The prototype that Pininfarina built was characterized by:
Antishock frame at differentiated resistance
This structure is fundamentally made of two longitudinal beams which extend from the front end as far as they reach the engine housing; these beams have a diminishing section towards the front part of the car, and this section has been calculated in such a way to give the most of stiffness of the central part where the driver is sitting. This central part, or cell, has been dimensionally defined following the experimental data about the “survival space”, taking care of the particular driving position of the driver and of the special safety belts adopted. To reach this aim, the parts of the car which surround this cell are calculated as to be ad deformable as possible in order to absorb the most possible part of the energy derived from the crash and to transmit to the driver’s cell only the fraction which the human body can support. The wing supports, the roll bar and the head-rest are structurally integrant part of the cell.
The Sigma G.P. is surrounded by a ring made by elements with omega section which has the function of supporting without deforming itself, the light shocks and grazings which happen in racing between cars at a low relative speed, and besides of avoiding the hooking which are so frequent between cars with uncovered wheels. These elements are deformable, too, in the case of violent crashes.
The car is equipped with special fuel tanks realized by the Pirelli Co. and derived from a study in cooperation between the Pirelli Co. and the Pininfarina Co. They can deform themselves very much, are insulating to heat, resistent to perforation and selfextinguishing. The thanks are placed in the side and out of the cell, between the deformable part of the cell. The fuel pipings are realized with armoured pipes, interrupted by selfsealing connectors so that in case of crashes the piping doesn’t break, but the selfsealing connector loosens without consequent fuel losses.