Chinook helicopter

CH-47 Chinook
A U.S. Army CH-47 departs a landing zone after unloading soldiers
Role	Transport helicopter
National origin	United States
Manufacturer	Boeing Rotorcraft Systems
First flight	21 September 1961
Introduction	1962
Status	In service
Primary users	United States Army Japan Ground Self-Defense Force Royal Netherlands Air Force See CH-47 operators for others
Produced	1962–present
Number built	Over 1,200 as of 2012
Unit cost	US$38.55 million (CH-47F, FY13)
Developed from	Vertol Model 107
Variants	Boeing Chinook (UK variants)

The Boeing CH-47 Chinook is an American twin-engine, tandem rotor heavy-lift helicopter. Its primary roles are troop movement, artillery placement and battlefield resupply. It has a wide loading ramp at the rear of the fuselage and three external ventral cargo hooks. With a top speed of 170 knots (196 mph, 315 km/h) the helicopter was faster than contemporary 1960s utility helicopters and attack helicopters, and is still one of the fastest helicopters in the US inventory. The CH-47 is among the heaviest lifting Western helicopters. Its name is from the Native American Chinook people.

The Chinook was designed and initially produced by Boeing Vertol in the early 1960s; it is now produced by Boeing Rotorcraft Systems. It is one of the few aircraft of that era – along with the fixed-wing Lockheed C-130 Hercules cargo aircraft – that remain in production and frontline service, with over 1,200 built to date. The helicopter has been sold to 16 nations with the U.S. Army and the Royal Air Force (see Boeing Chinook (UK variants)) being its largest users.

In late 1956, the United States Department of the Army announced plans to replace the Sikorsky CH-37 Mojave, which was powered by piston engines, with a new, gas turbine-powered helicopter. Turbine engines were also a key design feature of the smaller UH-1 "Huey" utility helicopter. Following a design competition, in September 1958, a joint Army–Air Force source selection board recommended that the Army procure the Vertol medium transport helicopter. However, funding for full-scale development was not then available, and the Army vacillated on its design requirements. Some in Army Aviation thought that the new helicopter should be a light tactical transport aimed at taking over the missions of the old piston-engined Piasecki H-21 and Sikorsky H-34 helicopters, and be consequently capable of carrying about fifteen troops (one squad). Another faction in Army Aviation thought that the new helicopter should be much larger to be able to airlift a large artillery piece, and have enough internal space to carry the new MGM-31 "Pershing" Missile System.