Royal Oak “Jumbo” Ultra-Thin Automatic Flying Tourbillon Chronograph (RD#5)
Model: 26545XT.OO.1240XT.01
To celebrate Audemars Piguet’s 150th anniversary, the latest masterpiece in this collection is unveiled, centered around one of the most prestigious yet technically challenging complications in watchmaking—the chronograph. Five years in the making, the Royal Oak “Jumbo” Ultra-Thin Automatic Flying Tourbillon Chronograph RD#5 is powered by the new Caliber 8100 movement, perfectly blending the flyback chronograph function with the flying tourbillon.
Impressively, the case retains the original dimensions of the Jumbo series—39mm x 8.1mm. The case’s middle layer is crafted from titanium, while the bezel, pushers, crown selector, and lugs are made of Block Metallic Glass (BMG)—a palladium alloy originally used in the unique Royal Oak “Jumbo” ultra-thin watch specially crafted for the Only Watch 202. BMG’s exceptional scratch resistance and durability make it ideal for a high-performance chronograph. The chronograph mechanism is breathtaking; it’s no exaggeration to say it reminds us that we often think a subject has been exhausted, only to find it’s just waiting to be examined from a different perspective—in this case, a truly unique perspective. Unlike traditional hammers and cams, this watch uses a rack and pinion mechanism for the zeroing action. Furthermore, the rack and pinion provides a concise way to generate the index pulse for the instantaneous minute jump. However, individually, both functions employ a complexity and unconventional design never before seen in chronographs. The question is, why?
The answer lies in the pursuit of a different kind of chronograph, with a redesigned control system architecture that results in a softer feel for the pushers. In traditional chronographs, the stiff feel of the pushers stems from the system surrounding the column wheel. Pressing the start or stop button moves the lever forward one notch. Each forward movement requires a spring to lift off a ratchet tooth and then spring back onto the next, resulting in a stiff, resistance-prone feel. Simultaneously, the rotation of the column wheel must also drive levers, each held in place by its own spring. The pressure applied to the column wheel must indirectly overcome these forces to lift it. In flyback chronographs, the load is reduced because the reset lever does not need to pass through the column wheel. Furthermore, the lever is typically longer, extending from the pusher to the column wheel. Pressing the pusher drives this long lever, which in turn rotates the column wheel via a spring-loaded pawl. This length introduces elasticity, absorbing energy before any movement occurs.
Due to the more direct connection, the reset button requires more force. Pressing the button winds a hammer spring, which must be strong enough to firmly strike the reset hammer against a cam on the chronograph wheel. When the reset button is pressed, the cam can be in any position, so the spring must provide enough energy to quickly return each chronograph wheel to zero in a clean, crisp motion, regardless of how many counters are operating simultaneously. Therefore, the reset button in a traditional chronograph is almost always the heaviest.
In the RD#5, the pushrod is closer to the column wheel, making the operating lever short and sturdy, requiring less force. It’s important to note that the column wheel does not directly drive the brake or clutch lever, but rather acts only on a hinged intermediate control lever. This control lever is connected to the clutch lever. As the column wheel rotates and releases, the control lever rotates accordingly, causing the clutch spring to engage the clutch wheel. The user only feels the resistance of the column wheel spring (still producing a crisp click), while the load on the clutch spring is borne internally by the mechanism. In other words, positioning and actuation are separate. The finger only needs to apply enough force to turn the column wheel, while the stored spring energy is responsible for the actual engagement and disengagement of the clutch.
Meanwhile, an auxiliary finger on the intermediate lever controls the second wheel. In stop mode, it presses the jump wheel, engaging it with the chronograph seconds wheel; in start mode, it retracts the jump wheel, releasing it. This ensures that the locking and unlocking of the chronograph seconds wheel is perfectly synchronized with the engagement and disengagement of the clutch, requiring no additional force on the column wheel.
Similarly, the absence of a cam and reset hammer reduces the load on the reset button. The seconds, minutes, and hours wheels are each connected to a gear with sector teeth. These gears mesh with their respective racks, which gradually accumulate energy as the gears rotate. Upon reset, the stored energy is released, driving the counters to zero. The reset button does not provide energy to drive the hands; it simply actuates a six-armed reset lever that simultaneously pushes or lifts the pawls and pinions of all the locking chronograph wheels. Once released, the rack springs back under its own spring, cleanly resetting the counters to zero. https://thepincodeindia.com/
