Rolls-Royce Phantom Drophead Coupe Revealed

Press Release

ENGINEERING The challenge in designing any convertible lies in retaining a high degree of torsional rigidity throughout the body while keeping weight down. Torsional rigidity is vital to minimise the scuttle shake associated with most convertible cars and to help maintain the car’s dynamic composure. Extensive testing and research were carried out before the engineering team were completely satis?ed. Tens of thousands of kilometres were driven over rough road surfaces to help identify and eliminate potential problems. The result is a spaceframe chassis that makes the Phantom Drophead Coupé perhaps the most rigid convertible available today. The clearest indicator of this incredible strength and stiffness can be seen in the rear-view mirror, which shows no vibration at all, even at high speed. A great deal of this is due to the modi?cations around the triangulated A-pillar. The entire windscreen surround was designed to be an integral part of the roll-over protection system. Consequently the A-pillar struts run right down to the ?oor of the car. Additional aluminium extrusions have been utilised, along with wider sills. The rear haunches have single extrusion beams running at waist height on either side. In all, more than 140 metres / 460 ft of weld go into each Phantom Drophead Coupé body – 20 metres / 65 ft more than in the Phantom. Incorporated into the rear spaceframe structure is the concealed roll-over protection system which deploys from within the rear head restraints in just a fraction of a second in the event of an accident. A ratchet system then locks them in place. Further adding to occupant safety, frontal impacts are absorbed by crumple zones directed into Y-shaped chassis members and the main understructure – the strongest part of the chassis. Side impact intrusion is minimised by the double-skinned ?oor construction, strong side sills and integral side impact bars in each door. Additional braces above and below the engine bay and under the rear axle add further rigidity to the spaceframe. Other safety systems include intelligent braking and restraint systems, combined with integral seatbelts. As a result, the Phantom Drophead Coupé is perhaps the safest convertible car on the market. The spaceframe is constructed at the BMW centre for aluminium competence in Dingol?ng, Germany. Manufactured to within a tolerance of just 0.1 mm / 0.004 in, each spaceframe is welded entirely by hand. They are then checked by a computer-guided machine to ensure absolute accuracy. One of the more interesting problems encountered by the engineering team was the proximity of the optional brushed steel bonnet to the aluminium front wings. These materials are not normally used alongside each other due to the adverse corrosion effects of aluminium on steel. An integral part of the testing process was a 20-year-old DeLorean car. Manufactured with stainless steel exterior panels, it provided an interesting case study into the long-term durability of the material. All of the panels used on the Phantom Drophead Coupé are unique to this car, representing some of the 1300 new parts used. Unlike on the Phantom, the front wings have been constructed from aluminium using the ‘superform’ technique, in which aluminium is heated to the critical temperature before being literally sucked down over a mould to form the large, complex shape. DRIVING The Phantom Drophead Coupé’s advanced aluminium spaceframe is at the heart of its re?ned, dynamic driving experience. Lightweight and exceptionally strong, it impacts positively on ride, comfort and safety. Its inherent rigidity is essential in isolating vibration and maintaining the hushed interior calm associated with the brand. The new car is shorter than the Phantom by 250 mm / 9.8 in, so turn-in is slightly quicker, making for a wholly more agile driving experience. A lower centre of gravity, combined with the reduced wheelbase and incredibly stiff body, produces a ride that is on the re?ned, comfortable side of sporty. Feedback from the wheels is informative but not intrusive. Imperfect road surfaces go unnoticed while feel through the steering wheel inspires con?dence. New spring dampers and lighter anti-roll bars have been engineered to maintain comfort without loss of agility. Self-levelling air struts continuously adjust for increased loading in harder cornering, giving drivers the ability to place the car through turns with absolute precision. The front double-wishbone suspension features a hydraulic mount to minimise vibration through the steering wheel. Multi-link rear suspension is designed for increased ride comfort with anti-lift and anti-dive technology. With no ?xed roof, much of the Phantom Drophead Coupé’s weight naturally sits lower and further forward than in the