Built for the USAF as a standard Grumman SA-16A Albatross, with the c/n G-153 and the US military serial 51-0472. Later allocated US Navy Bureau No 149822 and sold to Japan (as a UF-1?). Heavily converted by Shin Meiwa to carry out development testing for the PS-1 patrol flying boat and redesignated as the UF-XS. It now had four main engines as well as two internal turboshaft engines for a blown high-pressure air system. It also had a redesigned hull. In this configuration it carried out flight testing from 1962 to 1964 and was finally retired at Shimofusa in 1967. Between 1975 and 1993 it was on outside display at Tokai University in Shimizu City, then being restored by Shin Meiwa before moving to Gifu for permanent display inside. Gifu-Kakamigahara Air and Space Museum Kakamigahara City, Gifu Prefecture, Japan 15th March 2019

The following details on the UF-XS are from the excellent j-hangarspace.jp website:-

“To conduct tests using an experimental aircraft in the development of what was to become the indigenously produced, four-engined PS-1 anti-submarine patrol aircraft, the then Japan Defense Agency received the offer from the United States of a Grumman UF-1 Albatross amphibian (BuNo. 149822) and produced the UF-XS experimental amphibian in 1960. Although the Japanese had accumulated advanced flying boat technologies both before and during the Pacific War, the aim was to correct a major shortcoming by improving takeoff and landing performance in rough sea conditions. Fittingly, the UF-XS design team was headed by Shizuo Kikuhara (1906–91), who had been the chief designer of the wartime Type 2 Flying Boat.

To adapt the UF-1 for its role as an experimental flying boat, the main areas of modification thus involved the following: •A newly designed boat hull, based on a unique concept that included wave suppression devices, to enable the aircraft to take off from and land on the ocean in wave heights of the order of three meters. •The provision of a system to blow high-pressure air from two turboshaft engines added within the hull over the main wing flaps, ailerons, elevators and rudder to improve short takeoff and landing (STOL) performance as well as handling at low speeds. •The provision of automatic stabilization equipment to ensure stability and facilitate control at low speeds. •Changing the aircraft from a twin- to a four-engined configuration.

Taking to the skies for the first time at noon on December 25, 1962 (link), the UF-XS carried the tailcode オ(‘O’)-9911, the ‘O’ being the tail code of the JMSDF’s Omura Fleet Air Squadron. The aircraft continued to be utilized in a range of flight tests until 1964. The results obtained and conclusions derived from those tests were incorporated into the design of the PS-1 flying boat, the first aircraft of its kind to be built in Japan after the war, and have been handed down to the current US-2 amphibian.

At the conclusion of its test program, the UF-XS was moved to JMSDF Shimofusa air base in Chiba Prefecture, withdrawn from use in June 1967 and placed in storage there. In 1975, the aircraft was loaned to the Tokai University Social Education Center in Shimizu City, Shizuoka Prefecture, where it was kept out in the open (as shown in this January 1980 photo [link]) until acquired for display at the then Kakamigahara Aerospace Museum (now Gifu-Kakamigahara Air and Space Museum) in 1993. At the time the aircraft was brought to the museum, it was missing the two turboshaft engines that had been added to provide the high-pressure air and parts such as ducts. Due to the aircraft having been displayed outside, there were also places where metal corrosion had made inroads. Furthermore, as modifications had been carried out to install an opening and a steel passageway that had enabled visitors to enter the aircraft’s interior, the aircraft had ended up being significantly different to what it had looked like at the time when it was used as a flying testbed. For that reason, repair and restoration work based on the manufacturing plans of the time was carried out by ShinMaywa Industries, Ltd., the company (then known as Shin Meiwa Industry Co., Ltd.) that had originally modified the aircraft. When reproducing parts that had been lost, measures were taken to distinguish between original and other parts, for example by applying identification stamps to tell them apart.

As only one aircraft was produced for the purpose of PS-1 development, the UF-XS is a unique aircraft that represents the starting point of Japan’s postwar flying boat development that has continued to the US-2 amphibian. Having carried out the appropriate repair and restoration work to return the aircraft to the original condition of its flying testbed days, the UF-XS now has value as a cultural asset.