Vacheron Constantin Les Cabinotiers Armillary Tourbillon: Destined for the Rolls Royce Amethyst Droptail

Watchmaker Vacheron Constantin is teaming up with a car producer of equally high calibre to create a unique watch destined for the dashboard of a Rolls Royce. The formidable collaboration came about thanks to a client with a passion for luxury cars and fine watches alike.

The unique timepiece, christened Les Cabinotiers Armillary Tourbillon, is designed to aesthetically fit into the dashboard of an exquisite Rolls-Royce commission: the Amethyst Droptail. The eight-figure coachbuilt convertible is a bespoke motor car, of which Rolls Royce has pledged to only make four carefully curated models. The only other known model thus far is the sultry La Rose Noire Droptail, which is accompanied by a special Royal Oak Concept from Audemars Piguet. The estimated price of the Droptail stands at around 30 million dollars, making it likely the most expensive Rolls Royce to date.

The Amethyst Droptail by Rolls Royce

While Vacheron Constantin’s archives reveal that a watch was commissioned for an automobile in 1928, the Les Cabinotiers Armillary Tourbillon project represents a first in the company’s modern history. It was executed by the horology house’s Les Cabinotiers department, which creates special pieces that fulfil the wishes of its top clients. Let’s take a closer look at this highly unusual yet alluring timepiece.

The case

For all its beauty, complexity, and innovation, the watch itself is housed in a simple 43.8 mm stainless-steel case with a height of 19.90 mm. The client thoughtfully opted for steel due to the material also being used in the Rolls Royce model. The really interesting part, however, is the fact that Vacheron Constantin fit the watch with a fully integrated – but removable – steel holder mechanism so that the client can display the timepiece on the dashboard, nestled to the right between the driver and passenger seat. The holder showcases exquisite hand-guilloche finishing in 18-carat white gold, alongside the watchmaker’s emblem: the Maltese cross.

The dial

The sapphire crystal dial allows for an unobstructed view of this exquisitely finished watch’s inner workings, while matching perfectly to the Rolls-Royce Amethyst Droptail‘s interior. An outer ring in white with purple lettering presents the retrograde minutes along the upper half of the dial, while small seconds can be read on the armillary tourbillon. Meanwhile, the hours float above the exposed movement and brass rhodium opaline mainplate, while titanium hands point to the hour and minutes.

The movement

The real showstopper when it comes to the Vacheron Constantin Les Cabinotiers Armillary Tourbillon is the movement, which is the horology house’s calibre 1990. First developed back in 2016, Vacheron Constantin opted for the 1990 in light of its bi-retrograde hours and minutes display reminiscent of traditional automobile speedometers. It also provides the wow factor with its integration of an armillary tourbillon, with its ethereal design nodding to 18th century models of the celestial sphere.

The armillary tourbillon

Here things get technical: the armillary tourbillon features a cylindrical (as opposed to flat) balance spring coupled to the balance itself. Conceived by Jacques-Frédéric Hourier in 1814, this type of balance spring without terminal curves is a rarity in contemporary watchmaking. Rarity aside, however, it has an important purpose, as the cylindrical balance spring gives the tourbillon a perfectly concentric beat. This ensures enhanced isochronism, thus providing remarkable precision. Thanks to Vacheron Constantin’s special escapement consisting of a silicon escape-wheel and diamond-coated silicon pallet-lever, it can then transmit impulses of 2.5 Hz (18,000 vph) while avoiding any unwanted friction – all without the need for lubrication.

Four patents

The calibre 1990 holds no less than four patents. Firstly, there’s the escapement collet, which secures the end of the balance spring. It is made of titanium in order to match the material of the regulating organ, in turn resulting in improved regulator performance. Secondly, the architecture of the tourbillon carriages allows the mechanism to form the shape of a Maltese cross motif every 15 seconds – an aesthetic and technical feat that is certainly worth a patent.

Thirdly, the diamond-coated silicon pallet-lever is also patented for its aforementioned friction-resistant qualities. Last but not least, the handsome instantaneous retrograde system, controlled by a single minutes cam that perfectly synchronises the jump of the two hands at midnight or noon, also earns itself a patent.

Decoration of the highest calibre

Paying attention to the finest details, the mainplate of the calibre 1990 features a mauve-coloured NAC galvanic coating with a circular satin finish. This original shade matches perfectly to the Rolls Royce Amethyst Droptail’s leather seats. As one can also admire through the sapphire crystal dial as well as the caseback, the matching mauve bridges are sharply cut, hand-bevelled, and adorned with a Côtes de Genève pattern.

Calibre 1990: Facts and figures

Last but not least, the manual-winding calibre 1990 not only beats at a frequency of 2.5 Hz but also provides a solid power reserve of 58 hours. This is partly thanks to the inclusion of an oversized crown, which allows the wearer to wind the watch with the utmost ease. Unusually placed at 12 o’clock, the crown is reminiscent of vintage manual-winding chronometers, just as the minutes track on the dial recalls traditional speedometers.

Les Cabinotiers Armillary Tourbillon: A unique piece

Unsurprisingly, the price of the Les Cabinotiers Armillary Tourbillon (Ref. 9880C/000A-182C) remains under wraps. The unique piece conceived for the owner of the Rolls Royce Amethyst Droptail comes in a special wooden Les Cabinotiers box, which likewise aesthetically echoes the motor car’s interior.

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