1. Field
The present disclosure generally relates to airfoils, such as a wing box for an aircraft, and deals more particularly with an airfoil construction having a composite outer skin bonded to wing spars.
2. Background
Aircraft wings and/or control surfaces may employ a framework of spars, ribs and stringers that are covered with an outer skin. The spars may carry a majority of the wing load while the ribs both stiffen the wing and provide an airfoil shape for the wing skin. In the case of metal wing constructions, metal structures may be attached to the metal spars using fastener joints. However, the use of fastener joints may present difficulties in composite spar wing and control surface designs, in part because composites may have a lower bearing capacity than metals. Accordingly, composite wing constructions using fasteners may require reinforcements to increase their fastener bearing capacity in joint areas. The need to add reinforcements in the wing may reduce airfoil performance, add undesired weight to the aircraft and/or increase manufacturing costs.
Accordingly, there is a need for bonded joining of a composite wing and/or control surface structure and related fabrication method that may reduce or eliminate the need for fasteners in joints between a wing spar and a connected structures skin. There is also a need for an airfoil design such as a wing box that simplifies fabrication of wing components and allows pre-cured composite wing skins to be attached to pre-cured composite spars using adhesive bonding techniques in a secondary bonding operation.