Patek Philippe Watches

Ten Day Tourbillon 5101

What is left for a manufacture to do after it has broken almost all records in the domain of horological complications? Patek Philippe built the most complicated portable mechanical watch ever made (The Calibre 89), devised the world's most ingenious ensemble of complications (the Star Caliber 2000), and crafted the most fascinating Grande Complication wristwatch with astronomical indications (the Sky Moon Tourbillon). The answer is simple: It reasserts its leadership by combining challenging complications in a way that has never been attempted before. The result is the Ref. 5101P wrist chronometer with a power reserve of 10 days and a tourbillon.

 A closer look reveals a few cues that point to the remarkable personality of this watch: The dial has a 10-day power-reserve scale, displays the discreet inscription "Tourbillon", and bears the individual serial number of the movement. Once again, Patek Philippe transcended boundaries with the Ref. 5101P "10 DAY TOURBILLON" by fitting two mainspring barrels plus a tourbillon in the compact space of a rectangular form movement.

The basic caliber 28-20/220 with an energy storage capacity of 240 hours already existed - in the year 2000, it was presented in a limited edition for the Ref. 5100 "10 DAYS" wrist chronometer. For this reason, the development and construction of the new caliber 28-20/222 movement required "only" three years. The greatest amount of time was invested in the creation of a totally new tourbillon. To prevent the minute wheel or third wheel from obstructing the view of the tourbillon, the entire going train was relocated to the dial side. The tourbillon is now showcased on the bridge side as the dominant element. A look through the sapphire-crystal case back affords a splendid view of the circular-grained plate and the bridges with Geneva striping, six jewels secured in gold chatons, the mirror-polished tourbillon bridge, and the tourbillon cage which embraces the Gyromax balance wheel, one of the pioneering inventions to Patek Philippe's credit. As all mechanical calibres crafted by Patek Philippe, this movement also displays the Geneva Seal, recognized as the most prestigious official hallmark of impeccable craftsmanship.

To this very day, the tourbillon - French for whirlwind - is considered to be one of the most fascinating complications ever devised. It pays tribute to the unfaltering quest among watchmakers to continually improve the precision of their masterpieces. The function of the tourbillon makes a case in point. It was in the 18th century when inquisitive minds discovered that the spring of the balance - the beating "heart" that regulates portable watches - has a systemic error. Because of its helical shape, the spring's centre of gravity is not precisely in the middle. The consequence is that the regularity of its oscillations is affected by the earth's pull as soon as the watch is moved out of the horizontal position. The tourbillon corrects this interference because it suspends the balance wheel and balance spring in a cage that rotates about its own axis once a minute. Thus, the position error is automatically offset.

Rarely has this problem been solved with such acumen as with the tourbillon designs for the legendary Patek Philippe wrist chronometer movement No. 861 115 and in the tonneau-shaped Patek Philippe 34T wrist chronometer calibre which together dominated the precision competitions of the Geneva observatory in the 1950s and 1960s. The cages in these extraordinary movements inspired the design of the tourbillon of the Ref. 5101P. The Patek Philippe open-face chronometer with tourbillon calibre No. 198 411 deserves mention here as well: In 1962, it set the world precision record for mechanical watches at the observatory in Geneva. It remains unbroken to date.

The effort involved in attaining such benchmark levels of precision is aptly reflected in the tourbillon of the new Ref. 5101P "10 DAY TOURBILLON" model. Although the rotating cage alone is composed of 72 individual parts, it weighs only a scant 0.3 grams. This suggests how tiny the components must be. It takes a highly specialized watchmaker an entire week just to craft the cage. Several hundred steps as well as a steady hand and a trained eye are required to bevel the edges, satin-finish the flanks, apply chamfers, and polish the surfaces. Even the production of the seemingly simple, mirror-polished tourbillon bridge commands the attention of an experienced watchmaker for two whole days. And this by far does not exhaust the list of time-consuming operations.

