Lockheed P-2 Neptune


The Lockheed P-2 Neptune was a maritime patrol and anti-submarine warfare aircraft. It was developed for the US Navy 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 small number were converted and deployed as carrier-launched, 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. 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 U.S. Navy 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. It was not until 1944 that the program went into full swing. 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, 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 US Navy operations, the jet engines were run at full power 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 anti-submarine and/or anti-shipping operations as a safety measure should one of the radials develop problems.
Normal crew access was via 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. There was also a hatch in the floor of the aft fuselage, near the sonobuoy chutes.

Operational history

Early Cold War

Prior to the introduction of the P-3 Orion in the mid-1960s, the Neptune was the primary U.S. land-based anti-submarine 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:
As the P-2 was replaced in the US Navy 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, 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, the US Navy felt the need to acquire a nuclear strike capability to maintain its political influence. 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 US Navy Bureau of Ordnance built 25 outdated but more compact Little Boy nuclear bomb designs to be used in the smaller bomb bay of the P2V Neptune, there was enough fissionable material available by 1948 to build ten complete uranium projectiles and targets, although there were only enough initiators 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, therefore the crew had to either make their way to a friendly land base after a strike, or ditch in the sea near a U.S. Navy vessel. It was replaced in this emergency role by the North American AJ Savage, 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 US Navy was adopting fully jet powered nuclear strike aircraft.

Covert operations P2V-7U/RB-69A variants

In 1954 under Project Cherry, the US Central Intelligence Agency obtained five newly built P2V-7 and converted these 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 also acquired an older P2V-5 from the US Navy as a training aircraft in 1963. Test flights were made by lead aircraft at Edwards AFB from 1955 to 1956, all the aircraft painted with 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 ; these were painted in ROCAF/Taiwan markings. The ROCAF/Taiwan 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/Taiwan crew while conducting operational missions, but would be manned by CIA crew when ferrying RB-69A out of Taiwan or other operational area to US.
The P2V-7U/RB-69A flew with ROCAF/Taiwan Black Bat Squadron over China from 1957 to November 1966. All five original aircraft were lost with all hands on board. 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. 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 , reference CSHP-2.348, written in 1972 that covers CIA/ROCAF/Taiwan 34th Squadron's Black Op missions is known to exist. The CIA does not plan to declassify it until after 2022.

Vietnam War

During the Vietnam War, the Neptune was used by the US Navy as a gunship, an overland reconnaissance and sensor deployment aircraft, and in its traditional role as a maritime patrol aircraft. The Neptune was also utilized by the US Army's 1st Radio Research Company, 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. The US Army operated the P-2 from 1967 until 1972, flying 42,500 hours with no accidents. Observation Squadron 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 Republic of China Air Force secret 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. 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 down North Vietnam and the Laos border. The mission was requested by SOG for helping plan the insert or resupply of agents. Seven AAA sites, 14 early warning radar sites and two GCI radar signals were detected.

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. They were intensively used in 1978 during the Operation Soberania against Chile including over the Pacific Ocean.
During the Falklands War in 1982, the last two airframes in service carried out reconnaissance missions over the South Atlantic and on 4 May, after detecting a group of British warships, helped to direct an attack by two Dassault Super Étendards that resulted in the sinking of the British destroyer. The lack of spare parts, caused by the US having enacted an arms embargo in 1977 due to the Dirty War, led to the type being retired before the end of the war; Argentine Air Force Lockheed C-130 Hercules took over the task of searching for targets for strike aircraft.

Other military operators

The Canadian version of the Lockheed Neptune served as an anti-submarine, anti-shipping and maritime reconnaissance aircraft in the RCAF Maritime Air Command from 1955, replacing the Avro Lancaster maritime aircraft. The Canadian P2V7 was fitted with piston engines initially, though, in 1959, the Neptunes had two underwing Westinghouse J34 jet engine pods retrofitted, similar to those fitted to US Navy variants. Armament included two torpedoes, mines, depth charges, bombs carried internally plus unguided rockets mounted externally underwing. A total of 25 Neptunes served with nos. 404, 405 and 407 squadrons until 1960. Upon unification of the Canadian Forces in 1968, the Neptune was retired and retroactively re-designated the CP122, The RCAF Neptune was replaced by the Canadair CP-107 Argus in the same year.
With the founding of NATO in 1949 and the resulting additional maritime commitments it entailed for Britain, The Royal Air Force Coastal Command operated 52 P2V-5s, designated Neptune MR.1s as a stop-gap modern maritime patrol aircraft until sufficient numbers of the Avro Shackleton could enter service. The Neptunes were used from between 1952 and March 1957, being used for Airborne Early Warning experiments as well as for maritime patrol.
In Australia, the Netherlands, and the US Navy, its tasks were taken over by the larger and more capable P-3 Orion, and by the 1970s, it was in use only by patrol squadrons in the US Naval Reserve and the Dutch Navy. The US Naval Reserve retired its last Neptunes in 1978, those aircraft also having been replaced by the P-3 Orion. By the 1980s, the Neptune had fallen out of military use in most purchasing nations, replaced by newer aircraft.
on the 2007 WSA Complex fire in Oregon.
In Japan, the Neptune was license-built from 1966 by Kawasaki as the P-2J, with the piston engines replaced by IHI-built T64 turboprops. Kawasaki continued their manufacture much later than Lockheed did; the P-2J remained in service until 1984.

