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The Neptune’s Trident: The Navy’s Versatile and Adaptable Maritime Patrol Aircraft

The Lockheed P-2 Neptune Served With Distinction For Over Five Decades.

On May 17th 1945, the Lockheed XP2V-1 Neptune flew for the first time. The Neptune, like many other naval aircraft of the time, was adapted to many different missions and roles. The 1,105 P-2s were built in seven primary variants and 30 sub-variants. Kawasaki of Japan built another 83 P-2s. When Naval Reserve Patrol Squadron VP-94 Crawfishers retired their P-2Hs in April of 1978, 31 years of distinguished service with the US Navy came to a close.

The Neptune is unique in that it was and still is the only American naval land-based patrol plane ever purpose-designed and built. Lockheed actually began design work on a new land-based patrol bomber during early December of 1941. Lockheed was building the PV-2 Harpoon patrol bomber early in the war so it took until April of 1944 for the Navy Bureau of Aeronautics (BuAer) to contract with Lockheed to build the first two prototypes. After the prototype flew in 1945 production began in 1946 and the first operational P2V-1s went into service in 1947.

The design of the P-2 was predicated on the theory that a pair of the new Wright R-3350 Cyclone 18 cylinder radial engines would enable the Neptune to carry more payload farther than even the four engine heavy bombers in use at the time. The Boeing B-17 Flying Fortess was used by the Navy in small numbers as the PB-1 and PB-1W. The Consolidated B-24 Liberator was utilized by the Navy in much larger numbers as the PB4Y-1 and was the basis for the more specialized PB4Y-2 Privateer patrol bomber. But because the R-3350 engines were being used in Boeing B-29 Superfortresses at the time, Lockheed’s new maritime patrol platform was ready when called upon after the war ended.

The Navy, with an eye toward post-war public relations, decided to show the new design off. The third production P2V-1 was chosen for a record-setting mission. The crew named the Neptune “The Turtle” but somehow the Navy tweaked the moniker to “The Truculent Turtle.” On September 9th 1946 The Turtle took off from Perth in Australia using rocket-assisted takeoff (RATO) on a non-stop flight destined to end in the United States. Carrying a crew of four, a baby kangaroo, and all the avgas that could be Indian-wrestled aboard, The Turtle landed 55 hours and 18 minutes later at Naval Air Station (NAS) Columbus, Ohio- 11,236 miles away. It took 16 years and Air Force B-52s to best the flight of The Turtle. She now resides at the National Naval Aviation Museum at NAS Pensacola in Florida.

One role for which Lockheed didn’t design the Neptune was thrust upon it by political considerations. The Navy feared it would lose clout in Washington if it did not possess a nuclear strike capability. More sophisticated and practical weapons were on drawing boards, but those were years away from being operational. 12 P2V Neptunes became that stop-gap nuclear strike capability. The atomic weapons of the day were large and heavy and required large aircraft to carry them. Luckily the solution was never tested in actual combat. However, the sight and sound of a navy blue P2V being rocketed off a carrier flight deck by RATO bottles is one few who witnessed it will ever forget.

After becoming operational the Neptune quickly took up its duties tracking submarines and shipping all over the world. The P2V was the first Navy maritime patrol aircraft to combine radar, sonar (via sonobuoys), and Magnetic Anomaly Detection (MAD) sensors in the same airframe. These same three primary sensors have equipped every maritime patrol aircraft built since the P2V. The early variants of the Neptune carried none of these sensors.  They were equipped with offensive and defensive 20 millimeter gun turrets and were capable of employing all manner of anti-shipping and anti-submarine weaponry.

As the P2V developed it gained more powerful versions of the same R-3350 engines, different propellers, changes to and omission or inclusion of the offensive and defensive armament, modified landing gear enabling the aircraft to support arctic operations, avionics and mission-dedicated electronic equipment, airframe modifications including changes to the nose and tail, fuselage extensions, wingtip fuel tanks of various capacities, aerial searchlights, canopy configurations, and more. The P2V-5F variant added a pair of Westinghouse J34 jet engines, providing increased thrust for takeoffs and extra dash speed used when prosecuting or attacking targets. Future Neptunes would all be equipped to fly with “two turning and two burning.”

The first use of the Neptune in combat came during the Korean War. P2V-3s attacked ground targets day and night using bombs and rockets, laid naval mines in North and South Korean waters, flew electronic surveillance missions, and even flew transport missions when called upon to do so. Some Neptunes were modified with a special armored aft passenger compartment capable of seating six. After the Korean War ended the Navy changed the color schemes of most of its aircraft. In September of 1962, they changed their names too. The P2V became the P-2. The P2V-1 became the P-2A. The P2V-2 became the P-2B. The P2V-3 became the P-2C…and so on.

During the Cuban Missile Crisis in 1962, P-2s were instrumental in tracking Soviet shipping and submarines plying the shipping lanes (and sometimes avoiding them) back and forth between the Soviet Union and Cuba. But the P-2 flew most of its combat missions in Vietnam. Navy P-2s were used primarily for support and enforcement of Operation Market Time, the hundred month-long interdiction effort and blockade intended to halt the flow of arms from North Vietnam to South Vietnam predominantly by coastal shipping and small indigenous vessels.

In addition to maritime patrol duties, Navy Neptunes executed some other more specialized missions over Southeast Asia. Observation Squadron 67 (VO-67) Ghost Squadron earned the only Presidential Unit Citation awarded to a P-2 squadron while flying secret missions out of Nakhon Phanom Royal Thai Air Force Base in Thailand over the Ho Chi Minh Trail dropping Igloo White acoustic and seismic sensors during 1967 and 1968. VO-67 lost three of their 12 OP-2E aircraft and 20 crew members while flying these sensitive but dangerous missions.

