The wing of an aircraft is typically constructed from ribs, spars and skin panels (e.g., an upper skin panel and a lower skin panel). Specifically, the ribs are spaced apart from each other along the length of the wing. The forward ends of the ribs are connected to the forward spar, while the aft ends of the ribs are connected to the aft spar. The upper skin panel is connected to the upper portion of each rib, while the lower skin panel is connected to the lower portion of each rib.
Thus, the ribs, the spars and the skin panels define an enclosed wing box that, for certain aircraft, may be used as a tank for fuel storage purposes. Once the wing box is enclosed, any work that must be performed in the wing requires personnel to enter a confined space. Therefore, various safety precautions must be taken, which increases the overall cost of aircraft manufacture.
To avoid the confined space issue, split wing designs were developed. As one example, a two-piece rib was used, wherein the upper skin panel was connected to an upper rib portion and the lower skin panel was connected to a lower rib portion. Therefore, the wing box may be opened to facilitate work or inspection, and then closed by joining the upper rib portion with the lower rib portion. However, the process of aligning and joining the upper and lower rib portions is time consuming and the fasteners used add significant weight to the aircraft.
Accordingly, those skilled in the art continue with research and development efforts directed to the joining of structural members.