TURBOMACHINE DUAL SPOOL TRANSMISSION SYSTEMS

A turbomachine dual spool transmission system can include a transmission assembly (600) configured to connect to a combination output (107) of a dual spool differential (100) at a transmission input (603) to be driven by the combination output to turn a transmission output (605). The transmission assembly can be configured to provide a first output gear ratio in a first state and a second output gear ratio in a second state. The system can include the dual spool differential (100). The dual spool differential can include a gear assembly (101) configured to combine a low pressure spool input and a high pressure spool input into a combination output to provide an output speed range smaller than a low pressure speed range alone.