The Lockheed P2V (P-2) Neptune was a very successful post-war maritime patrol bomber that was developed during the Second World War, but didn’t enter service until after the war was over.
Work on the design began at Lockheed’s Vega subsidiary in September 1941, with John B. Wassall leading the design team. Temporary Design Designation V-135 called for a twin engined high winged aircraft, weighting 25,000-35,000lb, with power turrets and capable of carrying two torpedoes, bombs or depth charges in an internal bomb bay. It was to be powered by 2,000hp engines, preferably the eighteen cylinder Wright R-3350.
Work on the design was approved by Mac Short, vice president for engineering at Vega on 6 December 1941, bad timing for a new project. The US Navy wasn’t able to justify work on a long term project until 1943, and the first Letter of Intent ordering two XP2V-1 prototypes wasn’t issued until 19 February 1943. A contract for two prototypes was issued on 4 April 1944, followed on 14 April by one for fifteen aircraft.
This allowed work on the project to speed up, and the first prototype was ready for its maiden flight on 17 May 1945. The new aircraft outclassed the PV-2 Harpoon, with significantly better range and bomb load, good stability and single engine control. As a result it was ordered in substantial numbers after the Second World War.
On 16 December 1944 Lockheed received an order for 151 P2V-2s. After the end of the war this was reduced by 48, and then by 52, so only 51 of the wartime orders were delivered. One of these was probably the prototype, produced by modifying a P2V-1. Another 30 were ordered after the war, for a total of 80 production P2V-2s. Eventually 1,181 were produced, including some built in Japan.
The Neptune was a mid wing monoplane, with the wing carried just above the centre of the fuselage. The centre section was level, and there was slight dihedral outside the engine nacelles. The wing was straight, and the outer panel was tapered on the leading and trailing edges. Pods could be carried at the end of the wings. It had a very large vertical tail.
It had a semi-monocoque fuselage, entirely made of metal. The wings used a NACA 2419 modified airfoil, and were also all metal. The bomb bay was carried on the wing centre section, inside the fuselage. The wings also provided some buoyancy if the aircraft ditched, as did empty wing tip fuel tanks.
The Neptune had tricycle landing gear and nose wheel steering, with brakes on each main wheel.
One of the Neptune’s first tasks after entering Naval Service was an attempt to beat the World Distance Record, set by Col C. S. Irvine in the B-29 ‘Pacusan Dreamboat’. This stood at 7,916 miles for a flight from Guam to Washington D.C.
The Navy decided to use the third P2V-1 to try and break this record. All of the armament and combat equipment was removed, and fuel tanks installed everywhere they would fit, for a total of 8,592 gallons in the tanks and 140 gallons in the fuel pipes, for a total of 8.732 gallons. Washing, shaving and sleeping facilities were provided, along with a hot plate for cooking, to make sure that the three man crew had as comfortable a time as possible.
The modified aircraft, known as ‘Truculent Turtle’, took off from Perth, Australia, early on 29 September 1946, heading for Washington. The aircraft crossed the Pacific without any problems, but ran into headwinds over the US, and eventually had to land at Columbus, Ohio, some way short of its target. Even so it had flown 11,326 miles in 55 hours 17 minutes, breaking the distance record. This remained the overall un-refuelled distance record until 1962 when it was beaten by a USAF B-52 Stratofortress and the piston-engine record until 1986 when it was broken during Dick Rutan’s Voyager circumnavigation of the globe, flying over 26,000 miles without being refuelled.
A second P2V-1 (Seabiscuit) was modified for non-military use, with the armament removed and long range fuel tanks. This aircraft was used for polar exploration.
The Neptune entered regular Navy service in March 1947 when the first equipment went to Patrol Squadron, Medium Land based Two (VP-ML-2). By 1949 the type had replaced the PV-2 Harpoon in many squadrons, and was the standard patrol bomber.
The P2V-3C strategic nuclear bomber version entered service in September 1948, and the type remained in serve in that role until 1952 when it was replaced by the North American AJ-1. The idea was for the aircraft to take off from a carrier, attack its target and then use its long range to return to a land base. During this period some aircraft were based in Morocco, for use with the US Sixth Fleet.
The P2V saw extensive service during the Korean War, serving on anti-submarine patrols, naval blockades, weather and general reconnaissance, spotting for naval gun fire and other duties. Seven Nepture squadrons served in Korean, serving fourteen tours of duty between them. VP-1 saw the most service, carrying out four tours of duty over Korea from bases in Japan and Okinawa.
