Ram-air turbines

Claim 2

A ram-air turbine including a body portion, and a rotor mounted so as to be rotatable with respect to said body portion when the turbine is positioned in an airstream, said rotor comprising a hub and blades mounted upon said hub with freedom for movement about their longitudinal axes so that they are variable as to pitch, a double-acting fluid-pressure-operable blade pitch-change actuator, rotatable with said rotor and having at least one pitch-coarsening chamber and at least one pitchfining chamber, means by which the actuator drives said blades to effect blade pitch variation, a governor rotatable with the rotor and responsive to the rotational speed of the rotor, a valve associated with the governor and adjustable thereby in a normal range, being also adjustable by the governor to a position outside that range when the rotational speed of the rotor falls below a predetermined value, first conduit means connecting said valve to a source of high fluid pressure, second conduit means connecting said valve to a souRce of low fluid pressure, first ducting means connecting said valve to said pitch-coarsening chamber or chambers, and second ducting means connecting said valve to said pitch-fining chamber or chambers, adjustment of said valve by the governor through its said normal range when said speed is above said predetermined value controlling the supply of pressure fluid to, and the exhaust of fluid from, said actuator for corresponding pitch-change adjustment of the blades in either the pitch-coarsening direction or the pitch-fining direction whereby said speed is maintained substantially constant, and adjustment of the valve by the governor to said position outside that range conditioning said actuator for movement of the blades to a predetermined coarse pitch position.

Claim 3

A ram-air turbine as claimed in claim 1, wherein spring means are provided in association with the actuator, operative, when said speed is below the predetermined value, to move the blades to a coarse pitch position.

Claim 4

A ram-air turbine as claimed in claim 1, wherein the actuator is of vane-type.

Claim 5

A ram-air turbine as claimed in claim 1, wherein said fluid under pressure is derived from a pump driven by the ram-air turbine.

Claim 6

A ram-air turbine as claimed in claim 2, wherein said spring means is interposed between the two components of the actuator.

Claim 7

A ram-air turbine as claimed in claim 2, wherein the actuator is of the balanced type with both components connected to the blades so as both to contribute to blade pitch adjustment, the spring means acting equally and oppositely upon these components.

Claim 8

A ram-air turbine as claimed in claim 2, wherein the actuator is of balanced-vane type, the casing vanes and shaft vanes of which are both angularly movable, one in a direction opposite to the other in order to apply pitch-changing forces to the rotor blades at diametrically opposite points of the blades.

Claim 9

A ram-air turbine as claimed in claim 7, wherein said spring means comprises a single torsion spring.

Claim 10

A ram-air turbine as claimed in claim 1, wherein said valve is a spool valve and the governor comprises a pair of flyweights and a speeder spring, all of which are arranged coaxially with respect to the bladed rotor.

Claim 11

A ram-air turbine as claimed in claim 1, and so constructed as to be mountable upon an aircraft in a manner affording extendability of the turbine from a stowage zone within the aircraft into the slipstream of the aircraft, and retractability from the slipstream into the stowage zone.

Claim 12

A ram-air turbine including a body portion, and a rotor mounted so as to be rotatable with respect to said body portion when the turbine is positioned in an airstream, said rotor comprising a hub and blades mounted upon said hub with freedom for movement about their longitudinal axes so that they are variable as to pitch, a double-acting fluid-pressure-operable blade pitch-change actuator, rotatable with said rotor and having at least one pitch-coarsening chamber and at least one pitch-fining chamber, means by which the actuator drives said blades to effect blade pitch variation, spring means provided in association with said actuator for biassing it in a manner corresponding to pitch-coarsening of the blades, a governor rotatable with the rotor and responsive to the rotational speed of the rotor, a valve rotatable with the rotor and adjustable by the governor in a normal range, being also adjustable by the governor to a position outside that range when the rotational speed of the rotor falls below a predetermined value, first conduit means connecting said valve to a source of high fluid pressure, second conduit means connecting said valve to a source of low fluid pressure, first ducting means connecting said valve to said pitch-coarsening chamber or chambers and second ducting means connecting said valve to said pitch-fining chamber or chambers, adjustment of said valve by the governor through its said normal range when said speed is above said predetermined value Controlling the supply of pressure fluid to, and the exhaust of fluid from, said actuator for corresponding pitch-change adjustment of the blades in either the pitch-coarsening direction or the pitch-fining direction whereby said speed is maintained substantially constant, and adjustment of the valve by the governor to said position outside that range, which occurs upon such repositioning of the ram-air turbine in relation to the airstream as causes said speed to fall below said predetermined value, simultaneously placing said pitch-coarsening and pitch-fining chambers in communication with said low pressure source whereby said spring means automatically adjusts the actuator so that it moves the blades to a predetermined coarse-pitch position.

