Expect it to arrive in race cars first, but filter down to cars like the 911 GT3 RS later.
Porsche has devised a way to integrate a roll cage with a race car's roof structure in such a way that there is minimal intrusion into the cabin space without compromising on driver protection, which could soon spell the end of the scaffolding-style roll cages we know and love, but which are not street-legal in the USA. This is similar in principle to the Ford GT supercar, which has an FIA-grade roll cage built into its chassis.
According to a patent found by CarBuzz at the German Patent and Trademark Office (DPMA), the new integrated skeletal roll cage is designed to improve headroom for helmet-wearing drivers. There are other advantages over the traditional welded-tube design for an extra performance edge.
While the roll cage scaffolding in the rear half of a Porsche 911 GT3 RS cabin is impressive to behold, it robs the car of interior practicality. Roll cages also add extra weight, which is undesirable in a race car but, until now, has been an acceptable compromise for the added chassis rigidity and increased driver safety.
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Porsche's solution is an ingenious combination of the thinking behind a traditional roll cage and an integrated body structure. To this end, the pipes that make up a conventional roll cage are replaced by high-strength pressed-metal channels connected at intersecting nodes to create an endoskeleton with non-stressed outer panels.
These channels are designed to run longitudinally along the roof, join with reinforced roof pillars, and connect those pillars, either transversely or diagonally, into a stiff and deformation-resistant skeletal structure. Channels can be welded together traditionally or could be bonded with high-tech adhesives.
If adhesives are used, carbon fiber elements can replace some or all of the channel sections for even greater rigidity and further weight reduction. This creates a roof frame that combines the strength of a roll cage with the space efficiency and weight saving of a conventional unibody roof structure.
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This construction method also turns the roof panel into a mere cover. Because it doesn't have to perform any load-carrying duties, the roof cover panel can be made from lightweight composites or very thin metal, making it easier to sit flush with the skeletal structure underneath, thus reducing aerodynamic drag. Finally, this construction method allows for a flatter or shallower roof for further drag reduction.
More cabin space, improved outward visibility, easier access, reduced weight, and lower drag will improve the performance of a race car and its driver. Given Porsche's long-standing commitment to motorsport excellence, this may give them a new advantage over their competitors. And it will make road-going 911 GT-series cars so much easier to live with, if perhaps less spectacular to look at.
DPMA
There are other downsides to traditional roll cages, too. They usually restrict the size of the entry aperture due to their added braces, making for difficult entry and egress. They often restrict outward visibility for the driver while on the move because there's always a tube next to the A-pillar. The proximity of strengthening braces to the driver's helmet means padding must be added to the cage.
And, notably for Americans, roll cages are banned in street-legal cars, which is why Porsche's epic carbon fiber roll cage – and the green one from the GT3 RS Tribute to Carrera Package – in the new 911 GT3 RS as part of the Weissach Package is not available stateside. This integrated cage, however, would be legal as there are no exposed elements that pose a safety risk.
After many decades of successful motorsport, there is no doubt that Porsche's perfectionist engineers have long been looking into ways to solve these problems. Saving some weight would be motivation enough, but making the driving experience more comfortable for race car drivers must have motivated them – a comfortable driver can better concentrate on their driving and spend less time dodging the pipework around them.
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Keyword: Porsche Copies Ford GT With New Integrated Roll Cage Design