Following in the wake of German aviation pioneer Hugo Junkers, who first used corrugated aluminium to stiffen the fuselage skin of his aircraft, EADS aerostructure subsidiary Premium Aerotec has developed a composite wing spar for Boeing which has a sine wave-shaped vertical section to save weight.

The Augsburg-headquartered company designed and manufactured the 2.5m (8ft) wing spar demonstrator following a two-year technology project with the US airframer. This is not the first co-operation between the two firms, however, as Premium Aerotec is already supplying pressure bulkheads for the Boeing 787.

Premium Aerotec sine wave

The German manufacturer says the corrugated design can significantly reduce weight compared with conventional layouts with straight vertical sections, which typically need reinforcing either in discrete areas or across the full length.

A patented vacuum-assisted process was used to manufacture the corrugated spar as a monolithic component in a single, "one shot" infusion cycle. A huge amount of carbonfibres were used to weave the flange and caps together to avoid reinforcing the joint with additional material such as bolted or bonded doublers. This joining method alone saved about 10% weight, says the manufacturer.

Premium Aerotec is building an engineering centre in Augsburg, which is due to open next spring and accommodate about 300 staff.

Source: Flight Daily News