Sikorsky R-4 end of the boom near the tail rotor while others had it positioned at the midpoint of the boom. Additionally, some had short "stub" exhaust pipes from the engine while others had a much longer one which extended vertically and then aft above the main landing gear struts. Sikorsky R-4 The Sikorsky R-4 is a two-seat helicopter designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United
Igor I. Sikorsky Memorial Bridge also includes a system of concrete fenders that protects the bridge piers from ship collisions, a feature that was absent from the 1940 span. In 2006, the new bridge was formally dedicated as the Igor I. Sikorsky Memorial Bridge. Igor I. Sikorsky Memorial Bridge The Igor I. Sikorsky Memorial Bridge (also known as the Sikorsky Memorial Bridge, and the Housatonic River Bridge) carries the limited-access Connecticut Route 15 over the Housatonic River, between Stratford and Milford, Connecticut. The first bridge, known as the Sikorsky Bridge (not to be confused with the new Igor I. Sikorsky Memorial Bridge's name), on the