Abstract text

A rotor (38) for a gas turbine engine (10) has a low emissivity surface finish, or high emissivity surface finish (44), on at least a portion of its surface (42) to reduce temperature differentials between an upper portion and a lower portion of the rotor (38). This reduces bowing of the rotor (38) to allow the gas turbine engine (10) to be started without harmful vibrations of the rotor (38).