A helicopter (informally known as a "chopper") blade 120 sr is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally. These attributes allow helicopters to be used in congested or isolated blade mcx2 areas where fixed-wing aircraft would blade 450 usually not be able to take off or land. The capability to efficiently hover for extended periods of time allows a helicopter to accomplish tasks that fixed-wing aircraft syma helicopter and other forms of vertical takeoff and landing aircraft cannot perform.