Monochrome Watches
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The Impressive HYT Conical Tourbillon (Live Pics & Price)

Master watchmaker Eric Coudray creates a spectacular conical tourbillon complete with chaotic animation to accompany HYT’s signature fluid representation of the hours.

| By Rebecca Doulton | 3 min read |

Since 2012, HYT has cornered a niche in the market as the only watch brand to display time with fluids. There have been clepsydras since time immemorial, but HYT’s neon fluids pumped around the dial by bellows to indicate the hours are unique in the watch world. Celebrating ten years of watchmaking, HYT unveils a model animated by a conical tourbillon. The most complex timepiece to date, the conical tourbillon, created by master watchmaker Eric Coudray, rises above the spectacle of the retrograde fluid hours to perform its 30-second rotations, accompanied by an unusual ‘chaotic animation’ represented by three rotating spheres.

Space vessel

Using a similar spaceship case construction to the HYT Hastroid of 2022, with a pronounced domed sapphire crystal and hollowed lugs, the dimensions of the case – 48mm diameter x 52.30mm length x 25.15mm thickness – are significant. To lighten the load, the complex, multi-layered, 66-part case is made of carbon fibre and black-coated titanium. Viewed from the side, you can appreciate the complexity of the sandwich-style case with its matte brushed finishings and indented sides protected by an aerated grid.

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Fluid hours

True to form, HYT’s signature retrograde indication of the hours is represented by a green liquid. The science behind HYT’s fluid representation of time depends on two immiscible fluids placed inside a glass capillary and propelled by bellows. The left bellow pushes the green fluid along the tube, and the right bellow pushes the transparent fluid; the convergence of the two fluids marks the current time. Although they are less visible than in straightforward time models, you can see the bellows beneath the minutes track at 6 o’clock. The 3D luminous (Lumicast) hour numerals are arranged on a black grid-like structure, while a matte black arrow-shaped pointer indicates the minutes with white SLN.

Oblique Tourbillon

Eric Coudray’s conical tourbillon design was inspired by an inclined balance tourbillon developed by Walter Prendel in 1928. From his workshop in Saxony, Prendel’s oblique tourbillon, with its spring balance inclined at 30 degrees, completed one rotation in six minutes and was placed inside a pocket watch that has not been seen since it was sold at auction in 2021. Coudray’s suspended tourbillon movement features different inclinations: the spring balance is inclined at 30 degrees to the horizontal, the escape wheel at 15 degrees and the pallet at 23 degrees.

Chaotic animation

Designed to be viewed without a magnifying glass, the conical tourbillon suspended inside a sci-fi cage completes a clockwise revolution every 30 seconds. Adding to the spectacle, there are three green spheres rotating at different speeds on the periphery of the cage. Described as ‘chaotic animation’, the first sphere completes four turns a minute, the second five turns a minute, and the third six turns a minute, all in a clockwise direction. Designed to demonstrate the stability of the conical tourbillon’s rate, the rotating 2.5mm spheres are individually made by a glass blower. Extreme precision, requiring work to the nearest micron, is required to produce the spheres that are then manually filled with fluorescent liquid to glow in the dark. The unconnected, rapid movements of the animated spheres ensure the conical tourbillon keeps perfect time, providing a physical demonstration of its technical efficiency. You can see it below in our short video:

Calibre 701-TC

Eric Coudray, who has participated extensively with HYT, developed the calibre 701-TC, a manual-winding movement based on his H5 calibre with an escapement on top. Provided with a winding tool, this 533-component movement beats at a frequency of 21,600vph and delivers a 40-hour power reserve. The reverse side offers an unimpeded view of the bellows, the oversized feeler that connects the cam to the bellows, and the contemporary black-coated, sandblasted and satin-brushed finishings.

Matching the colour scheme of the case and dial, the embossed rubber strap is black with green stitching and is attached with a black-coated titanium pin buckle.

Availability & Price

The HYT Conical Tourbillon is a limited edition of eight pieces and retails for CHF 335,000. For more information, please consult

1 response

  1. So happy this brand survived. Yes yes, their very niche solution to a non-existing problem is comically expensive, labor intensive and offers limited usability but after all isn’t that what all of this is about? Shoulders of giants, I guess…


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