A new and improved gas turbine engine including a gas generator and a power turbine is disclosed. The power turbine includes a first rotor having a plurality of first turbine blade rows extending radially outwardly therefrom, and a second rotor having a plurality of second turbine blade rows extending radially inwardly therefrom. The power turbine is supported aft of the gas generator and is effective for receiving combustion gases therefrom and expanding the gases through the first and second turbine blade rows for extracting substantially all output power therefrom for driving the first and second rotors in counterrotating directions.

Counter rotation power turbine

An air propulsor having either a fixed or a variable pitch fan with blade loadings selected from a range intermediate between aircraft propeller and fan engine designs is configured so as to retain high takeoff thrust and good high-speed efficiency while providing a large reduction in noise generation. Noise is abated at its source by reducing rotative speed of the fan blades, uniquely selecting the number of stator vanes relative to the fan, and judiciously spacing the stator vanes relative to the fan and relative to each other.

Low noise prop-fan

An aircraft propelled by a turbojet having contrarotating fans, the turbojet being incorporated at the rear of a fuselage of the aircraft and in line therewith and including two gas generators that feed a working turbine having two contrarotating turbine rotors for driving two fans arranged downstream from the gas generators, and distinct air intakes for feeding each gas generator, the air intakes being connected to the fuselage of the aircraft so as to take in at least a portion of the boundary layer formed around the fuselage of the aircraft.

Aircraft propelled by a turbojet engine with contrarotating fans

A pitch feathering system for a gas turbine driven aircraft propeller having multiple variable pitch blades utilizes a counter-weight linked to the blades. The weight is constrained to move, when effecting a pitch change, only in a radial plane and about an axis which rotates about the propeller axis. The system includes a linkage allowing the weight to move through a larger angle than the associated pitch change of the blade.

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Propeller/fan-pitch feathering apparatus

The invention concerns the mounting of propeller blades to a ring-shaped rotor. The blades are of the variable pitch type, and the shank of each blade extends through a respective hole in the rotor. Each hole contains an annular shelf which is fastened to the wall of the hole and surrounds each shank. Each shank bears a pair of bearing races which sandwich the annular shelf in order to connect the blade to the rotor. Bearing rollers are positioned between the annular shelf and the bearing races.

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Propeller blade retention system

1,196,588. Gas turbine jet propulsion plant; axial-flow fans. BRITISH AIRCRAFT CORP. Ltd. Feb. 5, 1968 [Nov. 9, 1966], No. 50249/66. Headings F1C; F1J. [Also in Division G3] A gas turbine ducted fan aircraft engine has variable pitch fan blades 10 controlled by a pneumatic motor 15 which rotates with the fan and is supplied with motive fluid from the engine by way of a control valve 19. The engine is of the three-spool type, Fig. 1, and the fan blades 10 are driven through a connection 96 from a frusto-conlcal drum 9 carrying five stages of inwardly projecting turbine blades 91 to 95. The air supply for motor 15 is tapped from the low pressure compressor 2 via a bleed 151 and an internal passage 152, the latter communicating with a space 153 and thence via a hollow turbine blade 91 and a line 20 with the motor control valve 19. A signal air supply is also fed to valve 19 from bleed 151 via line 154, valve 155, line 156, chamber 158, hollow turbine blade 95 and line 23. The motor 15 is mounted on a bracket 97 attached to connection 96 and can adjust the pitch of the fan blades 10 by rotating a ring gear 13 relative to the fan annulus 12 via a worm 16 and pinion 17. The gear 13 is integral with a ring 14 mounted on _the annulus 12 and connected to each blade 10 by a link 18. Valve 19 has an internal spool, Fig.3, having pistons 24, 25 of unequal diameter at opposite ends co-operating respectively with chambers pressurized by a branch 21 from line 20 and by line 23. During normal forward thrust operation, valve 155, which is manually controlled by the pilot or linked to the engine power control, remains closed so that the spool of valve 19 is held in its lowest position, shown, under the action of the air pressure in line 21. In this position the lands 28, 29 on the valve spool permit air to flow from branch 22 of line 20 via port 27 to motor 15 so that the latter drives ring 14 until lug 141 on the ring abuts a stop 37. The ring 14 is held in this position by the air-pressure tending to rotate the motor further. When engine thrust is reduced to, say, 50% valve 155 is manually or automatically opened so that the spool moves upwards under the action of the pressure in line 23 to a central position, Fig.4 (not shown), in which the air pressure forces on the spool balance. The centrifugal force acting on a bob-weight 35 now acts to position the spool via a bell crank 33, link 32, beam 31 and extension rod 30 of the spool, so that land 29 covers port 27 and land 28 uncovers port 26 to allow air from line 22 to drive motor 15 in the reverse direction. Thus the blades 10 move towards a coarse pitch position, slowing the fan and reducing noise. When the blades 10 reach the desired position the follow-up action of beam 31 returns the spool to its central position so that further adjustment is prevented. When the engine speed falls to near zero r.p.m. the centrifugal force on the bob-weight is overcome by a spring 36 acting on the bell crank 33 so that the crank moves clockwise to the Fig. 5 position (not shown), causing the spool to rise and uncover port 26 permitting the motor 15 to move the blades 10 towards the feathered position. When that position is reached the follow-up action of beam 31 prevents further adjustment. Should reverse pitch of the blades 10 be required, valve 155 is manually fully opened so that the increased pressure in line 23 moves the spool upwards to the maximum extent thus fully opening port 26 so that motor 15 moves the blades into the reverse pitch position, Fig. 6 (not shown), with lug 142 abutting stop 38.

