Hybrid ram air turbine
An example a ram air turbine assembly (RAT) is mounted to an airframe and provides both electric power and hydraulic pressure. A turbine drives a drive shaft about an axis transverse to rotation of the turbine. The drive shaft in turn drives both a generator and a hydraulic pump at a common speed.
1. A ram air turbine assembly comprising:
a strut movable about a pivot axis between a deployed position and a stowed position;
a turbine supported by the strut;
a drive shaft rotatable about a first axis transverse to a rotation axis of the turbine and the pivot axis;
a generator driven by the drive shaft; and
a hydraulic pump driven by the drive shaft, wherein the drive shaft, generator and hydraulic pump are all movable with the strut between the deployed and stowed positions and are all aligned about the first axis transverse to the rotation axis of the turbine.
2. The ram air turbine assembly as recited in claim 1 , including a turbine shaft driven by the turbine, wherein the drive shaft is driven by the turbine shaft through a gearbox.
3. The ram air turbine assembly as recited in claim 2 , wherein the gearbox increases rotational speed of the drive shaft relative to the rotational speed of the turbine shaft.
4. The ram air turbine assembly as recited in claim 2 , wherein the gearbox includes a coupling shaft for back driving the turbine, generator and hydraulic pump.
5. The ram air turbine assembly as recited in claim 1 , including a coupling between the generator and the hydraulic pump.
6. The ram air turbine assembly as recited in claim 5 , wherein the coupling comprises a splined connection directly to a generator shaft.
7. The ram air turbine assembly as recited in claim 1 , including a swivel post supporting movement of the strut about the pivot axis between stowed and deployed positions, the swivel post including passages for communicating hydraulic fluid to the hydraulic pump.
8. The ram air turbine assembly as recited in claim 7 , wherein the swivel post includes a rotatable portion in fluid communication with a fixed portion.
9. The ram air turbine assembly as recited in claim 8 , wherein the rotatable portion includes openings that communicate with passages within the fixed portion.
10. A ram air turbine assembly comprising:
a generator supported within a generator housing;
a strut mounted to the generator housing, wherein the strut and generator housing are rotatable about an axis of rotation between a deployed position and a stowed position;
a gearbox supported on the strut;
a turbine driving the gearbox;
a drive shaft driven by the gearbox and extending through the strut to drive the generator; and
a hydraulic pump movable with the generator between the deployed and stowed positions, wherein the hydraulic pump is coupled to a shaft of the generator such that both the generator and hydraulic pump rotate at a common speed; and
a swivel post that supports movement of the generator and strut about the axis of rotation, wherein the swivel post includes fluid passages for communicating hydraulic fluid between the movable hydraulic pump and a static structure.
11. The ram air turbine assembly as recited in claim 10 , wherein the generator and the hydraulic pump are driven about an axis common to the drive shaft driven by the gearbox.
12. The ram air turbine assembly as recited in claim 10 , wherein the swivel post includes a fixed portion and a rotatable portion, the rotatable portion including at least one opening that communicates fluid to at least one passage in the fixed portion.
13. The ram air turbine assembly as recited in claim 10 , wherein the gearbox and turbine are mounted on a distal end of the strut relative to the generator.
14. The ram air turbine assembly as recited in claim 10 , wherein the swivel post includes a rotatable portion including annular channels in communication with openings defined within a fixed portion.
15. The ram air turbine assembly as recited in claim 14 , wherein the rotatable portion is received within the fixed portion.
16. The ram air turbine assembly as recited in claim 14 , wherein the annular channels include an inlet channel and an outlet channel and the openings defined in the fixed portion include an inlet opening in fluid communication with the inlet channel and an outlet opening in fluid communication with the outlet channel.
17. A method of providing emergency power in an aircraft including the steps of:
driving a drive shaft along a first axis transverse to a rotation axis of a turbine shaft driven by a turbine; and
driving a generator and hydraulic pump with the drive shaft at a common speed about the first axis, wherein the drive shaft, generator and hydraulic pump are all movable about a pivot axis with a strut between a deployed and a stowed position and are all aligned about a first axis transverse to the rotation axis of the turbine and the pivot axis.
18. The method as recited in claim 17 , including coupling the hydraulic pump to the generator for rotating the hydraulic pump at the common speed.
19. The method as recited in claim 17 , including increasing a speed of the drive shaft relative to a speed of the turbine shaft.
20. The method as recited in claim 17 , including routing hydraulic fluid through a swivel post, wherein the swivel post supports movement between deployed and stowed positions.