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. This prevented windmilling, allowing for economical piston-engine-only long-endurance search and patrol operations. The jet pods were fitted with intake doors that remained closed when the J-34s were not running. 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 Convair B-36, several Boeing C-97 Stratofreighter, Fairchild C-123 Provider, and Avro Shackleton aircraft were also so equipped.
īeginning with the P2V-5F model, the Neptune became one of the first operational aircraft fitted with both piston and jet engines. Potential use as a bomber led to successful launches from aircraft carriers. Production began in 1946, and the aircraft was accepted into service in 1947. 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. It was not until 1944 that the program went into full swing. 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. 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. P2V-2 of VP-18 over NAS Jacksonville, 1953ĭevelopment 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.