Improvements relating to Turbo-fan Aircraft Engines

1,212,593. Jet propulsion plant; turbines. BRITISH AIRCRAFT CORP. Ltd. Jan. 14, 1969 [Jan. 25, 1968], No.3954/68. Headings F1J and F1T. [Also in Division F2] A seal between two coaxial parts, one being stationary and the other rotatable (e.g. a seal for preventing the escape of gas through a gap 15 in a gas turbine jet propulsion engine) comprises an inwardly-facing channel 6 on the stationary part, a flange 13 on the rotatable part extending normal to the axis of rotation and into the channel, a container 7 including a heater 12 for supplying the metal gallium 14 in a liquid state to the channel at a point 9 closer to the rotational axis than the outer diameter of the flange, and means 10 for applying pressure to the container upon rotation of the parts so that upon rotation some of the liquid is expelled into the channel and on stopping the rotation the expelled liquid is returned into the container. The gap 15 is between the combustion chambers 5 and a rotary shroud 2a carrying ducted fan blades 1. Before the engine is started the heater 12 is used to melt the metal. The engine is then rotated and-pressure is transmitted to the container 7 via the duct 10 to transfer the liquid metal 14 by way of a duct 8 into the channel 6 where it is centrifuged to take up the position shown in Fig. 2. As the engine speed increases the gas pressure at the gap 15 displaces the level of the metal in one of the legs of the channel as shown in Fig. 1A such that the centrifugal force exerted by the displaced metal balances the pressure exerted by the gas. Following engine shut down, the metal returns to the container 7 via mouth 9 and duct 8 to solidify. Blades 13a, 13b or scollops may be provided on the flanks of the flange 13 and retaining lips 6a, 6b may be provided on the channel. The forces acting axially on the flange 13 due to unequal levels in the channel during operation are opposed to the thrust of the fan blades 1.

Improvements relating to rotary large diameter gas seals

1,041,048. Aircraft power plant. VICKERSARMSTRONGS (AIRCRAFT) Ltd. Sept. 2, 1963 [Sept. 25, 1962], No; 36415/62. Heading B7G. [Also in Division F2] The aft end of an aircraft fuselage 10 (Fig. 2, not shown) carries a cowl 12 spaced from the fuselage to form an intake 15 for boundary layer air drawn from the fuselage surface, the cowl being extended laterally at 14 to enclose on each side of the fuselage a pair of gas-turbine engines 11 which discharge into a volute 19. A fan 18 is mounted within cowl 12 on each side of the fuselage and is driven by jet gases from volute 19 impinging on tip turbine blades 181 of the fan, whereby the fans draw fuselage boundary layer air through intake 15.

Improvements in aircraft having jet-propulsion power-plants

1,195,027. Gas turbine jet propulsion plant; axial flow fans. BRITISH AIRCRAFT CORP. Ltd. Feb. 5, 1968 [Nov. 8, 1966], No. 50031/66. Headings F1C and F1J. A gas turbine ducted fan aircraft engine has a fan cowl 23 formed by inlet and exhaust sections 25, 26, respectively, both fabricated from radially spaced skins of light-gauge sheet material and joined to each other by an intermediate section 27 consisting of a single skin surrounding the periphery of the fan 18 and of sufficient thickness to contain accidentally detached fan parts. The outer and inner skins 40, 42, Fig. 3, of the inlet section 25 are braced by longitudinally extending ribs 44 having holes 48 to receive securing bolts for lugs 46 of the intermediate section 27. Similar ribs 45 brace the skins 41, 43 of the outlet section 26 and have holes 49 to receive securing bolts for further lugs 47 of section 27. Straps 50, 51 cover the access openings to the bolts. The single skin of section 27 may be formed of a single thickness of material or of a sandwich of two or more materials in surface contact. As shown in Fig. 1 the cowl 23 is applied to a three-spool type aft fan engine and is supported from the engine by radial struts 24, 28. Compared with a conventional fan cowl, shown dotted at 30, the cowl 23 is shorter and has a smaller external diameter, thus reducing drag. The cowl may also be applied to a front fan engine, Fig. 2 (not shown).

Improvements relating to Cowls for Turbo-Fan Aircraft Engines.

1,212,581. Toothed gearing. BRITISH AIRCRAFT CORP. Ltd. 29 Jan., 1969, No. 7459/68. Heading F2Q. A reduction gear drive to an aircraft control surface 10 comprises two separate reduction gearings 15, 16 whose outputs are connected to the control surface 10 and whose inputs are connected to one another by a torsion bar 20 stressed in torsion so as to load the two reduction gearings in opposite senses, the control surface 10 completing a prestressed closed loop. Gearing 15 comprises an input sun 131 meshing planet gears 132 mounted on a carrier 134 which incorporates a gear 135 meshing gears 136 supported on a fixed member 138. Gears 132, 136 mesh internal ring gears 133, 137 formed on a sleeve 17 secured to the control surface 10 by an arm 171. Input sun 131 is driven by a motor 11. Gearing 16 is similar to gearing 15 and is driven by a motor 12. Only one motor may be used to drive the gearings. In a modification, a member 30 splined to torsion bar 20 carries toothed portions 31, 32 meshing end portions of planet gears 33, the centre portions of which mesh a toothed annulus formed on a member 37. The planet gears 33 also mesh an internal ring gear 34 on a fixed member 35. A second stage planet gear is of similar construction and comprises planet gears 40 meshing sun gears 38, 39 on member 37, an internal ring gear 41 on a fixed member 42 and an internal ring gear 43 on a driven sleeve 17.

Wotton John

Papers

Improvements relating to Turbo-fan Aircraft Engines

Improvements relating to rotary large diameter gas seals

Improvements in aircraft having jet-propulsion power-plants

Improvements relating to Cowls for Turbo-Fan Aircraft Engines.

Improvements relating to power transmitting drive arrangements