An aircraft propulsion system includes a fan section that includes a fan shaft that is rotatable about a fan axis. The fan shaft includes a fan gear. The aircraft propulsion system also includes a boost turbine engine that includes a first output shaft that includes a first gear that is coupled to the fan gear. The boost turbine engine has a first maximum power capacity. The aircraft propulsion system further includes a cruise gas turbine engine that includes a second output shaft that includes a second gear that is coupled to the fan gear. The cruise turbine engine has a second maximum power capacity that is less than the first maximum power capacity of the boost turbine engine. The fan section produces a thrust that corresponds to power input through the fan gear from the boost turbine engine and the cruise turbine engine.

A turbojet engine capable of operation in an Air Turbo Rocket (ATR) mode includes a compressor, a rotatable turbine wheel comprising turbine blades, a non-rotating guide vane ring comprising guide vanes, a turbine shaft configured to power said compressor, a combustor, a gas generator, and a main combustor. The main combustor is configured to combust hot, fuel rich gas from the gas generator in air compressed by the compressor. Hot, fuel rich gas from the gas generator is directed towards the turbine blades by a directing means.

A turbojet engine capable of operation in an Air Turbo Rocket (ATR) mode includes a compressor, a rotatable turbine wheel comprising turbine blades, a non-rotating guide vane ring comprising guide vanes, a turbine shaft configured to power said compressor, a combustor, a gas generator, and a main combustor. The main combustor is configured to combust hot, fuel rich gas from the gas generator in air compressed by the compressor. Hot, fuel rich gas from the gas generator is directed towards the turbine blades by a directing means.

A gas turbine engine includes a first spool of a primary flow path and a second spool of a secondary flow path. The second spool is nonconcentric with the first spool. The second spool includes a boost compressor and a load compressor in fluid communication with an inlet plenum. An inlet duct assembly and an outlet duct assembly place the secondary flow path in communication with the primary flow path. The gas turbine includes a controller operable to vary open areas of variable inlet guide vanes to control a flow division between the boost compressor and the load compressor.

A gas turbine engine includes a first spool of a primary flow path and a second spool of a secondary flow path. The second spool is nonconcentric with the first spool. The second spool includes a boost compressor and a load compressor in fluid communication with an inlet plenum. An inlet duct assembly and an outlet duct assembly place the secondary flow path in communication with the primary flow path. The gas turbine includes a controller operable to vary open areas of variable inlet guide vanes to control a flow division between the boost compressor and the load compressor.

A gas turbine engine includes a first spool associated with a primary combustor, a second spool associated with a secondary combustor, and a third spool, each spool including a compressor and a turbine mounted to a shaft. A transmission and accessory gearing are enclosed within an housing of an accessory gearbox. The transmission rotationally couples the third spool to the second spool and accessory gearing. A method of operating the gas turbine engine includes supplying a first fuel flow rate to the primary combustor and supplying a second fuel flow rate to the secondary combustor within an intermediate speed range of the gas turbine engine.

A propulsion system includes a main gas turbine engine adapted for generating propulsive thrust during subsonic and supersonic flight operations and a supplementary propulsion unit adapted for generating additional thrust. The supplementary propulsion unit has an air intake and an exhaust for gas accelerated by the supplementary propulsion unit to provide the additional thrust and is adapted to generate the additional thrust during a limited range of subsonic flight operations, and to be dormant during other flight operations. The propulsion system has housing for the supplementary propulsion unit, including intake and exhaust covers which are moveable between deployed and stowed configurations. During the limited range of subsonic flight operations the intake and exhaust cover are moved to the deployed configuration to open the intake and the exhaust. During other flight operations the intake and exhaust cover are moved to the stowed configuration to close the intake and the exhaust.

A propulsion system includes a main gas turbine engine adapted for generating propulsive thrust during subsonic and supersonic flight operations and a supplementary propulsion unit adapted for generating additional thrust. The supplementary propulsion unit has an air intake and an exhaust for gas accelerated by the supplementary propulsion unit to provide the additional thrust and is adapted to generate the additional thrust during a limited range of subsonic flight operations, and to be dormant during other flight operations. The propulsion system has housing for the supplementary propulsion unit, including intake and exhaust covers which are moveable between deployed and stowed configurations. During the limited range of subsonic flight operations the intake and exhaust cover are moved to the deployed configuration to open the intake and the exhaust. During other flight operations the intake and exhaust cover are moved to the stowed configuration to close the intake and the exhaust.

A gas turbine engine utilizes one or more gas generators having a core inlet flowpath and an exhaust outlet. Adjacently offset from the core gas generator, is a propulsor assembly. An exhaust outlet of the core gas generator is fluidly connected to the propulsor assembly and exhaust from the gas generator drives a fan drive turbine.

A gas turbine engine utilizes one or more gas generators having a core inlet flowpath and an exhaust outlet. Adjacently offset from the core gas generator, is a propulsor assembly. An exhaust outlet of the core gas generator is fluidly connected to the propulsor assembly and exhaust from the gas generator drives a fan drive turbine.