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FUBACOMP is a pan-European consortium aimed at producing a fully wound fuselage section for a business jet using fibre placement technology and incorporating a number of components into the structure. The consortium partners, along with Advanced Composites Group (ACG), are Dassault Aviation (F), BAE Systems (UK), Eurocopter (F), Alenia (I), Eurocopter (D), Brunel University (UK) and CEAT (F). The consortium is partially funded by the European Commission.
(Published on June-July 2005 – JEC Magazine #18)
The main aim of the overall project is to develop a European capability that involves bringing together components manufactured by different companies in a range of countries and forming them into a one-part fuselage section. The finished component will include the windshield surround and the doorframe as integral parts of the structure.
ACG’s task is to design and manufacture the mandrel for the fibre placement of the fuselage section. The mandrel is 4.5m in length and 2.0m in diameter, with the profile of the forward end of a business jet fuselage. The key requirements for a fibre placement mandrel are that it should be lightweight, stiff and removable from the component after processing. Fibre placement with this type of component demands the use of a male tool; these requirements have led to the design and manufacture of a collapsible tool, such that there is sufficient clearance between the tool and the component for the tool to be withdrawn.
Critical weight saving
Many aspects of the requirements for a large, male fibre-placement tool mean that weight saving is critical. Rotational inertia is of considerable importance in ensuring that the tool responds to the control signal correctly, as too great a rotational inertia can restrict the speed at which the fibre placement machine is able to operate, with a subsequent reduction in the speed of lamination. In addition, issues with the handling of the tool during removal from the component mean that a lightweight tool is essential.
To minimise weight, the tool was manufactured from carbon-fibrereinforced epoxy using ACG’s well-proven LTM tooling route utilising a vacuum integral skin with a rigid backing structure to maintain dimensional stability. A significant issue for the use of a collapsible tool is in the achievement of a vacuum integral moulding surface for processing. This has been achieved by the use of dynamic seals on the joints where the tool splits for collapse; part of this seal design is the subject of a patent application. FUBACOMP is a development project for all of the partners Large-scale collapsible tools have not been manufactured before, and many lessons have been learnt during its construction.