Kawasaki P-2J

P-2J Neptune 4761

In the summer of 1963, Kawasaki engineers in an effort to improve the aging SP-2H Neptune's performance and extend its service life, considered plans to convert the Neptune to turboprop power. This new variant was intended to use many of the advanced systems used in the Lockheed P-3 Orion. During May 1965, a basic plan was drawn up for the P2V-7 "Kai", an abbreviation for the Japanese "Kaizo" (modified), which included a 54-inch fuselage extension between the wing leading edge and cockpit to accommodate improved electronic equipment. In place of APS-20 search radar, APS-80 radar was added, which operated on a shorter wavelength and accordingly, used a smaller dish antenna in a smaller radome. This was the same radar installed in P-3A and B Orions. The P-2J's rudder area was also increased. This was accomplished by extending the rudder chord one foot at the top.

GE T64-IHI-10 turboprop engines A pair of GE T64-IHI-10 turboprop engines, driving Sumitomo Precision 63E60-19 three-bladed, variable-pitch propellers, would supply main power. The change would require completely redesigned engine nacelles that in turn required a switch to dual main wheels of smaller diameter.

Two Ishikawajima J3-IHI-7C turbojets rated at 3,085 pounds of static thrust would augment the main power plants. The new power plant installation increased the Neptune's top speed to 403 mph, plus the turbo variant offered an increase in fuel capacity. Compared with the P-2H, the P2V-7 Kai's empty weight was reduced by 10,000 pounds. Ishikawajima J3-IHI-7C turbojet

The P2V-7 Kai could carry a 12,000-pound ordnance load. An additional crewmember known as a combat coordinator brought the total crew complement to twelve. Initially designated the GK-120, Kawasaki later changed to designation to P-2J during production. Construction of the prototype was under way during the summer of 1965 with the conversion of P2V-7 number 4637. Flight tests of the jet engines began on 5 October 1965. Renumbered 4701, the P-2J made its first flight on 21 July 1966, and was delivered to the JMSDF on 14 November 1966.

A total of 83 P-2Js were built by Kawasaki, with the first production model delivered to the JMSDF on 7 October 1969, and assigned to the 51st FS for tests. On 27 February 1971, the 1st FS completed its transition from P2V-7S to P-2Js, and the 2nd FS received its first turboprop Neptune on 28 April 1971. The P-2J gradually replaced the P2V-7 in service and the last machine was delivered to the JMSDF on March 14, 1979.

The last five P2V-7/SP-2Hs of the JMSDF being flown as photographic/chase aircraft, were retired at the end 1981. Four years later, Hachinoe-based P-2J squadrons were in the process of converting to P-3s, with patrol squadrons at Kanoya and Naha as soon as a sufficient number of Japanese-built Orions became available.

Three P-2J 's (serials 4717, 4719, 4757) were converted to UP-2J and re-serialled 9161/9163. The UP-2J was used for various support duties of the fleet such as target towing, drone launching and ECM training. The first UP-2J was delivered in December 1979. The type was initially delivered to the 51st Kokutai for operational test and development purposes, and to the UP-2J squadron, the 81st Kokutai, which was formed on March 30, 1983 with three UP-2J 's at lwakuni.

The turbine-powered P-2Js, EP-2Js and UP-2Js of the JMSDF would have the distinction of becoming the last operational Neptunes in the world.