Greubel Forsey Nano Foudroyante EWT

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 two founders Robert Greubel and Stephen Forsey have been working together for more than three decades now. They first met at Renaud et Papi in 1992 and later formed CompliTime – a specialist of highly complicated movements. It was here that the creation of the Double Tourbillon 30° regulator and the timepiece incorporating it commenced, which was presented at Baselworld in 2004, already under the aegis of Greubel Forsey.

For over 20 years, the commitment to research and invention has been at the heart of all Greubel Forsey’s Fundamental Inventions and timepieces. For many years the company was known for the most technically special and innovative timepieces – very attractive to a niche of extremely demanding collectors.

To celebrate the 20th anniversary (2004-2024), Greubel Forsey presents its 10th Fundamental Invention: the Nano Foudroyante EWT – a very technical, limited edition timepiece; kind of back to its roots.

The a manual-winding flyback movement has 428 components but measures only 31 mm in diameter within a pretty small, 37.9 mm case. The watch features nano foudroyante seconds, set within a flying tourbillon, with an oriented reading axis. The ‘seconde foudroyante’ or lightning seconds is a hand that makes one rotation every second. This complication consumes a large quantity of the mainspring’s energy in a watch.

As Greubel Forsey states, they 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 3Hz balance wheel produces two beats, totalling six beats per second, allowing the hand to divide the second into six distinct segments. By managing energy on a nanojoule scale, Greubel Forsey has radically rethought its design and construction. Compared to a traditional foudroyante that consumes 30μJ (microjoules) per jump, the Nano Foudroyante operates with only 16nJ (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.

The Nano Foudroyante EWT has a white gold case with a bezel and caseback crafted from tantalum. The latest novelty of Greubel Forsey will be limited to just 11 pieces and engraved with “2004 – 2024” and “20th Anniversary” to mark this milestone.