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Flow observations with tufts and lampblack of the stalling of four typical airfoil sections in the NACA variable-density tunnel

Description: From Summary: "A preliminary investigation of the stalling processes of four typical airfoil sections was made over the critical range of the Reynolds Number. Motion pictures were taken of the movements of small silk tufts on the airfoil surface as the angle of attack increased through a range of angles including the stall. The boundary-layer flow also at certain angles of attack was indicated by the patterns formed by a suspension of lampblack in oil brushed onto the airfoil surface. These obs… more
Date: October 1938
Creator: Abbott, Ira H. & Sherman, Albert
Partner: UNT Libraries Government Documents Department
open access

Operational treatment of the nonuniform-lift theory in airplane dynamics

Description: "The method of operators is used in the application of nonuniform-lift theory to problems of airplane dynamics. The method is adapted to the determination of the lift under prescribed conditions of motion or to the determination of the motions with prescribed disturbing forces" (p. 1).
Date: October 1938
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
open access

Hydrodynamic and aerodynamic tests of models of flying-boat hulls designed flow aerodynamic drag - NACA models 74, 74-A, and 75

Description: The present tests illustrate how the aerodynamic drag of a flying boat hull may be reduced by following closely the form of a low drag aerodynamic body and the manner in which the extent of the aerodynamic refinement is limited by poorer hydrodynamic performance. This limit is not sharply defined but is first evidenced by an abnormal flow of water over certain parts of the form accompanied by a sharp increase in resistance. In the case of models 74-A and 75, the resistance (sticking) occurs onl… more
Date: October 1938
Creator: Truscott, Starr; Parkinson, J. B.; Ebert, John W., Jr. & Valentine, E. Floyd
Partner: UNT Libraries Government Documents Department
open access

The drag of inflatable rubber de-icers

Description: Force tests on rubber de-icer models of several different profiles, at approximately one-third full scale, been carried out in the NACA 8-foot high speed wind tunnel. The conventional de-icer installation, deflated, added about 15 percent to the smooth-wing drag and, inflated, added about 100 percent. An improved installation with flash attaching strips added about 10 percent, deflated. The bulging, or ballooning, of de-icers from the wing surface is described and some remedies are discussed.
Date: October 1938
Creator: Robinson, Russell G.
Partner: UNT Libraries Government Documents Department
open access

N.A.C.A. Stall-Warning Indicator

Description: "The stall-warning indicator employs a total-head tube located close to the wing surface in a region wherein local stalling occurs before the main portion of the wing stalls. The artificial production of a localized stalled region is accomplished by means of a sharp leading edge extending a few inches along the span. An abrupt drop in the total pressure relative to a static reference taken at some convenient point occurs at the stall in this region" (p. 1).
Date: October 1938
Creator: Thompson, F. L.
Partner: UNT Libraries Government Documents Department
open access

A method of rapidly estimating the position of the laminar separation point

Description: From Summary :"A method is described of rapidly estimating the position of the laminar separation point from the given pressure distribution along a body; the method is applicable to a fairly wide variety of cases. The laminar separation point is found by the von Karman-Millikan method for a series of velocity distributions along a flat plate, which consist of a region of uniform velocity followed by a region of uniform decreased velocity. It is shown that such a velocity distribution can frequ… more
Date: October 1938
Creator: von Doenhoff, Albert E.
Partner: UNT Libraries Government Documents Department
open access

Methods of Testing Hosiery

Description: Report issued by the Bureau of Standards discussing laboratory testing of hosiery to determine production costs and to make comparisons. Different manufacturing methods and possible defects are presented. This report includes tables, illustrations, and photographs.
Date: October 11, 1938
Creator: Schenke, E. Max & Shearer, Howard E.
Partner: UNT Libraries Government Documents Department
open access

The influence of directed air flow on combustion in spark-ignition engine

Description: "The air movement within the cylinder of the NACA combustion apparatus was regulated by using shrouded inlet valves and by fairing the inlet passage. Rates of combustion were determined at different inlet-air velocities with the engine speed maintained constant and at different engine speeds with the inlet-air velocity maintained approximately constant. The rate of combustion increased when the engine speed was doubled without changing the inlet-air velocity; the observed increase was about the… more
Date: October 10, 1938
Creator: Rothrock, A. M. & Spencer, R. C.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Investigation of an N.A.C.A. 23012 Airfoil with a Slotted Flap and Three Types of Auxiliary Flap

Description: An investigation was made in the N.A.C.A. 7- by 10-foot wind tunnel to determine the aerodynamic section characteristics of an N.A.C.A. 23012 airfoil with a single main slotted flap equipped successively with auxiliary flaps of the plain, split, and slotted types. A test installation was used in which an airfoil of 7-foot span was mounted vertically between the upper and the lower sides of the closed test section so that two-dimensional flow was approximated" (p. 699).
Date: October 31, 1938
Creator: Wenzinger, Carl J. & Gauvain, William E.
Partner: UNT Libraries Government Documents Department
open access

Static Longitudinal Stability and Longitudinal Control of Autogiro Rotors

Description: The present report discusses three different systems of elevator control and their effects on the stability and maneuverability of autogiros: (a) ailerons and elevators (standard); (b) blade control (la Cierval); (c) gravity control (new).
Date: October 1938
Creator: Schrenk, M.
Partner: UNT Libraries Government Documents Department
open access

The Twisting of Thin-Walled, Stiffened Circular Cylinders

Description: On the basis of the present investigation of the twisting of thin-walled, stiffened cylinders the following conclusions can be reached: 1) there is as yet no generally applicable formula for the buckling moment of the skin; 2) the mathematical treatment of the condition of the shell after buckling of the skin is based on the tension-field theory, wherein the strain condition is considered homogenous.
Date: October 1938
Creator: Schapitz, E.
Partner: UNT Libraries Government Documents Department
open access

Full-Scale Wind-Tunnel Investigation of Wing Cooling Ducts, Special Report

Description: "The systematic investigation of wing cooling ducts at the NACA laboratory has been continued with tests in the full-scale wind tunnel on ducts of finite span. These results extend the previous investigation on section characteristics of ducts to higher Reynolds numbers and indicate the losses due to the duct ends. The data include comparisons between ducts completely within the ring and the conventional underslung ducts" (p. 1).
Date: October 1938
Creator: Nickle, F. R. & Freeman, Arthur B.
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Investigation of Air Inlet and Outlet Openings for Aircraft, Special Report

Description: "An investigation was made in the NACA 5-foot vertical wind tunnel of a large variety of duct inlets and outlets to obtain information relative to their design for the cooling or the ventilation systems on aircraft. Most of the tests were of openings in a flat plate but, in order to determine the best locations and the effects of interference, a few tests were made of openings in an airfoil. The best inlet location for a system not including a blower was found to be at the forward stagnation po… more
Date: October 1938
Creator: Rogallo, Francis M. & Gauvain, William E.
Partner: UNT Libraries Government Documents Department
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