Wing handling technology by Street Crane Company.
A Furmanite Pylon milling machine.
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A lightweight pylon milling machine has been designed and produced by Furmanite for BAE Systems Airbus for the manufacture of wings for the new A340-600 airliner. It attaches to the A-frame jig to enable the plateau sections of the wings (to which the pylons holding the outboard engines are attached) to be milled in-situ on the wing jig. The system obviates the need to remove the plateau to be milled flat for a precise fit, and also avoids the risk of distortion when re-fitted. Time and cost benefits are described as "substantial."
Furmanite worked closely with Airbus at the jig development stage to enable both milling machine and jig designs to be integrated. The result, says Furmanite, is a highly accurate "picture frame" milling machine that uses lightweight materials to ensure that the A-frames are not distorted when the machine is mounted. Milling accuracy is within 0.1 mm.
BAE Systems Airbus also has new handling systems at its Hawarden facility where wings are processed. This has involved collaboration between aerospace metal treatment specialist Metal Improvement Co. and overhead crane specialist Street Crane Co. The overhead crane system installed by Street handles single wing panels of up to 32.6-m length, allowing them to be loaded and unloaded from shot peening machines, transported along a bay, and rotated through 180° for location in storage racks.
Shot peening gives a curvature to the wing panel, but also increases fatigue resistance. Street Crane says extreme care is necessary in handling the wings, a requirement that is complicated by the need for them to be rotated. To achieve this, a turntable has been located between the beams of a double girder crane, and a supplementary support beam enables the wing panel to be secured at several points for stress-free handling. The wing panels are bulky and light, so load swing and instability were concerns. However, Thryster soft-start control provides progressive acceleration and deceleration on both long and cross travel. Seven double girder Street cranes with a maximum safe working load of 5 t have been installed at the BAE Systems facility.
Stuart Birch
Aerospace Engineering October 2000
