Vacheron Constantin designs bespoke Les Cabinotiers Armillary Tourbillon for Rolls-Royce Amethyst Droptail

September 2023

Vacheron Constantin designs bespoke Les Cabinotiers Armillary Tourbillon for Rolls-Royce Amethyst Droptail

A watch and automobile enthusiast has orchestrated a unique collaboration between luxury brands Vacheron Constantin and Rolls-Royce Motor Cars. Celebrating a mutual love for precision and craftsmanship, the project features a single-edition Les Cabinotiers Armillary Tourbillon watch, customised to integrate seamlessly into the dashboard of a Rolls-Royce Amethyst Droptail.


n response to a request from a client who collects both luxury cars and fine watches, Vacheron Constantin has created a unique 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 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 designs bespoke Les Cabinotiers Armillary Tourbillon for Rolls-Royce Amethyst Droptail

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.

Commissioned by a passionate 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.”

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.

Vacheron Constantin designs bespoke Les Cabinotiers Armillary Tourbillon for Rolls-Royce Amethyst Droptail

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.

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 designs bespoke Les Cabinotiers Armillary Tourbillon for Rolls-Royce Amethyst Droptail


Les Cabinotiers Armillary Tourbillon


Developed and manufactured by Vacheron Constantin
Mechanical manual-winding
35.50 mm diameter, 10 mm thick
Movement power reserve: approximately 58 hours
2.5 Hz (18’000 vibrations/hour)
299 components
45 jewels
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 Armillary tourbillon

Stainless steel
43.8 mm diameter, 19.90 mm thick
Transparent sapphire crystal caseback

Transparent sapphire crystal dial and brass rhodium opaline


Watch holder
Stainless steel and 18K white gold hand-guilloché for the background and Maltesse cross

Presentation box & accessory
Les Cabinotiers special box

The Europa Star Newsletter