structure   made   of   glass   cloth.   Reinforced   plastic   is fabricated into a variety of cell sizes. Composite and Carbon Fiber Materials High-performance  aircraft  require  an  extra  high strength-to-weight ratio material. Fabrication of composite materials satisfies this special requirement. Composite  materials  are  constructed  by  using  several layers  of  bonding  materials  (graphite  epoxy  or  boron epoxy).  These  materials  are  mechanically  fastened  to conventional substructures. Another type of composite construction   consists   of   thin   graphite   epoxy   skins bonded to an aluminum honeycomb core. Carbon fiber is    extremely    strong,    thin    fiber    made    by    heating synthetic fibers, such as rayon, until charred, and then layering in cross sections. Q4-6. Materials currently used in aircraft construc- tion are classified as what type of materials? Q4-7. What are the most common metallic materials used in aircraft construction? Q4-8. What  are  the  nonmetallic  materials  used  in aircraft construction? FIXED-WING AIRCRAFT LEARNING    OBJECTIVE: Identify    the construction features of the fixed-wing aircraft and    identify    the    primary,    secondary,    and auxiliary flight control surfaces. The   principal   structural   units   of   a   fixed-wing aircraft    are    the    fuselage,    wings,    stabilizers,    flight control  surfaces,  and  landing  gear.  Figure  4-5  shows these units of a naval aircraft. NOTE:   The terms  left  or  right  used in relation to any of the structural units refer to the right or left hand of the pilot seated in the cockpit. FUSELAGE The fuselage is the main structure, or body, of the aircraft.    It    provides    space    for    personnel,    cargo, controls, and most of the accessories. The power plant, wings, stabilizers, and landing gear are attached to it. 4-5 ENGINE NACELLE HORIZONTAL STABILIZER MAIN LANDING GEAR WING NOSE LANDING GEAR RADOME CANOPY AILERON LEADING EDGE OF WING FLAP ENGINE EXHAUST RUDDER ENGINE EXHAUST VERTICAL STABILIZER (FIN) ENGINE AIR INLET FAIRING ELEVATOR COCKPIT ANf0405 Figure 4-5.—Principal structural units on an F-14 aircraft.