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 helicopter in the US inventory.