Abstract: A multi-engine system includes a first gas turbine engine that includes a first compressor and a first turbine. The multi-engine system may further include a second gas turbine engine that has a second compressor and a second turbine. Still further, the multi-engine system may include a first crossover cooling network configured to route a first crossover airflow from the first compressor of the first gas turbine engine to the second turbine of the second gas turbine engine and a second crossover cooling network configured to route a second crossover airflow from the second compressor of the second gas turbine engine to the first turbine of the first gas turbine engine.

Abstract: A gas turbine engine includes a generator that is configured to be driven by a turbine section, an electric motor that is configured to receive at least a portion of electric power from the generator, a gearbox that is mechanically coupled to both the electric motor and the generator, and a control system that has an operational amplifier that is configured to synchronize operation of the electric motor and the generator. The operational amplifier electrically couples the electric motor to the generator and is configured to define an electrical gain that matches a mechanical gain that is defined by the gearbox.

Abstract: A turbofan gas turbine engine includes a fan section having a fan, a compressor section including a low pressure compressor and a high pressure compressor, a geared architecture including an epicyclic gear train, a turbine section including a low pressure turbine and a high pressure turbine, the fan driven by the low pressure turbine through the geared architecture, and a power density between 4.84 lbf/in3 and 5.5 lbf/in3.

Abstract: A gas turbine engine comprises a fan at an axially outer location, the fan rotating about an axis of rotation, delivering air into an outer bypass duct, a radially middle duct, and a radially inner core duct. Air from the inner core duct is directed into a compressor, and then flows axially in a direction back toward the fan through a combustor section, and across a core turbine section, and is then directed into the middle duct. A gear reduction drives the fan from a fan drive turbine section. A method of operating a gas turbine engine is also disclosed.

Abstract: A method of distributing power within a gas turbine engine is disclosed. In various embodiments, the method includes driving a high pressure turbine having a first stage and a second stage with an exhaust stream from a combustor, the first stage connected to a high pressure turbine first stage spool and the second stage connected to a high pressure turbine second stage spool; driving a high pressure compressor connected to a high pressure compressor spool via a differential system, the differential system having a first stage input gear connected to the high pressure turbine first stage spool, a second stage input gear connected to the high pressure turbine second stage spool and an output gear assembly connected to the high pressure compressor spool; and selectively applying an auxiliary input power into at least one of the high pressure compressor spool and the high pressure turbine.

Abstract: A gas turbine engine is disclosed. In various embodiments, the gas turbine engine includes a high pressure turbine having a first stage and a second stage, the first stage connected to a high pressure turbine first stage spool and the second stage connected to a high pressure turbine second stage spool; a high pressure compressor connected to a high pressure compressor spool; and a differential system having a first stage input gear connected to the high pressure turbine first stage spool, a second stage input gear connected to the high pressure turbine second stage spool and an output gear connected to the high pressure compressor spool.

Abstract: A gas turbine engine is disclosed. In various embodiments, the gas turbine engine includes a low speed spool; a first compressor, a turbine and a generator rotationally coupled via the low speed spool; a high speed spool; and a second compressor and a motor rotationally coupled via the high speed spool.

Abstract: A gas turbine engine includes a compressor section, a combustor fluidly connected to the compressor section via a primary flowpath and a turbine section fluidly connected to the combustor via the primary flowpath. Also included is a cascading cooling system having a first inlet connected to a first compressor bleed, a second inlet connected to a second compressor bleed downstream of the first compressor bleed, and a third inlet connected to a third compressor bleed downstream of the second compressor bleed. The cascading cooling system includes at least one heat exchanger configured to incrementally generate cooling air for at least one of an aft compressor stage and a foremost turbine stage relative to fluid flow through the turbine section.

Abstract: A turbine section for a gas turbine engine includes an independently controllable wheel downstream of the first static vane structure and a turbine rotor downstream of the independently controllable wheel. A method of generating thrust for a gas turbine engine, includes rotating a independently controllable wheel located downstream of a combustor and upstream of a turbine rotor to augment a swirl of a core flow combustion gases.

