Plastic is Fantastic – The Polystrand GT-Lite Project


With the goal of accelerated development and freedom of design, Polystrand, a thermoplastic composite manufacturer – and my employer – is preparing a program to compete in the Grand Touring (GT) classification in the Sports Car Club of America (SCCA). The SCCA, established in 1944, is the premier amateur auto racing organization in the United States, and the largest active motorsports membership organization in the world. Boasting a membership in excess of 40,000 enthusiasts, the SCCA sanctions auto racing events from grass-roots, regional level programs up to national level amateur and professional series. GT cars are purpose-built, highly modified replicas of series produced sport sedans. The class rules offer great freedom of construction by allowing one-off chassis designs, use of alternate materials, and a multitude of drivetrain and suspension options.


Why are we doing this? For the reasons we stated at the beginning of this story – one of the best places to showcase and develop new technology is on the racetrack, and the ultimate goal is for some of this technology to transfer into mass production.


In the composites industry, sometimes we get to work alongside some really great companies, and this project is one of those times. I’m sure you’ve all heard of PPG – not only are they one of the most recognized names in automotive refinishing, and a well-known sponsor in racing circles, they are also one of the largest manufacturers of glass fiber in the world (PPG was founded in 1883 as Pittsburgh Plate Glass). Much of the reinforcement we use in our composite materials is PPG fiber. While you may not think that fiberglass is a high tech product, you’d be amazed at the technology involved. The other major partner in this program is a company you may not have heard of – SANLUIS Rassini. SANLUIS Rassini Suspensions designs and produces leaf springs, parabolic springs and coil springs for OEMs in both North and South America, and they are the world’s largest designer and manufacturer of leaf springs for light vehicles. With decades of OEM suspension design experience, and some of the most sophisticated design and modeling tools available, they have the horsepower and the know-how to take what we develop from a one-off racecar to an OEM level project.


Enter the car – it’s a 1986 Honda CRX chassis, a purpose-built GT car that has consistently appeared in the SCCA Runoffs since first hitting the track in 1991. We acquired the car from Keith Maloney, a racer out of Parsons, KS, who was the second owner. Originally built by Kirk Olson, from Lakewood, CO, this car is a highly modified tub car, and there is very little about the chassis that resembles the stock Honda offering. After hundreds of hours of design and development – Kirk is a highly skilled engineer – the car features an SLA (Short Long Arm, aka double A-arm or double wishbone) front suspension, and a beam rear axle that utilizes a Mumford linkage to define the rear geometry. While you don’t see them very often, the Mumford linkage, when set up properly, gives you very good control of the rear roll center. We won’t go into the details here, because all that is about to change, anyway.

After a brief stay here in Colorado, it’s back on the transporter and off to Detroit. We're getting ready to rack up some frequent flyer miles as we head to the Motor City and the SANLUIS Rassini Suspension facility. They've got some pretty fancy hardware, and state of the art suspension modeling software. We'll be laser-scanning the chassis, developing a computer model of the existing suspension geometry, and implementing a new IRS suspension design. While we certainly hope to field a competitive racecar, we still need to remember that the primary goal of the project is to prove that composite materials can operate in a high stress suspension application. Not just any composites, but thermoplastic composites – we'll delve a little bit into what those are and why they're different in the next installment. Suffice it to say that these materials are quite a bit different than the composite leaf springs you may be familiar with (eg: Chevrolet Corvette). Right now, though, we're on a bit of a tight deadline to have the car ready to display at an automotive composites conference, and sparks will have to fly fast and furious (famous film franchise reference intended, alliteration unintentional).

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