Performance parts on the limit

Machined from airframe grade aluminium, the hinges are prismatic parts that are supplied in various lengths between 150 and 300 mm. Premier's managing director, Stuart Grant, says: "We precision drill a through hole before the part is machined by our customer. The hole is used as the datum point to machine a series of square serrations – castellations - so that it can be assembled together much like a large piano hinge." The Eurofighter Typhoon is built using one of the most advanced lean manufacturing processes employed anywhere in the world. Gardner Aerospace has Eurofighter DLF (Direct Line Feed) approval and stocks the hinges in part bins onsite at BAE Systems' Samlesbury assembly line, operating on a sophisticated Kanban system. Producing these particular parts required Premier's engineers to develop fixturing that would not crush the aluminium once the hole has been generated, which would alter the form of the hole and affect the performance of the hinge. The hole in the various parts is comparatively small, ranging from 2.8 mm up to 3.2 mm diameter. The Typhoon's wing is a multi-spar construction with integral fuel tanks. There are full span inboard and outboard flaperons and leading edge slats, with wing tips housing the advanced defensive aid sub-system. The main undercarriage attachment is located on each wing. Skins and spars are Carbon Fibre Composite (CFC), with the spars co-bonded to the lower skin. The ribs are carbon fibre reinforced with metallic hardpoints. Titanium is used for the wing/fuselage attachments and outboard flaperons.