Building The World's Largest Passenger Aircraft Wings - Part 2 - cadinfo.net

The Wing - Facts and Figures

The wing will be the largest ever produced for a civil airliner, at 17.7 metres from front to back where it meets the fuselage, and 36.3 metres from fuselage to wingtip - though being swept back, it's longer than this; the maximum length of metal in a single wing is 46 metres. The root of the wing - where it meets the fuselage - will have the internal height of an average domestic ceiling. The result will be an aircraft with a tip-to-tip wingspan of 79.8 metres - just inside the critical 80m measure that forms a practical working standard and means it will 'fit' existing runways, taxiways, and embarkation bridges.

Each wing has a surface area of 845 square metres - enough space for a good-sized building plot. It comprises approximately 25,500 different components from 52 major first-tier suppliers, over half of whom are UK based. Components also come from the Filton site, where metallic ribs are manufactured and the trailing edge of the wing assembled.

Each pair of wings is made up of:

• 20 aluminium alloy panels or 'skins'
• 124 ribs, 76 of which are metallic, and 48 made of carbon composite materials
• 6 aluminium alloy spars
• 314 wing stringers or stiffeners; 124 for the top wing skins, 190 for the bottom skins
• 16 leading 'edge', 6 trailing edge devices and 22 flying control surfaces
• 360,000 metres of wiring, piping and ducting to control the hydraulics and in turn the flaps, slats, spoilers and ailerons
• 750,000 fasteners (nuts, bolts and rivets).

The Wing - Design and Build

The challenging requirements have called for technological innovations in every area of the wings’ design and build, and a level of international collaboration that extends way beyond the Airbus wing design teams at Filton, and the other wing design offices in Bremen, Germany, Toulouse, France and Kansas, USA. Hundreds of companies are partnering Airbus on designing and manufacturing components for the wings with 12 - from Europe, Japan, and the USA, as well as the UK - working as full risk-sharing partners. It is truly an international effort, demanding technological innovation in both product and process, led by the British wing team.

The size and scale of the wing inevitably has led to challenges, but also opportunities. In order to meet the economic and environmental requirements, innovation has been required in virtually all areas of design: aerodynamics, structures, systems and design processes.

For example, engineers made extensive use of a software design process called KBE - Knowledge Based Engineering - which by capturing design knowledge and data speeded up the design process by around 40 per cent.. This process was applied to many different areas ranging from designing the optimum structure of the wing to the detailed design of individual component features. KBE facilitated the production of many hundreds of thousands more iterations; such methods have helped engineers design the most aerodynamic wing possible within the confines of a 80 metre box.

A rapid prototyping wind tunnel test process was developed which enabled many more design solutions to be tested. This rapid prototyping utilised a process called stereolithography in which a computer controlled laser is fired into a vat of liquid resin which then solidifies, resulting in a solid representation of the 3D computer geometry.

All design work runs parallel with continuing research into new materials, and the innovative use of existing materials for new or different applications, to maintain or increase structural strength without increasing weight disproportionately. The A380 wing is using new materials for virtually every component and has a new structural layout, containing air generation units within the wing, for example – a new challenge for designers. Other ‘firsts’ have been the use of composite wing ribs, which have significantly reduced weight, and, the addition of a ‘droop nose’; a movable high-lift device that has replaced the more common slat system on the inboard leading edge of the wing. The main advantage of this device the droop nose is a lower take-off drag than for a slat of comparable size, leading to an increase in the ratio between lift and drag. This will enable A380 to achieve a steeper climb gradient, helping to reduce noise on take-off and landing.

Working on the Components

Airbus has invested hundreds of millions of pounds in new buildings and facilities at Broughton to accommodate the wing manufacturing and assembly work. A new 22,000 sq.m building, the Stringer Manufacturing Centre is producing the bottom wing skin stringers (longitudinal stiffeners which strengthen wing skins) for the A380, and other Airbus models.

The scale of the task was such that they could not be absorbed into existing premises. The new facility can produce up to 200 km of stringers per year in an automated machining cell, which after forming are collated into complete 'panel sets' suspended in webbing, ready for attaching straight to the wing skins.

A 12,000 sq.m Skin Manufacturing Centre comprises two extensions to the previously existing Treatments Facility. Here 18 out of the 20 different aluminium alloy panels that form the eternal 'skin' of the wings for A380 are produced. The process for profiling the wing skin with 'facet' milling - used until now - has been replaced by 'strip process' milling.

This results in lower weight and simpler tooling for attaching the stringer. When milled, the skin varies in thickness between 6mm and 28mm and the largest single panel for milling is 35 metres long. All panels are machined at floor level, which together with a new system for vacuuming shards of sharp aluminium makes the job safer and more efficient.