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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Special Report
 Collection: Technical Report Archive and Image Library
Present Status of Lateral-Control Devices for use with Split Flaps, Special Report

Present Status of Lateral-Control Devices for use with Split Flaps, Special Report

Date: August 1, 1933
Creator: Weick, Fred E.
Description: The increased use of split flaps for the dual purpose of reducing the landing speed and shortening the landing glide of airplanes has established as acute the problem of obtaining satisfactory lateral control to be used in conjunction with the flaps with out the sacrifice of any of the effectiveness of the flaps. A large amount of work is being done on this problem by various organizations and individuals. Several of the devices developed seem usable, some of them unquestionably so. The present paper attempts to summarize the most promising results obtained to date. Topics covered include ordinary ailerons, external ailerons, floating ailerons, upper-surface ailerons, and spoilers. Although the external ailerons above the trailing edge of the wing and the spoilers at the rear of the wing appear quite promising, it would seem that probably the most satisfactory immediate solution of the problem, including the obtaining of light and smoothly graduated control forces, would in most cases be obtained by the use of the arrangement in which the flap is retracted ahead of ordinary narrow-chord ailerons and is deflected to the rear as well as downward when in use.
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Pressure Distribution on the Fuselage of a Midwing Airplane Model at High Speeds

Pressure Distribution on the Fuselage of a Midwing Airplane Model at High Speeds

Date: November 1, 1939
Creator: Delano, James B.
Description: The pressure distribution on the fuselage of a midwing airplane model was measured in the NACA 8-foot high speed wind tunnel at speeds from 140 to 440 miles per hour for lift coefficients ranging from -0.2 to 1.0. The primary purpose of the tests was to provide data showing the air pressures on various parts of the fuselage for use in structural design. The data may also be used for the design of scoops and vents. The results show that the highest negative pressures occurred near the wing and were more dependent on the wing than on the fuselage. At high speeds, the magnitude of the pressure coefficients as predicted from pressure coefficients determined experimentally at low speeds by application of the theoretical factor 1/(square root)1-M(exp 2) (where M is the ratio of the air speed to the speed of sound in air) may misrepresent the actual conditions. At the points where the maximum negative pressures ocurred, however, the variation of the pressure coefficients was in good agreement with the theoretical factor, indicating that this factor may afford satisfactory predictions of critical speed, at least for fuselages similar to the shape tested.
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A profile-drag investigation in flight on an experimental fighter-type airplane the North American XP-51

A profile-drag investigation in flight on an experimental fighter-type airplane the North American XP-51

Date: January 1, 1942
Creator: Zalovcik, J. A.
Description: None
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Profile-Drag Investigation of an Airplane Wing Equipped with Rubber Inflatable De-Icer

Profile-Drag Investigation of an Airplane Wing Equipped with Rubber Inflatable De-Icer

Date: December 1, 1939
Creator: Rodert, Lewis A.
Description: The National Advisory Committee for Aeronautics has made profile-drag measurements in flight of a wing which was equipped with a rubber inflatable de-icer and to which various stimulated ice formations were attached. Tuft observations at the stalling speed of the wing with the various drag conditions were made in order to determine the influence on the maximum lift coefficient. The de-icer installation caused an increase of from 10-20% in the profile drag of the plain wing and reduced CL(sub max) about 6%. Simulated ice, when confined to the leading-edge region of the de-icer, had no measurable influence upon the profile drag at the cruising speed. This ice condition, however, reduced the value of CL(sub max) to about three-fourths that of the plain wing. Simulated ice in the form of a ridge along the upper and lower de-icer cap-strips increased the profile drag by about 360% at cruising speed. This condition reduced the CL(sub max) to approximately one-half that of the plain wing value.
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Propeller-Design Problems of High-Speed Airplanes, Special Report

Propeller-Design Problems of High-Speed Airplanes, Special Report

Date: April 1, 1941
Creator: Dickinson, H. B.
Description: It is shown that on the basis of existing high-speed airfoil data, propeller efficiencies appreciably in excess of 40% do not appear possible at speeds above 500 miles per hour at 20,000 feet. The assumption that present propeller-blade thicknesses cannot be reduced radically, is implied. Until the reliability and applicability of the airfoil data are established, this conclusion must not be regarded as infallible. Dive tests with airplanes equipped with thrust meters and torque meters are proposed to provide an urgently needed check. The design of high-speed propellers is dictated wholly by compressibility considerations. The blade width, thickness, and pitch distribution; also the airfoil sections, the lift coefficient, the propeller diameter, and rpm must all be adjusted if reasonable efficiencies are to be maintained at airplane speeds that are now being approached. Research is urgently needed on: 1) airfoils at subsonic, sonic, and supersonic speeds; 2) propellers at high forward speeds in wind tunnels; 3)propellers in free flight at high speeds; and 4) jet propulsion and related devices. The breakdown of propeller efficiency indicated by airfoil data, should serve as an incentive for accelerated research on jet propulsion. This device may extend the attainable speed of current airplanes to the ...
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Radiator Design and Installation

