BMW has taken the wraps from a car that has been literally under wraps for several years. It is the GINA concept roadster that can morph its shape while under way thanks to the use of a man-made expansion-resistant fabric stretched across its metal and carbon-fiber structure.
GINA (Geometry and functions In “N” Applications) presents a near-seamless body that comprises four elements, the largest extending from the front of the car to the edge of the windshield and down its flanks to the trailing edge of the doors. Side panels extend from the front where the rocker panels emerge and stretch across the rear wheel arches to the bar of the car. A further component comprises the central rear deck.
Fabric has been used for the body covering of production cars in the past, particularly for some European models in the decade before World War II. The new material offers designers a significantly higher level of freedom of design and functionality, says BMW.
In fact, the concept offers the opportunity to challenge existing principles and conventional processes right down to fundamentals such as whether a car’s roof has to rest on pillars and be bordered by windows, whether all functions (such as lights) have to be visible at all times, and what are alternatives to steel and composite bodies.
Answers to these questions are regarded as giving a fresh steer to creativity at BMW. They also led to the company’s “twisted surfaces”—use of concave and convex shaping that, while being controversial, has given BMW models a highly distinctive profile.
The GINA Light Visionary Model, which was initially constructed in 2000-2001 under the design directorship of Chris Bangle, demonstrated some of the styling cues that were to be integrated into production models, notably the Z4 and 5 Series. To do so, it was decided that it would be necessary to move beyond all previous conceptions of car body configuration, design, and materials, and that is certainly what GINA provided. Underpinnings of the concept are from the low-volume V8-engined Z8.
The shape of the car can morph to meet particular driving mode requirements. Using electric and/or electrohydraulic systems, the rear spoiler can become larger at higher speeds, and the front air intake can widen for extra cooling or shrink to improve aerodynamics.
The interior of the car is also flexible, with the dashboard and seats changing their profile to facilitate entry and egress. When the headlights are switched on, the contour of the front of the car changes and parts of the fabric covers open to reveal them. Turn indicators and taillights are subcutaneous and shine through the fabric, which is permeable to light but not transparent. BMW describes the material as industrially produced hybrid fabric made from a stabilizing mesh netting support and an outer layer that is both water-repellent and resistant to high and low temperatures.
The material must also remain dimensionally stable. It is supported by a metal-wire structure. At specific points, the high-strength metal structure is enhanced by carbon struts. They are used mainly for round, moving contours with very small radii. The high-precision fit of the material to the metal mesh permits surface changes but does not compromise surface tension.
Access to the engine is via an opening that stretches down the center of what would be the hood of a normal car. It opens for about 0.5 m (19.7 in) like a piece of clothing or a travel bag and has clip locks to secure it.
BMW stated that some lessons learned via the GINA design philosophy had led to novel methods of manufacturing single components very quickly, cost efficiently, and with focus on individual components.
The processes were applied to the production of hoods for the Z4 range, says BMW. These models receive their distinctive contour lines at a separate production stage that differs significantly from conventional sheet metal processing. The lines are embossed into the hood with pinpoint precision by a robot-guided steel pin. The approach is said to allow for entirely new ways of individualized production.
Although some references have been made in the past to elements of GINA, it is only now that the concept has been fully acknowledged officially and revealed by BMW—and it's ironic that it moves immediately into the company’s new museum, formally opened in June.
The use of fabric bodies—as an entity or more likely as a partial application—introduces some fascinating possibilities and challenges. There is no suggestion at present that GINA will lead to a fabric-bodied production BMW, but with the free-thinking Bangle in charge, almost anything is possible.