Airfoil leading edge structure with boundary layer control

Claim 2

In the leading edge structure of an airfoil, a spar spanwise thereof, front opening jaws on the spar, a boundary layer control duct supported in the jaws, and having a longitudinally extending slot along the forward side thereof, which slot has coextensive, relatively upper and lower lips projecting outboard from the upper and lower edges thereof, the upper of which lips extends reentrantly upwardly and distantly away from the upper edge of the slot, and forms the overside of the leading edge of the airfoil, and the lower of which lips forms a throat with the upper lip, outboard of the slot, and has a deflector thereon which forms a convergent nozzle with the upper lip, through which the throat discharges upwardly over the outer surface of the upper lip, said duct being part cylindrical in cross section, and mounted in jaws of complementary cross section, with symmetrically radially oriented spacers interposed therebetween.

Claim 3

The leading edge structure according to claim 1 wherein the distal end edge of the upper lip coterminates with the upper surface skin of the airfoil, adjacent the top of the spar.

Claim 4

The leading edge structure according to claim 1 further comprising a section of skin depending from the lower lip and swept back below the duct to form the underside of the leading edge of the airfoil.

Claim 5

The leading edge structure according to claim 1 wherein the deflector is removably attached to the lower lip.

Claim 6

In an airfoil, a main frame having a spar which extends spanwise of the airfoil, and which has bracket means thereon that project relatively forwardly from the spar and define front opening jaws on the frame, a skin covering the frame at the periphery of the airfoil, and terminating at the rear of the jaws adjacent the spar, and a leading edge structure on the frame including a boundary layer control duct which is supported in the jaws and has a longitudinally extending slot in the relatively forward side thereof, said duct having upper and lower lips projecting from the upper and lower edges of the slot, the upper of which lips eXtends upwardly above the bracket means and rearwardly of the slot, and forms the overside of the leading edge of the airfoil, and the lower of which lips forms a throat with the upper lip, and has means thereon forming a nozzle whereby the throat discharges upwardly over the outer surface of the upper lip, said upper lip mating with the skin adjacent the top of the spar, to form a smooth continuous contour over the upper surface of the airfoil, said duct being supported in spaced relationship to the jaws and said leading edge structure being secured to the bracket means so that said structure is shiftable in relation to the frame as the structure undergoes expansion and contraction in use.

Claim 7

In an airfoil, a main frame having a spar which extends spanwise of the airfoil, and which has bracket means thereon that project relatively forwardly from the spar and define front opening jaws on the frame, a skin covering the frame at the periphery of the airfoil, and terminating at the rear of the jaws adjacent the spar, and a leading edge structure on the frame including a boundary layer control duct which is supported in the jaws and has a longitudinally extending slot in the relatively forward side thereof, said duct having upper and lower lips projecting from the upper and lower edges of the slot, the upper of which lips eXtends upwardly above the bracket means and rearwardly of the slot, and forms the overside of the leading edge of the airfoil, and the lower of which lips forms a throat with the upper lip, and has means thereon forming a nozzle whereby the throat discharges upwardly over the outer surface of the upper lip, said upper lip mating with the skin adjacent the top of the spar, to form a smooth continuous contour over the upper surface of the airfoil, said duct being supported in spaced relationship to the jaws and said leading edge structure being secured to the bracket means so that said structure is shiftable in relation to the frame as the structure undergoes expansion and contraction in use.

Claim 8

The airfoil according to claim 5 wherein the leading edge structure also includes a section of skin which depends from the lower lip of the duct and is swept back below the bracket means to form the underside of the leading edge of the airfoil.

Claim 9

The airfoil according to claim 6 wherein the swept-back skin section terminates in spaced relationship to the frame adjacent the bottom of the spar.

Claim 10

The airfoil according to claim 5 wherein the duct and jaws have complementary cross sections and are spaced apart by symmetrically disposed spacers interposed therebetween.

Claim 11

The airfoil according to claim 5 wherein the upper lip of the duct projects relatively forwardly from the upper edge of the slot, and thence extends reentrantly upwardly above the bracket means in spaced relationship to the main body of the duct.

Claim 12

In an airfoil, a main frame having a spar which extends spanwise of the airfoil, and which has bracket means thereon that project relatively forwardly from the spar, a skin covering the frame at the periphery of the airfoil, and terminating at the rear of the bracket means adjacent the spar, and a leading edge structure on the frame including a boundary layer control duct which is supported in the bracket means and has a longitudinally extending slot in the relatively forward side thereof, said duct having upper and lower lips projecting from the upper and lower edges of the slot, the upper of which lips extends upwardly above the bracket means and rearwardly of the slot, and forms the overside of the leading edge of the airfoil, and the lower of which lips forms a throat with the upper lip, and has means thereon forming a nozzle whereby the throat discharges upwardly over the outer surface of the upper lip, said upper lip mating with the skin adjacent the spar, to form a smooth continuous contour over the upper surface of the airfoil, said duct being supported in spaced relationship to the bracket means and being secured to the bracket means so that said duct is shiftable in relation to the frame as the duct undergoes expansion and contraction in use.

Claim 13

In an airfoil, a main frame having a spar which extends spanwise of the airfoil, and which has bracket means thereon that project relatively forwardly from the spar, a skin covering the frame at the periphery of the airfoil, and terminating at the rear of the bracket means adjacent the spar, and a leading edge structure on the frame including a boundary layer control duct which is supported in the bracket means and has a longitudinally extending slot in the relatively forward side thereof, said duct having upper and lower lips projecting from the upper and lower edges of the slot, the upper of which lips extends upwardly above the bracket means and rearwardly of the slot, and forms the overside of the leading edge of the airfoil, and the lower of which lips forms a throat with the upper lip, and has means thereon forming a nozzle whereby the throat discharges upwardly over the outer surface of the upper lip, said upper lip mating with the skin adjacent the spar, to form a smooth continuous contour over the upper surface of the airfoil, said duct being supported in spaced relationship to the bracket means and being secured to the bracket means so that said duct is shiftable in relation to the frame as the duct undergoes expansion and contraction in use.