Carbon fibers are used in Defense aircraft and civil aircraft. Airbus industries was the first civil aircraft manufacturer to use carbon prepregs for parts of the primary structure and cfrp was used in the tail fin of the Airbus A300.
Airbus A380 and A400M have used cfrp for the ailerons, flap track fairings, outer flaps, main and center landing gear doors, main landing gear leg fairing door, nose landing gear doors, central torsion box, belly fairing skins, upper deck floor beams, passenger floor panels and struts, pressure bulkhead, apron, horizontal stabilizer outer box, vertical stabilizer and tail cone. Some 1.5 tons are saved from the weight of the structure by using carbon fiber for the central wing box.
Mills has given a brief history of composites for airframe manufacturing and the part that carbon fiber played in early development. Probably the most notable were the McDoneel Douglas DC-10 rudder in 1968, the Deutsche Airbus A310 fin box in 1979 and the A320 horizontal stabilizer by Deutsche Airbus/CASA in 1984. These constructions were justified on lifetime ownership cost reduction through lower weight. The DC-10 rudder saved 38% weight and suffered little damage over a 15 years service life.
After the 1980s, applications tended to tail off due to the high costs of composite manufacture, so cost became the driving force for all new developments. The IM fiber types provided structures with higher stiffness and tape laying machines were developed to create double curvature and multi-axial non-crimp fabrics were stitched into preforms for impregnation by RTM. Triaxial braiding, combined with stitching and processed by RTM offers potential for future developments.
To reduce the cost of fabricating exit guide vanes on turbojet engines, Allied Signal has used braided carbon fiber impregnated with epoxy resin using a multicavity RTM tool instead of a compression molded prepreg tape.
Woven carbon fiber reinforced phenolic skins bonded to an aramid honeycomb are made by Hexcel for the flooring in the cabin and flight areas of Airbus aircraft.
A one-piece aircraft horizontal stabilizer has been demonstrated by Raytheon aircraft company using RTM and was 2.32m long with a tapered wing structure with internal spars to prevent buckling. The spars were built on mandrels, producing five cells to give the spars, which were covered with dry carbon fiber reinforcement, placed in the mold and then covered with carbon fiber fabric to give a single piece structure. Carbon fiber braid was chosen as the ideal reinforcement for the spars since it could be precisely positioned and kept in place. Some spars had two layers of braid.
Lockheed Martin used a carbon fiber braid preform and RTM processing to produce a 90KG demonstrator carbon composite tail, reducing the number of parts from 13 to 1 and eliminating over a 1000 fasteners with a 60% reduced production cost.
Scaled composites designed and fabricated the record breaking Voyager aircraft that flew around the world non-stop and non-refeuled with a crew of two. To achieve these aims in a time of nine days, the structural weight had ti be as low as possible, and the structure as well as the spars, were graphite tape skins on a Nomex honeycomb core.
Boeing have reported that each projected 7E7 twin aisle passenger jet scheduled for 2007 will use 25 tons of toughened carbon fiber/ epoxy laminate and sandwich material.