TECHNICAL FIELD

The present invention relates generally to electric taxi systems for moving aircraft independently without operating engines during ground operations and specifically to a method for moving aircraft with electric taxi systems that ensures optimal torque production by the electric taxi systems to move the aircraft during a broad range of ground travel conditions.

BACKGROUND OF THE INVENTION

Electric taxi systems that drive aircraft during ground travel independently without operation of the aircraft's main engines and external tow vehicles have been proposed by Applicant and others. Conventionally, these systems are expected to provide the torque required to drive aircraft nose or main landing gear wheels and to move an aircraft during ground operations. However, the design and operation of conventional electric taxi systems does not necessarily ensure that motors and other components of these systems produce the torque required to move an aircraft equipped with an electric taxi system during a broad range of operational or ground travel conditions. Such operational and ground travel conditions may include both situations when it is difficult to move the aircraft and situations when it is not difficult to move the aircraft or to keep the aircraft moving. Examples of ground travel conditions when it may be difficult to move an aircraft include, inter alia, push back of the aircraft from a gate or parking location and weather or other situations that cause an aircraft to be slowed or stalled during ground travel. Breakaway torque may be needed to get the aircraft moving in these situations.

Motors for electric taxi systems may be conventionally designed to provide a larger amount of torque than may actually be required during operation of the electric taxi system to drive the aircraft in most ground travel conditions. This is done to ensure that the electric taxi systems are capable of meeting maximum torque requirements during those ground travel conditions when maximum or breakaway torque is required to move the aircraft. As a result, the design of conventional electric taxi systems focuses on providing motors that will meet the highest torque requirements likely to be needed to move an aircraft during the most difficult aircraft ground travel conditions. Such motors may produce more torque than is actually needed to drive an aircraft during most ground travel and may present design and weight challenges for the electric taxi systems and the aircraft landing gear wheels and landing gears where they are installed. The operation of conventional electric taxi systems to optimize torque production by the electric taxi system and ensure that breakaway torque may be effectively produced in ground travel situations requiring this level of torque to get the aircraft moving has not been addressed.

There is a need, therefore, for an alternative approach to designing and operating aircraft electric taxi systems so that these systems have the capability for producing optimal torque to drive aircraft during most ground travel conditions, as well as the capability for producing a higher level of torque when maximum or breakaway torque is required to move the aircraft during challenging ground travel conditions. There is also a need for an electric taxi system with the foregoing capability that does not pose design and weight challenges or require motors and components that are over-engineered or oversized for operation of the electric taxi system during the majority of ground travel conditions.

SUMMARY OF THE INVENTION

Accordingly, it is a primary object of the present invention to provide an alternative approach to designing and operating aircraft electric taxi systems with motors and other components so that these systems have the capability for producing optimal torque to drive aircraft during a broad range of ground travel conditions, as well as the capability for producing a higher level of torque when maximum or breakaway torque is required to move the aircraft during challenging ground travel conditions.

It is another object of the present invention to provide an electric taxi system with the foregoing capability that does not pose design and weight challenges or require motors and components that are over-engineered or oversized for operation of the electric taxi system during the majority of ground travel conditions.

It is an additional object of the present invention to provide a method for operating an aircraft nose landing gear wheel-mounted electric taxi system to ensure that breakaway torque is produced by the electric taxi system during operation to move aircraft in a broad range of ground travel conditions, including those that require breakaway torque to move the aircraft.

It is a further object of the present invention to provide a method for operating an aircraft nose landing gear wheel-mounted electric taxi system with a motor that may be engineered to achieve optimal torque during operation of the electric taxi system to move the aircraft during ground travel when breakaway torque is not required and for operating the electric taxi system to produce breakaway torque when breakaway torque is required to move the aircraft.

It is yet another object of the present invention to provide a method for operating an aircraft nose landing gear wheel-mounted electric taxi system that incorporates angles at which the nose landing gear wheels may be turned away from a position parallel to a longitudinal axis of the aircraft into calculations of required maximum torque production by motors and other components of the electric taxi system so that the electric taxi system may be operated to produce an optimal level of torque to move the aircraft during any ground travel conditions.

In accordance with the aforesaid objects, an aircraft nose landing gear wheel-mounted electric taxi system and a method that facilitates the design and operation of an aircraft nose landing gear wheel-mounted electric taxi system to move an aircraft with optimal torque during a broad range of ground travel conditions are provided. Electric taxi systems may be designed with motors and components sized to produce optimal torque requirements to move aircraft during the majority of aircraft ground travel conditions. The nose landing gear wheel-mounted electric taxi system may be operated simultaneously in conjunction with nose landing gear steering as the aircraft is driven to meet maximum torque requirements and move the aircraft during ground travel conditions when higher maximum and/or breakaway torque is needed. Correlation of nose landing gear wheel angle when the aircraft's nose landing gear wheels are turned at angles from a longitudinal axis of the aircraft with the level of torque produced by an electric taxi system motor and components may be effectively used to design the electric taxi system motors and components and to operate the electric taxi system to move the aircraft. Turning the nose landing gear wheels through a range of angles may enable the electric taxi system to produce a level of torque required to move an aircraft during breakaway conditions. At other times when lower torque is needed, the aircraft may be driven with the nose landing gear wheels parallel to the longitudinal axis to produce optimal torque for electric taxi system-powered aircraft ground travel. Aircraft equipped with the electric taxi systems described herein may be driven with the electric taxi systems at optimal torque levels during a wide range of ground travel conditions requiring different levels of torque to move the aircraft.

Other objects and advantages will be apparent from the following description, drawings, and claims.

