Boeing engine started in 1943 and Boeing's gas turbines were designated models 502 (T50), 520 (T60), 540, 551 and 553. Boeing built 2,461 engines before production ceased in April 1968. Many applications of the Boeing gas turbine engines were considered to be firsts, including the first turbine-powered helicopter and boat. Vertol Aircraft Corporation was acquired by Boeing in 1960, and was reorganized as Boeing's Vertol division. The twin-rotor CH-47 Chinook, produced by Vertol, took its first flight in 1961. This heavy-lift helicopter remains a work-horse vehicle to the present day. In 1964, Vertol also began production of the CH-46 Sea Knight.
Boeing CH-47 Chinook In February 2010, the USAF announced plans to replace aging HH-60G helicopters, and deferred secondary combat search and rescue requirements calling for a larger helicopter. The Royal Air Force version of the CH-47C is designated Chinook HC1; its versions of the CH-47D are designated Chinook HC2 and HC2A. The export version of the CH-47C Chinook for the Italian Army was designated "CH-47C Plus". The HH-47D is a search and rescue version for the Republic of Korea Air Force. The CH-47DG is an upgraded version of the CH-47C for Greece. While the CH-47SD (also known as the "Super D") is a