Raytheon Aircraft is preparing to produce the first composite fuselage sections for its Hawker Horizon mid-size business jet. The Horizon fuselage will be the biggest pressurised structure yet produced using automated fibre placement, the company says.

Raytheon selected fibre placement to produce the fuselage of its Premier I light business jet, rolled out on 19 August. Compared with that of the Premier, the Horizon fuselage has a larger diameter and is longer, and will be produced in three sections rather than two.

The manufacturing technique produces a lighter structure with a larger internal diameter than an equivalent metal fuselage, says Raytheon. Compared with conventional layup, the amount of composites scrapped during production is reduced, to less than 5% Raytheon says, by direct placement of carbonfibre tows on to a mandrel.

Fuselage production involves fibre placement of inner and outer carbonfibre layers separated by Nomex honeycomb. The Horizon skins will be thicker than those of the Premier, but the same materials and processes will be used.

Seven Premier fuselages have been produced so far, and the number of defects - voids and delaminations in the composite material - has reduced significantly as the technique has been refined, says the company.

Raytheon is producing the mandrels for the Horizon, which will fly in late 1999, and has completed a proof-of-concept centre section to test the fuselage joint. Whereas the two Premier fuselage sections are bonded together, the three Horizon sections will be spliced, using two metal ringframes which will carry loads from the wing into the composite fuselage.

Source: Flight International