Rather than the energy from the mainspring flowing right into the escapement, it must first pass through Arnold & Son’s constant force mechanism. The controlled power supply charges a small hairspring, which releases a consistent quantity of power to the tourbillon once per second. With this mechanism, there will nevertheless come a point when the energy released by the twin barrels along with the constant force mechanism falls below a stage that is enough to keep up a normal output. When this happens, the watch stops instead of allowing an isochronal error to creep in the timekeeping.In addition to this intriguing solution, the Arnold & Son Constant Force Tourbillon features a deadbeat moments complication, which leads to the seconds hand to “tick” instead of sweep as one may expect in a mechanical timepiece. Exceptional consistency is attained thanks to the symmetry of this motion’s construction, in addition to the fact that the continuous force escapement remains stationary through performance, whereas the tourbillon cage moves once per minute. This is in an effort to decrease the influence of gravity on the escapement’s functioning. Assuming, though, that this watch is unlikely to be worn out in the presence of strong magnetic fields (it is barely suitable for use on a building site or while flying a helicopter, for instance), the complication perfectly matches the intended application.The Arnold & Son Continuous Force Tourbillon watch is a limited variant of which only 28 will be produced. It’s a 46mm 18ct rose gold case fitted with an anti-reflective sapphire crystal and a sapphire display back. The A&S5119 motion has 39 stones, a depth of 6mm, a 90-hour energy reserve, and works at 21,600vph. The NAC grey mainplate and the palladium-coated bridges are made of nickel-silver and hand-finished with polished edges and brushed surfaces, gold screw-down chatons, and bevelled and polished screw heads. The movement is almost perfectly symmetrical, and all the specialized elements are visible on the dial-side. The three-dimensional movement architecture is designed to echo the English tradition of marine chronometer structure.
In 2013, Arnold & Son raised eyebrows with their Ultra-thin Tourbillon Escapement “UTTE” watch which, back then, was the world’s thinnest tourbillon watch. The watch was just 8.34mm thick and housed the calibre A&S8200 which measures just 2.97mm thick. Though it has since lost the title of thinnest tourbillon watch to the Bulgari Octo Finissimo Tourbillon (hands-on here), the UTTE still remains an impressive masterpiece.
Skeletonizing a watch is no easy feat. And it’s doubly hard for an ultra-thin movement, mainly because the movement is already so thin that removing any more material is bound to affect structural rigidity. As a result, the A&S8200 calibre in the Arnold & Son UTTE Skeleton watch had to be thoroughly redesigned and re-engineered. The result is the A&S8220 calibre, which measures 3.3mm thick. The extra thickness, according to Arnold & Son, is necessary to guarantee rigidity as they sought to skeletonized the movement. Still, let’s face it, 3.3mm for a tourbillon movement with two barrels and a power reserve of at least 90 hours is seriously impressive.
The new A&S8220 calibre boasts some major revisions. For instance, the main plate has been heavily modified to reveal as much as possible of the inner workings. But perhaps what’s most visible to owners is that the tourbillon cage has been totally reworked to show off more of the mechanism while retaining the three-dimensional design that has become a signature of the earlier Arnold & Son UTTE watch. In addition, the tourbillon cage is relatively large as compared to the movement. It measures 14mm across, while the movement itself is 32mm. This means it’s the single most dominating component of the dial, and on top of that is the fact that the cage is fully hand-polished and chamfered, making it a real visual treat for owners.
And as you would expect, the A&S8220 calibre is also treated to the finest haute horlogerie finishing: The main plate and bridges are constructed using nickel silver and finished with Côtes de Genève rayonnantes; The edges are also polished and chamfered; The steel components, gears, and ratchets are all satin-finished with their edges polished and chamfered; The screws have bevelled and polished heads, and finally, the jewels are placed in polished countersinks; Reading of the time is done off a sapphire disc with printed numerals at 12 o’clock; The hour and minute hands are golden and feature white lacquered tips.
The Arnold & Son UTTE Skeleton comes in a 42mm 5N red gold case, which is as exquisitely crafted as the movement. It is stepped, tapering from top to bottom. The dial part, which is the widest section, also features an extra-large sapphire glass to showcase the caliber A&S8220 in all its glory. The bottom of the case is made narrower to fit snugly on the wrist.
The Arnold & Son UTTE Skeleton watch will be limited to just 50 pieces, and each watch will come with a hand-stitched brown or black alligator leather strap with a matching 5N red gold buckle with the Arnold & Son logo. Price is $76,750. arnoldandson.com