P2V-4 (P-2D) / MODEL 426

The P2V‑4 Neptune marked the next step in Lockheed’s long‑range maritime patrol line. Making its maiden flight on November 14, 1949, equipment of the Dash 4 was similar to the P2V-2S modified for the ASW mission.  52 examples were delivered by March 1951. This model incorporated major improvements in power, range, and antisubmarine capability. Powered by Wright Turbo‑Compound engines—initially the R‑3350‑26W (25), later replaced by the intended R‑3350‑30W (27)—it delivered stronger climb performance and a higher top speed than earlier variants. 

Fuel capacity increased substantially through enlarged internal tanks and 850‑gallon wingtip tanks, extending the aircraft’s reach to roughly 4,200 miles. The P2V‑4 also standardized the large APS‑20 radar radome first seen on the P2V‑3W, strengthening its role in long‑range detection. Armament remained heavy, with 20 mm cannon, .50‑caliber guns, and wing‑mounted rockets. A dedicated sonobuoy operator expanded the crew to eight, reflecting the Navy’s growing emphasis on acoustic submarine tracking. 

The outbreak of the Korean War pushed the U.S. Navy to take on a wide range of missions for the United Nations effort, including antisubmarine patrols, blockades, reconnaissance, gunfire spotting, and mine detection. Patrol Squadrons assigned to Fleet Air Wings in Japan, Korea, and the Formosa Strait carried much of this load, operating alongside flying‑boat units and PB4Y‑2 Privateers.

Seven Neptune squadrons—VP‑1, 2, 6, 7, 22, 29, and 57—saw action. Neptune units completed thirteen combat tours using P2V‑3, ‑4, and ‑5 aircraft from bases in Japan and Okinawa.

After fleet service, the -4 was passed to the reserves.  By the end of 1962 the last of the P2V-4’s, now redesignated P-2D, were retired.