Abstract: A turbine engine includes a core engine including a first spool and a second spool rotatable about a main engine longitudinal axis, a boost spool powered by a secondary drive system, and an accessory gearbox coupled to the core engine and the boost spool. A differential gear system is coupled between the core engine, the boost spool and the accessory gearbox for distributing power between the boost spool, the core engine and the accessory gearbox.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The compressor section includes a compressor electric motor that is electrically coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to a geared architecture to supplement power driving the fan section. A turbine generator driven by a portion of the turbine section provides electric power to the turbine electric motor.

Abstract: A turbine engine includes integrated electric machines in the compressor section and the turbine section to supplement power produced from fuel with electric power. The example compressor section includes a compressor electric motor that is coupled to a compressor generator. The example turbine section includes a turbine electric motor that is coupled to the geared architecture to supplement power driving the fan section. A turbine generator provides electric power to the turbine electric motor.

Abstract: A turbofan engine includes a fan section including a plurality of fan blades, a first spool including a first turbine section, a second spool including a second turbine section, a first electric machine, and a second electric machine. A gear system is coupled between the first spool, the second spool, the first electric machine, the second electric machine and the fan section for driving the fan section.

Abstract: A gas turbine engine turbine has a compressor section including a low pressure compressor and a high pressure compressor, a turbine section including a low pressure turbine and a high pressure turbine, the high pressure turbine rotatable with the high pressure compressor as a high pressure spool in a first direction about an engine longitudinal axis, the low pressure turbine rotatable as a low pressure spool in the first direction about the engine longitudinal axis, a power density of greater than or equal to 4.75 and less than or equal to 5.5 lbf/in3, a fan section including a fan having a plurality of fan blades, the fan connected to the low pressure spool via a geared architecture such that the fan is rotatable about the engine longitudinal axis in a second direction opposed to the first direction, and a bypass ratio greater than 6.

Abstract: An after-fan system for a gas turbine engine includes a variable pitch fan exit guide vane array. An after-fan turbine downstream of the variable pitch fan exit guide vane array and a control operable to vary a pitch of the variable fan exit guide vane array. A method of generating thrust for a gas turbine engine includes rotating a fan section with an array of fan blades; rotating an after-fan turbine downstream of the fan section; and varying a pitch of a variable fan exit guide vane array downstream of the fan section and upstream of the after-fan turbine.

Abstract: A gas turbine engine includes an engine spool with a turbine section, a propeller, a motor, and a variable drive arrangement. The variable drive arrangement mechanically couples the engine spool to the propeller, and includes a first gear connection rotationally coupled to the propeller, a second gear connection rotationally coupled to the engine spool, and a sprag clutch rotationally coupled to the first gear connection. The sprag clutch is configured to passively decouple the motor from the first gear connection when a torque input from the engine spool exceeds a torque input from the motor, and is configured to passively couple the motor to the first gear connection when the torque input from motor exceeds a torque input from the engine spool.

Abstract: An air foil includes a body and a filler. The body may include a chamber formed therein and includes a first metallic material. The filler may at least partially occupy the chamber of the body and may include a second metallic material. The second metallic material may have a comparatively more negative electrode potential than the first metallic material.

Abstract: A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall propulsive efficiency of the engine. In such engine architectures, a shaft driven by one of the turbine sections provides an input to the epicyclical gear assembly that drives the fan section at a speed different than the turbine section such that both the turbine section and the fan section can rotate at closer to optimal speeds providing increased performance attributes and performance by desirable combinations of the disclosed features of the various components of the described and disclosed gas turbine engine.

Abstract: A gas turbine engine according to an exemplary embodiment of this disclosure includes, among other things, a fan driven by a fan shaft rotatable about an engine axis; a fan drive electric motor providing a supplemental drive input to the fan; a turbine section driving an input shaft; a geared architecture driven by the input shaft of the turbine section and coupled to the fan shaft to provide a main drive input for driving the fan; and a generator including a rotor supported on the input shaft and a stator disposed on a static structure relative to the rotor, wherein the generator communicates electric power to power the fan drive electric motor.

Abstract: In accordance with one aspect of the disclosure, a stream diverter for a gas turbine engine is disclosed. The stream diverter may include a first air duct, a second air duct, a third air duct, and a door operatively associated with the second and third air ducts of the gas turbine engine. The door may have at least an open position allowing air from the second air duct to flow into the third air duct and a closed position preventing air from flowing between the ducts.