Fixed outboard engine tiltrotor with leading edge drive system and angled rotation spindle configuration
The present invention includes a rotorcraft drive system comprising: an engine positioned at an end of a wing between a mid-wing spar and an aft-wing spar; a spindle positioned forward from the engine, the spindle capable of rotation between a hover and forward flight position, wherein the spindle rotates about a rotation bearing on an inboard split rib and an outboard tip rib or in a cantilevered spindle configuration supported by the inboard tip rib; and a tilt axis driveshaft connected to the engine, wherein the tilt axis drive shaft connects to a plurality of gears and shafts that transmit power from the engine to a proprotor gear box when the spindle is in: a forward position, a hover position, and during a transition between the forward position and the hover position without loss of power to the proprotor gear box.
1. A rotorcraft drive system comprising:
a fixed engine positioned at a wingtip of a wing member between a mid-wing spar and an aft-wing spar, wherein a center of gravity of the fixed engine is forward from the aft-wing spar;
a spindle positioned forward from the engine, the spindle capable of rotation between a hover and forward flight position, wherein the spindle rotates about a rotation bearing on an inboard split rib and an outboard tip rib or in a cantilevered spindle configuration supported by the inboard tip rib;
an interconnect drive shaft connected to the fixed engine, wherein the interconnect drive shaft passes through the wing member between a forward wing spar and a mid-wing spar of the wing member; and
a tilt axis driveshaft connected to the engine, wherein the tilt axis drive shaft connects to a plurality of gears and shafts that transmit power from the engine to a proprotor gear box when the spindle is in: a forward position, a hover position, and during a transition between the forward position and the hover position without loss of power to the proprotor gear box.
2. The rotorcraft drive system of claim 1 , wherein the tilt axis driveshaft connects to the engine by a bevel gear.
3. The rotorcraft drive system of claim 1 , wherein the tilt axis driveshaft connects to the gears and shafts in the spindle by a bevel gear.
4. The rotorcraft drive system of claim 1 , wherein the tilt axis driveshaft further comprises a gear at an inboard end that connects to an interconnect drive shaft through a bevel gear located within the spindle, wherein the spindle is angled.
5. The rotorcraft drive system of claim 1 , wherein the plurality of gears and shafts that transmit power from the engine to a proprotor gear box further comprise an aft beveled gear that connects to a shaft that transmits power to a reducer gear connected to a proprotor input shaft that connects to the proprotor gear box.
6. The rotorcraft drive system of claim 1 , wherein the inboard split rib and an outboard tip rib form a cradle that supports the engine.
7. The rotorcraft drive system of claim 1 , wherein the shafts are composite shafts.
8. The rotorcraft drive system of claim 1 , further comprising a proprotor connected to the proprotor gearbox.
9. The rotorcraft drive system of claim 1 , wherein rotation of the spindle allows structural continuity for rotor loads in the primary structure.
10. The rotorcraft drive system of claim 1 , wherein the interconnect drive shaft is positioned behind the forward wing spar.
11. A method for transitioning a rotorcraft between a hover and forward flight mode comprising:
positioning a fixed engine at a wingtip of a wing between a mid-wing spar and an aft-wing spar, wherein a center of gravity of the fixed engine is forward from the aft-wing spar;
providing a spindle positioned forward from the engine, the spindle capable of rotation between a hover and forward flight position, wherein the spindle rotates about a rotation bearing on an inboard split rib and an outboard tip rib or in a cantilevered spindle configuration supported by the inboard tip rib;
positioning an interconnect drive shaft connected to the fixed engine, wherein the interconnect drive shaft passes through the wing member between a forward wing spar and a mid-wing spar of the wing member; and
connecting a tilt axis driveshaft connected to the engine, wherein the tilt axis drive shaft connects to a plurality of gears and shafts that transmit power from the engine to a proprotor gear box when the spindle is in a forward position, a hover position, and during the transition between the forward and hover positions without loss of power to the proprotor gear box.
12. The method of claim 11 , further comprising connecting the tilt axis driveshaft to the engine by a bevel gear.
13. The method of claim 11 , further comprising connecting the tilt axis driveshaft to the gears and shafts in the spindle by a bevel gear.
14. The method of claim 11 , further comprising connecting the tilt axis driveshaft that further comprises a gear at an inboard end to an interconnect drive shaft through a bevel gear located within an angled spindle.
15. The method of claim 11 , further comprising connecting the plurality of gears and shafts that transmit power from the engine to a proprotor gear box that comprise an aft beveled gear to a shaft that transmits power to a reducer gear connected to a proprotor input shaft that is connected to the proprotor gear box.
16. The method of claim 11 , wherein the inboard split rib and an outboard tip rib form a cradle that supports the engine.
17. The method of claim 11 , wherein the shafts are composite shafts.
18. The method of claim 11 , further comprising connecting a proprotor to the proprotor gearbox.
19. The method of claim 11 , wherein the rotation of the spindle allows structural continuity for rotor loads in the primary structure.
20. An aircraft comprising:
a fuselage connected to a wing member;
a fixed engine positioned at a wingtip of the wing member between a mid-wing spar and an aft-wing spar, wherein a center of gravity of the fixed engine is forward from the aft-wing spar;
a spindle positioned forward from the engine, the spindle capable of rotation between a hover and forward flight position, wherein the spindle rotates about a rotation bearing on an inboard split rib and an outboard tip rib or in a cantilevered spindle configuration supported by the inboard tip rib;
an interconnect drive shaft connected to the fixed engine, wherein the interconnect drive shaft passes through the wing member between a forward wing spar and a mid-wing spar of the wing member; and
a tilt axis driveshaft connected to the engine, wherein the tilt axis drive shaft connects to a plurality of gears and shafts that transmit power from the engine to a proprotor gear box when the spindle is in: a forward position, a hover position, and during a transition between the forward position and the hover position without loss of power to the proprotor gear box.
21. The aircraft of claim 20 , wherein the tilt axis driveshaft connects to the engine by a bevel gear, connect to the gears and shafts in the spindle by a bevel gear, and connects at an inboard end with a bevel gear located within an angled spindle.
22. The aircraft of claim 20 , wherein the plurality of gears and shafts that transmit power from the engine to a proprotor gear box further comprise an aft beveled gear that connects to a shaft that transmits power to a reducer gear connected to a proprotor input shaft that connects to the proprotor gear box.
23. The aircraft of claim 20 , wherein the wings are swept wings.