Jaeger-LeCoultre’s Dual Wing concept was introduced in 2007 as a solution to a problem facing all watches with a complication such as the chronograph. Usually the chronograph uses the same source of power, and the same gear train, as for the time functions. And so when you start the chronograph, the amount of energy delivered to the balance drop slightly, reducing its precision. For a watch designed to measure intervals of time, this is something of a contradiction. In the Dual-wing arrangement, there are two separate mechanisms, one for the time functions, and one for the complication.
Two gear trains, two mainspring barrels
The very first Dual-Wing watch, in the Duomètre collection, was a chronograph with the Jaeger-LeCoultre Calibre 380. Today the Duomètre Chronographe is the first chronograph wristwatch that doesn’t need a coupling system to start the chronograph, because of the separation of the two functions. There is one barrel and one gear train for the time functions, hours, minutes and seconds, and another barrel and gear grain for the chronograph function. Both mainsprings have a power reserve of 50 hours. They are both wound from the crown: turning it clockwise winds the time functions barrel, anticlockwise the chronograph barrel.
Unusual dial arrangement
The dial reflects this architecture. Hours and minutes are on the left-hand subdial, along with seconds shown by the long gold-plated centre-pivoted hand. Chronograph hours and minutes are shown on the right-hand subdial, in an analogue arrangement that is by far the most legible and immediate way of displaying elapsed time. The third, smaller subdial shows jumping sixths of seconds, a beautiful performance that will make you want to keep the chronograph running. At the bottom of the dial, two meters display the power reserve of each mainspring. It’s neat how the two functions are separated by different hand colours, gold-plated or rhodium-plated.
Sixths of seconds may seem a somewhat arbitrary choice for dividing seconds. Why not tenths, or fifths? But the movement runs at 21,600 vibrations per hour, 3 Hertz, six semi-oscillations per second. So a precision of sixths of seconds was the natural choice.
Monopusher chronograph control
The case is 42 mm in diameter, in pink gold, framing a dial in grey magnetite with goldplated appliques. The single pusher operates the chronograph, cycling through start, stop, reset. The watch has a brown leather strap with a gold folding clasp. The sapphire caseback displays the movement.
As for all its watches, Jaeger-LeCoultre tests the Dual-Wing Duomètre Chronographe with its 1,000 Hours Control, a series of checks lasting 1,000 hours and putting the watch through a battery of tests on precision, resilience to temperature, pressure, shocks, magnetic fields and water.
The watch costs €46,400 inclusive of VAT, £39,100 inclusive of VAT, $44,500 plus tax. It’s a modern masterpiece with all of Jaeger-LeCoultre’s hallmark innovation. Read more on the Jaeger-LeCoultre website.
Related article: 10 reasons why the Rolex Daytona Cosmograph chronograph is so famous
Related article: Astronomical watches