A. Lange & Söhne’s Tourbograph returns, this time with a new calibre fitted with additional complications
I t is par for the course for A. Lange & Söhne to unveil a technical powerhouse at each SIHH, and the trend continues this year with the Tourbograph Perpetual “Pour le Mérite”. This is the fifth entry in its Pour le Mérite series – a label that the manufacture reserves for its timepieces equipped with the fusée-and-chain mechanism. The fusée-and-chain transmission was conceived to improve a movement’s isochronism. The cone-shaped fusée subjects the barrel to a mechanical disadvantage via the chain, but this effect steadily decreases as the barrel unwinds, which evens out the diminishing torque from the mainspring. Practically speaking, this mechanism is somewhat anachronistic as modern mainsprings generate far more consistent torques over their operating ranges. As an exercise in miniaturisation and movement construction, however, it is quite a marvel, with the chain here comprising 636 parts alone. Incidentally, A. Lange & Söhne was actually the first manufacture to execute the fusée-and-chain mechanism in a wristwatch, when it unveiled the Tourbillon “Pour le Mérite” in 1994. The new timepiece is an evolution of 2005’s Tourbograph “Pour le Mérite”, and builds on the original’s fusée-and-chain mechanism, tourbillon regulator and rattrapante chronograph by adding two complications: the perpetual calendar and moon phase display. While this may seem straightforward – just stack a module on the dial side of the movement – the actual execution is anything but. For a start, the tourbillon already takes up around one third of the movement surface, so the perpetual calendar and moon phase complications have to be built around it, while taking care not to add too much height to the resulting movement. The greater depth that this results in also necessitated a redesign of the tourbillon bridge, which now extends into the calibre with a curve that mirrors the tourbillon aperture’s outline. Despite this new curved geometry, the tourbillon bridge is still black polished – according to A. Lange & Söhne, this is the first time the finishing technique has been applied to a curved surface. With a platinum case 43mm wide and 16.6mm high, the Tourbograph Perpetual “Pour le Mérite” is a stately presence on the wrist, to put it mildly. These dimensions are understandable considering how the timepiece is among A. Lange & Söhne’s most complicated watches. The movement’s complexity also informs its production – the watch has a limited run of just 50 pieces.
MOVEMENT: Manual-winding Lange Calibre L133.1 with 36- hour power reserve
CASE: 43mm in platinum; water resistant to 30m
STRAP: Black alligator leather with platinum deployant buckle
