NEW ALLOY IN DIRIGIBLES.

Otago Daily Times, Issue 20931, 22 January 1930, Page 8

NEW ALLOY IN DIRIGIBLES.

Again the contribution of the chemist to the development of the dirigible is s' lo .'™ in a description of the all-metal dinmble given in the Industrial Bulletin of Arthur D. Little, Inc. “The chemical contribution to this unique achievement \vas_ a development of alclad, an aluminium alloy of the duralumin type, coated with pure aluminium, which has been found more resistant to corrosion than aluminium alloys,” says the bullenon- c Alc ! ad , w fabricated in sheets .009 a 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 does not involve much extra weight as compared with the usual multiple 7&P9 ° £ fab I nC ; i ? he “ew dirigible, the 2MC2, was built for the United States Aavy. Its most unique features are in" lts (( mechanical construction. mal i ! l frame®. are simple hoops built up ot aluminium alloy irirders lightened by a cellular construction. Since the alclad sheets are stiff enough to carry longitudinal stresses, the interior of the hull is comparatively free from the tiewires or braces. The sheets are joined bv PeCl ? machine, which completes about 130 rivets a minute, applying three rows of rivets in a one-half inch lap, spacing the rivets 12 to the inch.”