Porsche has unveiled the new 911 Carrera Cabriolet with a newly-designed fibre-enhanced roof, an eye-catching feature on the unique panel bow convertible top. Porsche traditionally places high demands on the convertible top of the 911. As for all other 911 models in the past, this folding roof is therefore a completely own development. The innovative technology creates a coupé-like curved roof when the driver closes the soft top. With almost identical contours, the fabric roof elegantly spans the arc from the windscreen frame to the convertible top compartment lid. This is done without any visible bows underneath the fabric. There are also no sections interrupting the flowing design of the classic 911 flyline. Additionally, the new roof also helps when it comes to aerodynamics. Thanks to the new, lighter hydraulic roof drive, drivers can open or close the soft top in around 12 seconds at speeds up to 50 kmph.
The innovative panel bow convertible top design makes it possible to achieve this previously unattainable form for fabric roofs. Here, the entire soft top – apart from the side sections – spans a rigid roof surface composed of individual segments that Porsche has seamlessly positioned next each other. The four elements are the front roof frame, two panel bows and the rear window. Like the other segments, Porsche has made the window frame of the Carrera cabriolet out of magnesium. Porsche has connected all frame parts kinematically. That way, just one hydraulic cylinder on each side can move the convertible top. For the locking mechanism, Porsche has opted for the proven electric central closure mechanism supported by side centering pins.
There is no fixed connection between the panel bows and the soft top fabric. Porsche designers have made it such that the four magnesium segments fold flush over one another. Porsche engineers have done this in the proven Z-folding mechanism when the driver opens the roof. This unique design means that the opened roof package consisting of the roof fabric, frame, panel bows and rear window, at just 230mm high and around 550mm long, requires very little storage space. While the front section of the roof remains visible in the open position. When closed, the sickle-shaped convertible top compartment lid covers the rear portion. Porsche has lined the entire surface of the exterior fabric with an insulating mat. So, when the drivers closes the top, the occupants enjoy levels of climate and noise comfort that come very close to those of the Coupé.
The integrated and electrically operated wind deflector ensures increased comfort in the 911 Carrera Cabriolet at higher speeds. Porsche has secured the wind deflector on a U-shaped support hoop. Porsche designers have fully integrated this in the rear area when folded down and therefore does not restrict the space on the rear seats. The driver can raise the hoop within two seconds at the push of a button. A second movable frame element unrolls a mesh tensioned at right angles between the front seat backrests. The driver can open and close the wind deflector up to a speed of 120 km/h. When the top is open, it guarantees very good protection against draughts and minimum wind noise.
The basic elements of the aerodynamic concept for the 911 Carrera Cabriolet are the streamlined body surface contours, the convertible top, the enlarged variable rear spoiler and the cooling system with its adaptive air flaps at the front. The rear spoiler partly has a larger angle of attack to better suit the needs of the Cabriolet. Porsche have optimised the cross-sections of the air intakes and air outlets to improve cooling air routing. This enables the 911 Carrera Cabriolet to maintain the Coupé’s drag coefficient of 0.29 when the roof is closed – even though the cooling system has been adapted to the increased engine and braking power.
The open 911 Carrera S has an automatic roll-over protection system. This essentially consists of a compact, self-supporting portal frame made of welded, high-strength extruded aluminium sections. With its high strength, the supporting frame is also used for body reinforcement. As such, the system helps to improve the Cabriolet’s torsional rigidity.
In the event of an imminent roll-over, Porsche’s newly developed cassette modules behind the rear seats are extended by spring pressure; triggering takes place pyrotechnically by a micro gas generator. If the driver has closed the convertible top, a carbide metal pin on each of the two cassettes extends through the safety glass of the rear window. Accidental triggering is practically impossible. This is due to a high-precision airbag control unit with integrated roll-over sensor is responsible for sensing, actuation and continuous monitoring. This monitors every change in the body inclination, longitudinal and transverse acceleration as well as road contact.