urwerk - ZR012 , C3H5N3O9 (MB&F , Urwerk)
Luc Virginius / Chronopassion
urwerk - ZR012 , C3H5N3O9 (MB&F , Urwerk)

ZR012 , C3H5N3O9 (MB&F , Urwerk)


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C3H5N3O9 is an experimental platform, not a luxury brand.

See other pictures Luc Virginius / Chronopassion

ZR012 , C3H5N3O9 (MB&F , Urwerk)

Experiment ZR012 by C3H5N3O9 features Wankel engine inspired hour and minute indications in an asymmetrical zirconium case with articulated and compound lugs.
At first glance the time appears to be indicated by centrally rotating triangular rotors; however, the triangles are actually Reuleaux polygons; they rotate eccentrically rather than centrally and track complex epitrochroid curves rather than circles. The system was inspired by the Wankel engine, which features orbital Reuleaux polygon rotors rather than the reciprocating pistons that power the majority of our cars and machines today.
C3H5N3O9 is a platform created by Felix Baumgartner, Maximilian Büsser, Martin Frei and Serge Kriknoff to experiment with concepts, ideas and creations without the inherent limitations of a luxury brand.
Experiment ZR012
Indications: Experiment ZRO12 indicates hours and minutes with two Wankel engine inspired eccentric rotating Reuleaux polygons (triangular-shaped rotors). Hours are indicated by the lower rotor along the front of the 'dial', while minutes are indicated by the smaller upper rotor.
Epitrochoid curves: Time is by the tips of the Reuleaux polygon rotors tracing epitrochoid curves. To create the complex shape of the hour and minute epitrochoid curves with the high precision required 180 separate points were plotted. There is tolerance of just o.2omm between the triangular rotors - the special shape is actually called a Reuleaux polygon - and the hour and minute marked epitrochoids surrounding them.
Complication: The Reuleaux polygon (triangular-shaped) rotors are eccentric, i.e. not mounted directly to the central 'crankshaft' and they demand considerable time, skill and patience to set up correctly in assembly process. To ensure extremely high precision adjustment the fixed wheels can be rotated slightly (then re-fixed) to allow fine adjustment and synchronised precision between the hour and minute indicators.
Case: The Experiment ZR012 case is made from zirconium, which is derived from the mineral zircon. Visually zirconium is similar to titanium and is highly resistant to corrosion.
The case dimensions are 55mm x 44mm (excluding lugs). The articulated rear lug and compound front lug wrap ergonomically around the wrist and ensure a high level of comfort. 
Power reserve indicator: Turning Experiment ZR012 over reveals the power reserve indicator. The movement has autonomy of 39 hours and is wound by a large screw down crown.
Wankel engine 
The indications of Experiment ZR012 are inspired by the Wankel engine
In 1919, a 17-year-old German boy called Felix Wankel dreamt of a new type of engine. Despite no formal training, Wankel believed that he could design an engine in which the four stages of intake, compression, combustion and exhaust-took place in one rotation, rather than four separate reciprocations of a piston as in a normal engine. 
It was an ambitious goal, which others had been unsuccessfully attempting since the 16th century.  In 1924 Wankel created a small laboratory to develop his rotary engine and eventually tested the first prototype in 1957, over three decades later.
One of the main reasons development took so long is that Wankel’s orbital engine was based on a convex-triangle rotor rotating inside a epitrochoid combustion chamber. An epitrochoid is a very complex shape traced by a point on a small circle rotating around the perimeter of a larger circle and plotting that shape involves seriously complex mathematics.
x = cos(w1*t) + (R/L)*cos[(w1+w2)*t]
y = sin(w1*t) + (R/L)*sin[(w1+w2)*t]
In standard internal-combustion engines, pistons reciprocate four times for every cycle of power; in the Wankel engine, power is smoothly generated each rotation with fewer moving parts enabling the motor to be lighter, more compact and more reliable than reciprocating engines.
The epicycloid curve has been of special interest to astronomers over the centuries as the shapes are often found in the coronas of stars.  
Wankel was the first to use an epicyloid in an internal combustion engine. Experiment ZR012 is the first to use an epicyloid in a wristwatch.
About C3H5N3O9
C3H5N3O9 is both the molecular formula for nitroglycerine and a horological experiment.
Many of the most reactive (and most exciting) chemical reactions derive from combining seemingly innocuous ingredients. When Felix Baumgartner and Maximilian Büsser shared a pleasant lunch on a Geneva terrace in the summer of 2008, it started a horological chain reaction that four years later manifested as C3H5N3O9.
Urwerk founders Felix Baumgartner and Martin Frei had a concept featuring Wankel engine inspired indications that they had not yet developed, and they suggested their constructor Cyrano Devanthey could develop and produce a movement based on that.
MB&F partners Maximilian Büsser and Serge Kriknoff teamed up with independent watch designer Eric Giroud to design and produce the case. Experiment ZR012 was born!

