To further support and enable composite fuselage production for the Premier I and Hawker Horizon, Raytheon Aircraft has purchased four additional fiber-placement systems from Cincinnati Machine.
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Raytheon Aircraft in Wichita, KS, has added two more Viper FPS-3000 CNC fiber-placement systems from Cincinnati Machine and will add two more in 2001. The four new systems will join Raytheon's first Viper system, which has been in use since 1997 for the initial development and production of the Premier I business jet. The machines automate production of the composite fuselages for the Premier I as well as the new Hawker Horizon business jet. According to Cincinnati Machine, the fuselages are the largest CNC fiber-placed structures in the world with more than 80 mi of composite fiber tow in each fuselage.
Viper systems combine programmable 7-axis dexterity with individualized start/stop/cut control over 24 individual 0.125-in-wide fiber tows. According to the company, automated placement can eliminate time-intensive, costly hand layup on contoured and complex part geometries, while delivering good precision and repeatability.
The new system measures 90 ft long compared to the 60-ft system already employed at Raytheon. The longer length accommodates longer mandrels for the larger Hawker Horizon, which will seat 8-13 passengers. The Premier I fuselage is formed in two composite sections that are then bonded together, while the Hawker Horizon will be assembled from three fuselage sections. The mandrels are mounted in line for sequential layup, enabling one ship set to be produced per cycle.
With just four people, both sections for the Premier I fuselage can be produced on the fiber-placement system. Each mandrel, which provides the basic shape of the fuselage, are mounted horizontally in the system and rotated. The system places 24 tows of 0.125-in carbon-fiber prepreg over a rotating mandrel in multiple plies to first form the interior wall. This is then covered with a layer of Nomex honeycomb core and the exterior skin. The final ply on the outer surface is a hybrid carbon-fiber fabric containing fine metallic wires to provide lightning strike protection.
Plies for the interior and exterior layers are laid at various angles to the previous one to maximize strength. The system automatically maintains tow placement accuracy to less than 0.10 in while performing at layup speeds up to 1200 in/min. This process allows creation of tapered geometries, concave and convex surfaces, and small radii and cylinder shapes. Start/stop tow control allows for the creation of precision openings and edges, minimizing the need for subsequent trimming and hand finishing.
According to Hansel Tookes, President and CEO of Raytheon Aircraft, the automated fiber placement system "allows us to build complete fuselages in a fraction of the time required for similar metal structures, along with vastly reduced parts count, simplified assembly, reduced maintenance, and size and performance advantages."
Frank Bokulich
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Aerospace Engineering September 2000
