'Advanced Research' 5550P Patek Philippe Perpetual Calendar

Launched at Baselworld in 2011 as part of Patek’s ‘Advanced Research’ series, the 5550P was produced as a limited edition of just 300 pieces in platinum. A testbed for advanced silicon manufacturing made in tiny numbers, the 5550P is an eclectic hybrid of Patek QP aesthetic nods. It is unusual not just for its luminous dial and hands but also their bimetal appearance, but what’s inside. The 5550P is a rare instance of Patek Philippe being daring in contemporary times—visually and mechanically. And it isn’t yet collected with ferocity as one might expect.

Photography for this Find comes courtesy of a prior sale by A Collected Man, Supplemented by Phillips. 

The Advanced Research program itself was created in 2005 with the specific aim of pushing the boundaries of what’s possible in mechanical watchmaking through the adoption of new materials and design principles — particularly in the realm of silicon-based components. Previous Advanced Research calendars (there are 6 in total) focused on annual complications, but the 5550P was the first to carry these innovations into a perpetual calendar.

The calibre 240Q has an Si suffix, denoting an ‘Oscillomax’ silicon excapement, given its own cyclops on caseback. This is comprised of three silicon innovations: Spiromax® balance spring, a Pulsomax® escapement, and a GyromaxSi® balance wheel — the latter being a new silicon evolution of Patek’s classic Gyromax design. Because silicon parts are lighter, more resistant to temperature variations, and require no lubrication, the movement gains remarkable efficiency and reliability; power reserve increases from the typical 48 hours to about 70 hours, and chronometric stability is significantly improved. The counter is some fragility and unknown serviceability, both of which remain somewhat untested. Hence, the point of this very watch.

In-house engineers collaborated with prestigious scientific institutions like the CSEM and EPFL to create these components with new techniques. For all the flack Patek Philippe catch for being slow-moving, not innovative, and still utilizing the 240 Q, this is the counter argument. Patek Philippe do try new things, they’re just not normally in the public eye. But the 5550P was, and remains one of the collecting oddities of the 2010s whose market is not clearly established yet. Regardless of where values head, it is a remarkably interesting watch—visually and in the escapement. It is a bridge from traditional Swiss techniques toward the future. 

This example looks excellent. The case shows little to no signs of wear. or use. Hallmarks check out too. It comes with its full set from a well-regarded Swiss retailer.