Similar to the efforts to move toward electric vehicles, much research has focused on the idea of a more electric aircraft (MEA). The motivations for this research are similar to that for vehicles and include goals to reduce emissions and decrease fuel consumption. In traditional aircraft, multiple systems may use one type or a combination of types of energy, including electrical, hydraulic, mechanical, and pneumatic energy. However, all energy types have different drawbacks, including the sacrifice of total engine efficiency in the process of harvesting a particular energy, as with hydraulic and pneumatic systems. The goal for future aircraft is to replace most of the major systems currently utilizing nonelectric power, such as environmental controls and engine start, with new electrical systems to improve a variety of aircraft characteristics, such as efficiency, emissions, reliability, and maintenance costs. This paper provides an in-depth look into how the systems have—or will be—changed. Future aircraft capabilities such as electric taxi and gas–electric propulsion for aircraft are also included for discussion. Most recent commercial transport aircrafts are described as the current state-of-the-art electric aircraft system. Future goals, including those of NASA, are presented for future advances in MEA.

More Electric Aircraft: Review, Challenges, and Opportunities for Commercial Transport Aircraft

Bleed air systems for use with aircrafts and related methods are disclosed. An example apparatus includes a turbo-compressor including a compressor having a compressor inlet fluidly coupled to a low-pressure compressor of the aircraft engine and a compressor outlet fluidly coupled to a first system of an aircraft. The turbo-compressor also includes a turbine inlet fluidly coupled to a high-pressure compressor of the aircraft engine and a turbine outlet fluidly coupled to a second system of the aircraft.

Bleed air systems for use with aircrafts and related methods

A turbofan gas turbine propulsion engine includes a multi-speed transmission between the high pressure and low pressure turbines and associated high pressure and low pressure starter-generators. The multi-speed transmission reduces the operating speed range from the low pressure turbine to its associated starter-generator, and is configurable to allow the starter-generator associated with the low pressure turbine to supply starting torque to the engine.

More electric aircraft starter-generator multi-speed transmission system

A power take-off system for a gas turbine engine includes a starter coupled to a second spool, and a clutch assembly coupled between the starter and a first spool, the clutch assembly configured to couple the first spool to the starter when starting the gas turbine engine assembly. A method of assembling a gas turbine engine assembly that includes the power take-off system, and a gas turbine engine assembly including the power take-off system are also described.

Power take-off system and gas turbine engine assembly including same

A gas turbine engine assembly (10) includes a core gas turbine engine (13) and a fan assembly (12) coupled to the core gas turbine engine. The fan assembly is upstream from the core gas turbine engine. A low-pressure turbine (20) is coupled to the core gas turbine engine and is disposed downstream from the core gas turbine engine. The low-pressure turbine includes a disk (105) including a flange (107) and a plurality of splines (108) formed in the flange. A shaft (31) includes a first end (120) coupled to the fan assembly and a second end (122) that includes a plurality of splines (110). The shaft splines are configured to mesh with the flange splines such that torque is transmitted from the low-pressure turbine to the fan assembly via the shaft.

Gas turbine engine assembly and method of assembling same

A turbofan gas turbine propulsion engine includes a system to transfer power from the low pressure turbine to the high pressure turbine and/or extract additional load from the low pressure turbine during certain turbofan engine operational conditions. The systems include a hydrostatic power transfer system that includes a hydraulic pump and a hydraulic motor coupled to the low pressure and high pressure turbine, respectively. The systems additionally include a mechanical and electrical load shifting/loading sharing systems that use clutches and gear assemblies to share and/or shift load between the turbines.

More electric aircraft power transfer systems and methods

A turbofan gas turbine propulsion engine includes a system to transfer power from the low pressure turbine (128) to the high pressure turbine (126) and/or extract additional load from the low pressure turbine (128) during certain turbofan engine operational conditions. The systems include a hydrostatic power transfer system that includes a hydraulic pump (154) and a hydraulic motor (156) coupled to the low pressure and high pressure turbine (126), respectively. The systems additionally include a mechanical and electrical load shifting/loading sharing systems that use clutches and gear assemblies to share and/or shift load between the turbines

Brian L Flaherty

Papers

More electric aircraft power transfer systems and methods

A multi-spool gas turbine engine with a load shift and transfer system.