Sikorsky-Boeing’s SB-1 Defiant Helicopter

This can get so unbalanced that it threatens to tip the helicopter over altogether if you don’t stay beneath a defined maximum airspeed. Sikorsky’s technology puts two main rotors on top of each other, rotating in opposite directions, which balances out the lift profile on either side and allows the craft to fly much faster – up to twice the airspeed of a regular helicopter – while maintaining excellent handling and agility.