Airbus is stepping up studies of a mid-life update for its A320 family, as details emerge of a proposal to equip the narrowbody with large winglets. The winglet concept is being tested on the manufacturer's A340-300 development aircraft.

The large winglets form part of an advanced wing design being studied by Airbus UK, which could be included in a possible upgrade programme for the A320 family. The Filton, UK-based wing-design centre plans to approach Airbus senior management for project authorisation as early as January, sources say. Airbus says it evaluates new concepts on an ongoing basis.

The A320's enlarged winglets would be about 2m (6.6ft) long, with a maximum chord of about 1m, and would be canted outwards at about 45¡. The vertical wingtip fences on the current A320 family wing are only 0.76m tall.

The design would be similar to the 3.7m GKN Aerospace Services (GKNAS)-manufactured winglet being tested on the A340 as part of the European Awiator (aircraft wing with advanced technology operation) research programme.

The A340's large winglet - about twice as big as the production standard 1.9m winglet - features a sharp wing-to-winglet kink that improves vortex reduction; significant outboard cant to benefit from the extra lift of an increased effective wingspan; and a 2m chord at its base.

The winglets use an aluminium structure shrouded in resin-fused carbonfibre to improve the aerodynamic surface with very fine tolerances. The 200kg (440lb) winglets will be flight tested on the A340 until mid-December to establish the dynamic response of the modified wing, which includes local wingtip strengthening for increased loads.

Phase two of the large winglet tests is planned for mid-2005, for which GKN will supply a lighter all-composite starboard winglet. Target weight for the second batch of large "production representative" A340 winglets would be 170-180kg.

Source: Flight International