Wing-nacelle splice assemblies for tiltrotor aircraft

1. A propulsion and lift system of a tiltrotor aircraft comprising:

a wing including a torque box having an outboard end and a forward spar;

a wing tip assembly including a wing tip box having an inboard end and a forward spar;

a fixed nacelle coupled to the wing tip assembly; and

a wing-nacelle splice assembly having inboard and outboard sides, the inboard side of the wing-nacelle splice assembly coupled to the outboard end of the torque box, and the outboard side of the wing-nacelle splice assembly coupled to the inboard end of the wing tip box, thereby coupling the fixed nacelle to the wing;

wherein the wing-nacelle splice assembly further comprises a plurality of fasteners coupled to the forward spars of the torque box and the wing tip box.

2. The propulsion and lift system as recited in claim 1 wherein the inboard end of the wing tip box further comprises an inboard tip rib having an inboard flange, the wing-nacelle splice assembly coupled to the outboard end of the torque box and the inboard flange of the inboard tip rib.

3. The propulsion and lift system as recited in claim 1 wherein the torque box and the wing tip box each further comprise a lower skin, the wing-nacelle splice assembly further comprising a lower torque box shear strap coupled to the lower skins of the torque box and the wing tip box.

4. The propulsion and lift system as recited in claim 3 wherein the torque box and the wing tip box each further comprise an upper skin, the wing-nacelle splice assembly further comprising an upper torque box shear strap coupled to the upper skins of the torque box and the wing tip box.

5. The propulsion and lift system as recited in claim 4 wherein the wing tip assembly further comprises an inboard tip rib including an upper inboard flange interposed between the upper skins and a lower inboard flange interposed between the lower skins;

wherein the lower torque box shear strap is coupled to the lower skin of the torque box and the lower inboard flange; and

wherein the upper torque box shear strap is coupled to the upper skin of the torque box and the upper inboard flange.

6. The propulsion and lift system as recited in claim 5 wherein the upper inboard flange and the upper skin of the torque box each have outer and inner surfaces; and

wherein the upper torque box shear strap further comprises an outer strap and an inner strap, the outer strap coupled to the outer surface of the upper inboard flange and the outer surface of the upper skin of the torque box, and the inner strap is coupled to the inner surface of the upper inboard flange and the inner surface of the upper skin of the torque box such that the upper inboard flange and an outboard edge of the upper skin of the torque box are sandwiched by the outer and inner straps.

7. The propulsion and lift system as recited in claim 1 wherein the torque box and the wing tip box each further comprise an aft spar, the wing-nacelle splice assembly further comprising an aft spar splice coupled to the aft spars of the torque box and the wing tip box.

8. The propulsion and lift system as recited in claim 7 wherein the torque box and the wing tip box each further comprise a lower skin having an outer surface; and

wherein the wing-nacelle splice assembly further comprises an aft spar splice support at least partially covering the outer surfaces of the lower skins, the aft spar splice support disposed beneath and coupled to the aft spar splice to provide support thereto.

9. The propulsion and lift system as recited in claim 8 wherein the wing tip assembly further comprises an inboard tip rib including a forward inboard flange interposed between the forward spars and an aft inboard flange interposed between the aft spars;

wherein the plurality of fasteners are coupled to the forward spar of the torque box and the forward inboard flange; and

wherein the aft spar splice is coupled to the aft spar of the torque box and the aft inboard flange.

10. The propulsion and lift system as recited in claim 9 wherein the forward spar of the torque box further comprises a tab out adapted to overlap the forward inboard flange, the plurality of fasteners adapted to couple the tab out to the forward inboard flange.

11. The propulsion and lift system as recited in claim 1 wherein the wing further comprises a wing cove section having an outboard end and the wing tip assembly further comprises a wing tip cove section having an inboard end, the wing-nacelle splice assembly coupled to the outboard end of the wing cove section and the inboard end of the wing tip cove section.

12. The propulsion and lift system as recited in claim 11 wherein the wing cove section and the wing tip cove section each further comprise a lower skin, the wing-nacelle splice assembly further comprising a lower cove shear strap coupled to the lower skins of the wing cove section and the wing tip cove section.

13. The propulsion and lift system as recited in claim 12 wherein the wing cove section and the wing tip cove section each further comprise an upper skin, the wing-nacelle splice assembly further comprising an upper cove shear strap coupled to the upper skins of the wing cove section and the wing tip cove section.

14. The propulsion and lift system as recited in claim 13 wherein the wing tip assembly further comprises an inboard tip rib including lower and upper inboard flanges;

wherein the wing cove section further comprises an outboard cove rib including lower and upper outboard flanges;

wherein the lower cove shear strap is coupled to the lower outboard flange of the outboard cove rib and the lower inboard flange of the inboard tip rib; and

wherein the upper cove shear strap is coupled to the upper outboard flange of the outboard cove rib and the upper inboard flange of the inboard tip rib.

15. The propulsion and lift system as recited in claim 14 wherein the outboard cove rib includes an aft outboard flange and the wing tip cove section includes an aft cove spar; and

wherein the wing-nacelle splice assembly further comprises an aft cove splice coupled to the aft outboard flange of the outboard cove rib and the aft cove spar of the wing tip cove section.

16. A tiltrotor aircraft comprising:

a fuselage;

a wing including a torque box supported by the fuselage and having a forward spar and first and second outboard ends;

first and second wing tip assemblies including first and second wing tip boxes each having an inboard end and a forward spar;

first and second fixed nacelles each coupled to a respective one of the first and second wing tip assemblies; and

first and second wing-nacelle splice assemblies, the first wing-nacelle splice assembly coupled to the first outboard end of the torque box and the inboard end of the first wing tip box the second wing-nacelle splice assembly coupled to the second outboard end of the torque box and the inboard end of the second wing tip box;

wherein the wing-nacelle splice assemblies further comprise a plurality of fasteners coupled to the forward spars of the torque box and the wing tip boxes.

17. The tiltrotor aircraft as recited in claim 16 wherein the wing further comprises a wing cove section;

wherein the first and second wing tip assemblies each further comprise a wing tip cove section; and

wherein the first and second wing-nacelle splice assemblies each further comprise a box joint subassembly and a cove joint subassembly, each box joint subassembly coupled to a respective one of the wing tip boxes and a respective outboard end of the torque box, each cove joint subassembly coupled to a respective one of the wing tip cove sections and a respective outboard end of the wing cove section.

18. The tiltrotor aircraft as recited in claim 16 wherein each wing tip assembly further comprises inboard and outboard tip ribs having pillow block mounts protruding vertically therefrom and rotatably coupled to a pylon assembly.