K class blimp
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| K class | |
|---|---|
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| Type | Patrol airship |
| Manufacturer | Goodyear |
| Maiden flight | 6 December 1938 |
| Primary user | US Navy |
| Number built | 134 |
The K-class non-rigid airship was a class of blimps built by the Goodyear Aircraft Company of Akron, Ohio for the US 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 the backbone in the Navy’s aniti-submarine efforts in the Atlantic and Pacific Ocean areas.
[edit] Development
The K-Class blimp was a product of the austere times of the American depression. In 1937, the 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. The 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 cubic feet (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. The K-3 through 8 had only minor modifications to the K-2 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. A series of orders for more K-class blimps followed. Twenty-one additional blimps (K-9 through K-30) were ordered on October 14, 1942. On January 9, 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 cubic feet (11,780 m³) and those delivered thereafter used an envelope of 425,000 cubic feet (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-51 through 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.
[edit] Variants
After World War II, a series of modified K-Class blimps were introduced to the fleet. These modified blimps were designated ZP2K, ZP3K, ZP4K, and ZP5K.
- The ZP2K and ZP3K used a larger envelope, one with the volume increased to 527,000 cu ft (14,923 m³). Under the 1954 airship designation changes, these blimps became the ZSG-2 and ZSG-3, the 'S' signifying that the mission assigned to the airships was anti-submarine warfare.
- The ZP4K was delivered in 1953. It retained an envelope volume of 527,000 cu ft (14,923 m³) but it had an overall length of 266 ft (81.08 m). In 1954 it was re-designated ZSG-4.
[edit] Operational history
The K-ships were used for anti-submarine warfare (ASW) duties in the Atlantic and Pacific Oceans as well as the Mediterranean Sea. All equipment was carried in a forty feet long control car. The installed communications and instrumentation equipment allowed night flying. The blimps were equipped with the ASG-type radar, that had a detection range of 90 miles (167 km), sonobuoys, and magnetic anomaly detection (or magnetic airborne detection (MAD)) equipment. The K-ships carried four Mk-47 depth bombs, two in a bomb bay and two externally, and were equipped with a 50-cal (12.7 mm) Browning machine gun in the forward part of the control car. An aircrew of 10 normally operated the K-ships, consisting of a command pilot, two co-pilots, a navigator/pilot, airship rigger, an ordnanceman, two mechanics, and two radiomen.
The ability of the K-ships to hover and operate at low altitudes and slow speeds resulted in detection of numerous enemy submarines as well as assisting in search and rescue missions. The K-ships had an endurance capability of over 24 hours which was an important factor in the employment of ASW tactics.
The mooring system for the K-ship was a triangular 42 feet (12.8 m) high mooring mast that was capable of being towed by a tractor. For advance bases where moving the mooring mast was not needed, a stick mast was used. A large ground crew was needed to land the blimps and moor them to the mast.
The last "K Ship", a ZSG-4, the K-43 was retired in March 1959.
[edit] Airship Designations
During the life of the K-Class airship the US Navy used three different designation systems. From 1922 through World War II the Navy used a four character designator. The K-Class blimps were designated ZNP-K where the “Z” signified lighter-than-air; “N” denoted non-rigid; “P” denoted a patrol mission; and “K” denoted the type or class of airship.
In April 1947, the General Board of the US Navy modified the designation system for airships. The second character of the designator was dropped as the Board dropped the code for rigid airships so that the “N” for non-rigid was no longer needed. The designation for the K-Class blimps then became ZPK.
In April 1954, the designation system for lighter-than-air airships was further modified so that it conformed to the designation system for heavier-than-air aircraft. By this time the ZPK blimps had been retired from service and only the later version K-Class blimps were in service. Under the 1954 system the ZP2K blimp became the ZSG-2, the ZP3K became the ZSG-3, the ZP4K became the ZSG-4, and the ZP5K became the ZS2G-1. In new designation system, the “Z” signified lighter-than-air; the “S” was the type denoting an anti-submarine warfare mission; the numeral (i.e., “2”) was the model; and the “G” was the manufacturer’s letter. The final numeral denoted the series of the vehicle within the type/model.
[edit] Specifications (K-14)
General characteristics
- Crew: 9-10
- Length: 251 ft 8 in (76.73 m)
- Diameter: 57 ft 10 in (17.63 m)
- Volume: 425,000 ft³ (12,043 m³)
- Useful lift: 7,770 lb (3,524 kg)
- Powerplant: 2 × Pratt & Whitney R-1340-AN-2 radials,, 425 hp (317 kW) each
Performance
- Maximum speed: 78 mph (125 km/h)
- Cruise speed: 58 mph (93 km/h)
- Range: 2,205 miles (3,537 km)
- Endurance: 38 hours 12 min
Armament
- 1 × .50 M2 machine gun
- 4 × 350 lb (159 kg) Mark 47 depth charges
[edit] References
- Shock, James R. (2001). U.S. Navy Airships 1915-1962. Edgewater, Florida: Atlantis Productions. ISBN 0-9639743-8-6.
- Althoff, William F. (1990). Sky Ships. New York: Orion Books. ISBN 0-517-56904-3.
- Vaeth, J. Gordon (1992). Blimps & U-Boats. Annapolis, Maryland: US Naval Institute Press. ISBN 1-55750-876-3.
[edit] See also
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