Hiller ROE Rotorcycle
The Hiller ROE Rotorcycle was a single seat ultralight helicopter designed in 1953 for a military requirement. A total of 12 were produced for the United States Marine Corps. And in 1954, the Hiller Helicopters was selected by the US Navy's Bureau of Aeronautics to build this design of a one-man, foldable, self-rescue and observation helicopter. It featured a two blade rotor system. Its original empty weight was . Development. The helicopter folded up and could be carried on a sled-like carrier by two people or could be air-dropped to pilots trapped behind  enemy lines. The Marines did not accept the YROE due to its low performance, vulnerability to small-arms fire and the lack of visual references on the structure. This problem could cause the pilot to experience spatial disorientation at all but very low altitudes. The YROE or ROE never saw military service. In 1954, the United States Navy′s Bureau of Aeronautics selected Hiller to build its proposed design of a one-man helicopter. The XROE Rotocycle completed flight testing in mid-1957. It was demonstrated at the Pentagon in Arlington, Virginia, for military and other government officials in early April 1958 . Production was by Saunders-Roe, which made five for the United States Marine Corps and five for Helicop-Air of Paris. A Porsche engine of 62 hp (46 Kw) developed for the YROE completed trials by 1961.