Abstract: A turbofan engine includes an outer bypass duct and a gas turbine engine having an outer casing. The gas turbine engine is disposed in the outer bypass duct such that a bypass airflow passage is formed between the outer casing of the gas turbine engine and the outer bypass duct. The turbofan engine includes a turbine rear frame link assembly including a set of links coupled between the outer bypass duct and the outer casing to support the gas turbine engine relative to the outer bypass duct. The links are arranged around the gas turbine engine on a plane that is perpendicular to a centerline axis of the turbofan engine. None of the links extends through the bypass airflow passage at a position that intersects a radius extending in a vertically downward direction from the centerline axis.

Abstract: In one aspect, the present disclosure is directed to a turbine rear frame link assembly for a turbofan engine. The turbofan engine includes an outer bypass duct and a gas turbine engine having an outer casing. The gas turbine engine is disposed in the outer bypass duct such that a bypass airflow passage is formed between the outer casing of the gas turbine engine and the outer bypass duct. The turbine rear frame link assembly includes a set of links coupled between the outer bypass duct and the outer casing to support the gas turbine engine relative to the outer bypass duct. The links are arranged around the gas turbine engine on a plane that is perpendicular to a centerline axis of the turbofan engine. None of the links extends through the bypass airflow passage at a position that intersects a radius extending in a vertically downward direction from the centerline axis.

Abstract: Methods and systems for mitigating distortion of a shaft of a gas turbine engine are provided. One method comprises at least one step of applying intermittent rotary power to a shaft of a gas turbine engine. The step of applying intermittent power to the shaft is performed during a period where conditions of temperature differential in the engine exist capable of distorting the shaft. The methods and systems shorten the time needed to start a gas turbine engine in such a way that bowing of a shaft is not a significant problem.

Abstract: Methods and systems for mitigating distortion of a shaft of a gas turbine engine are provided. One method comprises at least one step of applying intermittent rotary power to a shaft of a gas turbine engine. The step of applying intermittent power to the shaft is performed during a period where conditions of temperature differential in the engine exist capable of distorting the shaft. The methods and systems shorten the time needed to start a gas turbine engine in such a way that bowing of a shaft is not a significant problem.

Abstract: An overhead door apparatus utilizing a torsion spring counterbalancing mechanism. The counterbalancing mechanism includes a worm drive ring-shaped gear winding mechanism for setting the appropriate torque or number of winds in the spring. A counting mechanism is provided to indicate to the installer the number of winds being given to the spring. The ring-shaped gear is a spur gear which is formed integrally with the fitting or cone which attaches by way of a threaded connection with one end of the spring. Means are also provided for accommodating spring growth and contraction during winding and unwinding using the winding mechanism and during normal raising and lowering of the door. A spring clip gear retainer is disclosed for preventing rotation or creep of the worm drive gear and spur gear during normal raising and lowering of the door.