Greubel Forsey Nano-Foudroyante EWT watch is here, a small watch with a big idea
Greubel Forsey’s latest watch combines a completely new type of foudroyante with GF’s first flying tourbillon, housed in a case that is classically styled and sized.
Greubel Forsey replica has been renowned for many reasons since the brand was founded in 2004, including the extremely meticulous hand-finishing of its movements, the delicate and almost microscopic construction of those movements, and perhaps most importantly the seemingly inexhaustible creativity that founders Stephen Forsey and Robert Greubel have brought to the creation of complications. The company has created many highly complicated watches, but is best known for its tourbillons, which over the years have included multi-axis, double and quadruple tourbillons, and high-speed tourbillons. In recent years, GF has also experimented with less complex but equally well-made watches in the Balancier collection, but lest it appear that GF is no longer in the supertourbillon business, they introduced the Tourbillon Cardan in 2023, which embeds a tilted tourbillon within a double-ring oscillating system. Today, GF announced the launch of its latest EWT, or “Experimental Watch Technology” invention, released in limited quantities – the Nano Foudroyante EWT – to celebrate the brand’s 20th anniversary since its founding in 2004.
The nomenclature of Greubel Forsey inventions is a little confusing; the company announced this as its 10th foundational invention, though it announced an earlier version of the Nano Foudroyante in 2017 as its third EWT invention, distinct from its other “foundational inventions” – the other two EWT inventions at the time were the Synthetic Diamond Binomial Escapement in 2009 and the Différentiel d’Egalité (Spherical Differential Constant Force Device, patented in 2006), the latter of which went into production watches in 2018; I don’t think the Diamond Binomial Escapement was actually ever produced. The original version of the Nano-Foudroyante was really more of a technology demonstrator, though, as you’d expect, it was pretty impressive.
The lightning-seconds hand (sometimes called the diablotine or “little devil”) rotates once per second, usually jumping in a different pattern corresponding to each unlocking of the escape wheel. Since the lightning-seconds hand is usually driven by a wheel mounted on the escape wheel axle, whatever gearing is used must be as light and low-inertia as possible so that the escapement can lock and unlock properly. (A more complex example of a lightning-seconds hand is the Centigraphe by FP Journe, which adds complexity by engaging and disengaging the lightning-seconds hand as the chronograph is turned on and off, incorporating a reset mechanism and a method of braking the lightning-seconds hand between jumps). Bugatti Chiron replica watches
The 2017 prototype introduced a new approach, using a tiny gear on the escape wheel axle that is actually much smaller in diameter than the escape wheel itself. This LIGA-made gear drives the crown wheel (also very small) on the tourbillon hand axle, and since this axle rotates at right angles to the plane of rotation of the go-wheel train, the actual tourbillon hand and dial are built into the watch’s caseband.
This time, however, GF has opted for something more complicated, but also more practical and creative.
If you are familiar with Greubel Forsey, the first thing you will notice and be surprised by is the size of the watch. Usually, GF watches are large, partly for practical reasons and partly for aesthetic reasons; for example, the Quadruple Tilted Tourbillon has many advantages, but it probably won’t prompt anyone to write or say “surprisingly wearable” (for example, the Quadruple Tourbillon GMT measures 46.5mm x 17,45mm, although in addition to the two double tourbillons, it also has a rotating miniature globe). On the other hand, the Nano Foudroyante measures only 37.9mm x 10.49mm in a white gold (case center) and tantalum (bezel, caseback) case, which is smaller than some fake Grand Seiko time and date watches.
The second thing you will notice are the two pushers at 2:00 and 3:00 on the side of the case. The watch is a column-wheel-controlled flyback chronograph with a central chronograph seconds hand and a 60-minute counter at 9:00. The running seconds hand is visible at 8:30 on the dial. So far, so good, and relatively conventional too, save for the slightly unusual sub-dial layout and the use of a mix of white gold and tantalum.
The main attraction, however, is the tourbillon, which is positioned slightly asymmetrically and visible through an aperture between 4:00 and 7:00. This is a first for GF in several ways. Arguably the first first is that this is a flying tourbillon, and despite GF having created so many tourbillon variations, it has never done a traditional flying tourbillon before (the closest thing is probably a gimbal, although technically the upper bridge is actually part of the innermost rotating ring). But what really catches your eye is the foudroyante dial that sits on top of the tourbillon.
