Operated by the U.S. Army, the Chinook is one of the heaviest lifting helicopters in the world. Named for the Chinook tribe of Oregon and Washington state, the helicopter entered service in 1962, and it has remained relevant ever since.
The helicopter’s story begins in 1956, when the U.S. Department of Defense decided to replace the Sikorsky CH-37 Mojave, a cargo helicopter with post engines.
The Department wanted a fresh design, something that used the recently invented gas turbine-powered engines.
The contract was awarded to Vetrol, and work began on what would become a timeless component of U.S. military power.
Vietnam Was a Hard Testing Ground for the CH-47
Vetrol’s final design is distinct among U.S. Army helicopters in that the helicopter features two rotors. Each is powered by a Lycoming T55 turboshaft engine and is mounted to either side of the helicopter’s rear pylon.
With two rotors, rotating in opposite directions, the Chinook does not need the anti-torque vertical rotor found on most helicopters. Instead, the Chinook can apply every single watt of power toward generating lift and thrust.
Additionally, the twin-rotor configuration is more stable than a single-rotor configuration in situations where weight is added or subtracted mid-flight – a helpful feature for a helicopter designed to lug troops and cargo.
(CH-47 Chinook) The World’s Largest, Fastest and Most Advanced Helicopter US Army