The Lockheed P-2 Neptune (designated P2V by the United States Navy (USN) prior to September 1962) was a maritime patrol and antisubmarine warfare (ASW) aircraft. It was developed for the USN by Lockheed to replace the Lockheed PV-1 Ventura and PV-2 Harpoon and was replaced, in turn, by the Lockheed P-3 Orion. Designed as a land-based aircraft, the Neptune never made a carrier landing, but a few were converted and deployed as carrier-launched (using JATO assist), stop-gap nuclear bombers that would have to land on shore or ditch. The type was successful in export and saw service with several armed forces.
Design and development
Development of a new land-based patrol bomber began early in World War II, with design work starting at Lockheed's Vega subsidiary as a private venture on 6 December 1941.Scutts Air International January 1995, pp. 42–43. At first, the new design was considered a low priority compared to other aircraft in development at the time, with Vega also developing and producing the PV-2 Harpoon patrol bomber. On 19 February 1943, the USN signed a letter of intent for two prototype XP2Vs, which was confirmed by a formal contract on 4 April 1944 with a further 15 aircraft being ordered 10 days later.Francillon 1982, pp. 258–259. The program did not go into full swing until 1944.Francillon 1982, p. 259. A major factor in the design was ease of manufacture and maintenance, and this may have been a major factor in the type's long life and worldwide success. The first aircraft flew in May 1945. Production began in 1946, and the aircraft was accepted into service in 1947. Potential use as a bomber led to successful launches from aircraft carriers.
Beginning with the P2V-5F model, the Neptune became one of the first operational aircraft fitted with both piston and jet engines. The Convair B-36, several Boeing C-97 Stratofreighter, Fairchild C-123 Provider, North American AJ Savage, and Avro Shackleton aircraft were also so equipped. To save weight and complexity of two separate fuel systems, the Westinghouse J34 jet engines on P2Vs burned the 115–145 Avgas fuel of the piston engines, instead of jet fuel. The jet pods were fitted with intake doors that remained closed when the J-34s were not running. This prevented windmilling, allowing for economical piston-engine-only, long-endurance search-and-patrol operations. In normal USN operations, the jet engines were run at full power (97%) to assure takeoff, then shut down upon reaching a safe altitude. The jets were also started and kept running at flight idle during low-altitude ( flight during the day and at night) antisubmarine and/or antishipping operations as a safety measure should one of the radials develop problems.
Normal crew access was by a ladder on the aft bulkhead of the nosewheel well to a hatch on the left side of the wheel well, then forward to the observer nose, or up through another hatch to the main deck. Also, a hatch was in the floor of the aft fuselage, near the sonobuoy chutes.
Operational history
Early Cold War
Before the P-3 Orion arrived in the mid-1960s, the Neptune was the primary U.S. land-based antisubmarine patrol aircraft, intended to be operated as the hunter of a "hunter-killer" group, with destroyers employed as killers. Several features aided the P-2 in its hunter role: Sonobuoys could be launched from a station in the aft portion of the fuselage and monitored by radio. Some models were equipped with "pointable" twin .50 cal (12.7 mm) machine guns in the nose, but most had a forward observation bubble with an observer seat, a feature often seen in images. The AN/ASQ-8 magnetic anomaly detector was fitted in an extended tail, producing a paper chart. Unmarked charts were not classified, but those with annotations were classified as secret. A belly-mounted AN/APS-20 surface-search radar enabled detection of surfaced and snorkeling submarines at considerable distances.
As the P-2 was replaced in the USN by the P-3A Orion in active fleet squadrons in the early and mid-1960s, the P-2 continued to remain operational in the Naval Air Reserve through the mid-1970s, primarily in its SP-2H version. As active fleet squadrons transitioned to the P-3B and P-3C in the mid- and late 1960s and early 1970s, the Naval Air Reserve P-2s were eventually replaced by P-3As and P-3Bs and the P-2 exited active U.S. naval service. VP-23 was the last active-duty patrol squadron to operate the SP-2H, retiring its last Neptune on 20 February 1970,"Third VP-22." Dictionary of American Naval Aviation Squadrons, Volume 2. Retrieved: 22 April 2011. while the last Naval Reserve patrol squadron to operate the Neptune, VP-94, retired its last SP-2H in 1978.
Nuclear bomber
At the end of World War II, USN leaders felt the need to acquire a nuclear strike capability to maintain the Navy's relevance (see Revolt of the Admirals). In the short term, carrier-based aircraft were the best solution. The large Fat Man nuclear munitions at that time were bulky and required a very large aircraft to carry them. The USN Bureau of Ordnance built 25 outdated but more compact Little Boy nuclear bombs to be used in the smaller bomb bay of the P2V Neptune. Enough fissionable material was available by 1948 to build 10 complete uranium projectiles and targets, although only enough initiators were available to complete six. The U.S. Navy improvised a carrier-based nuclear strike aircraft by modifying the P2V Neptune for carrier takeoff using jet-assisted takeoff rocket boosters, with initial takeoff tests in 1948. However, the Neptune could not land on a carrier, so the crew had to either make their way to a friendly land base after a strike or ditch in the sea near a USN vessel. It was replaced in this emergency role by the North American AJ Savage (transferred to the Pacific Fleet in October 1952), the first nuclear strike aircraft that was fully capable of carrier launch and recovery operations; it was also short-lived in that role as the USN was adopting fully jet-powered nuclear-strike aircraft.Swanborough and Bowers 1976, p. 458.
