Wear minimising undercarriage wheel spin mechanism - has brake cooling air or motor to match touchdown velocity and tyre speed

摘要

The friction forces on the tyres of aircraft undercarriage wheels are reduced by setting the wheels in rotation immediately before touchdown. The tangential velocity VRA of the tyre is made equal to the forward speed VAS of the aircraft at the instant of touch-down. The brake cooling air is used to rotate the wheels at the required speed. Alternatively, for short range aircraft the rotation imparted to the wheels during take-off is maintained by a motor. The force required to rotate the wheels can be reduced by deflating the tyres after take-off and re-inflating before touch-down, which reduces the moment of inertia of the wheels during flight and build-up of rotation.