Sikorsky H-19 Chickasaw

The Sikorsky H-19 Chickasaw (company model number S-55) was a multi-purpose helicopter used by the United States Army and United States Air Force. It was also license-built by Westland Helicopters as the Westland Whirlwind in the United Kingdom. The United States Navy and United States Coast Guard models were designated HO4S, while those of the U.S. Marine Corps were designated HRS. In 1962, the U.S. Navy, U.S. Coast Guard and U.S. Marine Corps versions were all redesignated as H-19s like their U.S. Army and U.S. Air Force counterparts.