Carbon fiber is generally considered one of the highest-quality materials available in the auto market- and for good reason. Attributed with its high strength, extremely light weight, and low heat conductivity, it’s often a go-to for things like body panels and driveshafts in high-performance applications.
However, as with any great thing, there are drawbacks. While it can offer an incredible performance increase over other materials, carbon fiber is both very brittle and very expensive. The Hellcat in the video felt the impact of both of those flaws when its carbon fiber driveshaft burst during take off.
While its not terribly common to see a carbon fiber driveshaft demolished by a car with only 900 horsepower, there are a number of reasons that this type of thing can happen. The foremost is hitting critical speed. When critical speed is reached, (assuming the joints don’t give way first) the driveshaft will ‘unravel’, sending large pieces of the dismantled shaft in all directions.
Since 900 horsepower would be nowhere near enough to push a (quality) carbon fiber driveshaft to it’s limits, and given the fact that all we’re seeing in the video are small shards of fiber, it’s likely that the Hellcat’s driveshaft failure was not due to reaching critical speed. Instead, it is more probable that what we see was caused by either weaknesses in the joints or by some form of dents, scratches, or other compromises in the shaft, as these can also lead to catastrophe.
The beauty of carbon fiber, however, is that- if and when it does fail- it shreds into fibers and minimizes collateral damage. Steel or aluminum, on the other hand, will soar through anything else on the car like a hot knife through butter. This is the very reason that the team was able to replace the driveshaft, perform necessary adjustments, and put the car back on the strip that same night.
Based solely off the video footage, it’s hard to tell whether credit should go to the crazy power of this Hellcat – for shattering the carbon fiber – or to the forgiving nature of carbon fiber driveshafts for not ripping the car’s belly in two. All we know is that it’s good to see the car recover so quickly and get back to running 10s by the end of the night.