Although the tourbillon as patented by Breguet is over 200 years old, watchmakers are constantly inspired to improve its gravity-defying effects. Such improvements have involved inclining the tourbillon cage at an angle, adding multiple tourbillons to the same movement and producing tourbillons that can rotate around two – and more recently three – different axes. Adding this third axis of rotation, however, which is usually the vertical axis, means that the tourbillon cage needs a lot more room to manouevre. As a result, we see some original new crystal designs.
For its tri-axial tourbillon model, which progressed from the drawing board to the assembly line in a mere eighteen months, Girard-Perregaux uses a domed lens within the sapphire crystal to provide space for the tourbillon mechanism. This consists of the familiar tourbillon cage, which performs one revolution in one minute about its own horizontal axis, a second mechanism that rotates the cage vertically once every 30 seconds and a bridge connected to the mainplate that rotates this entire assembly once every two minutes.
Despite a high level of hand finishing on the GP09300-0001 movement powering this 10-piece limited edition, the emphasis is on discretion. The dial side of the 48mm case in brushed rose gold shows just a small hour and minute sub-dial for the time and a curved power reserve indicator at 6 o’clock in order to ensure that the eye is not distracted from the tourbillon’s dance, which can also be admired through an aperture in the side of the case.
Harry Winston's Histoire de Tourbillon 5 is the first model in this series to be produced in rose gold and allocates a full 21mm of thickness for its tri-axial tourbillon to whirl around by using a domed “porthole” that covers the tourbillon at 9 o’clock. The movement beats at the same frequency as the Girard-Perregaux model, 21,600 vibrations per hour, and its tourbillon cage has a similar number of components and weight. But the rotation times about each axis are different: 45 seconds for the inner cage, 75 seconds for the intermediate cage and 300 seconds for the outer cage. This tourbillon also opts for a more technical look, with a black openworked movement visible immediately beneath the sapphire crystal and separate hour and minute discs, produced by galvanic growth for minimum thickness, arranged vertically alongside the tourbillon cage.
In Jacob & Co’s Astronomia Tourbillon, the tri-axial tourbillon is just one of four elements that are in constant rotation around the dial. Every 20 minutes the tourbillon cage, the Earth, the Moon and a dial for the hours and minutes, each positioned at the end of an arm radiating from the centre of the movement, perform a complete revolution around the dial. A special mechanism ensures that the time is always displayed the right way up as the subdial for the hours and minutes moves around the dial. Furthermore, in addition to its rotation about its own axis and its rotation around the dial on the end of one of the four arms, the tourbillon cage spins around a third vertical axis at a dizzying speed, completing one revolution in just five seconds.
This entire assembly seems to float in space above an aventurine background and underneath an almost hemispherical crystal. It may not be the most wearable of the three tourbillons, but you would hardly want to hide it under your shirtsleeve anyway.
