Greubel Forsey unveils their 8th Invention – the Tourbillon Cardan. A new interpretation of the tourbillon based on three pillars: a rapid rotating tourbillon, a revolving 30° inclined plane and two perpendicularly tilting rings.
Press Release information with commentary in italics.
New: Greubel Forsey Tourbillon Cardan – Invention #8.
The Greubel Forsey Tourbillon Cardan has a recommended retail of SGD 729,000 inclusive of GST. Greubel Forsey plans to build just 55 pieces of the calibre over the next 5 years, with 11 pieces in this novelty’s 45.5mm titanium case.
Commentary
We covered many of Greubel Forsey’s Inventions in a series of articles in our conversations with Stephen Forsey.:
- Invention #1 lost, and found! No 1 is the Double Tourbillon 30º, where a tourbillon lives within an inclined cage which also rotates.
- Invention #2. No 2 is the Quadruple Tourbillon, two double tourbillons connected by a spherical differential.
- Invention #3. Tourbillon 24 Secondes is a fast rotating tourbillon inclined at 25º.
- Invention #4 is the Spirale Binôme, which is a balance spring using a non-magnetic material.
- Invention #5 is the Différential D’Egalité which is a spherical differential. Both Invention 4 and 5 are used in many watches in the GF stable.
- Invention #6. Double Balancier – two separate oscillators on two inclined axis couled by a spherical differential.
- Invention #7
- In Conversation with Stephen Forsey: Part 1, Part 2, Part 3.
This latest novelty is the eighth in the series. And it is a fresh look at a new type of tourbillon, which they call the Tourbillon Cardan – translated as tourbillon dial.
The design is based on Greubel Forsey’s three pillars – the rapidly rotating tourbillon which makes one complete revolution every 16 seconds, GF’s fastest yet.
The tourbillon is also inclined at 30°, now considered as one of the classical inclination for GF first seen in Invention #1.
And finally putting this assembly on another assembly consisting of two rings. These rings have axels which are perpendicular to each other in a layout is quite similar to what is seen in the gimbal system of a marine chronometer. But instead of using gravity to place the gimbal rings, the GF tourbillon cardan rings are driven by the movement, making a constant rocking motion at a rate of one complete cycle in 48 seconds. The effect on the tourbillon is exactly the reverse of the marine chronometer’s gimbal. Instead of ensuring the balance is always upright, it puts the inclined tourbillon under a constant wave like motion. This dance of the angle of the balance, tourbillon and rings are timed precisely, and frankly the entire mechanism is quite mind boggling to think of.
We look forward to seeing it in operation soon. Greubel Forsey claims this constant motion in multiple axes provides the tourbillon cadran with improved chronometric performance. We expect to see the usual very high level of finissage on the new Tourbillon Cadran, with intelligent choices for the surfaces to showcase the different finishings on surfaces in juxtaposition to each other.
Release information
For many years, Greubel Forsey has been working on the development of a new type of tourbillon. Over the past three years, this tourbillon has transitioned from concept to reality and is now unveiled as the 8th Fundamental Invention of the Atelier. To reach a new level of chronometric precision, the Tourbillon Cardan is based on three pillars: a rapid rotating tourbillon, a revolving 30° inclined plane and two constantly tilting rings.
For 20 years, Greubel Forsey has been working from the standpoint that contemporary watchmaking is far from having exhausted all the technical possibilities of fine watchmaking. The Atelier has proven this on seven landmark occasions, developing Fundamental Inventions that rethink the basics of movement regulation and other major complications. This titanic undertaking, focused on chronometric performance, continues today with an 8th Invention: the Tourbillon Cardan.
An unprecedented tourbillon The Tourbillon Cardan is designed to reach new heights of chronometric precision. It combines three principles. The first: the tourbillon. The mechanism patented by Abraham-Louis Breguet in 1801 was designed to compensate for the differences in rate, in vertical positions. For Greubel Forsey, this was not the end, but the very beginning.
While most tourbillons have a revolution of 60 seconds, that of the 8th Fundamental Invention is almost four times faster. Just 16 seconds. This is the fastest yet for a Greubel Forsey tourbillon. It moves through more positions in less time, and therefore offers much a higher average performance.
What’s more, this tourbillon incorporates, for the very first time, the large balance wheel designed, developed and made in-house by Greubel Forsey. It benefits from the exemplary balance of its masses, its large size (12.6 mm) and its optimised oscillations. Its high inertia also makes it less sensitive to shocks and variations in speed.
Second principle: the 30° angle. The tourbillon, as it was conceived over two centuries ago, was designed for pocket watches worn vertically. For a wristwatch, its design needed to be totally rethought, optimised for the positions adopted in everyday 21st century life.
Third principle: this 30° high-speed tourbillon is guided by two mobile rings, linked by two 90° axes. In 48 seconds, they tilt backwards and forwards. This construction may seem reminiscent of gimbals, but is very different from a traditional gimbal where the two rings are free to move and their job is to keep the object they contain horizontal. In the Tourbillon Cardan, the tilt of the rings is controlled (+30° to -30° range), while the degree of inclination of the tourbillon is inclined (also 30°) and never varies, offering a better ratio of angular velocity to chronometric performance.
