Nano Foudroyante EWT

To celebrate the 20th anniversary (2004-2024), Greubel Forsey presents its 10th Fundamental Invention: the Nano Foudroyante EWT. The mechanism’s energy is managed at the nanojoule scale, significantly reducing the number of components and the overall dimensions. The result is a 37.9 mm timepiece that combines the world’s first perpetual Nano Foudroyante with Greubel Forsey’s first flying tourbillon and manual wind flyback. This timepiece, set in a white gold and tantalum case, will be limited to just 11 pieces.

What is nanomechanics? It is a realm beyond the miniaturization of components to the nanometric scale. When we talk about nanomechanics, we’re talking about controlling energy on a nanojoule scale within a mechanical movement. This revolution in energy management within a caliber allows for a drastic reduction in both energy consumption and the number of components.

To demonstrate the feasibility of nanomechanics, Greubel Forsey has reinvented the foudroyante second. Its hand completes one revolution per second, dividing it into segments according to the movement’s frequency. In this Nano Foudroyante, each oscillation of the 3 Hz balance wheel produces two beats, totaling six beats per second, allowing the hand to divide the second into six distinct segments. This is an energy-intensive complication by nature. However, by managing energy on a nanojoule scale, Greubel Forsey has radically rethought its design and construction.

Compared to a traditional foudroyante that consumes 30 μJ (microjoules) per jump, the Nano Foudroyante operates with only 16 nJ (nanojoules) per jump, reducing energy consumption by a factor of 1,800. The mechanism’s volume is therefore reduced by 90%. Here, the focus is not just on measuring fractions of a second but as a proof of concept for a completely new approach to watchmaking, which is why this Nano Foudroyante was chosen to be a perpetual display.

It eliminates the entire gear train required in a traditional foudroyante to divide the second, as the information is sourced directly, distributing and managing the energy from the movement through a minimal number of low-inertia wheels. Fewer components mean less volume: this Nano Foudroyante EWT is very compact, with 428 components, and the movement measures no more than 31 mm in diameter within a 37.9 mm case (the smallest ever built by Greubel Forsey).

There’s more: true to Greubel Forsey’s passion for the tourbillon, this Nano Foudroyante is integrated within a flying tourbillon—the first ever made by Greubel Forsey. Finally, an additional innovation: although this flying tourbillon rotates constantly, the Nano Foudroyante’s dial remains permanently aligned towards twelve o’clock for optimal readability.

Together with the flyback, these three features complete Greubel Forsey's 10th Fundamental Invention: a Nano Foudroyante, set within a flying tourbillon, with an oriented reading axis. This is just the foundation and not the end result: this 10th Invention is powered by a manual-winding flyback movement. This complication presented by Greubel Forsey, includes column-wheel control within the strong architectural design and exceptional finishing, a signature of Greubel Forsey.