A two-seat trainer helicopter averages flight speeds between 90 and 105 mph. A five-seat turbine helicopter can reach average cruising speeds between 130 and 145 mph. The maximum speed in some helicopters is about 255 mph.
The average speed of a helicopter is dependent upon the type of motor installed in the aircraft and the amount of power available. The size of the helicopter also makes a difference. Helicopters are powered by two types of engines: piston and turbine. Piston engines run on gasoline and put out less power than turbine engines. Turbine engines run on "jet-A" fuel, are much more powerful and produce faster speeds.