It was primarily used for aircraft firefighting and rescue in the close vicinity of air bases, but was later used as a short range overland search and rescue aircraft during the Vietnam War. Under the aircraft designation system used by the U.S. Navy pre-1962, Navy and U.S. Marine Corps versions were originally designated as the HTK, HOK or HUK, for their use as training, observation or utility aircraft, respectively. In 1947 Anton Flettner, a German aviation engineer, was brought to New York in the United States as part of Operation Paperclip. He was the developer of Germany's Flettner Fl 282 "Kolibri" (Hummingbird), a helicopter employing the "synchropter" principle of intermeshing rotors, a unique design principle that dispenses with the need for a tail rotor. Flettner settled in the US and became the chief designer of the Kaman company, where he designed new helicopters using the synchropter principle. The Huskie had an unusual intermeshing contra-rotating twin-rotor arrangement with control effected by servo-flaps. The first prototype flew in 1947 and was adopted by the US Navy with a piston engine. In 1954, in an experiment by Kaman and the US Navy, one HTK-1 was modified and flew with its piston engine replaced by two turbine engines, becoming the world's first twin-turbine helicopter. The Air Force later adopted a version with one turboshaft engine: HH-43B and F versions. This aircraft saw use in the Vietnam War with several detachments of the Pacific Air Rescue Center. During the war, the two-pilot HH-43 Huskie flew more rescue missions than all other aircraft combined, because of its unique hovering capability. The HH-43 was eventually replaced by newer aircraft in the early 1970s. For details of the 23 variants, click here.
