Counter rotating gear case for a drive unit

A method of installing a counter rotating gear case to a host drive unit, the method comprising:

• a. providing an assembled counter rotating gear case, comprising:
• i. a forward gear assembly;
• ii. an aft gear assembly;
• iii. a pinion gear assembly;
• iv. a spool adapter having a first portion and a second portion, wherein the forward gear assembly, the aft gear assembly, and pinion gear assembly are supported on the second portion of the spool adapter;
• v. wherein, the pinion gear assembly is disposed between the forward gear assembly and the aft gear assembly, and wherein the pinion gear assembly is operatively engaged with both the forward gear assembly and the aft gear assembly, such that rotation of one of the forward gear assembly or the aft gear assembly in one direction causes rotation of the other of the forward gear assembly or the aft gear assembly in a second direction opposite that of the first direction;
• and
• vi. wherein the forward gear assembly, comprises first set of drive gear thrust bearings, a forward drive gear, and a forward drive gear hub, wherein the first set of drive gear thrust bearings are positioned on a first side of the forward drive gear hub and the forward drive gear is fixedly attached to second side of the forward drive gear hub;
• and wherein the aft gear assembly, comprises a third set of drive gear thrust bearings, an aft drive gear, and an aft drive gear hub, wherein the third set of drive gear thrust bearings are positioned on a first side of the aft drive gear and the aft drive gear hub is fixedly attached to a second side of the aft drive gear;
• b. installing the assembled counter rotating gear case to a drive shaft of the host drive unit;
• and
• c. securing the installed assembled counter rotating gear case to the host drive unit.

A method of installing a counter rotating gear case to a host drive unit, the method comprising:

• a. providing an assembled counter rotating gear case attached to a host drive unit, the assembled counter rotating gear case, comprising:
• i. a forward gear assembly;
• ii. an aft gear assembly;
• iii. a pinion gear assembly;
• iv. a spool adapter having a first portion and a second portion, wherein the forward gear assembly, the aft gear assembly, and pinion gear assembly are supported on the second portion of the spool adapter;
• v. wherein, the pinion gear assembly is disposed between the forward gear assembly and the aft gear assembly, and wherein the pinion gear assembly is operatively engaged with both the forward gear assembly and the aft gear assembly, such that rotation of one of the forward gear assembly or the aft gear assembly in one direction causes rotation of the other of the forward gear assembly or the aft gear assembly in a second direction opposite that of the first direction;
• and
• vi. wherein the forward gear assembly, comprises first set of drive gear thrust bearings, a forward drive gear, and a forward drive gear hub, wherein the first set of drive gear thrust bearings are positioned on a first side of the forward drive gear hub and the forward drive gear is fixedly attached to second side of the forward drive gear hub;
• and wherein the aft gear assembly, comprises a third set of drive gear thrust bearings, an aft drive gear), and an aft drive gear hub, wherein the third set of drive gear thrust bearings are positioned on a first side of the aft drive gear and the aft drive gear hub is fixedly attached to a second side of the aft drive gear;
• b. unsecuring the installed assembled counter rotating gear case from the host drive unit;
• and
• c. removing the assembled counter rotating gear case from the host drive unit.