Heavy Attack Squadron 21 (VAH-21) Roadrunners operated four night and all-weather AP-2H attack variants from Cam Ranh Air Base over South Vietnam during 1968 and 1969. The AP-2Hs were the ultimate attack Neptunes, equipped with the same electro-optical sensor suite as the Grumman A-6C Intruder and were capable of attacking targets with grenade launchers, 7.62 millimeter Gatling guns, as well as bombs and napalm.

Have you ever seen a picture of a P-2 with ARMY painted on it? It’s (probably) not a fake. The Army’s First Radio Research Company (Aviation) Crazy Cats operated a handful of AP-2Es for 42,500 accident-free hours in and around Vietnam between 1967 and 1972. The Crazy Cats flew electronic reconnaissance missions out of Cam Ranh Air Base near Cam Ranh Bay. The Army Neptunes specialized in “ferret” missions, listening to and recording enemy voice and Morse code transmissions.

Even more secretive were the few United States Air Force Neptunes designated RB-69A. Under the innocuous-sounding code name Project Cherry, these Lockheed Skunkworks-modified electronic reconnaissance and intelligence aircraft were briefly operated by CIA crews from West German bases over the Iron Curtain. Other RB-69As were provided to the Taiwanese 34th Squadron Black Bats, who operated them from Taiwanese bases over mainland China between 1957 and 1966 inserting and dropping supplies to agents, dropping leaflets, and mapping Chinese air defense network installations. Every one of the RB-69As in Taiwanese service was lost and their crews killed. If you want to know more about these very black missions, the CIA currently plans to declassify them. In 2022.

Neptunes continued to do whatever they were asked to do after the Vietnam War ended. Several were modified to carry aloft, launch, and control drones. Others were used for training aircrews. The Lockheed P-3A Orion maritime patrol aircraft began replacing the Neptune beginning in the early 1960s. Naval Reserve patrol squadrons continued to operate P-2s through the 1960s and into the 1970s. But with the inevitability of time gradually the early-model P-3s replaced the late-model P-2s in both fleet and reserve patrol squadrons. Navy Patrol Squadron 23 (VP-23) Seahawks retired their last operational active duty Navy P-2s on February 20th 1974. But Neptune’s Trident served on.

Argentinian Neptunes were utilized to perform maritime surveillance of Chilean naval units during the 1978 conflict with Chile and similar surveillance of British naval units during the 1982 Falklands War, enabling Dassault Super Etendards to successfully attack several Royal Navy ships. The Canadians used 25 Neptunes between 1955 and 1960 as replacements for their aging Avro Lancaster bombers used for maritime patrol and surveillance. The Japanese Kawasaki P-2J was a Neptune powered by General Electric T-64 turboprop engines. The P-2J also received a further forward fuselage extension and revised aft control surfaces. These turbo-Neptunes served until replaced by license-built P-3C Orions in 1984.

Military operators of the P-2 Neptune series included Argentina, Australia, Brazil, Canada, France, Japan,  Netherlands, Portugal, Republic of China (Taiwan), United Kingdom, and the United States Army, Air Force, and Navy. Civilian operators include Aero Union, Minden Air, and Neptune Aviation Services. There are currently about 25 airworthy Neptunes, including fire bombers, a restored P-2H in Australia, and the Mid Atlantic Air Museum’s P-2H.

Here are six things you might not know about the P-2 Neptune:

  1. In order to take advantage of the J34 jet engines but not add a complete second fuel system for them, the Neptune’s pod-mounted J34 engines burned the same regular avgas (aviation gasoline) that its Wright R-3350 reciprocating engines did.
  2. The Neptune was one of the first aircraft designed from the start to be easily manufactured and maintained. Sub-assemblies allowed shorter assembly times. They also made it easier to maintain the P-2. A complete R-3350 engine change only took 30 minutes; a propeller change only 22 minutes. An outer wing panel change only took about 80 minutes.
  3. Firefighting Neptunes typically carry more than 2,000 gallons of chemical flame retardant “slurry” in quick-release tanks built into the former bomb bays of the modified P-2s. With military mission equipment removed these aging and due-for-replacement Neptunes are considered to be the nimblest P-2s- especially after depositing their loads on at-risk vegetation.
  4. The shape of the Neptune’s tail-mounted control surfaces could be altered in flight in order to maintain directional trim while fuel was burned off. This “varicam” tail was also used on subsequent Lockheed aircraft.
  5. Soviet MiG-15 fighters intercepted and shot down, with the loss of all ten crewmembers, a US Navy P2V-3W Neptune that was probing the defenses of the Soviet Navy base at Vladivostok on November 6th The standard whose-airspace-was-it arguments ensued, but evidently the MiG-15 pilots were decorated, leading Americans to believe the shoot down was not only deliberate but also likely approved by Soviet leadership. Years later witnesses told stories of survivors from this Neptune who were thoroughly interrogated and executed. Several other Neptunes were lost under similar circumstances during the Cold War.
  6. The configuration of the aircraft, with both reciprocating and jet engines, was shared by a few other designs. One was the Consolidated B-36 Peacemaker strategic bomber. Another was the Fairchild C-123 Provider. For a free lifetime subscription to Avgeekery.com, can you name six more operational aircraft similarly configured? Hint: There are a total of 12. No Googling!

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Written by Bill Walton

Bill Walton

Bill Walton is a life-long aviation enthusiast and expert in aircraft recognition. As a teenager Bill helped his engineer father build an award-winning T-18 homebuilt airplane in their Wisconsin basement. Bill is a freelance writer, an avid sailor, engineer, announcer, husband, father, uncle, mentor, coach, and Navy veteran. Bill lives north of Houston TX with his wife and son under the approach path to KDWH runway 17R, which means they get to look up at a lot of airplanes. A very good thing.

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