GB879969A - Improvements in by-pass and ducted fan gas turbine engines - Google Patents

Abstract

879,969. Jet propulsion engine thrust reversing means. ROLLS-ROYCE Ltd. Jan. 4, 1960 [Jan. 28, 1959], No. 3137/59. Class 4. [Also in Group XXVI] A by-pass or ducted fan gas turbine engine has the by-pass or fan air passage divided into two ducts situated along the sides of the engine, and flaps interconnected with the engine thrust reverser and situated on the sides of the engine downstream of the open ends of.the ducts, so that when the thrust reverser is operative, the flaps move to positions in which they reverse the flow of by pass or fan air. In the Figure, air from the upstream stages 10a of a low pressure compressor 10 driven by a low pressure turbine 15 is divided between a by-pass passage 13 and the downstream stages 10b. A high pressure compressor 14 is driven by a high pressure turbine 11. The passage 13 is split into two ducts 19. The turbine exhaust gases thrust reverser 21, which may be as in Specification 745,649, comprises valve members 22 which in the reversal position divert the turbine exhaust to parts 24 in the fairing, normally fixed by flaps 23. During reversal, flaps 23 are moved to the broken line position, opening the ports and also reversing the by pass flow from ducts 19. The ducts may alternatively derive air from a ducted fan comprising blades at the periphery of turbine 15, or a third free turbine. If the ducts 19 are short, one pair of flaps 19 is used downstream of the ducts for reversal of the air flow and another pair of flaps is used to cover and uncover ports 24, see Fig. 10 (not shown).