1, N-1 / 12, ZPG-2 / 5, ZPG-2W for 18 total ships in class.[1]
The N-Class, or as popularly known, the "Nan ship", was a line of non-rigid airships built by the Goodyear Aircraft Company of Akron, Ohio for the US Navy. This line of airships was developed through many versions and assigned various designators as the airship designation system changed in the post World War II era. These versions included airships configured for both anti-submarine warfare and airborne early warning (AEW) missions.
The initial version, designated ZPN-1, was a follow-on to the M-class blimp for patrol missions. The Nan ship used a significantly larger envelope than the M-ship although their overall lengths were similar. Two Wright R-1300 Cyclone 7 single-row, air-cooled radial engines powered the N-Class blimps.[2]
An initial contract was awarded to the Goodyear Aircraft Company for the prototype N-class blimp in the late 1940s, with delivery of the first on in 1952.[3] The ZPN-1 designation was changed to ZPG-1 in 1954, and then to SZ-1A in 1962. The envelope capacity for the ZPN-1 was 875,000cuft (24,777m3) and used the gas helium for lift.
The ZPN-1 was followed by an order for four improved N-class blimps that were delivered in 1954. These airships were designated ZP2N, and re-designated in 1954 as the ZPG-2. Three of the ZP2N airships were modified for an airborne early warning mission in the mid-1950s and were designated, originally, ZP2N-1W but at delivery were designated ZPG-2W. Their designation was changed to EZ-1B in 1962. The envelope capacity of these airships exceeded 1×10^6cuft (28,317m3). The ZPG-2W was equipped with the AN/APS-20 radar with its antenna installed beneath the gondola. An AN/APS-69 height-finding radar antenna was mounted on top of the envelope. The engines were installed in the control car and drove the propellers through extended shafts. The airship carried a crew of 21 to 25 and had an endurance capability of over 200 hours. The first ZPG-2W was delivered to the Navy at NAS Lakehurst in May 1955.[2]
Operationally the ZPG-2W was used to fill radar gaps in the North American early-warning network between the Contiguous Barrier and the Inshore Barrier during the Cold War. In a demonstration of the ability to stay on-station autonomously for considerably extended periods, ZPG-2 "Snow Bird" (BuNo 141561), pilot in command Cdr. Jack R. Hunt USN, supported by a naval crew of 12 plus a civilian flight engineer from Goodyear, made a record-breaking non-stop flight across the Atlantic and back. The airship departed NAS South Weymouth, Massachusetts, on Monday 4 March 1957, reaching the south-west tip of Portugal by the evening of 7 March despite adverse headwinds for some of the way, passed by Casablanca, Morocco, on the morning of 8 March, then turned back westwards over the Cape Verde Islands towards the Caribbean Sea, eventually landing at NAS Key West, Florida, on the evening of 15 March. The flight had covered a distance of 9,448mi (15,205km) in 264.2 hours, and in doing so had not only broken the lighter-than-air distance record of 6,980mi (11,233km) set by the Graf Zeppelin rigid airship in 1929 but also the aircraft endurance record without refuelling.[4]
One of the ZPG-2 airships was built or modified with external engines to test systems for the follow on ZPG-3W airships and is some times referred to as a ZPG-2 1/2.
A ZPG-3W of Airship Airborne Early Warning Squadron ONE (ZW-1) in 1960.
The follow-on and larger AEW blimp was the ZPG-3W, the largest non-rigid airship built to ever enter military service. It was used to fill radar gaps in the North American early-warning network during the Cold War between the Contiguous Barrier and the Inshore Barrier. The popular name for the ZPG-3W was Vigilance. The ZPG-3W was unique in that the huge antenna for the early warning radar was enclosed inside the helium-filled envelope. Four airships were delivered to the U.S. Navy.[2]
The first flight of the ZPG-3W was in July 1958.[5] The envelope of the blimp was used as a radome for the 42ft (12.8m) radar antenna, thus providing the airship with a clean aerodynamic shape. The airship was 403ft (122.8m) long and was almost 120ft (36.6m) high, containing some 1,500,000 cubic feet (42,450 cubic meters).[6] The endurance time of the airship could extend for days. This model of the N-class blimp was the largest non-rigid airship ever flown.
