What caused the LFA’s engineers to adopt CFRP?
Perhaps six years ago our engineers came to the realization that even aluminum, as advanced a material as it is, was not going to meet their goals for the vehicle—and weight was not the primary goal. In reality it had a lot to do with the handling feel (what the driver feels through the seat of the pants, through the feet and through the steering wheel.) Aluminum has a relatively low resonant frequency, giving it more flex at very low frequencies, so it doesn’t communicate the same sort of information to the driver about what’s happening between the tires and the road surface as a stiffer, higher resonant frequency structure like one made of carbon fiber plastic (CFRP). At that point, the engineers made the decision to move away from the aluminum structure and into a CFRP structure knowing that the powertrain had already undergone a lot of development and couldn’t be changed. The basic packaging, shape and weight were pretty far along and couldn’t be changed.
What challenges did that present?
The engineers were not just challenged to come up with a carbon fiber structure, just to do one that could completely replace the previously engineered aluminum structure and that met up on all the correct connecting points or hard points that had already been defined. Once they got those mules done, they came back and changed the aluminum body design to CFRP.
In this process, we needed to find a way to make carbon fiber—the newest, most advanced material—with better accuracy, consistency and on a more cost effective basis. To do this, we had to invent a loom, a special type of weaving machine, that didn’t exist before. It’s a circular loom, about six feet across, that’s able to produce a circular weave that has just the right thickness and the right number of carbon fiber threads at every point to give us all the structural properties we need for that part of the LFA.