Helicopter rotor of gravity fore-aft. However, it requires the expense of two large rotors rather than the more common one large main rotor and a much smaller tail rotor. The Boeing CH-47 Chinook is the most common tandem rotor helicopter. Coaxial rotors are a pair of rotors mounted one above the other on the same shaft and turning in opposite directions. The advantage of the coaxial rotor is that, in forward flight, the lift provided by the advancing halves of each rotor compensates for the retreating half of the other, eliminating one of the key effects of dissymmetry of lift: retreating blade
Boeing Chinook (UK variants) alongside Westland Sea King and Westland Wessex helicopters. Post-war, four Chinooks were operated by "ChinDet" (Chinook Detachment) which became No.1310 Flight in 1983. Subsequently, No. 78 Squadron was re-formed in 1986 from the merger of No. 1310 Flight and No.1564 Flight (Sea Kings) and operated two Chinooks as part of the Falklands Garrison. This was reduced to a single helicopter in the mid-1990s and the type was eventually withdrawn from the Falklands in 2006 in order to free up resources and craft for operations in Afghanistan. RAF Chinooks provided routine supply and support missions to the British military during Operation