The Model 360 was designated by the company as the UH-12 ("UH" for United Helicopters), which was first flown in 1948. The OH-23 trainer was jokingly nicknamed the "Hiller Killer" by United States Army Aviation student pilots who had to fly it. \u00a0 \nIn 1947, United Helicopters (later renamed Hiller Aircraft) developed the prototype Model 360X helicopter. A year later, on 14 October 1948 the Civil Aeronautics Authority (CAA) issued a production certificate for the Model 360. United Helicopters began producing the Model 360 as the UH-12. In 1949, the UH-12 became the first helicopter to make a transcontinental flight from California to New York. When Hiller upgraded the engine and the rotor blades, the company designated the new model as the UH-12A. It was the UH-12A that would be adopted by both the French and United States militaries, as well as being used by civil commercial operators in several countries. \u00a0 \nSpecifications below are for the H23C military model. \u00a0 \nFor operational history and details of the 13 military and 11 civilian variants, click here.