Phantom, due to the structural roll-over protection built into the A-pillar. Nonetheless, a 50:50 weight distribution has been maintained. Other heavy components – the engine, gearbox and propshaft, for example – sit as low as possible, again contributing to the low centre of gravity. Grip is provided by standard-?t Michelin PAX run-?at tyres, metrically sized at 540 mm (approximately 20 inches in diameter). These tyres enable the Phantom Drophead Coupé to run for at least 100 miles / 160 km at speeds up to 50 mph / 80 km/h before being replaced. A remarkable level of control still exists, even with a tyre fully de?ated. Optional 21-inch wheels with Goodyear run-?at EMT tyres are also available, sitting on nine-spoke rims. The inclusion of run-?at tyre technology removes the need for spare wheels and a jack, freeing up space in the luggage compartment. Since the weight of the wheels has a direct impact on ride comfort and driving dynamics, Rolls-Royce has developed a lightweight ceramic core to the wheels to reduce unsprung weight. Ample power is supplied by a 6.75-litre, naturally aspirated, V12 engine. Developing 453 bhp / 338 kW and 720 Nm / 531 lb ft of torque at 3500 rpm, delivery is smooth and abundant. Furthermore, with 75 per cent of engine power available at just 1000 rpm, progress from a standstill is easy and remains so throughout the rev range. The highly ef?cient unit uses direct injection and variable valve timing. The engine is mated to a six-speed ZF automatic shift-by-wire gearbox. The powerful V12 will accelerate the Phantom Drophead Coupé to 60 mph in under six seconds and on to a limited top speed of 149 mph / 240 km/h. It stops in equally impressive fashion, using 374 mm / 14.7 in ventilated disc brakes at the front and 370 mm / 14.5 in at the rear. Twin piston alloy callipers at the front and single piston callipers at the rear bring the large-diameter wheels to rest. The braking system incorporates the latest four-channel anti-lock system. Emergency Brake Assist steps in under heavy braking, immediately applying full force in an emergency. At rest, an electromechanical park brake can be applied via a button on the dashboard. For maximum active safety, the sophisticated braking system is supplemented by an advanced dynamic stability control system that gives outstanding car control in an emergency situation. Final testing was carried out in several locations around the world. The hot-weather tests took place in the sti?ing heat of Death Valley, USA and the Namibian desert, while cold-weather testing was undertaken in the harsh winter conditions of Scandinavia. CRAFTSMANSHIP Craftsmanship is a hallmark of Rolls-Royce. From the traditional wood and leather workshop skills to the complex welding of the aluminium spaceframe, a 21st century Rolls-Royce is a blend of hand crafted expertise and high-tech materials and techniques. With more than 350 man-hours invested in each car, not including the time taken to build the engine, nearly right is never acceptable. The maxim of company founder Sir Henry Royce still resonates around Goodwood today: “Strive for perfection in everything you do.� From day-to-day production cars to the often complex Bespoke requests, Rolls-Royce has a skilled team adept at meeting the challenges of crafting the ?nest cars for the most discerning customers. For example, a number of the individual leather pieces used in the Phantom Drophead Coupé are larger than those in the Phantom, which makes their selection and usage more dif?cult because of naturally occurring blemishes and imperfections. The skill comes in using each hide in such a way that these natural marks are hidden or discarded, minimising waste and resulting in a perfect ?nish. Other new materials, such as the teak and brushed steel, bring with them their own unique challenges. Wood is a de?ning feature of the Phantom Drophead Coupé, and the woodshop team can spend up to a month preparing, matching, shaping and ?nishing each car’s set. The teak deck is ?nished with a specially formulated oil blend to ensure a rich, natural, longer-lasting lustre. Its use on the Phantom Drophead Coupé is unlike any other in the automotive industry. With the brushed steel, the dif?culty lies in getting exactly the same look to each of the parts – the grille, the bonnet and the A-pillar. After a great deal of research and testing, machine-brushing ?nished by hand-polishing was deemed the best way of achieving a uniform grain. Craftsmanship can be found throughout the Phantom Drophead Coupé, from the largest, most visible parts down to the smallest, unseen detail. By constructing each car with the same enthusiasm and passion with which it was designed, Rolls-Royce ensures that each one will offer a unique motoring experience, both to its owners and to all those who will travel in it.