People who cherish mechanical watches appreciate the convenience of not having to readjust the hands each time they set their watch aside for a few days. Patek Philippe accommodated them three years ago with the unique Ref. 5100 "10 DAYS" - the world's first wristwatch with a power reserve of 10 days. This record-breaking energy reserve stands unchallenged to date, and for the first time is now also available in a tourbillon wristwatch.

To store this much winding energy, the calibre 28-20/222 movement features twin mainspring barrels matched in size to maximize their storage capacity. The two barrels are wound simultaneously and act similar to so-called communicating vessels. A coupling system with a slipping bridle spring on the first barrel prevents the mainsprings from being wound past their limit by disengaging the barrels as soon as they are fully wound. On the dial, the power-reserve indication at 12 o'clock informs the owner how long the movement will keep running before it has to be rewound.

When determining the transmission ratios in the winding train, Patek Philippe's engineers took into consideration that the effort required to fully wind the watch (about 100 revolutions of the crown) should correlate reasonably with the 10-day power reserve. Thus, half a turn of the crown is already sufficient to build up a power reserve of slightly more than one hour. In conventional watches, it takes one full revolution to do this.

A power reserve of 10 days is a milestone in the history of watchmaking. The technology behind this achievement and the aesthetic fashion in which it was incorporated into a captivating timepiece reflect the finest traditions of Patek Philippe, upheld for more than 160 years without interruption. The company's heritage has always been inspired by an innovative spirit and the determination to focus on utility. Patek Philippe will spare no effort to further expand its undisputed lead in horological complications and continuously explore ways to keep its products on par with changing lifestyles in an evolving world.

Typically enough for Patek Philippe, hardly anything on the outside of the Ref. 5101P suggests the complexity of its inner workings. Apart from the 10-day power-reserve indication, the dial merely has two subtle pointers of pedigree: The word "Tourbillon" and the serial number of the movement in delicate script. Although understatement is a hallmark of Patek Philippe, the fascinating complications of the Ref. 5101P are concealed at first sight for a very pragmatic reason. The oil needed to lubricate the tourbillon can decompose when exposed to ultraviolet radiation and therefore, it could lose its beneficial tribological properties within a matter of months. The consequences would be friction, wear, and a degradation of the rate accuracy of the watch. This is certainly not a tolerable fate for a timepiece designed for superior precision. Hence, Patek Philippe prefers not to expose tourbillons to direct sunlight through an aperture in the dial. But fortunately, the beautiful and intricately crafted tourbillon cage is visible through the sapphire-crystal case back and its steady, minute-by-minute rotation is indeed a mesmerizing sight to behold.

An inimitable movement like the caliber 28-20/222 deserves a case that does justice to its ingenuity. The accented rectangular shape of the platinum case in the art déco style is reminiscent of the great classics of the 1930s. It owes its subtle elegance to the sleek, three-tiered flanks and the anatomically curved silhouette which makes it gently hug the wrist - even though it is longer than fifty millimetres. The camber of the case is followed by the convex glass, ground in parallel planes inside and outside to prevent optical distortion. It protects the satiny sheen of the attractive "vintage rose" 18K gold dial with its subsidiary seconds display at 6 o'clock and the 10-day power-reserve scale at 12 o'clock. The hours and minutes are indicated by feuille hands made of black-oxidized gold and applied Breguet-style gold numerals that are also blackened. The sapphire-crystal case back reveals the meticulously decorated plate with jewels set in gold chatons and the intricate tourbillon. A discreet diamond positioned between the lugs at 6 o'clock indicates that the case of the Ref. 5101P is made of solid platinum. The watch is worn with a hand-stitched brown crocodile strap that is secured with a platinum prong buckle to match the case.

Further Reading

Patek Philippe

Complicated Wrist Watches

Giorgio Gregato, Paolo De Vecchi

Full details at: Greenwich Book

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