The ZPG-3W Vigilance was the last of the airships built for the U.S. Navy. The July 6, 1960, crash of a Lakehurst-based airship east of Long Beach Island killed 18 sailors, a loss that added pressure on the program. The Navy subsequently decommissioned its airship units at NAS Glynco, Brunswick, Georgia, and at Lakehurst on October 31, 1961. On August 31, 1962, the last two ZPG-3W ships made a ceremonial last flight over Lakehurst — the base log noted, "This flight terminates operation of non-rigid airships at Lakehurst," Steingold said.[7]
The specially designed and built AN/APS-70 Radar with its massive 42ft (12.8m) internal antenna was the best airborne radar system built for detecting other aircraft because its low frequency penetrated weather and showed only the more electronically visible returns. A large radome on top of the envelope held the height-finding radar.[2]
In 1986, a ZPG-2W envelope was used for the construction of the Piasecki PA-97 Helistat. On 1 July 1986, the PA-97 crashed immediately after liftoff on a test flight, killing one of its pilots.
The cockpit from the control car for ZPG-2, BuNo 141561, also known as Snow Bird, has been restored and is on display at the museum. Launching from NAS South Weymouth, Massachusetts in March 1957, this airship made two crossings of the Atlantic before touching down at NAS Key West, Florida. All told, Snow Bird spent just over eleven days aloft in covering 9,448 miles without refueling. For his performance on the flight, the airship commander, CDR Jack R. Hunt, USN, received the Harmon International Trophy (e.g., Harmon Trophy) for Aeronautics.[8]
Following its deflation in 1962, the control car of ZPG-3W number 2, BuNo 144243, was stored for many years at NAS Lakehurst. New Jersey. It is currently recorded as in storage at the National Museum of Naval Aviation at NAS Pensacola, Florida awaiting restoration.[9] Following storage at NAS Lakehurst, It had reportedly been in storage at AMARC / 309th Aerospace Maintenance and Regeneration Group at Davis-Monthan AFB, Arizona from at least 1993 until being relocated to the National Naval Aviation Museum (NNAM), at NAS Pensacola in 1995. At some point post-1995, the control car of 144243 was returned to the 309 AMARG at Davis-Monthan AFB due to space limitations at NNAM. Although currently residing in unprotected storage, it still represents a far less humid environment and protects the control car from further deterioration until it can be returned to NNAM for eventual restoration and display.
Under the 1962 unified Department of Defense air vehicle designation system, the ZPG-3W was re-designated the EZ-1C in late 1962.
Designation systems
Under the designation system established in April 1947, the first N-class airships were given the Navy designation of ZPN-1, (Z = lighter-than-air; P = patrol; N = type/class). In April 1954, the designation system was changed to mimic that used for heavier-than-air naval aircraft. With this change, the designation for the ZPN-1 became the ZPG-1 (Z = lighter-than-air; P = patrol; G=Goodyear (manufacturer); 1=first version). In the 1962 system, the ZPG-1 designation was changed to SZ-1A (S=anti-submarine warfare; Z=lighter-than-air type; 1=first vehicle in the type; A=first model in the series). The designations for later model blimps followed similarly.
Specifications (ZPG-2W)
3-view line drawing of the Goodyear ZPG-2W
General characteristics
Crew: 21
Length: 343ft 0in (104.57m)
Diameter: 76ft 0in (23.17m)
Height: 107ft 0in (32.62m)
Volume: 1,011,000cuft (28,628.33m3)
Powerplant: 2 × Wright R-1300-4,-4A Cyclone 7 radials , 800 hp (600 kW) each
Performance
Maximum speed: 80mph (128km/h, 70kn)
Endurance: over 200 hours
See also
Aircraft of comparable role, configuration, and era
A blimp, or non-rigid airship, is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships, blimps rely on the pressure of the lifting gas inside the envelope and the strength of the envelope itself to maintain their shape.
An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air.
Charles Emery Rosendahl was a highly decorated vice admiral in the United States Navy, and an advocate of lighter-than-air flight.
