15 August 2015

The Atomic Neptunes: The Navy's Interim Nuclear Bombers

P2V-3C JATO takeoff from the USS Midway
Not often realized in aviation history is the key role naval personnel played in the development and the deployment of the first atomic bombs that closed out the Second World War. In March 1943, Navy captain William Parsons was assigned to the Manhattan Project's Ordnance Division as he had had prior experience in the development of the proximity fuse for anti-aircraft shells. While he also contributed to the design of the atomic bomb's proximity fuse, he ultimately became responsible for the planning and execution of the US Army Air Force's use of the bombs against Japan. At Titian Island in the Marianas, it was Captain Parsons who was in charge of the bomb assembly and check out. The early bombs of those days had a core that was separate from the main core, this way the two parts were each of subcritical mass and unlikely to detonate as a safety measure. Once airborne, the "weaponeer" was responsible for inserting the core into the atomic bomb to arm it. The weaponeer also acted as the mission's tactical commander as they had the final authority on the bomb's use. On the Enola Gay's mission against Hiroshima, Captain Parsons was aboard as the weaponeer and armed "Little Boy" prior to its use. Parson's director of operations in the Manhattan Project was another naval officer, Commander Frederick Ashworth, a former Grumman TBF pilot. On the second mission against Nagasaki, Commander Ashworth was the weaponeer aboard Bock's Car. Though delivered to their targets by USAAF Boeing B-29 Superfortresses, both atomic bombs were armed by naval officers in flight and in essence, naval officers acted as the mission commanders. Despite the primacy of the Navy's carrier battle groups in the Pacific War, the Navy was well aware of the potential power of nuclear weapons in the postwar period. In September 1945 right after the Japanese surrender, the Chief of Naval Operations (CNO) established the Navy's "Special Weapons Division" which was headed by a vice-admiral. Planning immediately began for a new, much larger aircraft carrier that would carry the Navy's planned nuclear strike force. Until this supercarrier was launched, the three biggest aircraft carriers of the US Navy would be responsible for deploying nuclear weapons- these three ships were the Midway-class carriers- the USS Midway, USS Franklin D. Roosevelt, and the USS Coral Sea. In December 1945, the Navy laid out a three-phase carrier-based strategic bomber plan- Phase 1 called for modest capability bomber to speed its introduction and deployment to the fleet. That aircraft became the North American AJ Savage. Phase 2 was eventually dropped as it was decided to adopt the Allison T40 turboprop engine for an improved version of the AJ Savage- that aircraft was the failed XA2J Super Savage. Phase 3 was for the definitive jet-powered nuclear strike bomber that the Navy really wanted, and that aircraft would eventually become the Douglas A3D Skywarrior. 

North American Aviation received the contract to start work on the AJ Savage in June 1946. With the creation of an independent United States Air Force with the passage of the National Security Act of 1947, the assertive leadership of the USAF moved to become to sole user of nuclear delivery in the US military and pushed to relieve the Navy of its strategic ambitions. A rancorous conference chaired by Secretary of Defense James Forrestal in March 1948 in Key West, Florida, resulted in an agreement that the Navy could not only keep its land-based patrol bomber force but could continue development of its strategic air arm as it was consistent with the aims "to conduct air operations as necessary for the accomplishment of objectives in a naval campaign". Since the Navy's planned nuclear targets were all Soviet naval bases, it was given that the USAF's Strategic Air Command would be responsible for the targeting of Soviet urban and industrial centers while the Navy targeted naval bases and other military installations that threatened operations at sea. This didn't sit well with the USAF, but Forrestal's decision was further cemented at a second meeting held at the Naval War College in Newport, Rhode Island, in August 1948. As an interesting historical note to those meetings, the Navy had its own nuclear war plan independent of the USAF's plans until 1960, when both services' plans were integrated into what was called the Single Integrated Operations Plan, or SIOP. 

