Aerospace composites Best answer on the web

Posted in: darrelrussell.com edit
08 Jan 2009
  • What are some aerospace composites used in critical load bearing components.
    pro's/cons/challenges (i.e. landing gear reparability, etc)


  • I am looking for information on any composites used in aircraft where any type of load is involved. It does not have to be specific to a certain component. I am using the information in a powerpoint presentation so anything I can get will be useful.
    The plastic-matrix fuel tank sounded interesting.


  • gemini39a,

    What loads are you trying to support? Landing gear? Structural loads or other loads? In aircraft the most likely composites to be used are shaped composites, such as a fiber-reinforced, plastic-matrix fuel tank in place of a metal tank.
    You will find a lot of composites used in military aircraft, but not so much in civilian aircraft. This is due to the high cost of composites.
    Could you expand on your question a little bit more.

    krobert-ga


  • There are many factors/tradeoffs that affect the decision to use composite material. Advanced composite material is indeed used in critical load bearing structures but for items such as Landing gear, you have to the environment and maintainability. Aircraft Landing Gear are subject to very harsh environments (debris from tires, runways, harsh fluids, and so on).
    Carbon fiber is a very good substitute for traditional metal structures, but that does not mean it's right for every job. The strength of a fiber reinforced product is based on the continuity and orientation of the fiber whereas metal has more uniform strength characteristics. The bearing loads on landing gear coming in high impact waves from many directions and the fiber must be capable of distributing those loads without failure. Theoretically it can probably be done, but it is not practical.
    If you look at the modern commercial aircraft today, everything minus the fuselage pressure vessal is composite material (fairings, Flaps, Doors, Elevators, Rudders, Radomes, etc). In addition, there are other private and military aircraft that use composite material as primary structures (i.e. wings). Some aircraft are made entirely from composite material - except the engines and landing gear.
    Of course, when you say composite, that leaves your question open to the whole field of material used in "composite" products (theromsets, thermoplastics, metal matrix, glass reinfonced, carbon fiber, kevlar, core material, resin systems, and so on).


  • Look up the Beeachcraft Starship, the first certified all composit aircraft.
    Many articles about it will contain a lot of information about its novel
    construction. Then look at the Lanceair web site. They are one of the top
    composit kit plane builders.