Time-energy fundamentals

Greubel Forsey has been shaking up haute horlogerie since 2004 with its Fundamental Inventions.

Its 10th invention of all — the Nano Foudroyante, is the most disruptive when it comes to technology; from the standpoint of the independent brand and also the mechanical watchmaking universe.

In a hand-wound timepiece, the world’s first perpetual Nano Foudroyante joins Greubel Forsey’s inaugural flying tourbillon and flyback chronograph.

Today, we take a closer look at the new arrival from 2023 for Greubel Forsey — the Nano Foudroyante EWT, which arrives on the scene for the 20th anniversary of Robert Greubel and Stephen Forsey’s Atelier in La Chaux-de-Fonds, Switzerland, which first opened its doors in 2004.

During its first three years, their “Art of Invention” saw the release of the Double Tourbillon 30°, the Quadruple Tourbillon and the Tourbillon 24 Secondes.

The first of these inventions however resides right in the heart, literally, of such models that include the Double Tourbillon 30° Edition Historique that won the Aigiulle d’Or Grand Prix at the GPHG 2010.

Its ultimate third invention—the Tourbillon 24 Secondes Vision—was also awarded top honors in 2015 (GPHG).

The next year, Greubel Forsey applied for a patent for its Mechanical Nano effort out of its Experimental Watch Technology (EWT) Lab. Founded in 2005, the lab was one of the first proponents of nanomechanics for watchmaking, creating a new world of possibilities beyond the mere miniaturisation of components.

To prove that nanomechanics worked, Greubel Forsey reinterpreted the foudroyante, which provides fractions of a second. Its hand makes one full turn per second on a subdial divided into sections reflecting the frequency of the movement.

Within its Nano Foudroyante, each swing of the 3Hz balance wheel creates a pair of beats (6 beats per second in total), arriving at the final 6 beats per second. The complication, which is shown on a dial segmented in six, features a red hand.

The old mechanism requires 30 microjoules compared to just 16 nanojoules per jump for the novel Nano Foudroyante, a reduction in energy consumption factor of 1,800.

Moreover, EWT lab reputation designed and constructed the model differently. The whole gear train, which usually needs to divide the second, can be removed as the information comes directly which sends and handles the input energy using as few light wheels as possible.

The Nano Foudroyante forms part of the flying tourbillon on the commemorative timepiece, which is situated between 4 and 7 o’clock. The foudroyante dial hangs upright an extra innovation for improved reading of the foudroyante, while the tourbillon is constantly rotating.

There’s also a small seconds and a chronograph minutes counter on the dial.

Simply protecting mechanically an entire microchip means reducing literally the load of parts and the overall dimension.

As such, the movement is just 31mm in diameter.

Limited to just 11 pieces, the Nano Foudroyante EWT is the smallest Greubel Forsey that has been made, and it is presented in a 37.9mm white gold case, while both the bezel and caseback are made from tantalum and carry a sheen of grey-blue.

Powered by a manually-wound movement with exceptional finishing, the visible column wheel sports a 3D monobloc geometry, as shown as the translucent caseback.

Other engravings include “Nano Foudroyante” and “Greubel Forsey,” with a hand-hammered background, as well as “2004-2024” and “20th Anniversary” to celebrate the milestone.