The Lockheed P-2 Neptune (designated P2V by the United States Navy prior to September 1962) is a maritime patrol and anti-submarine warfare (ASW) aircraft.

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.

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.

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.

In normal US Navy 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 (500-foot (150 m) during the day and 1,000-foot (300 m) at night) anti-submarine and/or anti-shipping operations as a safety measure should one of the radials develop problems.

Before the P-3 Orion arrived 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.

At the end of World War II, the US Navy felt the need to acquire a nuclear strike capability to maintain its political influence.

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 US Navy was adopting fully jet powered nuclear strike aircraft.

The Neptune was also utilized 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.

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.

These aircraft helped escort the fast transport HMAS Sydney from Australia to South Vietnam on several occasions in 1965 and 1966.

During these sorties the Neptunes warned American aircraft operating over North Vietnam of Vietnamese surface to air missile launches.

Armament included two torpedoes, mines, depth charges, bombs carried internally plus unguided rockets mounted under the wings.

[20] Australia also acquired Neptunes to supplement and then replace the aging Avro Lincoln in the reconnaissance and anti-submarine role.

In August 1953, the rear and front turrets were removed and replaced with a MAD boom and a clear Perspex nose for observation.

[citation needed] The 320 Squadron of the Royal Dutch Navy retired its last seven Neptunes in March 1982 as they were being replaced by the Lockheed Orion.

A truce ended the conflict in September 1962, with Dutch New Guinea passing to UN control before becoming part of Indonesia, and the P2V-7s returned to Europe.

[29] 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, and to surpass the standing record set by a Japanese Tachikawa Ki-77.

[30] 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 (and a nine-month-old gray kangaroo, a gift from Australia for the National Zoo in Washington, D.C.) the aircraft set off on 9 September 1946, with a RATO (rocket-assisted takeoff).