IWC Schaffhausen Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS”

In collaboration with its partner Mercedes-AMG, IWC Schaffhausen has created the Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS”.

Available exclusively for future owners of the performance hybrid Mercedes-AMG ONE, this horological masterpiece features the Swiss luxury watch manufacturer’s patented constant-force mechanism, which transmits completely even impulses of force to the escapement.

The case is made of titanium aluminide (TiAl), an advanced high-tech material that is extremely challenging to machine. Thanks to its high temperature resistance, this intermetallic compound is also used for components of high-performance engines in motorsport. The striking design features details and colour codes are directly inspired by the Mercedes-AMG ONE hypercar.

IWC Schaffhausen Big Pilot’s Watch Constant-Force Tourbillon Edition AMG ONE OWNERS Ref. IW590502

The German performance and sports car manufacturer is planning to kick start the production of the Mercedes-AMG ONE. This two-seater hypercar will transfer the latest and most efficient Formula 1™ hybrid technology almost one to one from the racetrack to the street for the first time.

The performance hybrid will produce over 1,000 horsepower at a maximum speed of over 350 km/h. To accompany its launch, IWC has engineered a timepiece that combines the Swiss brand’s technically most advanced movements and complications with high-performance materials such as titanium aluminide (TiAl) and Ceratanium.

The Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS” (Ref. 590502) features IWC’s patented constant-force mechanism. This complication disengages the escapement from the direct flow of power through the wheel train and transmits completely even impulses of energy to the escape wheel.

As a result, even as the torque in the mainspring diminishes, the balance wheel oscillates with virtually the same amplitude. In combination with the tourbillon, which compensates for the negative influences of gravity, this ensures a highly exact rate.

The IWC-manufactured 94800 calibre is manually wound and stores a power reserve of 96 hours in its twin barrels. The fully blackened movement is visible through the sapphire glass back. The case back is made of Ceratanium®. Based on a special titanium alloy, this IWC-developed material is as light and rigid as titanium and, at the same time, almost equally as hard and scratch-resistant as ceramic.

IWC Schaffhausen Big Pilot’s Watch Constant-Force Tourbillon Edition AMG ONE OWNERS Ref. IW590502

The IWC Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS” reflects the unique competence acquired by the Schaffhausen based manufacture in machining titanium since the 1980s. The case is made of titanium aluminide (TiAl).

TiAl is lighter and harder than conventional titanium, highly resistant to corrosion, and biocompatible. This high-tech material belongs to the group of intermetallic compounds. Due to the specific mixing ratio of titanium and aluminium, atoms and electrons arrange themselves in a particular way. This causes the material to have certain nonmetallic properties in addition to the classic properties of a metal.

In the case of TiAl, it is its high temperature resistance that stands out. For this reason, the material is used for the turbine blades of modern jet engines, where lightness and temperature resistance are essential requirements. Its specific properties also make it the ideal choice for components of high-performance engines in motorsport.

Because titanium aluminide has a difficult machining behaviour, manufacturing a TiAl watch case is a real engineering feat. In addition, the requirements for the purity of the raw materials are very high, and the production of the titanium aluminide alloy is costly and complex.

Today, IWC is one of the few watch manufacturers capable of producing a titanium aluminide case. The case of the Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS” is elaborately finished with polished and sandblasted surfaces.

In addition to the constant-force tourbillon at 9 o’clock, the black dial also features a double moon phase display for the northern and southern hemispheres and a power reserve display at 4 o’clock, reminiscent of a tachometer.

The louvred, ring-shaped structure of the outer dial ring takes inspiration from the air inlets that dominate the front of the Mercedes-AMG ONE.

The design also features details in Petronas green – the signature colour of the Mercedes-AMG Petronas Formula One™ team, whose plug-in hybrid technology the new car brings to the street. A thin ring in Petronas green, for example, marks the transition between the polished and sandblasted parts of the case. Details in Petronas green can also be found on the dial and on some of the movement components.

The IWC Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS” is fitted with a two-tone rubber strap. Manufactured using the so-called multi-component injection moulding process, it is black on the outside and green on the inside. Numerous Mercedes stars in Petronas green are visible on the outer side of the strap.

The Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE OWNERS” will be available exclusively to the future owners of the Mercedes-AMG ONE.

Technical details

Model: IWC Schaffhausen Big Pilot’s Watch Constant-Force Tourbillon Edition “AMG ONE Owners” Ref. IW590502

Titanium aluminide (TiAl) case
Diameter: 46.2 mm
Height: 13.5 mm
Screw-in crown in titanium
Glass: Sapphire, convex, antireflective coating on both sides
Glass secured against displacement by drops in air pressure
See-through sapphire glass back with Ceratanium® case back ring
Water-resistant 6 bar

IWC-manufactured calibre 94800
Hand-wound mechanical movement
Frequency: 18,000 vph / 2.5 Hz
Jewels: 41
Power reserve: 4 days (96h)

Power reserve display
Tourbillon with integrated constant-force mechanism
Perpetual moon phase display for both northern and southern hemispheres

Black dial with rhodium plated hands

Integrated black and green rubber strap

Available exclusively to Mercedes-AMG ONE owners

Grand Seiko Kodo Constant-force Tourbillon

Grand Seiko presents its first mechanical complication watch that combines a constant-force mechanism and a tourbillon as one unit on a single axis.

Known as Kodo (the Japanese word for heartbeat), this revolutionary watch reveals its vitality both audibly and visually, thanks to the open-work design and the sapphire case back.

Grand Seiko Kodo Constant-force Tourbillon

In 2020, Grand Seiko introduced the “T0 Constant-force Tourbillon”, a concept movement which incorporated this patented mechanism. To bring the concept to life in a finished watch required the complete dedication of a team comprising designers, engineers and craftsmen and women entrusted with the assembly and finishing of the movement and the case.

Each and every one of the 340 components of the caliber was re-examined, and, where necessary, re-designed and re-engineered for production. The result is Caliber 9ST1. Not only is Caliber 9ST1 smaller than its concept movement predecessor but its high accuracy remains stable for longer thanks to the constant-force mechanism.

Furthermore, Caliber 9ST1 sets a new standard of accuracy, in which each movement is tested for a full 48 hours in each of six positions and at three temperatures. This is twice as long as the Grand Seiko and industry standard.

Each movement is assessed over the course of 34 days to verify its accuracy, and when the tests are completed and this new standard has been met or exceeded, the performance characteristics of each movement are defined in the individual certificate provided with every watch.

Grand Seiko Kodo Constant-force Tourbillon

From the inception of the project to the realization of Kodo in its finished form required ten years of skill, dedication and hard work.

Caliber 9ST1 is complex in its engineering and design but is based on the simple insight that the integration of a constant-force mechanism and a tourbillon as one unit on a single axis would deliver practical benefits.

Because there are no wheels or other components between the two mechanisms, there is no loss or change in the torque transmitted from the constant-force mechanism to the balance wheel.

This leads to an increased duration of 50 hours for the constant-force mechanism and a more stable amplitude of the balance. Together, these characteristics deliver the very stable accuracy of the movement. In addition, and crucially for Grand Seiko, the volume of the movement could be reduced, allowing the aesthetics of Grand Seiko to be respected and the watch to be eminently wearable and perfectly comfortable on the wrist.

The integration of the two mechanisms creates a dazzling visual effect. The inner tourbillon carriage rotates smoothly as the balance steadily vibrates at 8-beats per second and the outer constant-force carriage follows its rotation at exact one-second intervals.

The sounds of the escapement and of the once-per-second impulse of the constant-force mechanism harmonize with this regular visual rhythm to create, for both the eye and the ear, a deeply satisfying and re-assuring heartbeat.

There is a powerful yet gentle charm to the sound that is set to a 16th note or semi-quaver which is made possible by 9ST1 being the movement with the highest frequency ever to incorporate a constant-force mechanism.

The constant-force carriage has a ruby on one of its arms, which acts as a small seconds hand. The watch incorporates a hacking function so that the rotating tourbillon carriage can be stopped when the crown is pulled out, allowing the time to be adjusted to the precise second. The hour hand has an extra facet at its tip to enhance its readability. In addition, Kodo offers 10 bar water resistance.

