During World War 2 (1939-1945) the Japanese concern of Kawanishi excelled at development and production of large flying boat aircraft for various over-water roles - Search and Rescue (SAR), Anti-Submarine Warfare (ASW), general transport, reconnaissance and the like. However, the post-war era held no place for the company so it was restructured and reborn as "Shin Meiwa Industries". This allowed continuation of large aircraft production services into the post-war period and the company eventually evolved to become "ShinMaywa" of today.
While it still carried the Shin Meiwa name, engineers took to modifying an existing American-originated Grumman HU-16 "Albatross" flying boat (detailed elsewhere on this site) into a more modern product. This produced the "UF-XS" prototype. The twin-engine design of the original gave way to a four engine arrangement in which 2 x Pratt & Whitney R-1340 radials assisted the existing Wright R-1820 radials. The engines were all fitted at the high-mounted wing mainplanes with their wash set to go over and under the wing element and improve lift properties. The fuselage retained a boat-like hull and the flight deck sat over the short nose section. The tail unit exhibited a "T-style" wing arrangement to clear prop-wash and other forces at play. Pontoons were set under the wing mainplanes to allow for take-off and landing from water sources.
The result was an aircraft with improved on- and over-water capabilities - greater inherent power, increased operational ranges and Short Take-Off and Landing (STOL) performance. With authorization from authorities of the Japan Maritime Self-Defense Force (JMSDF), the design was pushed into testing under the "PS-X" designation in 1967 and a first-flight was recorded on October 5th of that year. The intended maritime role for the aircraft would be Anti-Submarine Warfare and general patrol. Two prototypes were contracted for.
Having cleared the requisite evaluations, the PS-X advanced as the "PS-1" when it was adopted for service in 1969. It was formally introduced in 1971 and twenty-three of the PS-1 form were acquired in all. In service, they carried torpedo, depth charges, rocket armament and sonobuoys primarily intended for use against enemy submarines and the crew numbered ten made up of airmen and position specialists. A dipping sonar gave a useful submarine-hunting quality but required the aircraft to be landed on the water's surface to operate. Power was from 4 x Ishikawajima T64-IHI-10 (GE T64) turboprop engines.
As it stood, the PS-1 was a functional aircraft but it lacked true amphibious capabilities as a flying boat - it was restricted to on-water operations in terms of landing and taking off and carried its own beaching equipment as a result. Thought then turned to a dedicated Search and Rescue (SAR) form which did away with the PS-1's military equipment fit and brought about implementation of a wheeled, retractable undercarriage for on-land take-off and landings as well as the requisite SAR equipment. This resulted in the "US-1", a true amphibious flying boat aircraft - of which six were constructed. A prototype was flown for the first time on October 15th, 1974. From the US-1 mark was also formed the "US-1A" standard which incorporated uprated engines for improved STOL performance. Fourteen were developed to this standard and introduced for service while powered by 4 x Ishikawajima T64-IHI-10J (GE T64) turboprop engines.
The PS-1 was removed from active service in 1989.
The series has since been succeeded by the ShinMaywa US-2 flying boat introduced in 2007 (detailed elsewhere on this site). This mark began as the US-1A "Kai" developed during the 1990s and was given Rolls-Royce AE 2100J engines with six-bladed propeller units. It was forced upon the JMSDF when funding for an all-new design could not be had. As such, it was taken on as the US-2.
The PS-1 / US-1/-1A family maintains a limited, active presence in the JMSDF inventory but its best flying days are clearly behind it - two US-1 are retained for the SAR role under the "special mission" categorization.
(OPERATORS list includes past, present, and future operators when applicable)
✓Special-Mission: Anti-Submarine Warfare (ASW)
Equipped to search, track, and engage enemy underwater elements by way of specialized onboard equipment and weapons.
Equipped to search, track, and engage enemy surface elements through visual acquisition, radar support, and onboard weaponry.
✓Special-Mission: Search & Rescue (SAR)
Ability to locate and extract personnel from areas of potential harm or peril (i.e. downed airmen in the sea).
✓Maritime / Navy
Land-based or shipborne capability for operating over-water in various maritime-related roles while supported by allied naval surface elements.
✓Intelligence-Surveillance-Reconnaissance (ISR), Scout
Surveil ground targets / target areas to assess environmental threat levels, enemy strength, or enemy movement.
109.8 ft (33.46 m)
108.8 ft (33.15 m)
32.6 ft (9.95 m)
51,368 lb (23,300 kg)
99,208 lb (45,000 kg)
+47,840 lb (+21,700 kg)
(Showcased structural values pertain to the Shin Meiwa US-1 production variant)
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