Aircraft flap hinge
Aerodynamic drag associated with a flap hinge assembly used to pivotally mount a flap to the trailing edge of an aircraft wing can be reduced when the cross-sectional area of the hinge fairing which surrounds the flap hinge assembly is reduced in size. The reduction in cross-sectional area of the hinge fairing is enabled when the flap hinge assembly attachment footprint to the underside of the flap box is also reduced. The flap hinge assembly has an internal support rib positioned between spars of the flap box structure internal to the skin, a hinge fitting exhibiting an actuation point and a hinge point positioned proximate a front spar of the flap box structure external to the skin, and a link passing through an aperture in the lower skin of the flap and coupling the internal support rib to the hinge fitting.
1. A flap hinge assembly of a flap pivotally mounting the flap to a trailing edge of an aircraft wing, the flap having a flap box structure including a plurality of spars, a plurality of ribs connecting between the spars, and a skin surrounding the spars and the ribs, the flap hinge assembly comprising:
an internal support rib positioned between the spars of the flap box structure and internal to the skin of the flap;
a hinge fitting having an actuation point, a hinge point, a horizontal load transfer face and a vertical load transfer face, the horizontal load transfer face and the vertical load transfer face of the hinge fitting positioned external to the skin of the flap respectively about a horizontal flange and a vertical web of a front spar of the flap box structure; and
a link passing through an aperture in a lower skin of the flap for coupling the internal support rib internal to the skin to the hinge fitting external to the skin.
2. The flap hinge assembly of claim 1 , wherein the hinge fitting extends external to the lower skin a chordwise distance from the front spar that is less than a distance between the front spar and a mid spar of the flap.
3. The flap hinge assembly of claim 1 , wherein the horizontal load transfer face of the hinge fitting has a first length approximately equal to a second length of the horizontal flange of the front spar, and the vertical load transfer face of the hinge fitting has a third length that is approximately equal to a fourth length of the vertical web of the front spar.
4. The flap hinge assembly of claim 1 , wherein the link comprises an elongated structure having a first hole at an upper end of the link and a second hole at a lower end of the link for coupling respectively to the internal support rib and the hinge fitting, the first hole positioned aft of the second hole.
5. The flap hinge assembly of claim 4 , wherein the internal support rib comprises a link attachment point positioned proximate a mid spar of the flap for coupling the first hole of the link to the internal support rib.
6. The flap hinge assembly of claim 4 , wherein the hinge fitting further comprises a connection flange for coupling the second hole of the link to the hinge fitting, the connection flange positioned between the hinge point and the horizontal load transfer face of the hinge fitting.
7. The flap hinge assembly of claim 6 , wherein the first hole, the second hole and the hinge point are aligned in a straight line.
8. The flap hinge assembly of claim 7 , wherein the straight line forms an aft angle relative to the lower skin that is greater than 90 degrees.
9. The flap hinge assembly of claim 5 , wherein the link attachment point is positioned between the front spar and the mid spar of the flap.
10. The flap hinge assembly of claim 5 , wherein the internal support rib comprises two webs connected together at a front region, a mid region and an aft region of the internal support rib to form spaces between the two webs, the link coupled in one of the spaces formed between the front region and the mid region.
11. A trailing edge flap for an aircraft wing comprising:
the flap comprising a flap box structure having a plurality of spars and a plurality of ribs connecting between the spars, a skin surrounding the flap box structure; and a flap hinge assembly for pivotally mounting the flap to a trailing edge of the aircraft wing, the flap hinge assembly comprising:
an internal support rib positioned between the spars of the flap box structure and internal to the skin;
a hinge fitting having an actuation point and a hinge point, the hinge fitting positioned proximate a front spar of the flap box structure external to the skin; and
a link comprising an elongated structure passing through an aperture in a lower skin of the flap and coupling the internal support rib through an upper end of the link to the hinge fitting through a lower end of the link external to the skin, the upper end of the link positioned aft of the lower end of the link.
12. The trailing edge flap of claim 11 , wherein the hinge fitting extends external to the lower skin a chordwise distance from the front spar that is less than a distance between the front spar and a mid spar of the flap.
13. The trailing edge flap of claim 11 , wherein the link comprises an elongated structure having a first hole and a second hole at respective ends of the link, the first hole and the second hole being coupled to the internal support rib and the hinge fitting respectively via pin joints acting in double shear.
14. The trailing edge flap of claim 13 , wherein the hinge fitting further comprises a connection flange for coupling the second hole of the link to the hinge fitting, the connection flange positioned between the hinge point and a horizontal load transfer face of the hinge fitting.
15. The trailing edge flap of claim 13 , wherein the internal support rib comprises a link attachment point positioned proximate a mid spar of the flap for coupling the first hole of the link to the internal support rib.
16. The trailing edge flap of claim 15 , wherein the link attachment point is positioned between the front spar and the mid spar of the flap.
17. The trailing edge flap of claim 13 , wherein the first hole, the second hole and the hinge point are aligned in a straight line.
18. The trailing edge flap of claim 17 , wherein the straight line forms an aft angle relative to the lower skin that is greater than 90 degrees.
19. A method for pivotally mounting a flap to a trailing edge of an aircraft wing, the flap comprising a flap box structure having spars and ribs connecting the spars, and a flap skin surrounding the spars and the ribs, the method comprising the steps of:
positioning an internal support rib between the spars of the flap and internal to the flap skin;
positioning a hinge fitting having an actuation point, a hinge point, a horizontal load transfer face and a vertical load transfer face proximate a front spar and external to the flap skin such that the horizontal load transfer face and the vertical load transfer face are positioned respectively about a horizontal flange and a vertical web of the front spar;
passing a link through an aperture in a lower skin of the flap; and
coupling the link to the internal support rib internal to the skin and to the hinge fitting external to the skin.
20. The trailing edge flap of claim 11 , wherein the hinge fitting further comprises a horizontal load transfer face and a vertical load transfer face positioned respectively about a horizontal flange of the front spar and a vertical web of the front spar.