Is Carbon Fiber Worth its Weight?

What do Rocket fuel tanks, Hypercars, and some of the world’s largest wind turbines have in common? Lately, they’re all built using the same composite material, carbon fiber. In fact, the excessive use of carbon fiber in the automotive industry has some traditionalist fans overwhelmed. And while many enthusiasts can’t seem to get enough of this revolutionary composite, others argue carbon fiber is nothing more than a flashy status symbol. The truth is, both assumptions are correct in their own way.

To better understand the world of composite materials, specifically carbon fiber, and how that material is used, we should revisit what carbon fiber really is.

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How it’s made:

A man-made, thin, sheet-like material, Polyacrylonitrile, or “PAN”, which is already around 60% carbon, is cooked at about 390 to 590 degrees Fahrenheit. As the Polyacrylonitrile (PAN) cooks, it gradually fades from its original off-white color, to the signature carbon-fiber grey we love so much. The slow baking process causes oxygen to bond with the carbon, forming a stronger, linear chain of atoms. The now Oxidized Polyacrylonitrile material is called Pyron. Though Pyron is considered very useful (used for making jet airplane brakes) a lot more heat is needed to burn out any hydrogen and nitrogen left in the material. To do this, Pyron is fed through super-heated furnaces (to the tune of 2,000-4,000 degrees Fahrenheit.) This is considered the most important stage of the process, as this is where carbon fiber is completely refined and gains most of its strength. But why cook the Polyacrylonitrile two separate times? Because the second time around the Polyacrylonitrile is heated in the complete absence of oxygen, to keep the material from burning up. Instead, the extreme heat causes atoms in the fiber to vibrate, so much so that hydrogen and nitrogen atoms begin to break free. The product of this second heating process is carbon atoms perfectly aligned forming crystalline chains. Now, the fibers are right around 98% pure carbon. The carbon fiber is then wound into a chord which can be woven together to make a fabric. To make specific parts for vehicles, the fabric is spread over a mold in the shape of the desired part. Then, resin is spread across the fabric and the piece along with the mold are put in a pressurized oven, called an autoclave, to be heated once again. The baking process that takes place in the autoclave solidifies the resin, giving the carbon fiber piece its rigidity.

 

Carbon fiber’s stiff rigidity is a large part of why it’s so valuable. Not only is this high-tech composite up to 10 times stronger than steel, and around 3 times lighter than the same metal; carbon fiber is extremely firm, especially when compared to other composites like fiber glass and Kevlar. To engineers like Horacio Pagani and Christian Von Koenigsegg, a stiff, strong, light-weight building material that’s easy to shape like carbon fiber might as well be gold to anyone else. In fact, Koenigsegg has been using this carbon composite on his cars for well over two decades; his latest cars are almost entirely carbon fiber. An all carbon fiber car might seem a bit excessive (chassis, rims, even some of the motor components) but this is Koenigsegg we’re talking about. In 2014, Koenigsegg introduced to the world the One:1, the first car ever to have a power-to-weight ratio of 1:1 (horsepower to kilograms). This awesome feat was accomplished by implementing the use of carbon fiber technologies and an engine capable of producing 1,360 horsepower. A key to one of Koenigsegg’s machines is a key to top speeds and performance no other car can match.

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While working for Lamborghini, Horacio Pagani made an even better version of the Countach using carbon fiber. His one-of-a-kind car, the “Countach Evoluzione”, weighed more than 1,000 pounds less than Lamborghini’s production vehicle. Now, Pagani Automobili manufactures cars with chassis made entirely of titanium infused carbon fiber. Carbon-based composites do a lot more than make these machines lighter, and in turn, quicker. The beautiful weaves of hardened carbon chords that wrap Pagani’s Hypercars have given them an artistic look that cannot be copied. For more about Horacio’s life and philosophy, see our post “Horacio Pagani: The Art of Science”.

 

So, is carbon fiber worth its weight? Definitely, if you’re in the business of building and/or driving hypercars. But what happens when a 2.5 million dollar Koenigsegg or Pagani aren’t exactly in the budget? That where we start to see carbon fiber’s hedonic value. In just a few decades this carbon composite has become a staple look for performance and luxury in the automotive world. And though putting a carbon fiber hood and fender flares on your heavy pickup truck probably won’t make a difference performance-wise, it gives the driver a small taste of a part of the auto industry that might be out of his or her price range. While we’d all love making the One:1 our daily driver, that isn’t really possible, so we settle for a couple carbon fiber accents around the interior of our sportscars.

 

 

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