Goodyear Type ZRS
As an extension of the Type ZR programme, the Navy was granted authority in 1926 to procure two large American-built rigid airships for long-range scouting purposes. A design competition was announced which was subsequently won by Goodyear-Zeppelin. In 1928 the company began the construction of the first ship, the ZRS-4, U.S.S. "Akron", of 612 million cubic feet capacity. It was an advanced airship design in many ways, being conceived from the start to make use of safe non-inflammable helium gas as the lifting agent. This made it possible to contain, within its length of 785ft, a hangar, 60ft by 75ft, capable of housing four small scout or fighter type aircraft. These could be launched and recovered in flight by means of a retractable trapeze device beneath the airship that was engaged by a hook on the aeroplane. The airship was powered by eight German-built 560 h.p. Maybach engines which were mounted within the hull and drove their propellers through shaft drives and gearing. These propellers could he used not only to provide normal longitudinal thrust,' forward and reverse, but could also be swivelled vertically upwards or downwards to give greater control of the ship during take off and landing.
"Akron" was commissioned on October 27, 1931, and made numerous long flights, experimenting with her unique aircraft squadron carried on board, and engaging in exercises with surface vessels of the U.S. Navy. Her range of over 5,000 miles and her complement of four Curtiss F9C-2 "Sparrowhawks" added a new dimension to naval air operations; the flying aircraft carrier. But the success was to be short-lived. Stationed at Lakehurst, "Akron" made 73 flights before being lost at sea in a violent storm on the night of April 34, 1933, with the loss of all but three of her crew. She had completed 1,695 flying hours.
Just two months later, on June 23, 1933, her sister ship, the ZRS-5 U.S.S. "Macon", was commissioned and went into service at Naval Air Station Sunnyvale, California. (Moffett Field). Apart from some minor modifications, she was a copy of ZRS-4, and carried the same number of Curtiss F9C-2 fighters. The experiments and the development of new operational techniques were resumed with good results and the future looked bright for the naval rigid airship.
While engaged on a naval exercise off the coast of California on February 12, 1935, "Macon" suffered a structural failure of the dorsal fin which resulted in the rupture of several gas cells in the stern of the ship. The airship began to descend, and despite all the efforts of the crew to regain control, she hit the sea and sank forty minutes later. Thanks to the safety precautions taken after the loss of "Akron", adequate survival equipment was on board, and of the 83 crew only two were lost.
This second major accident did not immediately bring to an end the U.S. Navy's rigid airship programme. A new training rigid of 3 million cubic feet (ZRN) was planned for service in 1938-40, and a giant 912 million cubic feet design, (ZRCV), capable of carrying nine Douglas-Northrop BT-1 dive bombers, was projected in 1937. In the event no funds were made available to build these ships, but as late as 1940 Goodyear were proposing 10 million cubic feet ships for use by the Navy. These were to be built in three forms; a hospital version (G.A.C. 1940 project number GZ-1); a carrier version (GZ-2); and a cargo version (GZ-3). Political and military considerations ruled against such projects being proceeded with, although some interest was shown in a revival of the ZRCV strike aircraft carrier concept in 1942.
XRS-5 U.S.S. "Macon”
Engine: 8 x 560 h.p. Maybach VL-II.
Maximum Diameter: 133ft.
Volume: 6,500,000 cu ft (95% full).
Maximum speed: 87 mph.
Cruising speed: 63 mph.
Range: 5,940 miles at 63 m.p.h. / 7,268 miles at 53 m.p.h.
Endurance: 108 hours at 63 m.p.h. / 158 hours at 53 m.p.h.
Fuel: 16,000 Imp.Gal.
Useful load: 160,644 lb.
Total number of flights: 54.
Total flight hours: 1,798.2.