Civilian firefighting

P-2/P2Vs have been employed in aerial firefighting roles by operators such as Minden Air Corp and Neptune Aviation Services. The fire fighters can carry 2,080 gal of retardant and have a service life of 15,000 hours. Neptune proposes to replace them with British Aerospace 146 aircraft, which have an estimated service life of 80,000 hours and carry upwards of 3,000 gallons of retardant.

"The Truculent Turtle"

The third production P2V-1 was chosen for a record-setting mission, ostensibly to test crew endurance and long-range navigation but also for publicity purposes: to display the capabilities of the US Navy's latest patrol bomber. Its nickname was The Turtle, which was painted on the aircraft's nose. However, in press releases immediately before the flight, the US Navy referred to it as "The Truculent Turtle".
Loaded with fuel in extra tanks fitted in practically every spare space in the aircraft, "The Turtle" set out from Perth, Australia to the United States. With a crew of four the aircraft set off on 9 September 1946, with a RATO. 2 1/2 days later, "The Turtle" touched down in Columbus, Ohio, from its starting point. It was the longest un-refueled flight made to that point beating the unofficial record held by the Japanese who had made a flight in a Tachikawa Ki-77. This would stand as the absolute unrefueled distance record until 1962, and would remain as a piston-engined record until 1986 when Dick Rutan's Voyager would break it in the process of circumnavigating the globe. "The Turtle" is preserved at the National Museum of Naval Aviation at NAS Pensacola.

Variants

Lockheed produced seven main variants of the P2V. In addition, Kawasaki built the turboprop-powered P-2J in Japan.
;XP2V-1
;P2V-1
;XP2V-2
;P2V-2
;P2V-2N "Polar Bear"
;P2V-2S
;P2V-3
;P2V-3B
;P2V-3C
;P2V-3W
;P2V-3Z
;P2V-4
;P2V-5
;P2V-5F
;P2V-5FD
;P2V-5FE
;P2V-5FS
;AP-2E
;NP-2E
;OP-2E
;P2V-6
;P2V-6B
;P2V-6F
;P2V-6T
;P2V-7
;P2V-7B
;P2V-7LP
;P2V-7S
;P2V-7U
;AP-2H
;DP-2H
;EP-2H
;NP-2H
;RB-69A
;Neptune MR.1
;CP-122 Neptune
;Kawasaki P-2J
AircraftNumber
P2V-114
P2V-280
P2V-353
P2V-3W30
P2V-452
P2V-5424
P2V-6/P-2F67
P2V-6B16
P2V-7/P-2H287
P2V-7B15
RB-69A5
Neptune MR.152
P-2J82

Operators

Military operators

There are a few Neptunes that have been restored and are on display in museums and parks.

Argentina

;On display
;;SP-2H
;Airworthy
;;SP-2H
;On Display
;;SP-2H
;In Storage
;;SP-2H
;Under Restoration
;;SP-2E
;;SP-2H
;On display
;;EP-2H
;Under restoration
;;SP-2H
;On display
;;SP-2H
;On display
;;P2V
;On display
;;P-2H
;Airworthy
;;P2V-5
;;P2V-5F/P-2E
;;P2V-7/P-2H
;;P2V-7S/SP-2H
;On display
;;P2V-1
;;P2V-5F/P-2E
;;P2V-5FS/AP-2E
;;P2V-5FS/SP-2E
;;P2V-5/SP2-E
;;
;;P2V-7/P-2H
;;P2V-7S/AP-2H
;;P2V-7S/SP-2H
;Under restoration
;;P2V-5FS/SP-2E

Accidents and incidents