NEW ALLOY IN DIRIGIBLES.

Auckland Star, Volume LX, Issue 307, 28 December 1929, Page 13 (Supplement)

NEW ALLOY IN DIRIGIBLES.

Again the contribution of the chemist 'to the development of the dirigible is shown iii a description of the all-metal 'Idirigible given in the "Industrial Bulletin" Oa Arthur D. Little, Inc. "The chemical contribution to this unique achievement was a development of alclad, an aluminum alloy of the duralumin type, ' coated with pure aluminum, which has been found more resistant to corrosion than aluminum alloys," says the bulletin. "Alclad is fabricated in sheets .0095 of an inch in thickness —about three times the thickness of a sheet of ordinary newspaper. It is Impermeable to hydrogen and helium, and for balloons of large sizes floes not involve much extra weight as compared with the usual multiple layers of fabric. The new dirigible, the ZMC2, was built for the United States Navy. Its most unique features are in its mechanical construction. "The main frames are simple hoops built up of aluminum alloy girders, lightened by a cellular construction. Since the alclad sheets are s'tiff enough to carry longitudinal stresses, the inferior of the hull is comparatively free from the tie-wires oV braces. The sheets are joined by a special riveting machine, which completes about 130 rivets a minute, applying three rows of rivets in a one-half inch lap, spacing the rivets Jwelve to the inch."