Greubel Forsey QP à Équation Prototype to Final

Author small-luxury-world provides an early look at the Greubel Forsey QP à Équation, initially presented as a working prototype at SIHH 2014. This article offers insights into the evolution of its design, comparing initial prototypes with the finalized version, and highlights the brand's innovative approach to traditional complications.

… but “only” presented as a working prototype.

The technical specs had been fixed and only the design had to be finalized. At the show people got a press release, but without pictures. Also we had been asked not to take any pictures of the back and so we (Magnus & me) didn´t talk about the watch yet. To be honest, I still don´t know (officially) if the watch is finalized but as I found some pictures of the back on their official homepage today I decided to share some more of our impressions. Am I (still) impatient? Maybe, but who would blame me here …

Some of the changes (front) are shown here:

(Proto on the left and current picture from the GF page on the right)

Let´s go ahead with a refreshing and new interpretation of one of the oldest complications, the perpetual calendar (QP). Two of those caught my attention last year. One was from Cartier (Rotonde de Cartier Astrocalendaire) and the second one is shown here from GF.

“The Mechanical Computer

The perpetual calendar remains one of the most representatives of horological complications and also one of the oldest. A direct descendant of the computus (Latin for calculation) that the clergy used to determine the religious and seasonal feasts of the seasons, these ancient mechanical perpetual calendars underpinned rural society from the early Middle Ages. A prime example can be found in the Strasbourg cathedral clock.

Comfort and clarity

This reinvention of the perpetual calendar integrates the Equation of Time into the perpetual calendar, as well as practical new functions and indications that improve clarity. The priority was to simplify the complete displays and make it easier to set the perpetual calendar by using the bi-directional winding crown. Despite the complete indications and functions, Greubel Forsey's mechanical computer with Equation of Time is as easy to set as a simple date feature.

You do not need obscure instructions or a special tool for multiple pushers. If your timepiece has stopped for several days and you need to take an imminent flight, simply pull out the crown checking the selection indicator near 2 o'clock. Turn the crown back and forth to change the calendar and all the different indications change by themselves. If you go too far, you just go back through the days until you get to the right date. It’s easy, intuitive and pleasant to use.

To meet this technical challenge Greubel Forsey developed a sophisticated coding mechanism: the mechanical computer for which three patents were filed. A stack of cams with movable fingers shift the indications on the front and back dials of the timepiece, the complete mechanism fitting entirely within the movement without increasing its dimensions. The cam for the months changes the month in a window on the front display and also moves the Equation of Time scale on the back. The years' cam controls the leap year indication on the front and that of the seasons on the back. The development of this coding device not only overturns conventional ways of setting the indications but also by displaying them simultaneously on front and back dials.

Just a glance at the subdial at 3 o’clock clearly reveals the three in-line windows that clearly indicate the day, the date and the month. The large date makes the calendar extremely legible.”

(Abstract; Press Release)

There are quite a few smart solutions shown, which I like a lot. The day, date and month are displayed inline in a large sub dial via individual windows (between 3 and 6); the large date in the center is very eye-catching and I guess it was not an easy task to find the extra space needed for the mechanics. The readability is quite good and the way it is done is a nice counterpart to the amazing tourbillon shown (between 9 and 12). To me even the prototype was great, but yes the latest (!?) version is even better to my eyes.

There is a lot of information at the same time and yes it is a busy dial, but it fits just perfect into the Greubel Forsey collection and their style. For me it was not love at the first sight (in general), but I think I could get used to it easily now. When it gets (seriously) complicated, I quite often need some more time to really appreciate it in full

My favorite feature was shown on the back – Equation of Time.

Horology seeks to measure time as regularly as possible; however the Earth orbits the Sun in an elliptical path.

(Picture credit; Blancpain)

As the Earth sweeps close past the Sun, the period between successive solar zeniths, or the solar day’s length, changes. This causes the difference between solar time and mean time to vary from a few seconds to as much as 16 minutes during the year. The Equation of Time is the conversion factor between solar and mean time.

If I thought about the complication Equation of time, two watches came to my mind so far – AP Jules Audemars (Ref. 26003) and Blancpain Le Brassus (Ref. 4238). Yes there are a few more examples from other brands as well, but those have been my favorites. The new one from GF is even smarter and more refined, to say the least.

