I've got a fair amount of experience designing and fabricating composite structures from my college days so maybe I can add some useful information.
I was team lead for the following unmanned aircraft competition for the 2005-2006 year (before they won).
http://www.xipiter.org/
The aircraft you see there is primarily composed of carbon fiber structures produced using a variety of techniques. The design shown on the website is pretty close to what we had when I was on the team, a configuration I did probably 80% of the structural design for.
Quote:
Originally Posted by Indpowr
Lamination meaning that a sheet of REAL carbon fiber is laid over top of a already pre-molded part (fiberglass, plastic) then resin etc is laid on top of it.
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The thing I would add here is that CF can also be had in whats known as "pre-preg" where the CF cloth comes from the factory with resin already in it. You then just lay up your CF layers on your mold and cure.
The end result is a lot more consistent than a wet lay up or vacuum assisted resin transfer molding (VARTM) technique but the materials cost is quite a bit higher. Storage is also more of an issue because you typically must store pre-preg under refrigerated conditions to keep it from curing on its own.
To give you an idea of the expense of pre-preg, our aircraft above had a wingspan of 128in and weighed in at 55 lbs. We used $5000+ in pre-preg carbon fiber to build it.
Quote:
Originally Posted by Indpowr
OEM Piece = x weight
Hydro Part = x plus the weight of paint
Carbon Fiber (Lamination) = x plus the carbon fiber materiel, resin, clear
Solid Carbon Fiber = a whole brand new part = less weight
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An improperly designed CF part can actually weigh more that an equivalent metal part. In order for a CF part to realize all the advantages of composite materials, you have to have very well defined load paths and you have to design the part such that its greatest load carrying capability is along those paths, with less load carrying capability in other areas. Treating CF like an isotropic material (same properties in all directions, ie black aluminum) which its not, will result in a lot of excess weight.
The
Beech Starship is a prime example of this phenomenon.
Maybe I'm going too deep into things but hopefully someone will find the information interesting...
