Diving Into The New Audemars Piguet Caliber 7138 — A Complicated Way To Celebrate The Brand’s 150th Anniversary
Marginal gains — the world of Haute Horlogerie moves forward in little steps. That is already a miracle since mechanical watchmaking is in its private universe where functionality is not an essential survival tool. Still, the leading traditional watchmaking houses continue to push the technical boundaries. You don’t get a sense of evolution when you look at the three new perpetual calendar watches — two Royal Oaks and one Code 11.59. However, closer inspection of the dials tells you something is going on. When diving into the new Audemars Piguet Caliber 7138, you will discover that the 422-part “QP” movement holding five patents is not about marginal gains but giant leaps.
When I tell you the new Audemars Piguet Caliber 7138 is a perpetual calendar movement you can operate using the crown, you will say this is not a novelty. And you’re right. In 1985, IWC introduced the Da Vinci, the first perpetual calendar designed by Kurt Klaus, in which all indications could be adjusted via the crown. Correctors on the side of the case are not that pretty to look at, and operating them is also not a joy. Klaus designed a system so you could use the crown to adjust the calendar, but it had a downside. It had no “rewind” function. Consequently, if you overshot something when setting it up, you’d have to get IWC to readjust the movement.
Before the new Audemars Piguet Caliber 7138
Ludwig Oechslin — a mathematical genius and restorer of clocks in the Vatican — devised a QP in 1996 to mark Ulysse Nardin’s 150th anniversary, which made date adjustments forward and backward via a single crown possible. The watch didn’t have a traditional perpetual calendar layout, though, and there was no moonphase indicator. The same goes for the QP that H. Moser & Cie. introduced in 2005. Again, this is crown-operated QP, but independent watchmaker Andreas Strehler, who created the watch’s movement, didn’t make something traditional — you can’t label a watch with a centrally mounted hand indicating the month “traditional.” Audemars Piguet made a one-crown-for-everything system and put it in a traditional-looking QP with a moonphase indicator and some functional design tweaks to improve readability.
Giulio Papi in the house
There’s a lot to say about perpetual calendars, but “easy to operate and read” is not a commonly heard description. Five years ago, Giulio Papi, AP’s technical director, started work on a new QP movement. Papi is somewhat of a legend. He’s one half of the famous complicated movement maker Renaud et Papi, founded in 1986. Both he and Dominque Renaud worked at AP before establishing their workshop and went on to create wonderful, complicated movements for almost every leading Haute Horlogerie brand. In 1992, AP, with CEO Georges-Henri Meylan at the helm, bought 52% of the company, and Renaud et Papi became Audemars Piguet Renaud et Papi (APRP).
Today, APRP is no more. Renaud left, and in 2018, AP bought out Papi. But Papi never really left. He’s back with AP. “I’m not a trophy or an ornament,” said renowned and celebrated watchmaker Papi just before explaining how the new Caliber 7138 works inside a special room inside the huge new AP manufacture in Le Brassus. “I’m here to work on interesting stuff.” One particular topic that Papi is particularly interested in is ergonomics. This wizard of mechanical complications wants to make things simple. A testament to that is the Code 11.59 Ultra-Complication Universelle RD#4. At first glimpse, the watch looks like a chronograph, but closer inspection reveals that it features no fewer than 40 functions, 23 of which are complications. Papi wanted the watch to be easy to read and operate, and the same principle is the foundation of the new QPs.
It’s all in the “gearbox”
Giulio Papi is the legend, but we must also mention Lucas Raggi, the AP’s research and development director, who played a major part in developing the new Caliber 7138. This 4Hz, 422-part movement has a 29.6mm (12¾-ligne) diameter, a 4.1mm thickness, and a 55-hour power reserve. It’s an easy-to-use movement that works intuitively and allows all adjustments via the crown.
The crown has four positions to adjust all the functions. The first position winds the watch clockwise. In the second position, the crown sets the date when turned clockwise and the month and the leap year by turning it counterclockwise. Pulling out the crown one little click further puts it in the third position. Now, the time can be manipulated bidirectionally. When pushing the crown back in one click, you reach the fourth and last position. The crown is now in position 2’, which allows you to set the day and week clockwise and the lunar phases counterclockwise.
Just turn the crown
The system works intuitively and easily, but that’s because of the complex mechanism. Driving it are an innovative lever and wandering wheels that mesh with the different calendar wheels in the 2 and 2’ positions. One patent protects the crown correction system with this 2’ position. The second patent is for the month and date correction via the crown. If you make a mistake while setting the watch, you can continue turning the crown until you reach the desired setting.
What’s very reassuring is that there’s no risk of damage. The movement protects itself from mishandling and even tells you when it wants to be left alone. In the sub-dial at 9 o’clock, there’s a no-correction zone marked in red between 21h and 3h to show when the watch cannot be set. However, if you haven’t noticed or are particularly stubborn and still start pulling and turning the crown, the date won’t move. The good thing is you also won’t damage the movement.
Aesthetics and ergonomics
The red warning signal brings us to the readability of this new QP with a traditional appearance. “In addition to making this high complication easy to use, we also worked on the overall aesthetics to combine high legibility with timeless refinement,” says Lucas Raggi. First, you may notice that AP did away with the American way of displaying the calendar functions (day, month, date) and opted for the European way (day, date, month). As a result, you will find the day indicator at 9 o’clock, the date at 12, and the month at 3. The week numbers are still printed on the inner bezel, just like in previous perpetual calendar models.
The logic in the indications is new and improved, but it also makes you wonder why nobody thought of it before. As in real life, Caliber 7138 ensures that everything starts with “1.” Also, the week begins on Monday. So, in the three new QPs, the first week of the year (“1”) appears at 12 and similarly. And “Monday” (day) and “1” (date) have been aligned at 12 o’clock to mark the start of the week and the first day of the month.
More legible spacing
Another upgrade in terms of readability is visible in the sub-dial at 12 displaying the date. The numerals are more evenly spaced, which adds to the readability. AP developed a date wheel with 31 special teeth to achieve this. The wheel has differently sized and shaped teeth to allow the hand to move correctly along the numerals. Not only do the sizes of the teeth vary, but so do the shapes and depth. There’s also a lot happening in the sub-dial at 3 o’clock. This sub-dial indicates both the month and leap year. The sub-dial at 9 o’clock also shows more than one indication. It doubles as a 24-hour indicator and shows the aforementioned no-correction zone.
A few models have undergone the Audemars Piguet ergonomics treatment. First, there’s the 41mm × 10.6mm Code 11.59 in 18K white gold (26494BC.OO.D350KB.01 / €109,800). Then, there are two 41mm × 9.5mm Royal Oak models, the steel ref. 26674ST.OO.1320ST.01 (€109,800) and the 18K sand gold ref. 26674SG.OO.1320SG.01 (CHF 130,000 ex. VAT). Finally, there are also three corresponding “anniversary” limited editions of 150 pieces showing a cursive brand logo and bearing an anniversary rotor. You can find out more about these three QPs and all other first-semester novelties here.
