The H-13D gave the Bell 47 its familiar look with the fishbowl canopy and was produced in the new Forth Worth plant which started manufacturing HSL helicopters on 2 January 1952. 51-2450 was one of the first H-13Ds off the line. A close contemporary, 51-2454, was already active with X Army Corps in Korea on 15 July 1952 when it was shot down. The photo was still issued by the Bell Aircraft Corporation, PO Box One in Buffalo, New York. Photo from: Bell