A series of variants based on the United States Army 's Boeing CH - 47 Chinook , the RAF Chinook fleet is the largest outside the United States .
The Boeing Chinook is a large , tandem rotor helicopter operated by the Royal Air Force ( RAF ) .
A series of variants based on the United States Army 's Boeing CH - 47 Chinook , the rotor helicopter   fleet is the largest outside the United States .
The Boeing Chinook is a large , tandem rotor helicopter operated by the Royal Air Force ( RAF ) .