Search Results

Tests of large airfoils in the propeller research tunnel, including two with corrugated surfaces

Description: This report gives the results of the tests of seven 2 by 12 foot airfoils (Clark Y, smooth and corrugated, Gottingen 398, N.A.C.A. M-6, and N.A.C.A. 84). The tests were made in the propeller research tunnel of the National Advisory Committee for Aeronautics at Reynolds numbers up to 2,000,000. The Clark Y airfoil was tested with three degrees of surface smoothness. Corrugating the surface causes a flattening of the lift curve at the burble point and an increase in drag at small flying angles.
Date: May 24, 1929
Creator: Wood, Donald H.
Partner: UNT Libraries Government Documents Department

The Gaseous Explosive Reaction at Constant Pressure: The Reaction Order and Reaction Rate

Description: The data given in this report covers the explosive limits of hydrocarbon fuels. Incidental to the purpose of the investigation here reported, the explosive limits will be found to be expressed for the condition of constant pressure, in the fundamental terms of concentrations (partial pressures) of fuel and oxygen.
Date: May 9, 1929
Creator: Stevens, F. W.
Partner: UNT Libraries Government Documents Department

The effect of cowling on cylinder temperatures and performance of a Wright J-5 engine

Description: This report presents the results of tests conducted to determine the effect of different amounts and kinds of cowling on the performance and cylinder temperatures of a standard Wright J-5 engine. These tests were conducted in conjunction with drag and propeller tests in which the same cowlings were used. Four different cowlings were investigated varying from the one extreme of no cowling on the engine to the other extreme of the engine completely cowled and the cooling air flowing inside the cowling through an opening in the nose and out through an annular opening at the rear of the engine. Each cowling was tested at air speeds of approximately 60, 80, and 100 miles per hour.
Date: May 2, 1929
Creator: Schey, Oscar W. & Biermann, Arnold E.
Partner: UNT Libraries Government Documents Department

Aerodynamic theory and tests of strut forms 2

Description: This report presents the second of two studies under the same title. In this part five theoretical struts are developed from distributed sources and sinks and constructed for pressure and resistance tests in a wind tunnel. The surface pressures for symmetrical inviscid flow are computed for each strut from theory and compared with those found by experiment. The theoretical and experimental pressures are found to agree quantitatively near the bow, only qualitatively over the suction range, the experimental suctions being uniformly a little low, and not at all near the stern.
Date: May 1929
Creator: Smith, R. H.
Partner: UNT Libraries Government Documents Department

Corrosion Embrittlement of Duralumin. VI: The Effect of Corrosion Accompanied by Stress on the Tensile Properties of Sheet Duralumin

Description: The effect of corrosion on the tensile properties of duralumin while stressed is shown in graphical form. According to the test results, duralumin sheet, coated with aluminum, maintains its initial properties unimpaired for corrosion periods as long as 60 days with an applied tensile stress as high as 20,000 lb/sq.in., which is approximately one-half the stress corresponding to the yield point as defined here. In these tests, that material which had been heat-treated by being quenched in cold water, though far inferior to similar material having the aluminum coating, was superior to the sheet material which was heat treated by being quenched in hot water.
Date: May 1929
Creator: Rawdon, Henry S.
Partner: UNT Libraries Government Documents Department

Curves Showing Column Strength of Steel and Duralumin Tubing

Description: Given here are a set of column strength curves that are intended to simplify the method of determining the size of struts in an airplane structure when the load in the member is known. The curves will also simplify the checking of the strength of a strut if the size and length are known. With these curves, no computations are necessary, as in the case of the old-fashioned method of strut design. The process is so simple that draftsmen or others who are not entirely familiar with mechanics can check the strength of a strut without much danger of error.
Date: May 1929
Creator: Ross, Orrin E.
Partner: UNT Libraries Government Documents Department

Good food habits for children.