Radiator Design and Installation

Date: May 1, 1939
Creator: Brevoort, M.J.
Description: The fundamental principles of fluid flow, pressure losses, and heat transfer have been presented and analyzed for the case of a smooth tube with fully developed turbulent flow. These equations apply to tubes with large length-diameter ratios where the f1ow is at a high Reynolds Number. The error introduced by using these equations increases as the magnitude of the tube length and the air-flow Reynolds Number approaches the values encountered in modern radiator designs. Accordingly, heat-transfer tests on radiator sections were made and the results are presented in nondimensional form to facilitate their use and for comparison with other heat-transfer data. In addition, pressure losses were measured along smooth tubes of circular, square, and rectangular cross section and the results were also correlated and are presented in nondimensional form. The problem of a radiator design for a particular installation is solved, the experimental heat-transfer and pressure-loss data being used, on a basis of power chargeable to the radiator for form drag, for propelling the weight, and for forcing the air through the radiator. The case of an installation within a wing or an engine nacelle is considered. An illustration of radiator design is carried through for an arbitrary set of ...
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Radiator Design and Installation - II, Special Report

Radiator Design and Installation - II, Special Report

Date: January 1, 1942
Creator: Tifford, Arthur N.
Description: A mathematical analysis of radiator design has been made. The volume of the radiator using least total power has been expressed in a single formula which shows that the optimum radiator volume is independent of the shape of the radiator and which makes possible the construction of design tables that give the optimum radiator volume per 100-horsepower heat dissipation as a function of the speed, of the altitude, and of one parameter involving characteristics of the airplane. Although, for a given set of conditions, the radiator volume using the least total power is fixed, the frontal area, or the length of the radiator needs to be separately specified in order to satisfy certain other requirement such as the ability to cool with the pressure drop available while the airplane is climbing. In order to simplify the specification for the shape of the radiator and in order to reduce the labor involved in calculating the detailed performance of radiators, generalized design curves have been developed for determining the pressure drop, the mass flow of air, and the power expended in overcoming the cooling drag of a radiator from the physical dimensions of the radiator. In addition, a table is derived from ...
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Relative Efficiencies and Design Charts for Various Engine-Propeller Combinations, Special Report

Relative Efficiencies and Design Charts for Various Engine-Propeller Combinations, Special Report

Date: September 1, 1936
Creator: Biermann, David
Description: The relative efficiencies of various engine-propeller combinations were the subject of a study that covered the important flight conditions, particularly the take-off. Design charts that graphically correlate the various propeller parameters were prepared to facilitate the solution of problems and also to c1arify the conception of the relationships of the various engine-propeller design factors. It is shown that, among the many methods for improving the take-off thrust, the use of high-pitch, large-diameter controllable propellers turning at low rotational speeds is probably the most generally promising. With such a combination the take-off thrust may be further increased, at the expense of a small loss in cruising efficiency, by compromise designs wherein the pitch setting is slightly reduced and the diameter is further increased. The degree of compromise necessary to accomplish the maximum possible take-off improvement depends on such design factors as overspeeding and overboosting at take-off as well as depending on the design altitude. Both overspeeding and designing for altitude operation have the same effect on the take-off thrust as compromising in that the propulsive efficiency is increased thereby; boosting the engine, however, has the reverse effect on the propulsive efficiency, although the brake horsepower is increased.
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The Relative Hydrodynamic Resistance of Various Types of Rivet Heads from Tests of Planning Surfaces, Special Report

The Relative Hydrodynamic Resistance of Various Types of Rivet Heads from Tests of Planning Surfaces, Special Report

Date: July 1, 1935
Creator: Truscott, Starr
Description: The Committee was requested to investigate the effect of various types of rivet heads on hydrodynamic resistance. The proposal was made to obtain the resistance of the various types of rivets by tests of planing surfaces on which the full size rivets would be arranged. The testing methods, results and conclusions are given.
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A Remote Indicating Hinge-Moment Balance, Special Report

A Remote Indicating Hinge-Moment Balance, Special Report

Date: August 1, 1941
Creator: Stoller, Morton J.
Description: This report describes an electrical hinge-moment balance for use with wind-tunnel models of aircraft. A brief description of the principle of operation and operating experience with the balance is given in part I. Part II gives constructional details and part III gives theoretical considerations. Extensive constructional information is given to enable the reproduction of the equipment.
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