Joint for use in aircraft construction

Abstract

A joint for use in aircraft construction, for example a wing, comprises: a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface; and a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end. The first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap. The exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap. The first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface.

The invention claimed is: 
     
       1. A joint for use in aircraft construction comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface;   (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end;   wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface.   
     
     
       2. A joint as claimed in claim  1  9, wherein the thickness of the first portion of the butt-strap at the junction is small compared to the thickness of the cover skin. 
     
     
       3. A joint as claimed in  claim 2 , wherein the thickness of the distal end of the first portion of the butt-strap is substantially zero. 
     
     
       4. A joint as claimed in claim  1  9, wherein the first portion of the butt-strap is located so that, adjacent to the junction, the exterior surface of the skin is substantially coplanar with the exterior surface of the first portion of the butt-strap. 
     
     
       5. A joint as claimed in  claim 1 , wherein the first portion of the butt-strap is located so that, adjacent to the junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a curved substantially continuous exterior surface. 
     
     
       6. A joint as claimed in  claim 1  for use in aircraft construction comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface; 
 (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end; 
 
       wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface, wherein the joint includes filler or a filler plate located in a recess channel formed by the distal end of the first portion of the butt-strap and the exterior surface of the cover skin adjacent the junction. 
     
     
       7. A joint as claimed in claim  1  9, wherein the first portion is wedge-shaped. 
     
     
       8. A joint as claimed in claim  1  9, wherein the tapering portion forms an angle of approximately 3° at its distal portion. 
     
     
       9. A joint as claimed in  claim 1  for use in aircraft construction comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion said distal portion having an exterior-facing surface; 
 (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end; 
 
       wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface, wherein the skin is of substantially the same thickness in the proximal portion and in the distal portion and the distal portion is offset from the proximal portion at an angle that orients the exterior-facing surface of the distal portion so that it is complementary to the tapering first portion of the butt-strap. 
     
     
       10. A joint as claimed in claim  1  9, wherein the first portion of the butt-strap is connected to the skin by a fastener. 
     
     
       11. A joint as claimed in  claim 1 , wherein the butt-strap comprises a second portion for connection to an aircraft structure. 
     
     
       12. A joint as claimed in claim  1  9, wherein the butt-strap comprises a second portion for connection to an aircraft structure, and wherein the aircraft structures include a leading-or trailing-edge structure. 
     
     
       13. A joint as claimed in claim  1  9, wherein the cover skin is made of a composite material. 
     
     
       14. A joint as claimed in claim  1  9, wherein the butt-strap is made of a metallic material. 
     
     
       15. A joint as claimed in  claim 1 , further comprising a filler plate arranged to fill a space between the aircraft structure and the second portion of the butt-strap. 
     
     
       16. A joint as claimed in  claim 15  wherein the plate is wedge-shaped. 
     
     
       17. A joint as claimed in claim  1  9, wherein the distal portion of the skin is truncated at the upper or lower surface of its distal end. 
     
     
       18. A joint as claimed in  claim 17  wherein the truncated region has a shape complementary to the shape of a third portion of the butt-strap, the third portion being between the first portion and the second portion. 
     
     
       19. A joint as claimed in  claim 17 , wherein the truncated region acts to retain the skin against the butt-strap. 
     
     
       20. A joint as claimed in claim  1  9, wherein the cover skin further comprises a proximal portion and wherein the proximal portion and the distal portion of the second exterior surface of the skin meet to form a step region. 
     
     
       21. A joint as claimed in  claim 20  wherein the step region retains a distal end of the butt-strap. 
     
     
       22. A joint as claimed in claim  1  9, wherein a plurality of said butt-straps is spliced together by connection to an aircraft structure. 
     
     
       23. A joint as claimed in claim  1  9, wherein the butt-strap comprises a portion that extends into a pylon region of the wing. 
     
     
       24. An aircraft structure, aerodynamic surface, wing, fin or horizontal stabilizer, incorporating a joint as claimed in  claim 1 . 
     
     
       25. A wing incorporating a joint as claimed in  claim 1 , wherein the exterior-facing surface of the distal portion of the skin is formed in a first region of the wing's leading or trailing edge by moulding and in a second region of the wing's leading or trailing edge by machining. 
     
     
       26. A wing as claimed in  claim 25  wherein the moulded region of the distal portion runs parallel to spars of the wing. 
     
     
       27. A wing as claimed in  claim 25 , wherein the machined region is located at an undercarriage rib of the wing. 
     
     
       28. A joint as claimed in claim  1  9, wherein the butt-strap comprises a second portion for connection to an aircraft structure, and wherein the second portion of the butt-strap has the same form as the first portion and functions in a similar manner to said first portion. 
     
