GB1099971A - Power plants of the gas turbine type for helicopter aircraft - Google Patents

Abstract

1,099,971. Driving helicopter rotors. BRISTOL SIDDELEY ENGINES Ltd. Jan. 5, 1967 [Jan. 11, 1966], No. 1346/66. Heading B7G. [Also in Division F1] A power plant for a helicopter aircraft is of the gas turbine type and comprises an air compressor, combustion equipment and a turbine which is arranged to drive the air compressor, the turbine or a further turbine being arranged to drive the helicopter rotor, a further turbine separate from the turbine or turbines driving the compressor and helicopter rotor being provided and arranged to drive a fan for impelling air through a duct to a cold propulsion nozzle. Means are provided by which the proportions of the hot gases which are caused to act on the turbine driving the fan and which pass through a bypass passage direct to atmosphere can be varied. In Fig. 1 the first turbine 1 is connected to drive an air compressor, not shown, and the gases discharging from the turbine 1 are directed on to a second turbine 5 mounted on a shaft 6, the shaft 6 being connected to shaft 21 which in turn is connected through gearing 23, 24 to shaft 22 by which the helicopter rotor is driven. The gases discharging from the turbine 5 pass through a duct 11 which divides into two passages 12, 13, the gas flow through the inner passage 13 being directed by guide vanes 20 on to turbine blades 18 which thus drive fan blades 17 mounted on a rotor 16. The fan blades 17 are disposed in annular duct 9 and the air impelled by the fan blades is discharged through " cold " propulsion nozzle 10. The hot gases passing through the outer duct 12 by-pass the turbine 18 and discharge through a " hot " propulsion nozzle, the cross-sectional area of which is controlled by pivoted flaps 19, the flaps thus serving to control the proportions of hot gases which pass through the turbine 18 and the by-pass passage 12. Control flaps may alternatively be provided as indicated at 24. In a second embodiment, Fig. 2, the turbine 26 drives the helicopter rotor, the gases from the turbine 26 passing through two ducts 33, 34, the gases passing through the inner duct 34 being guided by vanes 36 on to turbine rotor blades 37, the turbine being connected through shaft 38 to drive ducted fan 39. The fan takes in air through inlet 41 and discharges it through " cold " propulsion nozzle 42A. The gases passing through the outer duct 33 by-pass the turbine 37 and discharge together with the exhaust gases from the turbine 37 through hot propulsion nozzle 31. Control flaps 47 are provided to control the proportions of gases passing through the turbine 37 and the by-pass passage 29.