In response to a request from a client, Vacheron Constantin has created a unique Les Cabinotiers Armillary Tourbillon timepiece designed to fit into the fascia of an exquisite Rolls-Royce Coachbuild commission – the Rolls-Royce Amethyst Droptail.
Working closely with the British luxury house on the technical specifications and finishing details, Vacheron Constantin developed this single-edition timepiece to perfectly complement the Rolls-Royce Amethyst Droptail’s interior suite.
Designed to be displayed on the fascia, which is finished in Calamander Light open pore wood veneer, the timepiece is housed within an elegant, fully integrated yet removable holder mechanism.
The two luxury houses worked closely together to ensure a seamless integration of the timepiece into the Rolls-Royce Amethyst Droptail’s fascia panel.
The watchmakers at Vacheron Constantin suggested to the client to equip this unique timepiece with the exceptional calibre 1990, a hand-wound in-house complication movement incorporating certain technical developments derived from Reference 57260, the most complicated timepiece in the world presented by the Maison in 2015.
This choice was notably influenced by the bi-retrograde display with instantaneous return of the hours and minutes. This function is reminiscent of traditional motor car speedometers featuring sweep hands. The hands return to zero at startling speed, but not without exerting a great deal of tension.
This particularly demanding mechanism requires special attention to ensure the accuracy of the display and the resistance of the materials used. In this case, the hands are made of titanium, which is extremely light and sturdier than steel.
In addition, this type of configuration with time-related indications on the upper part of the dial provides all the space needed for the mechanical ballet of the tourbillon. On this model, the latter appears in a complex “armillary” version.
This term is a nod to the work of 18th century French watchmaker Antide Janvier who invented a moving sphere with a planetary gear known as an armillary. Visually, this tourbillon evokes the interlocking circles and armillas (graduated metal discs) of the famous scientific instrument modelling the celestial sphere.
The construction of this type of tourbillon consists of two nested carriages rotating around two different axes at a speed of 60 seconds per rotation to form a sphere in perpetual motion.
Given the watch’s vertical position on the car fascia, the presence of such a regulator at the heart of the mechanism is fully justified. The tourbillon was developed at the beginning of the 19th century precisely to remedy the isochronism problems affecting the balance-spring of pocket watches, which were also generally vertically housed in a fob.
In contrast to a flat balance-spring, the cylindrical balance-spring coupled to the balance is another technical feature of this timepiece’s mechanism. Invented by Jacques-Frédéric Houriet in 1814, this type of balance-spring without terminal curves gives the tourbillon a perfectly concentric beat, thereby also ensuring enhanced isochronism and hence remarkable precision.
To transmit the impulses corresponding to a rate of 18,000 vibrations per hour (2.5 Hz), Vacheron Constantin has developed an escapement consisting of a silicon escape-wheel and pallet-lever with diamond pallets – both materials that reduce friction without the need for lubrication to enhance the mechanism’s reliability.
Four patents have been filed for the technical innovations featured in Calibre 1990. First, there is the instantaneous retrograde system, controlled by a single minutes cam that perfectly synchronises the jump of the two hands at midnight or noon.
The patented escapement collet – a component securing the inner end of the balance-spring – is made of titanium. The fact that this material matches that of the regulating organ results in improved regulator performance.
The third patent concerns the architecture of the tourbillon carriages, which rotate every 15 seconds to form a Maltese cross motif, the Vacheron Constantin emblem. The last patent relates the diamond-coated silicon pallet-lever, which offers greater resistance to wear and an optimised friction coefficient.
It is worth noting that for practical reasons, the crown has been deliberately oversized to facilitate winding and ensure a 58-hour power reserve. Positioned at 12 o’clock, it is reminiscent of vintage hand-wound chronometers, just as the minutes track recalls traditional speedometers.
Vacheron Constantin’s mechanical engineers had to develop a holding mechanism that, above all, would meet the precise dimensions of the Rolls-Royce Amethyst Droptail’s fascia compartments.
The holder was also designed to be removed from its housing if necessary and to allow the watch to be rotated through 180° for setting, winding and admiring the reverse of the calibre. The holders’ slightly curved outer frame is made of polished steel, with a bevelled steel inner frame laser-textured with a black PVD coating.
The base watch is affixed to a white gold base-plate, adorned with a hand-crafted sunburst guilloché motif featuring an applied Maltese cross. The holder can be covered with a steel lid, secured with a Maltese cross-shaped lock. When the watch and holder are removed from the fascia and placed in their box, an identical empty holder takes its place.
The attention devoted to details and finishing demonstrate the meticulous care lavished on the project by the Rolls-Royce Coachbuild and Vacheron Constantin teams.
The sapphire dial of the timepiece reveals the full beauty of Calibre 1990, including a mainplate featuring a mauve-coloured NAC galvanic coating with a circular satin finish – an original shade matching the hue of the Rolls-Royce Amethyst Droptail’s leather seats.
On the dial side, the bridges are sharply cut, hand-bevelled and adorned with a Côtes de Genève pattern also found on the rear-side bridges in the same mauve colour.
The Vacheron Constantin Les Cabinotiers Armillary Tourbillon watch and its accessories can be kept in a display case in the same Calamander Light open pore wood and the Amethyst leather used for the interior of the Rolls-Royce Amethyst Droptail. The interior of the case itself is slightly curved like the motor car’s fascia.
Model: Vacheron Constantin Les Cabinotiers Armillary Tourbillon Designed Exclusively for Rolls-Royce Amethyst Droptail, Reference 9880C/000A-182C
Developed and manufactured by Vacheron Constantin
35.50 mm diameter, 10 mm thick
Movement power reserve: approximately 58 hours
2.5 Hz (18’000 vibrations/hour)
Main plate and back bridges in mauve PVD and face bridges with NAC treatment
Hallmark of Geneva certified timepiece
Retrograde hours and minutes
Small seconds on tourbillon
43.8 mm diameter, 19.90 mm thick
Transparent sapphire crystal caseback
Transparent sapphire crystal dial and brass rhodium opaline
Stainless steel and 18K white gold hand-guilloché for the background and Maltesse cross
Presentation box & accessory
Les Cabinotiers special box
« Pièce unique », « Les Cabinotiers » and « AC » hallmark engraved on the back of the timepiece