel. A low-wing monoplane model was tested with and without the split flaps in 12 spinning attitudes chosen to cover the probable spinning range. The changes in coefficients produced by adding the split flaps are given for longitudinal force, normal force, and rolling and yawing moments about body axes. The results obtained indicate that the use of split flaps on an airplane is unlikely, in any case, to have much beneficial effect on a spin, and it might make the spin dangerous. The change in the spin will depend upon the aerodynamic and inertia characteristics of the particular airplane. A dangerous condition is most likely to be attained with airplanes which are statically stable in yaw in the spinning attitude and which have large weights distributed along wings.
Date: December 1934
Creator: Bamber, M J
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic effects of wing cut-outs

Description: In connection with the interference program being conducted in the NACA variable-density wind tunnel, an analysis was made of available material with the object of presenting a qualitative discussion on wing characteristics as affected by cut-outs and of determining means for their quantitative calculation.
Date: 1934
Creator: Sherman, Albert
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic forces and moments exerted on a spinning model of the NY-1 airplane as measured by the spinning balance

Description: A preliminary investigation of the effects of changes in the elevator and rudder settings and of small changes in attitude upon the aerodynamic forces and moments exerted upon a spinning airplane was undertaken with the spinning balance in the 5-foot vertical tunnel of the National Advisory Committee for Aeronautics. The tests were made on a 1/12-scale model of the ny-1 airplane. Data by which to fix the attitude, the radius of spin, and the rotational and air velocities were taken from recorded spins of the full-scale airplane. Two spinning conditions were investigated. All six components of the aerodynamic reaction were measured and are presented in coefficient form refereed to airplane axes. The results indicate that the change in yawing moment produced by the rudder with the elevator up was the only component of force or moment produced by the elevator and rudder that could not have been balanced in an actual spin by small changes in attitude and angular velocity.
Date: February 7, 1933
Creator: Bamber, M J & Zimmerm, N, C h
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic forces and moments of a seaplane on the water

Description: This report gives the results of wind-tunnel tests with a seaplane model as a contribution to the solution of the aerodynamic problems. In the tests it was assumed that the seaplane rested motionless on the water and was exposed, in various positions with respect to the supposedly flat surface of the water, to a uniform air current 0 to 360 degrees.
Date: November 1933
Creator: Kohler, M
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic forces and moments on a spinning model of the F4B-2 airplane as measured by the spinning balance

Description: The aerodynamic forces and moments on a 1/12-scale model of the F4B-2 airplane were measured with the spinning balance in nine spinning attitudes with three sets of tail surfaces, namely, F4B-2 surfaces; F4B-4 fin and rudder with rectangular stabilizer; and with all tail surfaces removed. In one of these attitudes measurements were made to determine the effect upon the forces and moments of independent and of simultaneous displacement of the rudder and elevator for two of the sets of tail surfaces. Additional measurements were made for a comparison of model and full-scale data for six attitudes that were determined from flight tests with various control settings. The characteristics were found to vary in the usual manner with angle of attack and sideslip. The F4B-2 surfaces were quite ineffective as a source of yawing moments. The F4B-4 fin and F4B-2 stabilizer gave a greater damping yawing moment when controls were against the spin than did the F4B-2 surfaces but otherwise there was little difference. Substitution of a rectangular stabilizer for the F4B-2 stabilizer made no appreciable difference in the coefficient. Further comparisons with other airplane types are necessary before final conclusions can be drawn as to the relations between model and full-scale spin measurements.
Date: February 1935
Creator: Bamber, M J & Zimmerman, C H
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic Investigation of a Cup Anemometer

Description: Results of an investigation wherein the change of the normal force coefficient with Reynolds Number was obtained statically for a 15.5-centimeter hemispherical cup.
Date: July 1934
Creator: Hubbard, John D. & Brescoll, George P.
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic principles of the direct lifting propeller

Description: The purpose of this report is to make the complicated processes on the direct-lift propeller amenable to analysis and observation. This is accomplished by placing the physical phenomena, starting with the most elementary process, in the foreground, while limiting the mathematical treatment to the most essential in view of the fundamental defects of the theorems. Comparison with model experiments supplements and corroborates the theoretical results.
Date: January 1934
Creator: Schrenk, Martin
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aerodynamic rolling and yawing moments produced by floating wing-tip ailerons, as measured by spinning balance

