An assembly for mitigating thermal bow in a rotor of an aircraft engine, the assembly comprising: a start-up device coupleable to the rotor and configured to accelerate the rotor; and a start-up module coupled to the start-up device; wherein: the start-up device and the start-up module are configured to coordinate operations to accelerate the rotor to at least a threshold speed within a predetermined amount of time prior to initiating fuel flow and ignition to the aircraft engine; the start-up module comprises a speed module that determines the threshold speed based on a relationship of time and a set of conditions for the rotor detected at start-up of the aircraft engine; and said assembly comprises a set of sensors coupled to the rotor, wherein: the start-up module further comprises an input module that receives, from the set of sensors, a set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine, and the speed module is configured to determine the threshold speed based on one or more sensor inputs of the set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine. a start-up device coupleable to the rotor and configured to accelerate the rotor; and a start-up module coupled to the start-up device; wherein: the start-up device and the start-up module are configured to coordinate operations to accelerate the rotor to at least a threshold speed within a predetermined amount of time prior to initiating fuel flow and ignition to the aircraft engine; the start-up module comprises a speed module that determines the threshold speed based on a relationship of time and a set of conditions for the rotor detected at start-up of the aircraft engine; and said assembly comprises a set of sensors coupled to the rotor, wherein: the start-up module further comprises an input module that receives, from the set of sensors, a set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine, and the speed module is configured to determine the threshold speed based on one or more sensor inputs of the set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine. the start-up device and the start-up module are configured to coordinate operations to accelerate the rotor to at least a threshold speed within a predetermined amount of time prior to initiating fuel flow and ignition to the aircraft engine; the start-up module comprises a speed module that determines the threshold speed based on a relationship of time and a set of conditions for the rotor detected at start-up of the aircraft engine; and said assembly comprises a set of sensors coupled to the rotor, wherein: the start-up module further comprises an input module that receives, from the set of sensors, a set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine, and the speed module is configured to determine the threshold speed based on one or more sensor inputs of the set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine. the start-up module further comprises an input module that receives, from the set of sensors, a set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine, and the speed module is configured to determine the threshold speed based on one or more sensor inputs of the set of sensor inputs corresponding to the set of conditions for the rotor detected at the start-up of the engine.