US-1 / PS-1 - Kai Flying Boat

First flown 16 October 1974; first delivery (as US-1) 5 March 1975; all now have T64-IHI-10J engines as US-1As. The US-1A is in service with Japan's Maritime Self-Defense Forces, and is active in search and rescue far from Japan's shores in the Pacific Ocean and the Sea of Japan. A characteristic of this aircraft is that its superior performance permits it to land on rough seas and continue its rescue activities. Moreover, it has a long range and can search over a wide area for a long time. In addition, since it is an amphibian that can land on either land or sea it can rescue people at sea and on remote islands that do not have airstrips, then land at an airstrip on land so that the victim(s) can be rapidly transferred to a hospital. Since this aircraft's first rescue at sea, from a Greek vessel in 1976, until March 1999, this model aircraft has made 548 rescues during which 550 people were rescued.

For Japan based on the exclusively defense-oriented policy, it is extremely important to carry out constant warning and surveillance over Japanese territory and its surrounding airspace and waters. The Japan Maritime Self-Defense Force [JMSDF] carries out constant warning and surveillance operations over vessels moving in the waters surrounding Japan, through patrol aircraft and vessels, and engages in collecting information on movements and equipments of foreign vessels. In case of emergency, it is important to search and rescue the crew of aircraft or submarines in distress from the viewpoint of respecting for their lives and maintaining their morale. The JMSDF possesses rescue amphibian, US-1A for the maritime rescue operations, rescue helos for the aerial rescue in the vicinity of the air-base, and submarine rescue vessel for rescuing submarines.

Since 1960 ShinMaywa Industries, Ltd. has developed STOL technology which made it possible for aircraft to operate in rough seas in which operation was previously impossible. In developing the PS-1/US-1, a UF-1 supplied by the United States Navy to the Japanese Defense Ministry was modified and a 3/4-size model called the UF- XS was produced, and tests of the performance of the hull in waves, of the roll damping mechanism and of the high lift mechanism were conducted.

The history of ShinMaywa's amphibian aircraft dates back to 1957, when the �spray suppressor� was invented by a group of engineers who were overcome with a burning desire to �once again manufacture aircraft with our own hands.� ShinMaywa's direct ancestor is Kawanishi Aircraft Company, which produced over 2,800 aircraft between 1928 and 1945. After the company made a fresh start in November 1949 as Shin Meiwa Industry Company Limited (later renamed as ShinMaywa Industries, Ltd.), following the lifting of the ban on aircraft development / manufacturing in Japan in 1952, Shin Meiwa once more set for ourselves the goal of developing new aircraft.

Yearning to resume the aircraft business, then President Ryozo Kawanishi set up an aviation committee within the company in 1953 with a view toward developing a new amphibian. Our amphibians from the Kawanishi Aircraft Company era and ones manufactured by overseas companies at the time shared a common weakness in poor seaworthiness. It was said that new applications of amphibians could be opened up if a craft could be developed that had good seaworthiness and thus could take off and land on rough seas. After analyzing marine survey reports from the Pacific and Atlantic, our development team decided on the goal of developing an amphibian that could take off and land on rough seas with wave height of 3 meters, thus kicking off the project to develop �made-in-Japan� amphibians.

The biggest challenge for the task of landing on rough seas with wave height of 3 meters was how to go about �eliminating splashes while taxiing on the water.� An idea originating with designer Shizuo Kikuhara led to the commencement of a research project in 1953, which culminated in the invention of a �spray suppressor� some four years later. It was this invention that would go on to solidify our position as a leading manufacturer of amphibian aircraft.

The second challenge Shin Meiwa were faced with was the development of a high-lift device. For safe takeoff and landing at sea, it was necessary to substantially lower the cruising speed during takeoff and landing. After research efforts began in 1955, a series of wind tunnel tests were performed until the cruising speed during takeoff and landing was able to be reduced to 45 knots (83 km/h), thereby enabling STOL (short takeoff and landing). These two new technologies resulted in the completion of a foundational design for a new amphibian in 1959.

