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Causes of cracking of ignition cable

Description: From Summary: "The experiments described here show that the cracking at sharp bends, observed in the insulation of internal combustion engine high tension ignition wires after service, is due to a chemical attack upon the rubber by the ozone produced by the electric discharge that takes place at the surface of the cable. This cracking does not occur if the insulating material is not under tension, or if the cable is surrounded by some medium other than air. But it does occur even if the insulation is not subjected to electric stress, provided that the atmosphere near the cable contains ozone. The extent of this cracking varies greatly with the insulating material used. The cracking can be materially reduced by using braided cable and by avoiding sharp bends."
Date: February 1921
Creator: Dempsey, J. B. & Silsbee, F. B.
Partner: UNT Libraries Government Documents Department

The Effect of the Nature of Surfaces on Resistance as Tested on Struts

Description: The chief concern was to measure the variations of resistance brought about by the nature of the surface of the struts. The struts were spanned with aviation linen, and then covered with one coat of varnish. The top surface was not perfectly smooth after this treatment, being slightly rough owing to the threads and raised fibers of the fabric. The results of the measurements of the surfaces are shown by the dotted lines of the curves plotted in several figures.
Date: February 1921
Creator: Wieselsberger, G.
Partner: UNT Libraries Government Documents Department

Effect of the Reversal of Air Flow Upon the Discharge Coefficient of Durley Orifices

Description: Experiments were conducted to obtain information on the relationship between the coefficients for flow in two directions through thin plate orifices at low velocities. The results indicate that the ratio of the orifice discharge coefficient from standard orifice C(sub s)(sup 1) to the discharge coefficient from the reverse flow C(sub s) is always less than unity with increasing ratio of box area to orifice area. Even for areas as low as twenty, the ratios of the coefficients are not much less than unity. It is probable, however, that when the ratio of box area is less than twenty, the ratio of discharge coefficients would be greatly reduced. Specific results are given for the case of an apparatus for the laboratory testing of superchargers.
Date: February 1921
Creator: Ware, Marsden
Partner: UNT Libraries Government Documents Department

Loads and Calculations of Army Airplanes

Description: By comparing airplanes of known strength that have resisted all the usual and even extreme air loads with those that under like conditions were found to be insufficiently strong, the researchers, aided by scientific investigations, developed standards which are satisfactory for the calculation of airplane structures. Given here are standards applicable to loads on wing trusses, load factors for use in stress analysis, load factors required in sand testing, loads on control surfaces, loads on wing ribs, loads on landing gear, and rigidity of materials.
Date: February 1921
Creator: Stelmachowski
Partner: UNT Libraries Government Documents Department