There is provided a rotor bow mitigation system and method for an aircraft engine. At least one value of at least one engine parameter prior to a shutdown of the engine is obtained, the at least one engine parameter comprising a first temperature internal to the engine. A second temperature external to the engine is measured and a motoring duration and a motoring interval for the engine are determined based on at least the first temperature and on the second temperature. Upon detecting a start indication for the engine, the engine is motored for the motoring duration and at the motoring interval.

A tool assembly for safely rotating a heavy turbine generator rotor for alignment and maintenance purposes. The tool assembly includes a plurality of segments mounted to an outer face of a coupling affixed to an end of a shaft of the rotor, where the segments include a plurality of segment teeth extending beyond an outer edge of the coupling. A tool is positioned adjacent to the coupling and includes a support assembly, a hydraulic ram and a ratcheting pawl. The ratcheting pawl includes a drive pin positioned to engage the teeth of the segments, where extension of a piston rod from the hydraulic ram causes the coupling and shaft to rotate.

A method of mitigating thermal rotor bow in a rotor assembly of a turbine engine may include performing a plurality of motoring cycles. The plurality of motoring cycles may include receiving feedback on a temperature within a turbine engine in a post-shutdown state, actuating a starter motor when the temperature is greater than a predetermined threshold, operating the starter motor for a motoring time to exhaust some residual heat from the turbine engine, and shutting down the starter motor after the motoring time.

A method of mitigating thermal rotor bow in a rotor assembly of a turbine engine may include performing a plurality of motoring cycles. The plurality of motoring cycles may include receiving feedback on a temperature within a turbine engine in a post-shutdown state, actuating a starter motor when the temperature is greater than a predetermined threshold, operating the starter motor for a motoring time to exhaust some residual heat from the turbine engine, and shutting down the starter motor after the motoring time.

A gas turbine engine includes a turbine section that includes a fan drive turbine. A geared architecture includes a sun gear in driving engagement with the fan drive turbine. A plurality of planet gears surrounds the sun gear. A ring gear surrounds the plurality of planet gears. A deflection limiter mechanically attaches the ring gear to an engine static structure. The deflection limiter includes a first support fixed to the ring gear that has a first interlocking feature and a second support fixed to the engine static structure that has a second interlocking feature. The first and second interlocking features define at least one of a radial clearance of between 0.005 inches (0.127 mm) and 0.080 inches (2.032 mm) or a circumferential clearance of between 0.005 inches (0.127 mm) and 0.250 inches (2.032 mm). A fan section includes a plurality of fan blades in driving engagement with the geared architecture through a fan drive shaft.

A gas turbine engine includes a turbine section that includes a fan drive turbine. A geared architecture includes a sun gear in driving engagement with the fan drive turbine. A plurality of planet gears surrounds the sun gear. A ring gear surrounds the plurality of planet gears. A deflection limiter mechanically attaches the ring gear to an engine static structure. The deflection limiter includes a first support fixed to the ring gear that has a first interlocking feature and a second support fixed to the engine static structure that has a second interlocking feature. The first and second interlocking features define at least one of a radial clearance of between 0.005 inches (0.127 mm) and 0.080 inches (2.032 mm) or a circumferential clearance of between 0.005 inches (0.127 mm) and 0.250 inches (2.032 mm). A fan section includes a plurality of fan blades in driving engagement with the geared architecture through a fan drive shaft.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.

An actuator system including a harmonic drive operable to drive a variable vane system of a gas turbine engine.