Zenith Defy El Primero Fusee Tourbillon
Zenith reinterprets the fusee & chain constant force mechanism in a modernistic style.
Housing the new El Primero 4805 SK calibre, a manual-winding movement that follows the DEFY code of avant-garde movement architecture with an open three-dimensional impact, the DEFY Fusee Tourbillon is available in two distinct editions in Carbon and Platinum.
Upon a first glance, it’s immediately clear that the DEFY Fusee Tourbillon’s calibre is out of the ordinary. The spoke design of the bridges is amplified by their bicolor finish, where the top satin-finished surface is given a black treatment, while its polished sides are a lighter grey rhodium tone. The layout of the bridges offers a balanced layout of the various functions and complications. On the top half of the movement, one can admire the uniquely conceived fusee and chain constant force mechanism. The chain, which consists of 575 individually hand-assembled components, features a bold blued treatment: a first for a wristwatch fusee and chain system. On the opposite end at 6 o’clock, a tourbillon cage with an entirely new construction featuring an off-centered balance wheel makes a full rotation every 60 seconds. Like the chain, the tourbillon cage is embellished with a striking blue colour, reinforcing the visual effect of the DEFY Fusee Tourbillon’s unique moving parts. Positioned at the edge of the dial between 4 and 5 o’clock, a red-tipped hand indicates the power reserve, a handy feature when manually winding the DEFY Fusee Tourbillon with its 50-hour power reserve.
As a mechanical movement’s mainspring unwinds, the torque it delivers to the regulating organ drops, resulting in less efficient chronometric performance of the movement. A centuries-old solution to counter this and achieve constant force lies within the power source and its transmission. Known as the “fusee and chain” system, it features miniature chain is coiled around a conical “fusee” and attached to the mainspring barrel. As the mainspring unwinds, more of the chain wraps around the barrel, detaching itself from the wide conical base of the fusee. The greater turning movement provided by the fusee compensates the weakening mainspring pull, thus maintaining the torque and, consequently, the amplitude of the regulating organ constant throughout the duration of the mainspring’s autonomy.
By combining the fusee and chain mechanism with a tourbillon regulating organ, Zenith places precision at the forefront of its unique take on haute horlogerie. Highlighting the unique technical and aesthetic prowess of the piece, the DEFY Fusee Tourbillon is produced in two different editions.
The first version features a light yet robust carbon case, crown and buckle head. The carbon fibre treatment even extends to the open dial, with the central skeletal element and surrounding flange ring giving off the unique shimmer of this material. To complete the high-tech look, the DEFY Fusee Tourbillon in carbon is fitted on a black rubber strap with a “Cordura” fabric effect and blue stitching. A second strap is also supplied, in black rubber with a woven carbon effect. The DEFY Fusee Tourbillon in carbon is limited to 50 pieces.
The second version of the DEFY Fusee Tourbillon, limited to just 10 pieces, is crafted in platinum. The exposed movement provides a vibrant, voluminous view, where the mix of materials and tones add visual depth, from the anthracite base plate of the movement to the blued chain and tourbillon cage topped with a set of geometrical bridges in two tones. The strap is made of a black rubber core coated with black alligator leather.