Aircraft

In addition to the composite structures used in the current 747, the new design will add composite flaps, ailerons, spoilers and a new lower rudder. "We've created a double-hinge rudder for increased engine-out capability," says 747 chief project engineer Corky Townsend.

A new integrated system dubbed "spudders", or spoilers and rudder, is also being developed to help control in the event of an engine-out condition. The system, which triggers ground spoilers to asymmetrically activate will "automatically kick in" if an engine is lost, Townsend adds.

The spoilers and outboard ailerons will be fly-by-wire controlled to enable manoeuvre load alleviation. This has also enabled around 900kg (1,980lb) of weight saving from the wing and body structure. The leading edge of the wing, which is deeper in cross-section and therefore structurally lighter, is also to be gapped for improved lift.

Boeing continues to study the use of body-angle controlled descents rather than pure-flap controlled approaches in a bid to cut noise that would involve the electronic tail strike protection system feeding directly into a pitch augmentation system.

Studies of noise characteristics have concluded that Boeing can now guarantee QC1 (London Quota Count) noise levels for the passenger version and hope to offer it on the freighter.