When Eric Coudray amplifies Prendel’s tourbillon

The tourbillon is a mechanical device invented by Abraham-Louis Breguet to improve the precision of mechanical watches by counteracting disruptions to the isochronism of the balance caused by Earth’s gravity. The principle is to place the movement’s regulator and escapement in a cage rotating around its own axis in order to obtain a range of vertical positions and ensure mutual compensation and thus release itself from the pull of the Earth.

Watchmakers have been working on perfecting this system for more than two centuries and there are numerous interpretations and variations on the theme, from the original principle patented in 1801 by Abraham-Louis Breguet to Omega’s central tourbillon in 1995.

However, one of the most important steps in the evolution of the tourbillon is not one of the most well-known. This was the development in 1928 of an oblique tourbillon by the German watchmaker Walter Prendel.

In his workshops in Groitzsch, a part of Saxony which is as well-known as Switzerland for the development of cutting-edge watches, Walter Prendel aimed to prove the relevance of his research – based on the theories of master watchmaker Alfred Helwig – into improving the stability and regularity of the rate of his oblique tourbillon with a spring-balance inclined at 30° to horizontal. This would be demonstrated through the creation of a unique pocket watch equipped with his ingenious device, completing one rotation in 6 minutes. A key milestone, this historic watch has not been seen since it was sold at auction in Geneva in 2021.

It was in the early 2020s that master watchmaker Eric Coudray, winner of the Prix Gaïa and familiar with the complex works of Walter Prendel, decided to continue this work to improve the tourbillon, using this oblique tourbillon as his base. Eric Coudray devised his conical tourbillon, which he called the “Cônillon”, a revision and reinterpretation of Prendel’s oblique tourbillon.

Given its advances in contemporary fine watchmaking, it was only logical that HYT would decide to include a tourbillon in the design of the mechanical movement for its new watch. Of course, the independent company turned to Eric Coudray, closely associated with the development of the brand for many years, to help it achieve this.

In the same way that the ebb and flow of the fluids in HYT watches are visible and evident, the capacities of the conical tourbillon can be understood without a magnifying glass or other tools by any discerning watch lover thanks to the unusual dynamic animation.

At the very heart of the dial, where the conical tourbillon completes a clockwise revolution in 30 seconds, there are three spheres rotating at different speeds which are easy to observe: the first completes four turns a minute, the second five turns a minute, and the third six turns a minute, clockwise.

These rotations introduce a particularly bold form of chaos as, paradoxically, they demonstrate the stability of the conical tourbillon’s rate. Any observer would intuitively be tempted to think that their contradictory forces would cause disruption, upsetting the equilibrium, which seems to fly in the face of strict watchmaking logic.

On the contrary, they demonstrate the perfect stabilisation of the rhythm of the tourbillon as, unlike other types of animation which are positioned after the balance in the chain of movement, the animated spheres in the HYT Conical Tourbillon are cut across by the energy produced by the four cylinders in order to reach the regulating organ.

The unconnected, rapid movements of the animated spheres ensure the conical tourbillon keeps perfect time, providing a tangible demonstration of its technical efficiency.

Click here to read more about the Conical Tourbillon