We eagerly awaited our appointment at Watches & Wonders 2024 with Jaeger-LeCoultre to get our hands on one of the most exciting releases of 2024 in Geneva. The Duometre Heliotourbillon Perpetual marks a new era for the Duometre Collection with an innovative tourbillon constructed on three axes a first for Jaeger-LeCoultre. Pushing the boundaries of haute horlogerie, the new Jaeger-LeCoultre Calibre 388 features an entirely new tourbillon construction that makes the tourbillon spin on three axes to create a ‘spinning top’ effect. This new calibre 388 also incorporates a perpetual calendar with a grande date indication at 3 o’clock.
The redesigned case of the Duometre collection measures 44 mm in diameter and the 18K pink gold case is a complex structure of 34 separate parts and the lugs are screwed rather than integrated, to enable multiple finishing techniques. A mixture of polished, satin-brushed, and micro-blasted surfaces creates a fascinating play of light with every movement of the wrist.
Incorporating almost eight decades of accumulated expertise in the tourbillon regulating mechanism, the Duometre Heliotourbillon Perpetual features a newly developed tourbillon configuration that rotates on three axes. In doing so, it creates a completely new kinematic effect for Jaeger-LeCoultre resembling a spinning top. Fitted with a cylindrical hairspring, the Heliotourbillon takes this thinking further, with a newly developed construction comprising three titanium cages rotating on three axes.
The first cage is set at a 90-degree angle to the balance wheel and rotates perpendicular to it. The second cage is set at 90 degrees to the first —thus, on the same plane as the balance wheel. Together, these two cages are constrained by an axis tilted at 40 degrees and make a full rotation in 30 seconds. The third cage is perpendicular to the second and makes a full rotation in 60 seconds. Supported by ceramic ball bearings to minimize friction, the tourbillon consists of 163 components and weighs less than 0.7 grams.
A feature of Calibre 388 is that the hours and minutes can be set either backwards or forwards without compromising the perpetual calendar. Because normally, a perpetual calendar is set over time —the hour and minute hands—, adjusting the time backwards desynchronizes and can damage the calendar mechanism. In Calibre 388, the relationship between the winding and calendar assemblies is such that the perpetual calendar mechanism moves forward only and cannot be dragged backwards when the time is set backwards. Other notable features of Calibre 388 include a Grande Date display: a classical yet rare complication sought-after by watch connoisseurs, it is set at the 3 o’clock position on the hours-and-minutes sub-dial, ensuring great legibility. The year indication shows the last digit of a leap year in red —a Jaeger-LeCoultre patent— and the moon-phase indication is accurate to 122 years.
On the dial of the Duometre Heliotourbillon Perpetual, the triangular arrangement that directly expresses the underlying mechanism with its two barrels and gear trains has been turned 90 degrees, as if the winding crown forms the apex of the triangle, the time dial is flanked by the two power reserves, and the ‘base’ of the triangle is formed by the moon-phase indicator and days on one side and the months and years on the other. On the vertical axis, the two sides of the dial are separated by a gold bridge with contrasting areas of microblasting and beveling, creating an intriguing play of light —and echoing the finishes on the watch case.
The left-hand side of the dial is open-worked to provide a fascinating view of the tourbillon performing its ‘spinning top’ rotation —a kinematic effect created by the combination of the three cages rotating on different axes and at different speeds. A sapphire crystal window in the side of the case offers another way to view this captivating mechanical show.
The tourbillon is set above a background of deep blue lacquer representing a starry sky and, as it spins, red triangles set on the third cage indicate 20-second intervals marked on a sapphire crystal arc that floats above the starry blue background. On the main dial refined finishes abound, with applied hour indexes and frames around the date and year, and a mix of opaline, brushed and azuré surfaces creating subtle contrasts between the different indications.
The Movement
Turning over the new Jaeger-LeCoultre Duometre Heliotourbillon Perpetual reveals the complex in-house calibre 388 that is exquisitely decorated. Introduced in 2007, the patented Duometre mechanism features two barrels and two separate gear trains linked to a single regulating organ. As you can see these two barrels are labeled with ‘Regulateur’ at the top and ‘Heures Minutes’ at the bottom. One gear train powers the time indications and the other drives all additional functions, thus ensuring a high degree of operating accuracy. This 655-part manual wound movement features 89 jewels and provides a power reserve of 46 hours when fully wound while beating at a frequency of 28,800 vph.
On the Wrist & Price
On the wrist, the new 44 mm case of the Duometre collection wears true to its size and remarkably well. A huge improvement in terms of case design. As far as the complications, this watch is simply superb without any flaws in concept, design, or execution. The new Jaeger-LeCoultre Duometre Heliotourbillon Perpetual is limited to 20 pieces.
Sticker Price USD 438,000. For more info on Jaeger-LeCoultre click here.