Description: The investigation described in this report was made to determine the effectiveness of floating wing-tip ailerons as an airplane control in the spin. In these tests the ailerons, not being balanced, were set parallel to the axis of rotation, which is probably very nearly the attitude that balanced floating ailerons would assume in a spin. The tests were made with the spinning balance in the N.A.C.A. 5-foot vertical tunnel. The model was tested with and without the ailerons in 12 spinning attitudes chosen to cover the probable spinning range. Rolling- and yawing-moment coefficients are given as measured for the model with and without the ailerons, and computed values are given for the ailerons alone. The addition of floating wing-tip ailerons to the model doubled the rolling-moment coefficient and increased the yawing-moment coefficient by 0.05 and more. Both moments were in a sense to oppose the spin.
Date: March 1934
Creator: Bamber, Millard J
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic safety of airplanes

Description: This report presents several hypotheses regarding airplane safety, mainly concerning the nondimensional coefficient of air, speed, acceleration, and wing area on aerodynamic considerations of safety.
Date: September 1932
Creator: Kahn, Louis
Item Type: Report
Partner: UNT Libraries Government Documents Department

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

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.
Date: June 1933
Creator: Weick, Fred E. & Sanders, Robert
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aerodynamic wind vane and the inherent stability of airplanes

Description: The design of the wind vane described rests on the following line of reasoning: An airplane, originally in equilibrium about its C.G. is assumed to be deflected from this position through an angle (delta)i, the variation (delta)i being so sudden that the path of the C.G. and the airplane speed do not change while it is taking place. The aerodynamic forces acting on the wings, tail surfaces, fuselage, etc., which, as a whole, exerted a zero moment (M(sub G) = 0) about the center of gravity at the instant of equilibrium, now exert a moment M(sub G) not equal to 0.
Date: February 1931
Creator: Lapresle, A
Item Type: Report
Partner: UNT Libraries Government Documents Department

Aeronautical education and research at the Swiss Institute of Technology in Zurich

Description: Progress in the scientific and practical fields of aviation has caused the Swiss Institute of Technology to organize lectures and practical training courses in all three branches of aeronautics and to found centers of scientific research, laboratories, etc., in order to supply the government and industries with scientifically and technically trained engineers.
Date: April 1931
Creator: Karner, L & Ackeret, J
Item Type: Report
Partner: UNT Libraries Government Documents Department

The aeronautical laboratory of the Stockholm Technical Institute

Description: This report presents a detailed analysis and history of the construction and operation of the aeronautical laboratory of the Stockholm Technical Institute. Engines and balances are discussed and experimental results are also given.
Date: March 1935
Creator: Malmer, Ivar
Item Type: Report
Partner: UNT Libraries Government Documents Department

Air conditions close to the ground and the effect on airplane landings

Description: This report presents the results of an investigation undertaken to determine the feasibility of making glide landings in gusty air. Wind velocities were measured at several stations between the ground and a height of 51 feet, and flight tests were made to determine the actual influence of gusts on an airplane gliding close to the ground.
Date: April 3, 1934
Creator: Thompson, F L; Peck, W C & Beard, A P
Item Type: Report
Partner: UNT Libraries Government Documents Department

Air flow around finned cylinders

Description: Report presents the results of a study made to determine the air-flow characteristics around finned cylinders. Air-flow distribution is given for a smooth cylinder, for a finned cylinder having several fin spacings and fin widths, and for a cylinder with several types of baffle with various entrance and exit shapes. The results of these tests show: that flow characteristics around a cylinder are not so critical to changes in fin width as they are to fin spacing; that the entrance of the baffle has a marked influence on its efficiency; that properly designed baffles increase the air flow over the rear of the cylinder; and that these tests check those of heat-transfer tests in the choice of the best baffle.
Date: November 7, 1935
Creator: Brevoort, M J & Rollin, Vern G
Item Type: Report
Partner: UNT Libraries Government Documents Department