It was based on the third Bell 30 prototype, which was the company's first helicopter designed by Arthur M. Young. The 47 became the first helicopter certified for civilian use on 8 March 1946. Early models varied in appearance, with open cockpits or sheet metal cabins, fabric covered or open structures, some with four-wheel landing gear. Later model D and Korean War H-13D and E types settled on a more utilitarian style. The most common model, the 47G introduced in 1953, can be recognized by the full "soap bubble" canopy, exposed welded-tube tail boom, saddle fuel tanks and skid landing gear. The aircraft used in the award-winning M*A*S*H television series was a Bell H-13 Sioux, the U.S. Army equivalent of the Bell 47D-1. Being the first certified helicopter, the utilitarian Bell 47 chalked up a wide variety of firsts. For a summary of the many variants, click here, and for specifications and differences of the various models, click here. Specifications listed below are for the Bell 47G-3B model.