Wingbox

The wingbox of a fixed-wing aircraft is the primary load-carrying structure of the wing, which forms the structural centre of the wings and is also the attachment point for other wing components such as leading edge flaps, swing wings, trailing edge flaps and wing-tip devices. The wingbox continues beyond the visible wing roots and interfaces with the fuselage in the centre wingbox, which forms the structural core of an aircraft.

The wingbox is so called since, on many designs, the combination of the forward and rear wing spars and the upper and lower wing skins together form a natural "box" shape running through the wing.^[1] While internal wing structure commonly provides much of the strength via a combination of spars, ribs and stringers, the external skin typically carries a proportion of the loads too. On many aircraft, the inner volume of the wingbox has also been used to store fuel, which is commonly referred to as being a wet wing design.^[1]

In recent years, there has been an increasing use of composite materials within the wingbox; this trend has largely been pursued to achieve lower weights over designs only using conventional materials.^[2][3] Specifically, carbon fibre has become a popular material due to its very high strength-to-weight ratio.^[4] During January 2017, European aerospace conglomerate Airbus Group announced that they had created the world's first single-piece composite center wingbox, stating that it represented a 20 per cent reduction in the cost of manufacturing by being easier to assemble.^[5]