     
       29. A method of manufacturing a joint for use in aircraft construction comprising forming a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface, forming a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end wherein the method further comprises connecting the first portion of the butt-strap to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface. 
     
     
       30. A method as claimed in  claim 29  wherein the exterior-facing surface of the distal portion of the skin is formed by moulding. 
     
     
       31. An aircraft constructed using one or more joints as claimed in  claim 1 . 
     
     
       32. A joint as claimed in claim 10, wherein said fastener is a bolt including a tapered washer. 
     
     
       33. A joint as claimed in claim 10, wherein said fastener is a bolt including a tapered collar. 
     
     
       34. A method of manufacturing the joint as claimed in claim 6, the method comprising: forming a cover skin having an interior surface, an exterior surface and a distal portion said distal portion having an exterior-facing surface, forming a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end wherein the method further comprises connecting the first portion of the butt-strap to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface. 
     
     
       35. A method of manufacturing the joint as claimed in claim 9, the method comprising: forming a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface, forming a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end wherein the method further comprises connecting the first portion of the butt-strap to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface. 
     
     
       36. An aircraft wing, an aircraft fin, or an aircraft horizontal stabilizer, incorporating a joint comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface;   (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end;   
       wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface, wherein the joint includes filler located in a channel formed by the distal end of the first portion and the exterior surface of the cover skin adjacent the junction. 
     
     
       37. An aircraft wing, an aircraft fin, or an aircraft horizontal stabilizer, incorporating a joint comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion said distal portion having an exterior-facing surface;   (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end;   
       wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface, wherein the skin is of substantially the same thickness in the proximal portion and in the distal portion and the distal portion is offset from the proximal portion at an angle that orients the exterior-facing surface of the distal portion so that it is complementary to the tapering first portion of the butt-strap. 
     
     
       38. A wing incorporating a joint as claimed in claim 6, wherein the exterior-facing surface of the distal portion of the skin is formed in a first region of a wing's leading or trailing edge by molding and in a second region of the wing's leading or trailing edge by machining. 
     
     
       39. A wing incorporating a joint as claimed in claim 9, wherein the exterior-facing surface of the distal portion of the skin is formed in a first region of a wing's leading or trailing edge by molding and in a second region of the wing's leading or trailing edge by machining. 
     
     
       40. An aircraft constructed using one or more joints each comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion, said distal portion having an exterior-facing surface;   (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end;   
       wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that, at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface, wherein the joint includes filler located in a channel formed by the distal end of the first portion and the exterior surface of the cover skin adjacent the junction. 
     
     
       41. An aircraft constructed using one or more joints each comprising:
 (i) a cover skin having an interior surface, an exterior surface and a distal portion said distal portion having an exterior-facing surface;   (ii) a butt-strap having a first portion for connection to the skin, said first portion having an interior surface, an exterior surface and a distal end;   
       wherein the first portion of the butt-strap is connected to the distal portion of the skin such that a junction is formed between the exterior surface of the skin and the exterior surface of the first portion of the butt-strap and wherein the exterior-facing surface of the distal portion of the skin is of a shape complementary to the shape of the interior surface of the first portion of the butt-strap and wherein the first portion of the butt-strap tapers towards its distal end such that at said junction, the exterior surface of the skin and the exterior surface of the first portion of the butt-strap form a substantially continuous exterior surface, wherein the skin is of substantially the same thickness in the proximal portion and in the distal portion and the distal portion is offset from the proximal portion at an angle that orients the exterior-facing surface of the distal portion so that it is complementary to the tapering first portion of the butt-strap. 
     
     
       42. A wing as claimed in claim 38 wherein the moulded region of the distal portion runs parallel to spars of the wing. 
     
     
       43. A wing as claimed in claim 39 wherein the moulded region of the distal portion runs parallel to spars of the wing. 
     
     
       44. A wing as claimed in claim 38, wherein the machined region is located at an undercarriage rib of the wing. 
     
     
       45. A wing as claimed in claim 39, wherein the machined region is located at an undercarriage rib of the wing. 
     
     
       46. A method as claimed in claim 34 wherein the exterior-facing surface of the distal portion of the skin is formed by moulding. 
     
     
       47. A method as claimed in claim 35 wherein the exterior-facing surface of the distal portion of the skin is formed by moulding.