Gas turbine engines have typically been employed as auxiliary power units (APUs) in aircraft to provide electrical power. In a conventional APU, the gas turbine engine has a rotatable drive shaft that is connected to a gear train housed in a gearbox for transferring force to and from the drive shaft. The gearbox can define interfaces for a number of accessories to be mounted on the gearbox. The accessories can be coupled to the gear train, and thus, to the drive shaft of the engine. These accessories can include a starter, a generator, an oil pump, and a fuel control component. Many conventional gearboxes also include an integral oil tank for supplying oil to the oil pump, accessories, gear train, and engine.
Aircraft manufacturers are continually seeking ways to reduce the weight, complexity, and costs of the APUs. The gearbox and oil tank can be a significant contributing factor to the cost and weight of the APU. Conventional gearboxes are relatively large, complex, and are integrally formed with the oil tank.
It is desirable to provide an APU having a gearbox and an oil tank with improved characteristics and performance, for example, a lighter and smaller gearbox. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.