The basics are the same as the non-tourbillon 2017 version, but obviously the earlier model did not have the foudroyante hand and dial on the tourbillon itself. Since the escape wheel is on the tourbillon cage (as all tourbillons are), in principle it’s just a matter of figuring out how to move the foudroyante hand off the escape wheel, but – and this is a big but – there’s little room for the drive gears unless you can scale them down small enough to make the whole thing possible. Tourbillons with foudroyante have been made before, but never on the tourbillon itself. The foudroyante dial is a satellite – that is, it’s geared so that its vertical axis never changes; the 6 is always at the top of the dial, no matter where the one-minute flying tourbillon is in its orbit. Those interested in balance will notice that the weights on the tourbillon cage are quite asymmetrical, due to the foudroyante mechanism; GF compensates for this with a platinum counterweight (hidden on the bottom of the cage). luxury cheap Watches
The actual nano-drive system is in a housing beneath the tourbillon dial – I presume it’s directly above the escape wheel – while the satellite gears needed to keep the system’s vertical axis upright appear to be located below the “GF” on the central axis of the tourbillon itself. The energy required to drive the tourbillon is very small – and I quote GF: “Compared to a conventional tourbillon that consumes 30μJ (microjoules) per jump, the nanotourbillon consumes only 16nJ (nanojoules) per jump, reducing energy consumption by a factor of 1,800. As a result, the device is 90% smaller.” (A joule is an SI unit roughly equivalent to the energy required to lift a medium-sized tomato one meter off the ground. If you’re a Newton fan, use an apple). The 2017 system consumed a bit less energy – GF told us at the time that it consumed 5 nanojoules per jump – but this is still in the order of 16nJ, and is very reasonable given the adaptability of the drive system to the tourbillon.
If you want to quibble about terminology, “nanotechnology” usually refers to mechanisms on a scale of 1 to 100 nanometers (billionths of a meter), that is, the size of individual atoms and molecules, but I think we can forgive GF a little exaggeration on this point. By comparison, 160 nanojoules is the energy of a flying mosquito. It’s fascinating watchmaking, and it’s fascinating engineering.
Of course, there’s more to the story than nanojoule engineering. First, if you’re interested in this watch (and I hope you are by now) and in GF in general, you’d hope that they didn’t give up anything in terms of movement finishing, and that seems to be the case.
The movement is extremely compact; just 31mm in diameter (if that number makes your eyes light up, there’s a reason, it’s the smallest movement GF has ever made). The movement has a uniform upper bridge (GF hasn’t provided a caliber name yet, but there’s absolutely no reason to think you wouldn’t recognize this movement immediately), and as far as I can tell, there’s not a single internal corner that isn’t as sharp as a sashimi knife, which is nice. GF has a habit of engraving text on the dials and movements of some of its watches that expresses its design philosophy, and here we see a bit of that, but in keeping with GF’s 37mm high quality cheap watches, the scale is modest and understated, only on the central chronograph seconds wheel.
If you want to know how much effort any brand or watchmaker puts into perfecting its movement, two good places to look are the stabilizing pins and screws; the stabilizing pins visible on the movement are domed and black/mirror polished; the screws have beveled slots and heads, and every visible surface (including the slot, the slot bevel, and the bottom of the slot itself) is black polished. And of course, the beveled countersunk holes.
Greubel Forsey is one of three contemporary independent watch brands that I wish I had collected from the beginning – the other two are MING and MB&F, and all three have some personal reasons (I say that, but when it comes to watches, I guess all reasons are personal). One of the most memorable moments I’ve had as a journalist and collector was sitting next to Stephen Forsey at a dinner in New York in the early 2000s, just as the brand was launching in the US, and I listened to him speak for an hour about the theory and practice of the tourbillon and the principles of the multi-axis tourbillon, and I remember at the end, when I asked him if all these complications really offered any real chronometric advantage, he said: “It’s always a struggle to gain more than you lose.” It’s great to see that GF is still pushing the boundaries of mechanical timepieces, and surprisingly, they’re doing so in a 37.9mm watch; putting the Nano Foudroyante in a large case would defeat the purpose of the whole exercise.
I hope to see it one day – limited to 11 pieces, price on request. I don’t quite like the odds, but as a decades-long watch enthusiast, I don’t ask why, but why not? I’m glad it exists.
Greubel Forsey Nano Foudroyante EWT: Case, 37.9mm x 10.49mm, white gold case, tantalum bezel and caseback; water-resistant to 30m. Rhodium-plated gold dial, engraved and black lacquered hour-markers and tourbillon minute ring opening; gold small seconds and chronograph minute counter. Movement, Nano Foudroyante mounted on a one-minute flying tourbillon, monopusher flyback chronograph; manual winding at 3Hz, power reserve 24 hours with chronograph on. White gold pin buckle, hand-engraved GF logo.
