Chassis Dual Frame is a concept patented by Franco Sbarro.
Sbarro want to dissociate "the dynamic structure functions from the structural functions of protection and comfort ". Practically, this meant designing a car in two separate pieces:
a mechanical module (module 1 : active safety) with mechanics and rolling structure. An engine gearbox assembly firmly attached to a chassis with central beam, wich includes all the suspension elements, thereby ensuring rigidity and precision.
an "envelopping" module (module 2 : passive safety). It's the body, made of composites. It ensures all the driving and comfort aspects.
The p neumatic link elements, which can be compred with double action jacks, offer a wide scope fot link control. The two major parameters can be adapted : car body height and hardness.
The advantages of Dual Frame
Great savings in terms of weight have been achieved throught the judicious choice of materials and the different monocoque design. Less mechanical elements are used, monocoque made of composites is lighter than metal. A car with dual frame can be built weighting between 800 to 1150 kg, accordinf the fittings incorporated. For comparison, a Ferrari 599 GTB Fiorano weight 1700 kg!
The pneumatic link can be hardened or softened in accordance with the required objectives : racing, GT or specific use (high position to drive along bad roads...)
What future for Dual Frame ?
Franco Sbarro of course used Dual Frame on many prototypes, among them the two Helios, the first cars to be equipped. Similarly, the students used the Sbarro Dual Frame for their various projects, proving that this system can be easily exploited. Hopefully this great system, which meets the expectations of car manufacturers, will find its way and will be quickly offered to the general public and not only to Franco Sbarro's customers.
text Philippe Calvet & Espera, automatic translation (so be indulgent !)