Claim 13

A ram-air turbine including a body portion, and a rotor mounted so as to be rotatable with respect to said body portion when the turbine is positioned in an airstream, said rotor comprising a hub and blades mounted upon said hub with freedom for movement about their longitudinal axes so that they are variable as to pitch, a double-acting fluid-pressure-operable blade pitch-change actuator, rotatable with said rotor and having at least one pitch-coarsening chamber and at least one pitch-fining chamber, means by which the actuator drives said blades to effect blade pitch variation, spring means provided in association with said actuator for biassing it in a manner corresponding to pitch-coarsening of the blades, a governor rotatable with the rotor and responsive to the rotational speed of the rotor, a valve rotatable with the rotor and adjustable by the governor in a normal range, being also adjustable by the governor to a position outside that range when the rotational speed of the rotor falls below a predetermined value, first conduit means connecting said valve to a source of high fluid pressure, second conduit means connecting said valve to a source of low fluid pressure, first ducting means connecting said valve to said pitch-coarsening chamber or chambers and second ducting means connecting said valve to said pitch-fining chamber or chambers, adjustment of said valve by the governor through its said normal range when said speed is above said predetermined value Controlling the supply of pressure fluid to, and the exhaust of fluid from, said actuator for corresponding pitch-change adjustment of the blades in either the pitch-coarsening direction or the pitch-fining direction whereby said speed is maintained substantially constant, and adjustment of the valve by the governor to said position outside that range, which occurs upon such repositioning of the ram-air turbine in relation to the airstream as causes said speed to fall below said predetermined value, simultaneously placing said pitch-coarsening and pitch-fining chambers in communication with said low pressure source whereby said spring means automatically adjusts the actuator so that it moves the blades to a predetermined coarse-pitch position.

Claim 14

A ram-air turbine including a body portion, and a rotor mounted so as to be rotatable with respect to said body portion when the turbine is positioned in an airstream, said rotor comprising a hub and blades mounted upon said hub with freedom for movement about their longitudinal axes so that they are variable as to pitch, a double-acting fluid-pressure-operable blade pitch-change actuator of balanced-vane type, rotatable with said rotor and having at least one pitch-coarsening chamber and at least one pitch-fining chamber, means by which the actuator drives said blades to effect blade pitch variation, casing vanes and shaft vanes of said actuator being both angularly movable, the casing vanes in a direction opposite to the shaft vanes in order to apply pitch-changing force through said means to each said blade at diametrically opposite points thereon, a torsion spring provided in association with said actuator for biassing it in a manner corresponding to pitch-coarsening of the blades, a governor rotatable with the rotor and responsive to the rotational speed of the rotor, a valve rotatable with the rotor and adjustable by the governor in a normal range, being also adjustable by the governor to a position outside that range when the rotational speed of the rotor, falls below a predetermined value, first conduit means connecting said valve to a source of high fluid pressure, second conduit means connecting said valve to a source of low fluid pressure, first ducting means connecting said valve to said pitch-coarsening chamber or chambers, and second ducting means connecting said valve to said pitch-fining chamber or chambers, adjustment of said valve by the governor through its said normal range when said speed is above said predetermined value controlling the supply of pressure fluid to, and the exhaust of fluid from, said actuator for corresponding pitch-change adjustment of the blades in either the pitch-coarsening direction or the pitch-fining direction whereby said speed is maintained substantially constant, and adjustment of the valve by the governor to said position outside that range, which occurs upon such repositioning of the ram-air turbine in relation to the airstream as causes said speed to fall below said predetermined value, simultaneously placing said pitch-coarsening and pitch-fining chambers in communication with said low pressure source whereby said torsion spring automatically adjusts the actuator so that it moves the blades to a predetermined coarse-pitch position.