North American AJ-1 Savage, the Neptune's replacement.
With the prototype North American XAJ Savage making its first flight in May 1949, it was imperative during the development of the Savage that the Navy establish some sort of nuclear delivery capability from its aircraft carriers as soon as possible. The most ideal candidate aircraft to get some sort of interim capability fielded was the Lockheed P2V Neptune. In 1946, a modified Neptune named "Truculent Turtle" made a record-breaking long distance flight from Australia to Ohio, over 11,000 nautical miles without refueling. With the plans for the Midway-class carriers to operate in the Mediterranean with the nuclear-armed Neptunes, a flight from the eastern Med to Moscow was significantly less than that of the Truculent Turtle's flight and if the targets were coastal naval bases, the range required was even less. With a gross weight well in excess of the catapults of the Midway-class ships, the modified Neptunes would use eight 1,000 lb-thrust JATO rockets with a near-full length deck run of 900 feet and the starboard wingtip clearing the island by only 10 feet. The modified Neptunes were designated P2V-3C and only twelve such aircraft were ordered- since there were only three Midway-class ships and a small number of the Mk 1 bomb (based on the Little Boy design) available, the interim strike force would be very small until the AJ Savage became operational. The more advanced Mk 4 bomb which was based on the Fat Man design used on Nagasaki was too large for the Neptune's bomb bay- but the AJ Savage was designed from the outset to be able to carry the larger Mk 4 bomb. 

At first it was planned to give the P2V-3Cs the ability to return to the carrier after their missions. One of the twelve aircraft modified got a tail hook and around 128 field arrested landings were practiced both at Lockheed's facility at Burbank Airport and at the Navy's flight test center at NAS Patuxent River in Maryland. These flights were flown by another naval aviator who was a veteran of the Manhattan Project, Commander John Hayward. During the war he was assigned to China Lake where he worked on the implosion device used on Fat Man to start the nuclear chain reaction that resulted in detonation. Commander Hayward even flew the P2V-3C on touch and goes off the USS Franklin D. Roosevelt, but no arrested landings at sea were made. It was found that the Neptune's structure wasn't strong enough for carrier landings and the aircraft that Hayward flew on land-based arrested landings had numerous structural deformities as a result. Since there wasn't time to beef up the structure of the Neptune, the P2V-3Cs would have be craned aboard the Midway-class ships dockside and then, after completion of the mission, either ditch alongside the carrier or land at a friendly airfield. This made the P2V-3C aircraft pretty much a single-use weapon. 

Internal layout of the P2V-3C. Note the fuel tanks in the nose and aft fuselage.
Additional fuel tanks were added in the wings and fuselage of the Neptune to create the P2V-3C. Total internal fuel over a standard P2V patrol bomber was increased by an astounding 75%! The P2V-3C carried 4,120 gallons of fuel over the standard P2V's 2,350 gallons. Anything unnecessary to the nuclear delivery mission was deleted, especially if it caused drag- so the dorsal gun turret, nose turret, rocket launcher provisions on the wings and multiple antennas were removed. An AN/APS-31 search and navigation radar replaced the nose turret and it worked with a radar bomb sight. Even the astrodome was removed to reduce drag, sextant shots for navigation would be done via a periscope. Since the mission endurance of the P2V-3C would outlast the oil capacity of the Wright R-3350 radial engines, a 38-gallon oil tank was installed (in fact, the navigator sat on it) with plumbing to keep the engines replenished with oil during the mission. To further save on weight, even the emergency hydraulic system was removed from the P2V-3C. A pair of 20mm tail guns were kept for self defense along with radar detection equipment (but no countermeasures or jamming capability was installed) and the crew was reduced to just four: pilot, copilot/weaponeer, bombardier/navigator, and radioman/tail gunner. 

The first P2V-3C takeoff from a carrier took place in April 1948 fro the USS Coral Sea and a rapid series of demonstrations were made at increasing weights to show that a fully-fueled and loaded Neptune could make it off the carrier with a JATO-assist deck run. On one demonstration flight, Captain Hayward had the second Secretary of Defense, Louis Johnson, in the right seat. It was Johnson who succeeded Forrestal as SecDef and interestingly, just months before his flight on a P2V-3C demonstration takeoff, he had canceled the Navy's first supercarrier, the USS United States. Through 1948, the Navy conducted a series of long range missions from a Midway-class carrier to demonstrate the concept, a simulated weapon delivery and recovery to a friendly air base. Should the Neptune crew elect to ditch along side the carrier, a special flap was added to the underside of the P2V-3C called a "hydroflap" that helped keep the nose of the aircraft from boring into the water during ditching. 