In the spirit of the GMT, Greubel Forsey continues to put time to better service; where the back of the timepiece is not just there to showcase for fine hand finishing, but also provides a new way to tell the time. The most frequently sought calendar information, namely the day, date and month, is displayed in a line on the front dial (as already mentioned and shown before). Information that is less often required is on the back of the timepiece. Thus the two sides show indications that you need to know regularly on the front, and indications accessed less frequently on the back.

On the back of the QP à ÉQUATION you find the Equation of Time indication, the seasons and the current year in four figures. The indications on the back are made up of two superimposed transparent discs in synthetic sapphire crystal. The first disc is driven by the date wheel and has a scale in minutes indicating the difference between solar and mean time.

The second disc, which goes around once a year, has a figure shaped like a manta ray, and divided into four sections in red and blue to show whether the Equation of Time is positive or negative. To find out, look where the red line (positive difference) or the blue line (negative difference) crosses the scale. This Equation of Time display is unprecedented and provides a clearer appreciation of the Earth’s elliptical orbit around the sun as well as the equinoxes and solstices. Did I already mention: smarter J

Before we come to more details/facts I would like to share some live impressions from the presentation we got (last year):

… Greubel Forsey also told us that this watch can be set both forwards and backwards without fear of damaging the mechanism. Once more – smart, comes to my mind …

QP à Équation

In white gold - Millésimé

Mechanical hand-wound movement

with patented tourbillon 24’’

Calibre GF07

Movement

Movement dimensions

• Diameter: 36.40 mm

• Thickness: 9.60 mm

Number of parts

• Complete movement: 570 parts

• Tourbillon cage: 86 parts

• Weight of the cage: 0.37 g

Number of jewels

• 65

• Olived-domed jewels in gold chatons

Power reserve

• 72 hours

Barrels

• Two coaxial series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension

Balance wheel

• Free sprung variable-inertia balance with gold mean-time screws (10 mm diameter)

Frequency

• 21’600 vibrations/hour

Balance spring

• Phillips terminal curve

• Geneva-style stud

Main plates

• Nickel silver, frosted and spotted, hand-bevelled with countersinks, straight-grained fl anks

Bridges

• Nickel silver, frosted and spotted, hand-bevelled, straight-grained fl anks, polished countersinks, nickel-palladium treatment

• 4 engraved gold plates, one with the individual number

• Flat black polished steel tourbillon bridges, hand-bevelled

• Synthetic sapphire crystal mobile encoder Bridge

Tourbillon cage

• Inclined at a 25° angle, 24-second rotation

• Cage pillars in Avional

• Titanium cage bridges

• Gold counterweight

Gearing

• Involute circle profi le

• Tangential inclined gear with profi led teeth, on fixed wheel and escape wheel pinion

Dial displays

• Hours & minutes

• Little second

• 72-hours power reserve on a sector

• Day of the week, date and month indicators

• Leap year indicator

• Day-and-night indicator

• Function selector indicator

Back displays

• Year indicator disks

• Equation of time with seasons, solstices and equinoxes indicators

Exterior

Case

• In white gold with asymmetrical convex synthetic sapphire crystal

• Transparent back with fl at asymmetrical synthetic sapphire crystal

• Polished bezel, centre band with handfinished straight graining

• Three-dimensional, variable geometryshaped lugs

• Raised polished engraving “QP à Équation ” and “Greubel Forsey ” on a hand-punched background

• Hand-engraved individual number

• Gold security screws

Case dimensions

• Diameter: 43.50 mm

• Thickness: 16.00 mm

Water resistance of the case

• Water-resistant 3 atm - 30 m - 100 ft (standard NIHS 92-20/SN ISO 22810:2010)

Crown

• In white gold with engraved and black lacquered GF logo

Dial

• In anthracite gold, multi-level

Hands

• Hours and minutes in polished gold, with Super-luminova

• Small second in polished gold

• Power reserve in polished gold

• Leap year indicator hand in black polished Steel

Strap and clasp

• Hand-sewn black alligator

• White gold folding clasp, hand-engraved with the Greubel Forsey logo

That is all for now, but I guess it is no secret anymore that I like the watch a lot. Hope we will get more details/pictures from fellow PuristS attending SIHH 2015, soon.

Oliver