Claim 15

A ram-air turbine including a body portion, and a rotor mounted so as to be rotatable with respect to said body portion when the turbine is positioned in an airstream, said rotor comprising a hub and blades mounted upon said hub with freedom for movement about their longitudinal axes so that they are variable as to pitch, a double-acting fluid-pressure-operable blade pitch-change actuator of balanced-vane type, rotatable with said rotor and having at least one pitch-coarsening chamber and at least one pitch-fining chamber, means by which the actuator drives said blades to effect blade pitch variation, casing vanes and shaft vanes of said actuator being both angularly movable, the casing vanes in a direction opposite to the shaft vanes in order to apply pitch-changing force through said means to each said blade at diametrically opposite points thereon, a torsion spring provided in association with said actuator for biassing it in a manner corresponding to pitch-coarsening of the blades, a governor rotatable with the rotor and responsive to the rotational speed of the rotor, a valve rotatable with the rotor and adjustable by the governor in a normal range, being also adjustable by the governor to a position outside that range when the rotational speed of the rotor, falls below a predetermined value, first conduit means connecting said valve to a source of high fluid pressure, second conduit means connecting said valve to a source of low fluid pressure, first ducting means connecting said valve to said pitch-coarsening chamber or chambers, and second ducting means connecting said valve to said pitch-fining chamber or chambers, adjustment of said valve by the governor through its said normal range when said speed is above said predetermined value controlling the supply of pressure fluid to, and the exhaust of fluid from, said actuator for corresponding pitch-change adjustment of the blades in either the pitch-coarsening direction or the pitch-fining direction whereby said speed is maintained substantially constant, and adjustment of the valve by the governor to said position outside that range, which occurs upon such repositioning of the ram-air turbine in relation to the airstream as causes said speed to fall below said predetermined value, simultaneously placing said pitch-coarsening and pitch-fining chambers in communication with said low pressure source whereby said torsion spring automatically adjusts the actuator so that it moves the blades to a predetermined coarse-pitch position.

Claim 16

A ram-air turbine including a rotor having blades whose pitch is variable, a governor responsive to the rotational speed of the rotor, an actuator of balanced-vane type, the casing vanes and shaft vanes of which are both angularly movable, one in a direction opposite to the other in order to apply pitch-changing forces to the rotor blades at diametrically opposite points of the blades for effecting pitch variation of the blades, and a valve whose position is controlled by the governor for directing fluid under pressure to at least one part of the actuator to effect pitch variation in one direction and for directing fluid under pressure to at least one other part of the actuator to effect pitch variation in the other direction, when the rotatiOnal speed of the rotor is above a predetermined value, and for connecting all the part of the actuator to a source of low pressure when said speed is below the predetermined value, and spring means comprising a single torsion spring associated with the actuator, operative when said speed is below the predetermined value, to move the blades to a coarse pitch position.

Claim 17

A ram-air turbine including a rotor having blades whose pitch is variable, a governor responsive to the rotational speed of the rotor, an actuator of balanced-vane type, the casing vanes and shaft vanes of which are both angularly movable, one in a direction opposite to the other in order to apply pitch-changing forces to the rotor blades at diametrically opposite points of the blades for effecting pitch variation of the blades, and a valve whose position is controlled by the governor for directing fluid under pressure to at least one part of the actuator to effect pitch variation in one direction and for directing fluid under pressure to at least one other part of the actuator to effect pitch variation in the other direction, when the rotatiOnal speed of the rotor is above a predetermined value, and for connecting all the part of the actuator to a source of low pressure when said speed is below the predetermined value, and spring means comprising a single torsion spring associated with the actuator, operative when said speed is below the predetermined value, to move the blades to a coarse pitch position.