Carbon doesn't melt??????

Question

In the Boeing versus Airbus thread of last night, a poster claimed that Carbon didn't melt and was more fire resistant than ally yum yum.
Please show proof of this.
The poster also listed a plethora of Aircraft "Made of Carbon". The truth of that is that the panels, covers, Fin/rudder etc. were carbon. The A400 is the 1st aircraft to have a fully carbon wing spar and it's not in the sky yet.
The fighters and B-2 are so compact in design that the carbon spars are short and stiff. And, the pilot can always pull the "mummy" handle if he gets a fire.
The 787 has a fabricated carbon spar method, but it will still melt to black powder at about 575 deg F.
The fact is, no airline manufacturer has had the nerve to try a full carbon A/c primary structure until now, and I do not believe the industry is ready for it. I am involved in making such A/c structures.

Carbon skins cannot be used to cover the APU bay, and they are not even in direct flame.

The Wikipedia is referring to Carbon "The element". Carbon Fibre cloth or UD tape has a 30 to 45% resin content.

I've double checked at work.
In a local fire, such as a hotspot, the carbon may last a little longer than the ally. 11 minutes not 10 to burn a hole.
In a real fire such as a fuel burn the carbon fibre composite components will be gone in 15 minutes. The ally will hand on for a few minutes more, but the ally will retain more strength for longer because of it's ability to dissipate the heat.

Answer 1

"Each carbon filament is made out of long, thin filaments of carbon sometimes transformed to graphite. A common method of making carbon filaments is the oxidation and thermal pyrolysis of polyacrylonitrile (PAN), a polymer based on acrylonitrile used in the creation of synthetic materials. Like all polymers, polyacrylonitrile molecules are long chains, which are aligned in the process of drawing continuous filaments. When heated in the correct conditions, these chains bond side-to-side (ladder polymers), forming narrow graphene sheets which eventually merge to form a single, jelly roll-shaped or round filament. The result is usually 93-95% carbon. Lower-quality fibre can be manufactured using pitch or rayon as the precursor instead of PAN. The carbon can become further enhanced, as high modulus, or high strength carbon, by heat treatment processes. Carbon heated in the range of 1500-2000 °C (carbonization) exhibits the highest tensile strength (820,000 psi or 5,650 MPa or 5,650 N/mm²), while carbon fibre heated from 2500 to 3000 °C (graphitizing) exhibits a higher modulus of elasticity (77,000,000 psi or 531 GPa or 531 kN/mm²). For further literature see Rose, Ziegmann and Hillermeier."

The above quotation is from Wikipedia explaining how carbon fiber is synthesized. Note how hot is heated for tensile strength.

Answer 2

It doesn't matter. Any aircraft on fire has about ten minutes before complete structural failure. Considering carbon doesn't burn at low temperatures and epoxy resin is used in heat shields, I don't think it could be much worse.

Wikipedia says carbon doesn't melt:

http://en.wikipedia.org/wiki/Carbon

And the B2 is hardly compact. It is 336,500lbs and has a wingspan of 172ft.

Like I said, resin is used for ablative heat shields that withstand 4000deg F, far hotter than an aircraft fire.

Answer 3

Carbons ability to melt and catch fire are two completely different things. I watched a diamond burn on the discovery channel, they made no mention of any melting point, which is moot if the stuff burns easily!

Answer 4

Pure carbon has a much higher melting point than 575 I believe, and its mixed with other ingredients to stiffen and strengthen it anyway.