National Geographic : 1992 Jan
FIN DESIGN Fins were bolted onto two main rings, with leading edges supported by an intermediate ring. This design had long been suspect in the loss of the Macon, but the attachments held. FRAMING Aseries of rings linked by longi tudinal girders, made of four sided duralumin sections, com posed the framework. MAIN FRAME 17.5 This ring failed, causing the top tail fin to tear loose, ripping holes inhelium cells and fatally crippling the ship. I /," OUTER COVER Lightweight cotton cloth was painted with six coats of aircraft dope, two of them containing aluminum pigment to reflect the sun's heat and minimize its effects on the lifting gas inside. THE EYES OF THE NAVY AN AIRCRAFT CARRIER IN THE SKY This elaborate flying wasps' nest was three times longer than a Boeing 747. The U.S.S. Macon was 785 feet long, 133 feet in diameter, and weighed more than 240,000 pounds. Duralumin, an alloy of alu minum, formed herframe. Her skin was cotton cloth, painted with aircraftvar nish, or dope, to make it taut, waterproof, and smooth. Twelve independently filled cells of nonflammable helium provided lift. For all her size she was a low-altitude air craft, operating below a ceiling of 5,000 feet; her greatest lift came near the earth's surface, where air is densest. Built by the Goodyear Zeppelin Corporation of Akron, Ohio, the Macon and the Akron were both designed by a team of German engineers headed by Karl Arnstein.