With the deployment of the P2V-3C nearing, the Navy formed three Special Weapons Units- one each for each of the Midway-class aircraft carriers. Based and trained at Kirkland AFB in Albuquerque, New Mexico, where the Department of Energy in cooperation with the USAF had a nuclear technical facility, each unit would be responsible for the assembly, maintenance, and check out of each weapon. The technology of the day meant it took about 50 men and 80 hours to carry out a bomb aseembly and disassembly for maintenance checks. Modifications to each Midway-class carrier provided for facilities for bomb handling, storage, and maintenance with a special Marine Corps detachment for security. The first Navy heavy attack squadron was Composite Squadron 5 (VC-5), established at Moffett Field, California on 9 September 1948. VC-5's commanding officer was Commander Frederick Ashworth, the weaponeer on Bock's Car. In the following January, Captain John Hayward assumed command with Ashworth as his XO. The first P2V-3Cs were delivered to the squadron in November 1948. JATO training at NAS Patuxent River began in February 1949 and by March, three aircraft were craned aboard the USS Coral Sea for its first exercises. By April 1949, all three Midway-class carriers were ready for deployment- all three would be homeported at Norfolk, Virginia, on the East Coast since their deterrent patrols would be in either the Mediterranean or North Seas. 

JATO launch from the USS Franklin D. Roosevelt
It was by this time that the wisdom of using the Neptune as an interim aircraft proved wise- North American was running into development issues with the AJ Savage. Even though the deployment of the P2V-3C coincided with the arrival of the first AJ Savage aircraft, the early AJs were so unreliable and trouble-prone, most training had to be done with the Neptunes. By April 1950, VC-5 was sending detachments to the carriers that had both the AJ Savage and the P2V-3C Neptune. The AJs were used for carrier landing qualifications since the Neptunes lacked return provisions. The first operational deployment took place in January 1951 when VC-5 went aboard the USS Franklin D. Roosevelt. The aircraft weren't on the ship, though- the FDR left Norfolk for the Mediterranean with its complement of bombs and its attendant Special Weapons Unit. Six AJ Savages and three P2V-3C Neptunes departed Norfolk later for Port Lyautey, Morocco, to catch up with the carrier. Continued problems with the AJ kept them shore based. Since the Neptunes couldn't return to the ship, they were also shore-based in Morocco as well and would be craned aboard the carrier had tensions increased. It wasn't a practical arrangement but it was the only arrangement. So as to not alert the Soviets, Neptunes were craned aboard which ever Midway-class carrier was in the Mediterranean and practice launches carried out on a routine basis. Depending on the planned mission range, no more than three to four P2V-3C Neptunes could operate from the carrier- few of the carrier's air wing could be on deck as the Neptunes lacked wing folding and took up a lot of space. When not spotted for takeoff at the rear of the deck (the angled deck had yet to be retrofitted to the Midway-class), the Neptunes were parked on the forward deck but their size meant that only the port catapult could be used the carrier air wing. Needless to say, many carrier captains and CAGs despised the Neptunes! 

By 1952, the problems with the AJ Savage had been ironed out enough that they could assume the nuclear delivery role from the Neptunes. While the Savage was smaller with wing folding and could return to the ship, their large size still had them universally disliked as they got in the way of flight deck operations. The Savages, though, could operated off the smaller Essex class ships, which expanded the number of available carriers for nuclear deterrent patrol. One of the reasons the Midway-class ships didn't participate in the Korean War was that they were needed in the Mediterranean for deterrent patrols. The P2V-3Cs were reconfigured to P2V-3Bs and sent ashore to act as training aircraft for the crews bound for the AJ Savage. The Neptune's role as an interim nuclear bomber was brief, less than two years, but it gave the Navy valuable experience in not just operating large aircraft from carriers but also with nuclear weapons handling. 

Source: Strike From the Sea: US Navy Attack Aircraft From Skyraider to Super Hornet 1948-Present by Tommy H. Thompson. Specialty Press, 2009, pp42-56. "Naval Aviation Centennial: Neptune's Atomic Trident (1950)" US Naval Institute Blog, 6 February 2011. Photos: 


  1. A minor correction: neither the Little Boy bomb (Hiroshima) or the Fat Man bomb (Nagasaki) had cores that could be loaded in flight. That innovation appeared later in the Mk. 4 nuclear bomb. What Parsons did during the Hiroshima mission was to insert the black powder charge which, when armed, fired the uranium "bullet" toward the uranium target. This formed the critical mass which caused the actual nuclear explosion.

  2. It's Kirtland AFB, not Kirkland. Autocorrect? It did it to me typing this entry! Lol!

    1. Indeed- some days autocorrect is my own worst enema. Dang it, see what I mean?