Japan has one godzilla of a seaplane.
- By Tim Wright
- Air & Space magazine, January 2003
(Page 2 of 4)
The U.S. Navy was impressed enough with the Emily to have transported one after the war for testing at its Patuxent River facility in Maryland. Surface tests were conducted in the Chesapeake Bay, but engine failures brought the testing to a premature close, and the aircraft was exiled to the Norfolk Naval Air Station in Virginia, where it was wrapped in plastic and relegated to the station’s lost and forlorn. By then, it was the last known Emily in the world. In 1980 the Navy, at the request of the Japanese government, returned the orphaned Emily to Japan. It recently underwent a major restoration and is on display at the Museum of Maritime Science on Tokyo’s waterfront.
During the war the Kawanishi factory in Kobe, a coastal city about 20 miles southwest of Kyoto, built 167 Emily flying boats before the U.S. Army Air Forces added the factory to the strike list of B-29s raiding Japan. At one time, the factory was the largest enclosed structure in Asia. By war’s end, it was a twisted ruin. Today, as ShinMaywa workers climb over a US-1A brought in for overhaul, sunlight streams through bullet holes left in the factory walls.
For Kawanishi, the postwar years were difficult ones. While Japan was under U.S. occupation, the company was forbidden to build aircraft. Its workers transferred their skills in aluminum and metal working to making pots and pans, and later the company expanded into building and maintaining trucks. Before long, the massive hangars where the Emily had been assembled were rebuilt and filled with hundreds of trucks in various stages of construction or repair. Kawanishi changed its name to ShinMaywa to escape some of the notoriety that stemmed from its World War II operations.
At the outbreak of the Korean War, ShinMaywa was invited back into the aircraft business as a maintenance depot for U.S. military transports. The company had retained its expertise in flying boat construction and seized the opportunity to continue working with the technologies it had developed during World War II. Among its areas of interest was short-takeoff-and-landing (STOL) technology for marine aircraft.
With the help of the U.S. Navy, ShinMaywa acquired a Grumman UF-1 Albatross, an amphibious search-and-rescue aircraft with a 2,850-mile range that served not only the Navy but the U.S. Air Force and Coast Guard as well. The Albatross could accommodate a crew of six and was powered by two 1,425-horsepower Wright R-1820 engines. To create a STOL aircraft, ShinMaywa added two 600-hp Pratt & Whitney R-1340 engines, stretched the nose, and refitted the aircraft with a high T-tail. The modified Albatross was named the UF-XS and became a research platform for investigating STOL technologies.
The limiting factor in open-ocean operations is the impact stress created by waves slamming against the hull during takeoff and landing; reducing takeoff and landing speeds reduces the stress on the aircraft. ShinMaywa experimented with an array of high-lift devices to enable the UF-XS to take off and land at slower speeds. The tailplane and outer sections of the wings had leading edge slats. Flaps on the inner sections of the wings’ trailing edges could be deflected as much as 80 degrees, and on the outer sections, as much as 60 degrees. Engineers augmented these movable surfaces with an experimental system for controlling the boundary layer.
The boundary layer is a thin layer of air molecules near the surface of an aircraft (or any object moving through the air) that, because of the air’s viscosity, moves at a different velocity from the air farther from the surface. In fact there are a number of “layers” in the boundary layer, all flowing at slightly different velocities.
As an aircraft approaches the low speeds associated with landing, the boundary layer flowing over the wing becomes increasingly turbulent and the wing loses lift. To retain smooth flow, and therefore lift, as long as possible at slower speeds, ShinMaywa devised a system to blow air over the flaps and the elevator to keep the airflow smooth, enabling the aircraft to maintain lift and control at low speed. The air was produced by a 1,250-hp General Electric T58 turboshaft engine mounted in the aircraft cabin.