# US 2019/0168864 A1 · Aircraft electric taxi system design and operation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168864 A1 - Document ID: US20190168864A1 - Status: Published application - Kind: A1 - Application number: 16/207,118 - Filed: 2018-12-01 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Borealis Technical Limited - Applicants: Borealis Technical Limited - Inventors: Isaiah W. Cox; Jan Vana; Joseph J. Cox; Yonatan Rotenberg - Web page: https://patentgrep.com/patent/US20190168864A1 ## CPC - B64C 25/36: Arrangements or adaptations of wheels, tyres or axles in general - B64C 25/405: {Powered wheels, e.g. for taxing} - B64C 25/50: Steerable undercarriages; Shimmy-damping - Y02T 50/80: Energy efficient operational measures, e.g. ground operations or mission management - B64C: AEROPLANES; HELICOPTERS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A method for designing and operating an aircraft nose landing gear wheel-mounted electric taxi system moves aircraft with optimal torque during a broad range of ground travel conditions. Electric taxi system components may be sized to produce optimal ground travel torque to move aircraft during the majority of aircraft ground travel conditions and operated to produce a maximum or breakaway torque to move the aircraft with the electric taxi system when a higher level of torque is required. Turning the nose landing gear wheels to a selected angle or through a range of angles simultaneously as the electric taxi system is operated produces the breakaway torque required to get the aircraft moving. 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. ## Claims ### Claim 1 A method for operating aircraft nose landing gear wheel-mounted electric taxi systems designed to produce optimal torque levels required to move aircraft during ground travel conditions requiring different levels of torque for electric taxi system-powered aircraft ground travel, comprising: a. providing an aircraft equipped with an electric taxi system mounted completely within each one of a pair of nose landing gear wheels, and operating the electric taxi systems to move the aircraft during ground travel conditions requiring a plurality of different levels of torque comprising at least ground travel torque and breakaway torque; b. determining an optimal levels of ground travel torque and an optimal level of breakaway torque required to move the aircraft, wherein the optimal level of ground travel torque is less than the optimal level of breakaway torque; c. providing an electric drive motor for each electric taxi system sized to produce a level of torque corresponding to at least the optimal level of ground travel torque, aligning the nose landing gear wheels parallel to a longitudinal axis of the aircraft, and simultaneously driving the aircraft with the electric taxi systems during a majority of ground travel; d. turning the nose landing gear wheels to form an angle with the longitudinal axis of the aircraft that produces at least the optimal level of breakaway and simultaneously operating the electric taxi systems and moving the aircraft when the optimal level of breakaway torque is required to move the aircraft; and e. then turning the nose landing gear wheels to be aligned parallel to the longitudinal axis of the aircraft, and simultaneously continuing to drive the aircraft at the optimal ground travel torque during the majority of ground travel. ### Claim 2 (depends on 1) The method of claim 1, further comprising operating the electric taxi systems and producing the optimal level of breakaway torque only when required during ground travel to move the aircraft from a stationary condition and operating the electric taxi systems to drive the aircraft at the optimal ground travel torque at all other times during electric taxi system-powered ground travel. ### Claim 3 (depends on 1) The method of claim 1, further comprising providing a drive motor for each electric taxi system sized to produce at least the optimal ground travel torque for the aircraft when the nose landing gear wheels are aligned parallel to the longitudinal axis during simultaneous operation of the electric taxi system to move the aircraft during the majority of ground travel and to produce at least the optimal breakaway torque for the aircraft when the nose landing gear wheels are turned to form the angle with the longitudinal axis that causes the breakaway torque to be produced during simultaneous operation of the electric taxi system to get the aircraft moving. ### Claim 4 (depends on 3) The method of claim 3, further comprising providing the drive motor for each electric taxi system sized to produce an effective breakaway torque level that is about twice as great as the optimal ground travel torque level, turning the nose landing gear wheels to the angle with the longitudinal axis of the aircraft, simultaneously operating the electric