First to perform a complete ''loop'' (a first in Helicopter flight) and the first Helicopter to have an Auto-pilot Device installed, The US Piasecki HUP ''Retriever' was a Tandem Rotor Military Helicopter, first introduced into The US inventory in 1949. (340) Models were deployed with The US Navy and Army (with several allied Countries deploying them as well). However, with technology advancing, The US retired The ''Retriever'' in 1958 (although France continued with The Model until 1965). A Utility and Cargo Transport Aircraft, The ''Retriever'' was popular with The US Navy for Rescue Missions with The Army using them for a variety of field operations (heavy equipment movements). Many of The ''Retrievers'' saw overseas duties. Piloted by (2) and capable of transporting (4) additional, The ''Retriever'' was 57-feet in length with a Twin Rotor Radius of 35-feet each. Power came from a Single Continental Radial Engine capable of 550-HP. They achieved 105-mph with an operational ceiling of 10,000-feet. The Model could support up to 10,000-lbs of cargo weight. Many ''Retrievers'' can be found on-display at Museums throughout The World.