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The K-class non-rigid airship was a class of blimps built by the Goodyear Aircraft Company of Akron, Ohio for the United States Navy.
These blimps were powered by two radial air-cooled engines mounted on outriggers on the side of the control car that hung under the envelope. Before and during World War II, 135 K-class blimps were built, configured for patrol and anti-submarine warfare operations and were extensively used in the Navy’s anti-submarine efforts in the Atlantic and Pacific Ocean areas.
The K-class blimp was a product of the austere times of the American depression. In 1937, K-2 was ordered from Goodyear as part of a contract that also bought the L-1. The L-class was Goodyear’s standard advertising and passenger blimp. K-2 was the production prototype for future K-class airship purchases. K-2 flew for the first time at Akron, Ohio on December 6, 1938 and was delivered to the Navy at NAS Lakehurst, New Jersey on December 16. The envelope capacity of the K-2—404,000 ft³ (11,440 m³)—was the largest for any USN blimp up to that time. K-2 was flown extensively as a prototype, and continued to operate testing new equipment, techniques, and performing whatever tasks were needed, including combat patrols in World War II.
On October 24, 1940, the Navy awarded a contract to Goodyear for six airships (K-3 through K-8) that were assigned the designation Goodyear ZNP-K. These blimps were designed for patrol and escort duties and were delivered to the Navy in late 1941 and early 1942. K-3 through K-8 had only minor modifications to K-2‘s design, the only major change was in engines from Pratt & Whitney R-1340-16s to Wright R-975-28s. The Wright engine/propeller combination proved excessively noisy and was replaced in later K-ships with the Pratt & Whitney engines. The K-3 cost $325,000.
A series of orders for more K-class blimps followed. Twenty-one additional blimps (K-9 through K-30) were ordered on 14 October 1942. On 9 January 1943, 21 more blimps (K-31 through K-50) were ordered. The envelope size of K-9 through K-13 was increased to 416,000 ft³ (11,780 m³) and those delivered thereafter used an envelope of 425,000 ft³ (12,035 m³).
The final contract for the K-class blimp were awarded in mid-1943 for 89 airships. Four blimps from this order were later canceled. The remaining deliveries were assigned numbers K-51through K-136. But, the number K-136 was not assigned to a specific airship as the control car assigned for K-136 was used to replace the car for K-113. The original car for K-113 was destroyed in a fire.