Enhanced wing efficiency via differential thermal coefficient of expansion spar caps
AssigneeNorthrop Grumman Systems Corporation
InventorCHARLES R. SMITH
Life of this patent
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Abstract
An aircraft structural component, for example, a wing spar that has an I-beam shape having upper and lower spar caps coupled by a web therebetween and that provides structural support for an aircraft wing. The wing spar may be fabricated as a graphite composite that is thermally cured to have a certain stiffness. In one embodiment, the wing spar is fabricated so that the upper spar cap has a higher CTE than the web, which creates tension forces in the spar cap when the spar is thermally cured and then cooled. Therefore, when the wing spar is mounted to the wing and the aircraft is in flight, compression forces on the wing skin act to relieve the tension forces in the spar cap, which reduces the compression buckling load on the wing.
Claims20
An aircraft wing comprising:
- an outer aircraft skin including an upper skin portion and a lower skin portion defining a chamber therebetween;
- and
- a wing spar extending some length of the wing and being positioned within the chamber, said wing spar including an upper spar cap coupled to an inside surface of the upper skin portion, a lower spar cap coupled to an inside surface of the lower skin portion, and a web formed to the upper and lower spar caps, wherein the upper spar cap is configured in a manner that causes it to have built-in tension so that compression forces on the upper skin portion during flight operate to reduce the tension in the upper spar cap.
An aircraft component comprising:
- an aerodynamic portion that is under compression loading during aircraft flight;
- and
- a structural portion coupled to the aerodynamic portion that is configured in a manner so that it has built-in tension that operates to reduce the compression loading on the aerodynamic portion.
An aircraft wing comprising:
- an outer aircraft skin including an upper skin portion and a lower skin portion defining a chamber therebetween;
- and
- a graphite composite wing spar that is thermally cured and is positioned within the chamber and extends some length of the wing, said wing spar including an upper spar cap coupled to an inside surface of the upper skin portion, a lower spar cap coupled to an inside surface of the lower skin portion, and a web formed to the upper and lower spar caps, wherein the upper spar cap and the lower spar cap have a higher coefficient of thermal expansion (CTE) than the web so that the upper and lower spar caps are under tension after the spar is cooled so that compression forces on the wing during flight operate to reduce the tension in the upper or lower spar cap.
Dependencies are inferred from the claim text.