Description: Describes how to assist young children in transitioning from milk to solid food. Suggests ways to establish regular eating times, encourage self-feeding, and help the child develop a positive attitude toward eating.
Date: May 1929
Creator: Schmidt, C. Rowena
Partner: UNT Libraries Government Documents Department

Ocher and Ochery Earths

Description: Report about ocher or ochery earth, "a natural mineral pigment composed largely of clay permeated with hydrated iron (ferric oxide)" (p. 2). It includes information about the uses of choer, substitutes, artificial ocher, mining and local deposits, import and export of ocher, and related information.
Date: May 1929
Creator: Santmyers, R. M.
Partner: UNT Libraries Government Documents Department

On the Strength of Box Type Fuselages

Description: The present investigation relates to a box-type fuselage with sides consisting of thin smooth sheet metal, stiffened by longitudinal members riveted to the flanged channel-section bulkheads or transverse frames and to the semicircular corrugated corner stiffenings. The results obtained in this particular case can be applied to a great number of similar structures.
Date: May 1929
Creator: Mathar, J.
Partner: UNT Libraries Government Documents Department

Technical report of the 1928 Rhon soaring-flight contest

Description: Report presenting some information on the gliders that participated in the 1928 Rhön soaring flight contest. Almost all of the gliders represented an improvement over gliders used in the previous years. A great increase in the skill of the glider pilots is also noted.
Date: May 1929
Creator: Lippisch, A.
Partner: UNT Libraries Government Documents Department

Investigation of damping liquids for aircraft instruments

Description: "This report covers the results of an investigation carried on at the Bureau of Standards under a research authorization from, and with the financial assistance of, the National Advisory Committee for Aeronautics. The choice of a damping liquid for aircraft instruments is difficult owing to the range of temperature at which aircraft operate. Temperature changes affect the viscosity tremendously. The investigation was undertaken with the object of finding liquids of various viscosities otherwise suitable which had a minimum change in viscosity with temperature" (p. 405).
Date: May 16, 1928
Creator: Keulegan, G. H.
Partner: UNT Libraries Government Documents Department

Theories of flow similitude

Description: The laws of comparison of dynamically similar fluid motions are derived by three different methods based on the same principle and yielding the same or equivalent formulas. This report outlines the three current methods of comparing dynamically similar motions, more especially of fluids, initiated respectively by Newton, Stokes (or Helmholtz), and Rayleigh. These three methods, viz., the integral, the differential, and the dimensional, are enough alike to be studied profitably together. They are treated in succession then compared. (author).
Date: May 7, 1928
Creator: Zahm, A. F.
Partner: UNT Libraries Government Documents Department

The Variation in Engine Power With Altitude Determined From Measurements in Flight With a Hub Dynamometer

Description: "The rate of change in power of aircraft engines with altitude has been the subject of considerable discussion. Only a small amount of data from direct measurements of the power delivered by airplane engines during flight, however, has been published. This report presents the results of direct measurements of the power delivered by a Liberty 12 airplane engine taken with a hub dynamometer at standard altitudes from zero to 13,000 feet. Six flights were made with the engine installed in a modified DH-4 airplane" (p. 323).
Date: May 7, 1928
Creator: Gove, W. D.
Partner: UNT Libraries Government Documents Department

Aerodynamic theory and test of strut forms. Part I

Description: This report presents the first part of a two part study made under this title. In this part the symmetrical inviscid flow about an empirical strut of high service merit is found by both the Rankine and the Joukowsky methods. The results can be made to agree as closely as wished. Theoretical stream surfaces as well as surfaces of constant speed and pressure in the fluid about the strut are found. The surface pressure computed from the two theories agrees well with the measured pressure on the fore part of the model but not so well on the after part. From the theoretical flow speed the surface friction is computed by an empirical formula. The drag integrated from the friction and measured pressure closely equals the whole measured drag. As the pressure drag and the whole drag are accurately determined, the friction formula also appears trustworthy for such fair shapes. (author).
Date: May 1928
Creator: Smith, R. H.
Partner: UNT Libraries Government Documents Department