In response to a request from a client who collects both luxury cars and fine watches, Vacheron Constantin, the Manufacture has created a unique timepiece designed to fit into the fascia of an exquisite Rolls Royce Coachbuild commission – Rolls-Royce Amethyst Droptail. Working closely with the British luxury house on the technical specifications and finishing details, Vacheron Constantin developed this single-edition Les Cabinotiers Armillary Tourbillon 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.

Mechanical engineering inspires boundless passions. Whether housed within a motor car or inside the case of a watch, these fuel the inexorable need to master space and time by means of dedicated artefacts. Therefore it is unsurprising that so many clients of luxury with a particular affection for motor cars are also drawn to High Watchmaking – and vice versa.

For Vacheron Constantin, this mutual attraction was reflected in a special request from one of its clients’ to create a fascia timepiece, destined to be housed in a singular coachbuilt commission – Rolls-Royce Amethyst Droptail. This request included some specific and demanding criteria. The timepiece was to blend seamlessly into the motor car’s highly bespoke interior and reflect its aesthetic codes. It had to be elegant and removable, but meet exacting engineering standards for shock resistance and robustness.

Vacheron Constantin’s Les Cabinotiers department – which specialises in crafting bespoke timepieces in accordance with clients’ wishes – was particularly honoured to respond to this request.

While Vacheron Constantin’s archives reveal that a watch was commissioned for an automobile in 1928, this project, designed to fit perfectly within a very particular Rolls-Royce Coachbuild commission, represents a first in the company’s modern history. This in itself was reason enough to accept the challenge, given the celebrated British luxury marque’s commitment to excellence and meticulous attention to detail.

A technical challenge

Commissioned by a revered client who appreciates both the highest expression of Rolls‑Royce Motor Cars and bespoke Vacheron Constantin timepieces, this horological masterpiece presented a wonderful technical challenge. The two luxury houses worked closely together to ensure a seamless integration of the timepiece into the Rolls-Royce Amethyst Droptail’s fascia panel.

Vacheron Constantin master watchmakers worked together with the Rolls-Royce Coachbuild design team to ensure the shapes, materials and colours of the timepiece were in perfect harmony with its environment – all in keeping with Vacheron Constantin’s perpetual pursuit of excellence dedicated to the customer.

“The two centuries-old brands share a quest for perfection that consists of constantly pushing the limits of feasibility”, explains Christian Selmoni, Vacheron Constantin’s Director of Style and Heritage. “This philosophy is an excellent catalyst for innovation and good taste, both technically and aesthetically.”

An exceptional calibre

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 regulator – designed to compensate for the effects of gravity on the smooth running of the movement – 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 – a particularly rare phenomenon in contemporary watchmaking – 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. This performance is all the more remarkable in that the instantaneous double retrograde mechanism requires driving torque throughout the power reserve.

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.

A shared obsession with detail

While the construction of movements – however complex, such as calibre 1990 – has been familiar territory for Vacheron Constantin since its creation in 1755, fitting them inside a motor car is altogether new. 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 main plate 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 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.

Vacheron Constantin and Rolls Royce share the same culture of devoting their expertise to meeting the most demanding personalised luxury requirements. Delivered with the car on 24 August 2023, the one-off Vacheron Constantin Les Cabinotiers Armillary Tourbillon watch is to this motor car what time measurement is to the world of speed: essential.

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