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The K-class blimp 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 Pratt & Whitney Wasp nine-cylinder radial air-cooled engines, each mounted on twin-strut outriggers, one per side of the control car that hung under the envelope. Before and during World War II, 134 K-class blimps were built and 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 G-Class Blimps were a series of non-rigid airships (blimps) used by the United States Navy. In 1935, instead of developing a new design airship, the Navy purchased the Goodyear Blimp Defender for use as a trainer and utility airship assigning it the designator G-1. Defender was built by the Goodyear Aircraft Company of Akron, Ohio and was the largest blimp in the company’s fleet of airships that were used for advertising and as passenger airships. Goodyear built additional G-class airships for the Navy during World War II to support training needs.
The L-class blimps were training airships operated by the United States Navy during World War II. In the mid-1930s, the Goodyear Aircraft Company built a family of small non-rigid airships that the company used for advertising the Goodyear name. In 1937 the United States Navy awarded a contract for two different airships, K-class blimp designated K-2 and a smaller blimp based upon Goodyear's smaller commercial model airship used for advertising and passenger carrying. The smaller blimp was designated by the Navy as L-1. It was delivered in April 1938 and operated from the Navy's lighter-than-air facility at Lakehurst, New Jersey. In the meantime, the Navy ordered two more L-Class blimps, the L-2 and L-3, on September 25, 1940. These were delivered in 1941. L-2 was lost in a nighttime mid-air collision with the G-1 on June 8, 1942.
The J-class blimps were non-rigid airships designed by the Navy Bureau of Aeronautics and Goodyear Tire & Rubber Company in the early 1920s for the US Navy.
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The D class blimp was a patrol airship used by the US Navy in the early 1920s. The D-type blimps were slightly larger than the C-type and had many detail improvements. The Navy continued the practice of dividing the envelope production between Goodyear and Goodrich. The control cars were manufactured by the Naval Aircraft Factory. The major improvements over the C-type blimps were a better control car design and easier, more reliable controls and instrumentation. The engines were moved to the rear to reduce noise and allow better communications between crew members. The fuel tanks were suspended from the sides of the envelope. The envelope was identical to the C-type, except an additional six-foot panel was inserted for a total length of 198 feet (60 m) and a volume of 190,000 cubic feet (5,400 m3). The last of the D-Class, D-6, had a different control car designed by Leroy Grumman who later founded the Grumman Aircraft Engineering Corporation.
The K-1 was an experimental blimp designed by the United States Navy in 1929. The K-1 was not the prototype of the later K-class blimps.
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The Akron-class airships were a class of two rigid airships constructed for the US Navy in the early 1930s. Designed as scouting and reconnaissance platforms, the intention for their use was to act as "eyes for the fleet", extending the range at which the US Navy's Scouting Force could operate to beyond the horizon. This capability was extended further through the use of the airships as airborne aircraft carriers, with each capable of carrying a small squadron of airplanes that could be used both to increase the airship's scouting range, and to provide self-defense for the airship against other airborne threats.
The AN/APS-20 was an airborne early warning, anti-submarine, maritime surveillance and weather radar developed in the United States in the 1940s. Entering service in 1945, it served for nearly half a century, finally being retired in 1991. Initially developed at Massachusetts Institute of Technology (MIT) under Project Cadillac, the radar was developed to be carried by aircraft to extend the sensor range of ships by placing a radar at altitude. Although developed for carrier-borne operation, first being installed in the single-engined General Motors TBM-3W Avenger, it was also used in larger four-engined airframes, the last being a fleet of Avro Shackleton AEW.2 which were converted from maritime patrol aircraft. Similarly, although developed for detecting aircraft, it saw extensive service in anti-submarine and maritime patrol roles and was one of the first radars to be used in researching extreme weather like hurricanes by agencies like the Environmental Science Services Administration (ESSA). As well as the United States, the radar was used by a large number of services in other countries, including the French Navy, Japan Maritime Self-Defense Force (JMSDF), Royal Air Force (RAF) and Royal Canadian Air Force (RCAF). Early versions of the radar could see a low-flying aircraft at 65 nautical miles and a ship at 200 nautical miles. This was improved, so that later versions had a range against aerial targets of 115 nautical miles.
References
↑ Sky Ships: A History of the Airship in the United States Navy, Althoff, W.F., Pacifica Press, c1991, ISBN0-935553-32-0, Appendix E
1 2 3 4 Sky Ships: A History of the Airship in the United States Navy, Althoff, W.F., Pacifica Press, c1991, ISBN0-935553-32-0
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