초록 ▼

A propulsion system for use primarily in V/STOL aircraft is provided with a variable cycle, double bypass gas turbofan engine and a remote augmenter to produce auxiliary lift. The fan is oversized in air-pumping capability with respect to the cruise flight requirements of the remainder of the engine

A propulsion system for use primarily in V/STOL aircraft is provided with a variable cycle, double bypass gas turbofan engine and a remote augmenter to produce auxiliary lift. The fan is oversized in air-pumping capability with respect to the cruise flight requirements of the remainder of the engine and a variable area, low pressure turbine is capable of supplying varying amounts of rotational energy to the oversized fan, thereby modulating its speed and pumping capability. During powered lift flight, the variable cycle engine is operated in the single bypass mode with the oversized fan at its maximum pumping capability. In this mode, substantially all of the bypass flow is routed as an auxiliary airstream to the remote augmenter where it is mixed with fuel, burned and exhausted through a vectorable nozzle to produce thrust for lifting. Additional lift is generated by the high energy products of combustion of the variable cycle engine which are further energized in an afterburner and exhausted through a thrust vectorable nozzle at the rear of the engine. In the cruise operating mode, the fan is driven at a slower rotational speed and all of the bypass flow is directed to a variable area bypass injector where it is mixed with the variable cycle engine products of combustion and exhausted as a mixture through the rear nozzle. The variable cycle engine can be selectively operated in the single or double bypass mode during cruise to maximize efficiency as the aircraft speed is varied. Because the total installed thrust is available in the forward cruise mode, an aircraft powered by the propulsion system of the present invention has substantially greater capabilities in the areas of excess power, acceleration time and combat ceiling when compared to prior art conceptions embodying separate lift plus lift/cruise engines. Additionally, by not having to develop and maintain a separate lift engine system, a substantially lower aircraft lift cycle cost is possible.

대표청구항 ▼

A propulsion system for use in V/STOL aircraft comprising a core engine for generating high energy products of combustion, a bypass duct, having upstream and downstream ends, that bypasses the core engine, a fan upstream of said core engine for pressurizing both a bypass flow stream and a core engin

A propulsion system for use in V/STOL aircraft comprising a core engine for generating high energy products of combustion, a bypass duct, having upstream and downstream ends, that bypasses the core engine, a fan upstream of said core engine for pressurizing both a bypass flow stream and a core engine flow stream, said fan being oversized in air-pumping capability with respect to the aircraft cruise requirements of the core engine, a low pressure turbine, having means to vary the area of the turbine nozzle to extract varying amounts of energy from the products of combustion from the core engine for driving the fan at varying rotational speeds and for producing bypass flow in excess of core engine requirements during lift mode operation, valve means at the upstream end of the bypass duct for modulating the relative amounts of flow in the core engine flow stream and the bypss flow stream, a remote augmenter to which the bypass stream is ducted, mixed with fuel and burned to produce thrust in the lift operating mode, a nozzle with means for selectively vectoring thrust and for exhausting the core engine high energy products of combustion, and a continuation of the bypass duct for routing the bypass stream to the thrust vectorable nozzle when operating in other than the lift mode.