GAS TURBINE ENGINES

Assignee

BRITISH AEROSPACE PLC, 11, STRAND, LONDON, WC2N 5JT

Filed

Jun 19, 1987

Granted

Jan 24, 1995

Location

FARNHAM GB

Abstract

A variable cycle gas turbine bypass engine includes a first fan 1 located at an inlet to the engine so as to provide air to a compressor 2 driven by a turbine 11 and to a bypass duct 13 surrounding the compressor housing. A second fan 5 located in the bypass duct 13 is driven by a free turbine 12. A controllable area auxiliary air intake 4 and bypass duct blocker doors 3 are located between the first and second fans 1, 5. Control means are effective for selectably operating the bypass duct blocker doors 3 and the auxiliary air intake 4 to vary in operation the bypass ratio of the engine. Thus in conventional wing-borne flight, the intake 4 is closed and the bypass duct 13 is unobstructed, and the combined exhausts from the bypass duct 13 and the turbines 10, 11 and 12 pass to a tailpipe 14, which has a vectorable nozzle 8, to produce forward thrust. In jet-borne flight, however, the doors 3 block the bypass duct 13, the auxiliary air intake 4 is opened to admit air to the second fan 5, and a vectorable nozzle 9 with associated blocker doors 3a and the nozzle 8 are operated by the control means respectively to receive air from the first fan 1 and the exhausts from the second fan 5 and the turbines 10, 11 and 12.

Source: Google Patents