GB1190365A - Gas Turbine Engines - Google Patents

Abstract

1,190,365. Gas turbine ducted fan engines. DOWTY ROTOL Ltd. April 11, 1967 [May 25, 1966; Feb.3, 1967], No.23429/66 and 5267/67. Heading F1J. A gas turbine engine of the ducted fan by-pass type comprises a fan having flow-varying blading and rotatable in a fan duct, the blading being formed in tiers to provide at least two concentric annular flow paths, the blade portions of at least one of the flow paths being adjustable either relatively with respect to the blading of the other flow path or flow paths, or in unison with such blade portions of the other flow path so as to provide the said flow variation. The forward portion comprising the ducted fan assembly of a gas turbine ducted fan engine is shown in Fig.1, the assembly comprising a fan rotor 7 which is connected to driving shaft 25 which is drivingly connected to the compressor and turbine assembly, not shown, through reduction gearing 21. The fan blade assembly 1 comprises two-tier blading- inner blading 3 which is disposed in inner flow duct A, and outer blading 4 disposed in outer flow duct B, the flow ducts A and B being defined between an inner shroud 5 and an inner casing, and between an outer shroud 2 and the inner shroud 5. The inner blading 3 is of hollow form and is secured to the fairing member 6 also to the forward portion 5a of the inner shroud 5. The outer blades 4 are angularly adjustable, each blade comprising a stem portion 9 which passes through a hollow inner blade 3 and is mounted at its inner end in bearings 10 in the hub assembly 7. A gear pinion 12 is secured to the stem portion 9, an angularly adjustable gear member 13 engaging the gear pinions 12 of all the blade members 4 whereby they can be angularly adjusted simultaneously by means of a hydraulic actuator 14 which comprises a piston 18 disposed in a cylinder 19. Fluid under pressure is supplied through a duct 16 under control of valve 15. The piston assembly includes a sleeve member 18a which slides on a cylindrical spigot 20, being guided thereon by means of splines 28. The sleeve member is also formed with helical splines 27 which engage corresponding splines formed in the hub 26 of the gear member 13. Thus as the piston 28 is moved axially, the ring gear 13 is rotated and the outer fan blades 4 are angularly adjusted. The air flowing through the inner duct A passes to the compressor of the engine. Fixed stator blades 60 are disposed in the flow ducts A and B downstream of the fan blades 3 and 4. The engine in the Fig.1 embodiment is a single shaft engine while that of Fig.2 is a three-shaft engine, the further turbine 30 driving the fan assembly 3, 4 through shaft 32. In Fig.3 the outer blades 4 are rotatably mounted in the shroud portion 5a and are adjustable by means of the actuator 14 which drives ring gear 41 which engages pinions 42 mounted on shafts 43, each shaft 43 passing through a hollow inner blade 3 and carrying at its outer end a gear pinion 44 which engages with two gears 45 mounted on the spindle portions 9 of adjacent blades 4. In Fig. 5 the inner fan blades 3 are also angularly adjustable, the outer blades 4 being adjustable by means of an actuator 14 through gear member 13 and pinions 12 while the inner blades 3 are adjustable by means of an actuator 55 through gear member 54 and pinions 53. In Fig.6 the outer blades 4 are non-adjustably mounted in the fan rotor 7 at 59, the inner blades 3 being mounted for angular adjustment, the blade spindles 51 carrying pinions 53 which are engaged by a gear member 54 which is angularly rotatable by an actuator 55. In Fig.7 the outer blades 4 are again angularly adjustable, and the stator blades 60 in the outer flow duct B are also angularly adjustable by means of an actuator 65, the gear 64 engaging gear pinions 63 mounted on the spindles 61 of the stator blades 60. Movement of the fan blades 4 and stator blades 60 is co-ordinated by means of the device 67.