The U.S. Navy invited Kikuhara to Washington, D.C. in 1959. Meeting with high-ranking officers from the Navy, Kikuhara managed to obtain a promise to the effect that the U.S. Navy was prepared to offer all-out support for the project in terms of technology and materials if the Japan Maritime Self-Defense Force (JMSDF) would make an official request.

Kikuhara replied by saying that he wanted the U.S. Navy to provide one of its amphibians so that he could test the new technology with an experimental plane before setting about the development in earnest. His request was accepted, and the Grumman Albatross was made available to ShinMaywa.

In 1960, the Defense Agency of Japan (now the Ministry of Defense) decided on a policy concerning the development of a new anti-submarine patrol plane. Meanwhile, having arrived at our Konan Plant in December 1960, the Albatross was remodeled into the UF-XS experimental plane.In 1961, an Amphibian Development Division was established with Kikuhara appointed as chief designer, thereby gradually giving concrete shape to the development and manufacture of new amphibians with cooperation from Fuji Heavy Industries Ltd. and NIPPI Corporation. Featuring the new technology, the UF-XS made a successful maiden flight in December 1962. The JMSDF continued experimentation with the UF-XS until 1964 to confirm its outstanding seaworthiness.

The success of the UF-XS's experimental flight prompted the Defense Agency to allocate a full-sized budget for the project to develop new amphibian aircraft for anti-submarine patrols, thus laying the groundwork for promotion of the project through public-private partnership.

In January 1966, the company signed a contract with the Defense Agency for development of the first model of the new amphibians and then established a PX-S project promotion committee. With cooperation from Fuji Heavy Industries Ltd. and NIPPI Corporation, Shin Meiwa proceeded with the development and manufacture of this amphibian, which made its debut flight on October 17, 1967 [other sources report 05 October 1967].

One of the technological requirements of the project was the �ability to take off and land on rough seas with wave height of 3 m.� The takeoff test that Shin Meiwa conducted on rough open seas off the Kii Channel in April 1968 was such that it attracted much attention from both Japan and abroad. The record of the test on April 23, when the maximum wave height hit 4 m, stated that they even received the mistaken impression that the PX-S was sinking when it landed. This test served to demonstrate the PX-S's extremely good seaworthiness. After a series of test flights, Shin Meiwa delivered the PX-S to the JMSDF in August 1968.

After testing the production aircraft entered service with the JMSDF. Then in October 1970, the JMSDF gave the PX-S an official name, marking birth of the �PS-1 aircraft.� �PS� stands for �Patrol Seaplane,� and up until 1979 the company manufactured a total of 23 PS-1 aircraft, which were put into service by the JMSDF for anti-submarine patrolling. In 1970 an amphibian version was designed and first flown on 16 October 1974. The plane's first land take-off occurred on 03 December 1974.

The PS-1 was subsequently redesignated the US-1 to reflect a change in mission from anti-submarine warfare to at-sea rescue, and production of the US-1A STOL Search and Rescue Amphibian is continuing to this day. This is the only large flying boat in production today. The US-1A amphibian uses its superior performance, including the ability to land on rough seas, in such operations as search and rescue at sea and emergency transport to isolated islands. In addition, it is expected to find application as a firefighting aircraft and in transport systems to isolated islands which lack airstrips.

The aircraft is fitted with a T-tail unit, retractable beaching chasis, a single-step hull, and wing-mounted stabilizing floats. The aircraft is powered by four General Electric turboprop engines and a fifth gas turbine engine is located inside the fuselage. This fifth engine provides compressed air for the aircraft's STOL boundary control system.

Shin Maywa Industries Ltd. (formerly the Shin Meiwa Industry Company Limited) started in 1918 with the limited partnership Nippon Aircraft Manufacturing, the first aircraft manufacturer in Japan. The company then became the Aircraft Division of Kawanishi Machine Manufacturing Company, and in 1928 went independent as Kawanishi Aircraft Company Limited. Until the end of World War II Kawanishi built 2,862 aircraft, including a number of flying boats. With the large increases in size of land-based aircraft during World War II, the need for flying boats decreased, and flying boats disappeared from the commercial airlines.