The tourbillon (French for whirlwind) is among the most desirable and expensive complications for a watch, invented by Abraham-Louis Breguet in the late 1700s and patented in 1801. Technically, it’s not a complication as it doesn’t provide additional functionality like a date or power reserve indicator, but rather a device to improve accuracy. Originally designed for pocket watches, a tourbillon cage houses both the balance wheel and escapement, and rotates 360 degrees every minute to counter the forces of gravity. Pocket watches remained static most of the time and the movement could run fast or slow based on this constant position. By rotating the regulating organs continuously, positions that cause fast or slow errors are simply cancelled out. This is an obsolete concept today as wristwatches are in constant motion, but it remains an incredible and difficult piece of engineering. True watchmaking art.
The Carrousel - Isn’t that a tourbillon, too?
The carrousel is a rarity these days, generally only seen with one brand, Blancpain. At first glance, it looks and functions exactly like a tourbillon, but there’s a key difference. A tourbillon is powered by a single source that rotates the cage and animates the balance and escapement, while a carrousel has two power leads - one that rotates the cage and another that powers the balance and escapement. All power comes from the mainspring for both, but it’s split into two for the carrousel. From a functionality standpoint, they do the same thing, but to get around Breguet’s patent at the time, this tourbillon modification was made. The carrousel is the brainchild of Danish watchmaker Bahne Bonniksen, who had great admiration for Breguet and his work. He invented it almost 100 years after the tourbillon in 1892 and it was consequently less fragile than early tourbillons that were notoriously temperamental.
Tourbillon and a Single Power Source
There are many tourbillon variations, but most rotate on a single-axis. This is usually exposed on the dial side and held by a narrow bridge on one or both sides. This design is the least complicated and often utilized as an entry level tourbillon, however prices can range from low-end Asian produced tourbillons to optimistically priced Swiss variations. Of course, materials play an important roll as well like heavier brass for the cage, which can reduce costs but also impede performance. The goal is to make the tourbillon cage as light as possible, so advanced watchmakers utilize materials like titanium to shave a cage's weight and improve performance.
Flying tourbillons like the ones used at Horage are held at one point in the back, so the front is fully exposed and “flies” in its aperture without visible support. Most single-axis tourbillons have a pinion under the cage and are powered by the fourth wheel in the movement, which is otherwise designed for a small seconds hand within a sub-dial. At Horage, we have gone a step further and utilize a bearing construction which improves the cage's impact resistance. There’s also a stationary gear under the tourbillon cage that seems to have no purpose, but a small gear under the escapement meshes with it as the cage rotates, powering the escapement. The escapement itself provides controlled impulses for the balance wheel, keeping everything from quickly spinning out of control like an open balloon. What was meant to power a small seconds hand is now powering an entire cage with regulating organs, which is no easy feat. Tourbillons are asymmetrical with the escapement hanging from one side, but everything must be in perfect balance. Tolerances are incredibly tight and unforgiving, and Breguet managed to perfect this in the late 1700s by hand. We use a single-axis flying tourbillon for the Tourbillon 1 and Lensman 1 (with more models to come).
Carrousel and a Double Power Source
Looking at the carrousel’s cage, it’s actually a large gear that meshes with a much smaller gear that rotates it (usually at the bottom left), while a second set of gears via a separate power lead operates the balance and escapement. Again, it ultimately achieves the same purpose, but in a different way that bypassed the tourbillon patent. It’s much less common than the tourbillon and Blancpain has amazing watches that show both features on the dial, such as ref. 2322 3631 55B and ref. 92322 34B39 55B. The tourbillon is always at the top with the carrousel at the bottom, and prices are predictably stratospheric. Being simpler and versatile, tourbillons are more widely used by far and it's great to see Blancpain (and few others) keeping the carrousel relevant.
This video thoroughly explains the difference between the tourbillon and carrousel under magnification.
Horage Tourbillon
With our K-TOU movements, we developed a true titanium flying tourbillon that's powered by a single source. This is very efficient and comes with a 5-day power reserve via one barrel. The titanium cage is very lightweight at just 0.29 grams (one of the lightest in the industry) and thin at 3.4mm. It features an anti-magnetic silicon escapement and hairspring, which also reduces weight, and accuracy is within chronometer standards of -4/+6 seconds per day. Horage is among a small handful of independent watchmakers that have fully developed and engineered a ground-up tourbillon, and we're already producing the second generation. Other brands are starting to offer tourbillons at price points across the board, but not all are created equal. Simply attaching the name "tourbillon" seems to be the easy entry point to haute horology and brands often use off-the-shelf movements from a very select few movement providers. True enthusiasts can spot the differences and understand the complexity and value at hand when comparing movements across the market.
We were inspired by legends of the past, particularly Abraham-Louis Breguet, and wanted to bring a thoroughly modern tourbillon to a broader range of enthusiasts with unprecedented affordability. We also wanted to challenge ourselves with such a complex and difficult piece of watch engineering, and see if it truly improves the accuracy of a wristwatch. Although our K1 automatic and K2 micro-rotor movements are accurate to within chronometer standards, we found that our tourbillons can increase accuracy by a discernible amount. It's a testament to the brilliance of early pioneers and innovators like Abraham-Louis, who developed his original "whirlwind" by hand in the late 1700s.
Engineering Wonders
Neither the tourbillon or carrousel are actually necessary for accuracy today, but both remain engineering marvels that can enhance the wonders of a mechanical movement if executed effectively. There’s aesthetic freedom with the tourbillon and it can grow in complexity with multi-axis variants and so on, but the carrousel provides a similar spectacle when compared to single-axis counterparts. Despite being invented hundreds of years ago, both the tourbillon and carrousel are still one of the hardest mechanical features to produce. Investing in advanced engineering and developing a brand's own IP will separate the trend chasers from the true movement makers.
We Want to Hear From You!
Sound off in the comments about additional topics of interest, so we can be sure to cover what you want to read in future articles. And please share this with friends and anyone interested in watchmaking, and let's keep the conversation going. Also, be sure to sign up for our newsletter (here) and keep an eye out for new products as we're always in the process of development. Check out journal entries as well (here) and a detailed section on performance watchmaking at Horage (here).
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Erik Slaven
I could understand the mechanisms ,and the differences between Tourbillon and Carrousel very well.
I'm looking forward to see the next video.