Technical specifications

Experiment ZR012 Technical specifications
Experiment ZR012 is an edition of 12 pieces in zirconium and 12 pieces in black zirconium
Hours and minutes are indicated by two Wankel engine inspired Reuleaux polygon rotors tracing epitrochoid curves
Dimensions without lugs: 55mm x 44mm
Case and lugs: natural zirconium or black zirconium case with titanium lugs. The black zirconium will be available in the second half of 2013
Number of case components: 60
Compound front lug, articulated rear lug
Sapphire crystal with anti-reflective treatment both sides
Water resistance: 30m - 100’ - 3atm
Strap and buckle: Brown calf leather strap. Titanium and white gold folding buckle.
Movement dimensions: 32.65mm x: 41.35mm: 11.55 mm
Number of components: 328
Number of jewels: 42
Manual winding
Power reserve: 39h
Balance frequency: 28'800
Finishing: satin finishing, sandblasted, circular graining on movement, black PVD treated components, black ruthenium treated components
Number of plots to create epitrochoids for hours and minutes: 180
Tolerance between hour and minute indication rotors and inside of epitrochoids: 0.20mm

Who's who

Laurent Picciotto has been a partner for many of the watches at Chronopassion right from the outset. And in some cases, he’s there even before the start. Urwerk is one of those instances, working as it does on the principle of subscription. In 2002, when the brother of one of the brand’s founders went to rue Saint Honoré, all he had in his pocket were drawings; all he had in his mind were projects, or even just visions. But these were enough to win over the owner of the premises. The idea involved of a new way of telling the time, satellites, and more besides. So did Urwerk’s founders have their heads in the clouds? “In appearance only,” says Laurent Picciotto. “Urwerk’s staff and its work are very discreet, but the roadmap is anything but approximate. It’s meticulous, professional work, perhaps somewhat on the fringes of our little watchmaking universe – but with a very clear vision of who they are and where they’re going.” The first Urwerk fulfilled all this promise: it imposed its style, a completely new movement and an all-new way of telling the time. The watch made its own mark amongst more familiar ranges of contemporary watches. However, the new features did not win everybody over right away: “When the first watch arrived in 2004, by subscription, we had to do a lot of evangelism,” admits Laurent Picciotto. In the end passion, pragmatism and this educational approach won the day – and the timepiece was a great success. Chronopassion quickly became established as the exclusive retailer for Urwerk in France. The store now accounts for a significant share of the brand’s worldwide sales. Some ten years after its launch, Urwerk is still cultivating its individuality. It remains faithful to its founding principles – displaying the time using satellites – but makes constant changes at regular intervals: “I’m still amazed by the brand’s ability to bounce back,” stresses Laurent Picciotto. That’s why Chronopassion’s boss has continued to work with Urwerk, offering every one of the models developed so far. Certain limited editions have been literally snapped up. The beginnings of a queue actually formed in rue Saint Honoré for these timepieces – or at least, enough people to be sure that demand would definitely outstrip the scarce supply. Laurent Picciotto believes this is due to “customers who suddenly rediscover the child inside themselves. There are some who have very traditional tastes but who really go to pieces when they see an Urwerk.” Is it rational to swear by the likes of Bréguet or Audemars-Piguet and then abruptly go overboard for the satellite craziness of Urwerk? Of course not. But then again, as playthings go an Urwerk is anything but rational.

Journalist : Olivier Müller (01/13)

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