Chronometric power reserve
The Tourbillon Cardan has four barrels. This is a remarkable construction at Greubel Forsey (occurring just once in 20 years). They are coaxially stacked, with a slipping mainspring to prevent excess tension during winding. They offer 80 hours of chronometric power reserve. Beyond that point, the timepiece still runs very well, but maybe outside the rigorous Greubel Forsey precision tolerances.
A new kind of aesthetic
As the tourbillon cannot be held in place by a fixed upper bridge, this function is performed by the two arched cardan rings. Without adopting the traditional construction, Greubel Forsey’s 8th Fundamental Invention creates a new type of tourbillon with a flying appearance, which is both original and patented. A seemingly complex construction but with a very small number of components, it offers an open, airy aesthetic that leaves the eye free to admire its kinematics.
100% hand-finished
Some components of the Tourbillon Cardan require up to three days for hand finishing alone. A number of unique finishes have been developed specifically for this timepiece. Among them, the movement plates are in frosted nickel silver, with polished bevels and straight grained flanks while a titanium mainplate presents a large polished flank as a backdrop to the cardan. Even more particular: the upper bridge of the tourbillon cage is made of frosted titanium with straight grained flanks and polished bevels, above and below. Finally, the arch is barrel-polished. It takes more than 30 hours to finish this single component.
The cardan’s rings are matt finished, with polished bevels and straight grained flanks, while the lower plate is frosted by hand, a task that requires a particularly special expertise from the Atelier Manufacture. Finally, there are two dials (hours & minutes and seconds), one circular grained with polished flanks and a very large mirror finish angle, the other with a polished exterior flank.
Greubel Forsey has also developed a high domed sapphire crystal for this piece. It houses the full height of the tourbillon and cardan system, offering a highly architectural technical vision. The view is completely unobstructed over the balance wheel measuring 12.6 mm in diameter. You can admire the majestic swaying of the two cardan rings into which it fits.
A maximum of 11 pieces per year The Tourbillon Cardan will be available in a 45.5 mm titanium case. This metal was chosen for its modernity and lightness, in keeping with the airy aesthetic of the Cardan tourbillon.
Greubel Forsey plans to build just 55 pieces of the calibre over the next 5 years.
Greubel Forsey Tourbillon Cardan Technical Details
Tourbillon Cardan In titanium
Hand-wound movement with patented Cardan
Tourbillon
Cardan Tourbillon • hours and minutes • small seconds • power-reserve
Movement
Movement dimensions
- Overall diameter: 39.60 mm
- Thickness: 13.53 mm
Number of parts
- Movement: 389 parts
- Cardan tourbillon cages: 98 parts
- Weight of the cage: 0.92 g
Number of jewels
- 49
- Olived-domed jewels in gold chatons
Chronometric power reserve
- 80 hours
Barrels
- Four coaxial series-coupled fast-rotating barrels (1 turn in 2.7 hours), one of which is equipped with a
- slipping spring to avoid excess tension
- Relief-engraved text, circular-grained, black treatment, polished chamfer
Balance wheel
- In-house variable-inertia with 6 gold mean-time screws
- (12.60 mm diameter)
Frequency
- 21’600 vibrations/hour
Balance spring
- Phillips terminal curve
- Geneva-style stud
Bridges and main plates
- Titanium and nickel silver, frosted and spotted, polished bevelling and countersinks, straight-grained flanks
- Hand-bevelled and openworked cage pillars
Movement side
- Flat black polished steel tourbillon bridge, polished bevelling and countersinks
- Gold plate engraved with the individual number, circular-grained, polished bevelling, straight-grained
- flanks
Cardan Tourbillon
- Ultra-fast inner tourbillon cage (1 rotation in 16 seconds) in titanium, barrel-polished and hand-
- bevelled, inclined at a 30° angle with gold counterweight
- Outer flying Cardan cages, 48-seconds cycle, double variable tilt at 30°, polished and hand-bevelled,
- straight-grained flanks
Gearing
- Involute circle profile
- Conical gearing with profiled teeth
Displays
- Hours and minutes
- Small seconds
- Power reserve on a sector
Exterior
Case
- Titanium with high domed synthetic sapphire crystal
- Transparent back with high domed synthetic sapphire crystal
- Hand-polished bezel, caseband with hand-finished straight graining
- Titanium security screws
- Raised polished engraving “Tourbillon Cardan” and “Greubel Forsey” on a hand-punched background
Case dimensions
- Caseband diameter: 45.50 mm
- Bezel diameter: 46.00 mm
- Case height: 13.81 mm
- Height on synthetic sapphire crystals: 18.15 mm
Water resistance of the case
- Water-resistant 3 atm – 30 m – 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown
- Titanium, polished, with GF logo
Dial side
- Multi-level gold dial with openworked pillars, circular-grained with engraved and lacquered minute-circle, polished flanks
- Gold hour markers
- Small seconds and power-reserve indicators in gold, engraved and lacquered
- Engraved and lacquered GF logo
Hands
- Hours and minutes in polished steel, with Super-
LumiNova
- Small seconds and power-reserve in polished steel, hand-polished countersink, flat black polished head
Strap and clasp
- Non-animal material, hand-sewn
- Titanium folding clasp, engraved GF logo
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