Covert operations P2V-7U/RB-69A variants In 1954, under Project Cherry, the US Central Intelligence Agency (CIA) obtained five newly built P2V-7 aircraft and converted them into P2V-7U/RB-69A variants by Lockheed's Skunk Works at Hangar B5 in Burbank, California, for the CIA's own private fleet of covert ELINT/ferret aircraft. Later, to make up for P2V-7U/RB-69A operational losses, the CIA obtained and converted two existing US Navy P2V-7s, one in September 1962 and one in December 1964, to P2V-7U/RB-69A Phase VI standard, and it also acquired an older P2V-5 from the USN as a training aircraft in 1963. Test flights were made by lead aircraft at Edwards AFB from 1955 to 1956 with all the aircraft painted with a dark sea blue color, but with USAF markings. In 1957, one P2V-7U was sent to Eglin AFB for testing aircraft performance at low level and under adverse conditions.
The initial two aircraft were sent to Europe, based at Wiesbaden, West Germany, but were later withdrawn in 1959 when the CIA reduced its covert aircraft assets in Europe. The CIA sent the other two P2V-7U/RB-69As to Hsinchu Air Base, Taiwan, where by December 1957, they were given to a "black op" unit, the 34th Squadron, better known as the Black Bat Squadron, of the Republic of China Air Force (ROCAF); these were painted in ROCAF markings. The ROCAF P2V-7U/RB-69A's mission was to conduct low-level penetration flights into mainland China to conduct ELINT/ferret missions, including mapping out China's air-defense networks, inserting agents via airdrop, and dropping leaflets and supplies. The agreement for plausible deniability between US and Republic of China governments meant the RB-69A would be manned by ROCAF crew while conducting operational missions, but would be manned by CIA crew when ferrying RB-69As out of Taiwan or other operational areas to US.
The P2V-7U/RB-69A flew with ROCAF Black Bat Squadron over China from 1957 to November 1966. All five original aircraft were lost with all hands on board; two crashed in South Korea and three were shot down over China. In January 1967, two remaining RB-69As flew back to NAS Alameda, California, and were converted back to regular US Navy P2V-7/SP-2H ASW aircraft configurations.Baugher, Joe. "U.S. Navy/U.S. Marine Corps Aircraft Bureau Numbers (Third Series: 15)." www.joebaugher.com. Retrieved: 4 October 2010.Baugher, Joe. "U.S. Navy/U.S. Marine Corps Aircraft Bureau Numbers (Third Series: 19)." www.joebaugher.com. Retrieved: 4 October 2010. Most of the 34th Squadron's black-op missions remain classified by the CIA—though a CIA internal draft history, Low-Level Technical Reconnaissance over Mainland China (1955–66), reference CSHP-2.348, written in 1972 that covers CIA/ROCAF 34th Squadron's black-op missions is known to exist. The CIA did not plan to declassify it until after 2022.
Vietnam War
During the Vietnam War, the Neptune was used by the USN as a gunship, as an overland reconnaissance and sensor deployment aircraft, and in its traditional role as a maritime patrol aircraft. The Neptune was also used by the US Army's 1st Radio Research Company (Aviation), call sign "Crazy Cat", based at Cam Ranh Air Base in South Vietnam, as an electronic "ferret" aircraft intercepting low-powered tactical voice and Morse code radio signals.Mutza Air Enthusiast Twenty-nine, p. 42. The US Army operated the P-2 from 1967 until 1972, flying 42,500 hours with no accidents.Mutza Air Enthusiast Twenty-nine, p. 77. Observation Squadron 67 (VO-67), call sign "Lindy", was the only P-2 Neptune aircraft squadron to ever receive the Presidential Unit Citation, flying Igloo White missions sowing seismic and acoustic sensors over the Ho Chi Minh trail. VO-67 lost three OP-2E aircraft and 20 aircrew to ground fire during its secret missions into Laos and Vietnam in 1967–68. The ROCAFsecret 34th Black Bat Squadron's RB-69A/P2V-7U ELINT/SIGINT aircraft flew a low-level electronic reconnaissance from Da Nang Air Base, flying over Thanh Hóa Province on 20 August 1963 to investigate an air resupply drop zone that turned out to be a trap for a ROCAF C-123B airdrop mission 10 days earlier due to the air-inserted agents having been captured and turned. The next year, an air-defense radar-mapping mission was also flown by 34th Squadron's RB-69A/P2V-7U aircraft into North Vietnam and Laos on the night of 16 March 1964. The RB-69A took off from Da Nang, flew up the Gulf of Tonkin before coasting in near Haiphong, then flew along the North Vietnam and Laos border. The mission was requested by the Studies and Observations Group for helping plan the insert or resupply of agents. Seven AAA sites, 14 early-warning radar sites, and two ground-controlled interception radar signals were detected.Pocock, Chris. The Black Bats: CIA Spy Flights Over China From Taiwan, 1951–1969. Atglen, Pennsylvania: Schiffer Publishing, 2010. .
Royal Australian Air Force (RAAF) Neptunes were also involved in the Vietnam War. These aircraft helped escort the fast transport from Australia to South Vietnam on several occasions in 1965 and 1966. RAAF Neptunes also occasionally operated as airborne early-warning aircraft over Thailand using their AN/APS-120 radar; this was done only when the aircraft were transiting through Thai airspace on other taskings. During these sorties, the Neptunes warned American aircraft operating over North Vietnam of Vietnamese surface-to-air missile launches.
Falklands War
The Argentine Naval Aviation had received at least 16 Neptunes of different variants since 1958, including eight former RAF examples for use in the Escuadrilla Aeronaval de Exploración (Naval Exploration Squadron). They were intensively used in 1978 during the Operation Soberania against Chile, including over the Pacific Ocean."AS Neptune." Historia y Arqueologia Marítima. Retrieved: 15 July 2010.