taxi system, and moving the aircraft at the effective breakaway torque level. ### Claim 5 (depends on 1) The method of claim 1, further comprising turning the nose landing gear wheels to form a sharp angle with the longitudinal axis of the aircraft within the range of from about 1 degree to about 90 degrees. ### Claim 6 (depends on 1) The method of claim 1, further comprising providing an electric drive motor with a gear system for each electric taxi system, simultaneously aligning the nose landing gear wheels parallel to the aircraft longitudinal axis and driving the aircraft with the electric motor and gear system and producing at least the ground travel torque, and producing a breakaway torque that is about twice as large as the ground travel torque by simultaneously turning the nose landing gears to form the angle with the longitudinal axis of the aircraft and driving the aircraft with the electric motor and gear system. ### Claim 7 (depends on 2) The method of claim 2, further comprising when said stationary condition comprises pushback, operating the electric taxi systems and simultaneously turning the nose landing gear wheels to the angle with the longitudinal axis that produces the optimal breakaway torque to move the aircraft during pushback. ### Claim 8 (depends on 1) The method of claim 1, further comprising during a stationary ground travel condition requiring a level of breakaway torque to move the aircraft, operating the electric taxi systems while simultaneously turning the nose landing gear wheels from a position parallel to the longitudinal axis through a plurality of angles with the longitudinal axis to an angle that produces the level of breakaway torque at which the aircraft can move, and then driving the moving aircraft with the landing gear wheels turned parallel to the longitudinal axis. ### Claim 9 (depends on 8) The method of claim 8, further comprising instructing pilots driving the aircraft equipped with the electric taxi systems to move the aircraft during the stationary ground condition when the level of breakaway torque is required by operating the electric taxi systems, turning the nose landing gear wheels from the parallel position through the plurality of angles to the angle that produces the level of breakaway torque, simultaneously operating the electric taxi system with the nose landing gear wheels turned to the angle that produces the level of breakaway torque and moving the aircraft first with the breakaway torque, then turning the nose landing gear wheels to the parallel position, and moving the aircraft with the optimal ground travel torque. ### Claim 10 (depends on 1) The method of claim 1, further comprising identifying a specific nose landing gear wheel angle from the aircraft longitudinal axis required for the electric taxi system to produce at least the optimal breakaway torque to move a specific aircraft when the electric taxi system is operated simultaneously with the nose landing gear wheels turned at the identified angle, and testing the effective torque output of the drive motor for each electric taxi system. ### Claim 11 An aircraft nose landing gear wheel-mounted electric taxi system with a drive motor engineered to produce optimal torque during most electric taxi system-powered aircraft ground travel and to produce breakaway torque during ground travel situations requiring breakaway torque, comprising: a. an electric drive motor comprising a rotor element and a stator element sized to produce an optimal level of torque to power a nose landing gear wheel-mounted electric taxi system to move an aircraft during a majority of aircraft ground travel conditions, wherein said optimal level of torque is less than a level of breakaway torque required to move the aircraft from a stopped condition; b. said electric drive motor and components of said electric taxi system comprising at least a gear system and a clutch assembly are mounted completely within each one of a pair of nose landing gear wheels, wherein said electric drive motor is mounted adjacent to an axle in each said nose landing gear wheel, said gear system is mounted outwardly of said motor, and said clutch assembly is mounted to transfer torque through said gear system from said electric drive motor to said nose landing gear wheel, and said components are sized to produce said optimal level of torque; and c. nose landing gear wheel steering operable to move said pair of nose landing gear wheels from a nose wheel steering position parallel to a longitudinal axis of said aircraft to a plurality of sharp nose wheel steering angles within the range of from about 1 degree to about 90 degrees from said longitudinal axis, wherein at least one of said plurality of sharp nose wheel steering angles increases said optimal level of torque produced by said electric drive motor and said electric taxi system to said level of breakaway torque.