The P2V began to be phased out in favour of the turbo-prop powered P3V Orion in August 1962, bit it would take fifteen years for the switch to be completed. The P2V was used for a variety of roles during the Vietnam War, including Operation TRIM (Trails & Roads Interdiction, Multisensor) and dropping sensors on the Ho Chi Minh Trail. They were also used on their standard anti-submarine and maritime reconnaissance duties early in the war.
The P2V/ P-2 had been replaced in all operational Fleet Patrol Squadrons by the start of the 1970s. It remained in use with the Reserves until 1978, when VP-94 gave up its last SP-2Hs.
The P2V was also used by the US Marines, who had two P2V-2s for airborne electronic aircrew training.
The US Army had seven R-69As which were used with side-looking airborne radar and other ELINT equipment to look over the border into Soviet and Chinese air space, starting in 1954.
Argentina purchased eight ex-British P2V-5s in 1958 and another eight aircraft directly from US surplus. Some of the SP-2Hs from this second batch were still in service during the Falklands War, when they were used to guide the Super Etendards that attacked HMS Sheffield on 4 May 1982.
Australia was the first overseas operator of the type, receiving two P2V-5s in 1951. Another ten were purchased and they were used by No.11 Squadron, RAAF, until 1969. They were followed by twelve P2V-7s, which were used by No.10 Squadron between 1961 and 1978-79.
Brazil received 14 P2V-5s from the RAF, and designated them as the P-15. They carried out 22,761 hours of flight time before the last one was retired in June 1976.
The Canadians purchased twenty-five specially modified P2V-7s in April 1953 and used then with Nos.404, 405 and 407 Squadrons from 1955 until they were replaced by the Canadair CP-107 Argus in the early 1970s. Some of the surplus P2V-7s were then used as fire fighting aircraft.
Chile operated four SP-2Es until 1978-79 when they were replaced by Embraer EMB-111ANs.
The French received thirty-one P2V-6s in 1953, using them to equip three Flotilles, two in Algeria and one in French Morocco. They were followed by thirty-four P2V-7s, which were used by five units. This made the French the largest customer for Lockheed built aircraft. The French used their aircraft for a wide range of missions, and didn’t replace the last few aircraft until 1984.
The RAF received fifty two P2V-5s which were used as maritime reconnaissance aircraft. They were delivered from 1952, and were replaced by the Avro Shackleton in 1956-57.
Japan purchased sixteen Lockheed built P2V-7s from 1955. This was followed by forty-eight aircraft that were assembled by Kawasaki in Japan, with the last delivered in June 1965. This meant that Japan was producing the Neptune several years after production had ended in the United States.
The P2V-7 was followed by the P-2J, a Japanese designed modification of the aircraft that used turbo-prop and jet engines. Eighty three of these aircraft was completed, and they in the mid 1980s they became the last Neptunes still in operational service, although soon after that they were replaced by Japanese built Lockheed Orions.
The Dutch received twelve P2V-5s for used as maritime patrol aircraft over home waters. These were withdraw from service in 1960-62 and went to Portugal. Another fifteen P2V-7Bs, armed with four 20mm cannon, were delivered in 1961-62 and were briefly used in the war against Indonesia. Fourteen of these aircraft returned to the Netherlands after the Indonesian victory in 1962, and remained in use until 1982.
The Portuguese used the twelve aircraft received from the Dutch until 1977.
The prototypes were powered by two 2,100hp Wright Cyclone R-3350-8 engines. They were armed with six 0.5in machine guns, carried in nose, dorsal and tail turrets. The bomb bay could carry four 2,000lb bombs, eight 1,000lb bombs, sixteen 500lb bombs, twelve 325lb depth charges or two 2,165lb torpedoes. Four 11.75in Tiny Tim rockets or 16 5in HVAR could be carried under the wings. The crew of seven consisted of a pilot, co-pilot, radio operator, bombardier/ navigator/ nose gunner, radio counter measures/ radio operator, dorsal gunner and tail gunner. It had self sealing fuel tanks inside nylon plastic shells.
The second prototype was badly damaged when the fin leading edge came off the aircraft during a test flight. The pilot managed to land the badly damaged aircraft.
The first prototype completed the test programme, then went to the Navy in July 1946.
The P2V-1 was almost identical to the prototypes, apart from the use of US Navy operational equipment, and two Wright R-3350-8A engines providing 2,300hp. The P2V-1 used a four blade propeller.
The P2V-2 was powered by two Wright R-3350-24W engines, capable of producing 2,500hp each at take off and 2,800hp with water injection. It had a three blade Hamilton Standard propeller. The nose gunner’s position was replaced by a metal nose that carried six 20mm cannon. The first eight carried the original Bell tail turret with two machine guns, and the remaining 72 gained an Emerson turret with two 20mm cannon.
Two P2V-2s were modified for polar exploration in 1949. They were given retractable ski landing gear, a retractable tail boom containing magnetic field equipment and cameras. They were used on Operation Ski Jump, and late in Operation Deepfreeze II of 1956.
The third P2V-2 was uses as a prototype for an anti-submarine warfare version. The bomb bay was reduced in size to make space for a ventral radome that carried APS-20 search radar. Extra fuel tanks were installed in the fuselage. The P2V-2S made its maiden flight on 2 April 1948.
The P2V-3 was powered by 3,200hp R-3350-26W with jet stack exhausts, which increased power but also made more noise. Fifty three were delivered between August 1948 and January 1950.
The P2V-3 was used as an anti-submarine aircraft, general patrol aircraft, torpedo bomber, low level and medium level bomber, rocket attack aircraft and photo reconnaissance aircraft.
The P2V-3B was the designation given to five aircraft modified for trials of a close support version of the Neptune. One was converted from a P2V-3, three from the P2V-3C and one from a P2V-3W.
The P2V-3C was a version of the aircraft modified for use from aircraft carriers as nuclear bombers. Eleven were produced by modifying P2V-3s, and one by modifying a P2V-2. The nose cannon and dorsal turrets were removed, and the aircraft could carry a 9,700lb 14 kiloton Mk.I atomic bombs. They were delivered between September 1948 and August 1949, and were used as carrier launched bombers. None ever landed on a carrier. Three were later converted into P2V-3B close support aircraft.
The P2V-3W was an airborne early warning aircraft that carried a APS-20 radar set in a ventral radome, and had room for two radar specialists. Thirty were built from new and delivered between November 1949 and February 1951. One was later turned into a P2V-3B close support aircraft.
Two P2V-3s were turned into VIP combat transport aircraft, with space for six passengers in an armoured cabin in the aft fuselage. The crew was reduced to five, and only the tail turret was retained. They were delivered in June and September 1950.
P2V-4 ‘Snorkel Snipper’ (P-2D)
The P2V-4 was the first production version of the Neptune to be given wing tip fuel tanks. These could also carry electrical equipment.
The first twenty five aircraft were powered by the 3,200hp R-3350-26WA engine. They were followed by twenty seven aircraft that used the 3,250hp R-3350-30W compound engine, which used a turbine to capture some of the energy lost in the exhaust gases and feed it back into the main engine. The first of the conventionally powered aircraft made its maiden flight on 14 November 1949 and the first of the compound powered aircraft on 20 March 1950. The last was delivered in March 1951.
The P2V-5 was the most numerous version of the Neptune, and was produced in a number of variants distinguished by their model numbers.
The first 23 aircraft were powered by two 3,250hp R-3360-30WA turbo-compound engines. They had an Emerson nose turret that carried two 20mm cannon, larger wing tip fuel tanks, mounted centrally on the end of the wing and a remote controlled searchlight on the starboard tank.
The -11 has space for an ECM operation, bringing the crew up to nine. A total of 147 were built, for the US Navy, RAF and RAAF.
The -13 had a 17ft long extension to the tail that carried a Magnetic Anomaly Detector. 98 were built for the US Navy.
The -15 had the Mad extension, a glazed nose, and only carried two 0.5in guns in the dorsal turret. Eighty were built for the US Navy.
The -16 was similar to the -13, but added an aircraft captain’s position. Twelve were built and went to the Dutch Navy.
The -45-15 was identical to the -15 apart from the use of the 3,500hp R-3350-32W turbo-compound engine. Sixty four were produced for the US Navy.
The P2V-5F was produced in an attempt to increase the engine power available for the increasingly heavy Neptune. Two 3,250lb thrust Westinghouse J34-WE-34 turbojets were added, mounted in pods carried under the wing. They were used to add extra power at take off or for short bursts in power. At the same time the main engines were upgraded to the 3,500hp R-3350-32W. A large number of the older aircraft were converted to this standard.
The P2V-5FD was the designation for nine aircraft converted to carry and operate drones..
The P2V-5FE carried extra electronic equipment
The P2V-5FS was an anti-submarine warfare version of the aircraft that was given AQA-3 Jezebel long range acoustic search equipment and Julie explosive echo sounding gear.
The P2V-6 was given a longer bomb bay and could carry out mine laying and photographic reconnaissance missions. It was powered by two 3,250hp R-3350 WA engines. 67 were built, 35 for the US Navy and 32 for the French Aeronavale.
P2V-6B/ P2V-6M/ MP-2F
The P2V-6B was an anti-shipping version that could carry two Fairchild AUM-N-2 Petrel missiles under the wings. Sixteen were produced for the US Navy, and delivered in 1953.
The P2V-6F was the designation for those P2V-6s that were given the 3,400lb Westinghouse J34-WE-36 turbojets in under wing pods.
The P2V-6T was a crew trainer produced by converting a number of P2V-6s.
The P2V-7 was the last production version of the Neptune. It was powered by the 3,500hp R-3350-32W and 3,400lb thrust J34-WE-36 turbojets, had a smaller ventral radome, smaller wing tip fuel tanks and a revised cockpit with a clear bulging canopy. They all carried two 0.50in guns in the dorsal turret and the MAD tail. Three versions were produced
The Model 726-45-14 was the basic version. 287 were produced, including 148 for the US Navy, some for the French Aeronavale and 48 that were assembled in Japan by Kawasaki.
The Model 726-45-17 had different crew accommodation. 114 were produced for the US, French, Japanese and Canadians.
The Model 826-45-14 was built without the jet pods, but they were added later. 25 were built, all for Canada.
P2V-7B (Model 726-45-81).
This version had a metal covered nose that carried four 20mm cannon. Fifteen were built for the Dutch Naval Air Service (the MLD).
Four P2V-7Ss were completed with retractable skis, and were used by the Antarctic Development Squadron Six (VXE-6). No armament or operational equipment was carried in order to make space for the survey and photographic equipment needed in their specialist role.
The P2V-7S was given the same Julie/ Jezebel submarine detection gear as the P2V-5FS.
The P2V-7U/ RB-69A was an electronic surveillance aircraft produced for the USAF (thus the B-69 designation). Five were built from new and two were converted from existing Navy aircraft. They later came back to the Navy and were modified to the PS-2H standard.
The P2V-7KAI was a single P2V-7 from the Japanese batch that was modified to act as a prototype for the mixed power propeller-turbine and turbo-jet P-2J. It made its maiden flight on 21 July 1966
Six AP-2Es were produced by modifying existing P-2Es to serve as electronic surveillance aircraft for COMINT/ SIGINT. They served with the 1st Radio Research Company of the US Army in South Vietnam.
The NP-2E was the designation given to two P-2Es used as test beds for the OP-2E
Twelve OP-2Es were produced by modifying existing aircraft, They were used to drop acoustic and seismic sensors which were dropped along the Ho Chi Minh Trail between November 1967 and July 1968 in an attempt to detect movement. The aircraft also had chaff dispensers, camera pods and mini guns under the wings.
The RP-2E was the designation for an aircraft used as an electronic platform by the US Army in Vietnam.
The AP-2H was a dedicated ground attack version, produced for night operations over the Mekong Delta. Four were produced by having all of the anti-submarine warfare equipment removed and replacd with AN/ APQ-92 search radar, FLIR (forward looking infra red) kit, low light level television, side looking airborne radar, DIANE (Digital Integrated Attack and Navigation Equipment) and ‘Black Crow’ equipment designed to detect vehicle ignitions. They were armed with two 20mm cannon in a tail turret, two minigun pods and four bombs below the wings.
The DP-2H was a version of the P-2H modified to operate drones.
The EP-2H was the designation for three aircraft converted to act as airborne relay platforms for UHF data from drones.
NP-2H was a single aircraft converted for tests.
The P-2J was a modified version of the aircraft produced by Kawasaki in Japan. The standard piston engines were replaced by Japanese built 2,850ehp General Electric T64-IHI-10 turbo-prop engines and the Westinghouse jets by Japanese Ishikawajima J3-IHI-7C turbojets. The initial prototype was followed by a version with a longer but lighter fuselage, APS-80 search radar, twin wheel main undercarriage and more powerful engines. This version was put into production, and eighty two were delivered between October 1958 and March 1979.
The EP-2J was the designation given to two aircraft modified to carry ELINT equipment.
The UP-2J was the designation given to four aircraft modified from 1978 for ECM training, air-to-surface and surface-to-surface missile simulations, target towing and drone launching/
Engines: Two Wright R-3350-24W
Power: 2,800hp at take off
Wing span: 100ft
Length: 78ft 3in
Height: 28ft 1in
Empty weight: 33,962lb
Gross weight: 54,000lb
Maximum weight: 63,078lb
Maximum speed: 320mph
Service ceiling: 26,000ft
Normal range: 3,980 miles
Maximum range: 7
Engines: Two Wright R-3350-32W and two Westinghouse J34-WE jet engines
Wing span: 103ft 10in
Length: 91ft 8in
Height: 28ft 1in
Empty weight: 43,011lb
Gross weight: 70,000lb
Maximum weight: 80,000lb
Maximum speed: 364mph
Service ceiling: 33,000ft
Normal range: 4,350 miles