Grand Seiko Kodo Constant-force Tourbillon

The sapphire crystal case back reveals the beauty of the movement’s finishing and its intricate construction.

Thanks to the integration of the two key mechanisms, Caliber 9ST1 has room to breathe within the case and there is sufficient space for light to penetrate, through both the front and back of the case, revealing the beauty of the hand finishing. For the same reason, the delicate interplay of light and shadow that is central to the Grand Seiko aesthetic is there to be enjoyed in the subtle shade gradations, angles and textures. Each major component is painstakingly finished by hand using a variety of techniques to endow the overall movement with the quiet yet enduring sparkle that is the hallmark of Grand Seiko.

The case is constructed from both Platinum 950 and Grand Seiko’s Brilliant Hard Titanium to achieve a long-lasting beauty. Some case parts of both materials are Zaratsu polished and others have a hairline finish; both processes are completed by hand by highly skilled craftsmen and women to ensure that, from every angle, a visually pleasing harmony is revealed. The two case materials combine most evidently at the tapered end of the lugs where a small open space between each lug adds a lightness and unique aspect to the overall design.

Grand Seiko Kodo Constant-force Tourbillon

Grand Seiko’s expertise in hand polishing is evident in the way that the Platinum 950 and Brilliant Hard Titanium surfaces are perfectly harmonized.

The watch is offered with a calf strap specially treated in the same traditional way as was used to create the high-durability material once used in the armor of Samurai. The strap’s surface is painted by hand with Urushi lacquer in a multi-coating process that gives the strap a delicate sheen. The watch also comes with an alternative crocodile strap.

The watch was designed by an elite group of Grand Seiko’s watchmakers and designers who will be a part of the new studio, the Atelier Ginza, to be situated in Ginza, Tokyo, where Kintaro Hattori started his business in 1881. The studio’s aim is to create truly unique watches that reflect the determination of Kintaro that his company should always strive to make the world’s finest watches.

The Grand Seiko Kodo will be available as a limited edition of twenty in October 2022.

Technical details

Model: Grand Seiko Kodo Constant-force Tourbillon: SLGT003

Caliber 9ST1
Driving system: manual-winding
Vibrations: 28,800 vibrations per hour (8 beats per second)
Accuracy: +5 to -3 seconds per day (when static for 48 hours)
Power reserve: 72 hours
Number of jewels: 44
Constant-force Tourbillon (Constant-force: 50 Hours)
Diameter: 35.0mm, Thickness: 7.98mm

Platinum 950 and Brilliant Hard Titanium case
Box shaped sapphire crystal with anti-reflective coating
See-through case back
Water resistance: 10 bar
Magnetic resistance: 4,800 A/m
Diameter: 43.8mm, Thickness: 12.9mm

Calf strap with Platinum 950 three-fold clasp with push button release
Double-sided crocodile strap included

Approximate recommended retail price in Europe: €370,000

Limited edition of 20 pieces

Andreas Strehler Trans-axial® Remontoir Tourbillon

Independent Swiss master watchmaker Andreas Strehler has developed a new movement which combines his Remontoir d’égalité (constant force) with a Tourbillon.

In Andreas Strehler watches, the energy for operating the movement is stored in twin mainspring barrels. The running down of the two mainsprings is limited by an epicyclical gear. Only the optimal part of each mainspring is used where the power supplied is practically constant.

Even by using the highest-grade lubricants and the tightest tolerances in manufacturing each component, the flow of energy from the mainsprings will be subject to variations. Changes in temperature or in the position of the watch will cause such variations. To filter these variations, Andreas Strehler employs a Remontoir d’égalité or constant force escapement.

In Andres Strehler’s Remontoir d’égalité,t he energy supplied from the twin mainspring barrels through the gear train is accumulated in a spring, acting on a satellite arm held in position by the star wheel (the satellite). One tooth of this star wheel is resting on the palette-stone of the palette arm.

This palette arm constantly moves ahead. Every second, the palette arm releases the star wheel. The star wheel turns by one tooth and the satellite arm jumps ahead by 6°. The satellite wheel then rests again against the palette-stone and the cycle starts anew.

When moving ahead by 6°, the satellite arm recharges the spring which drives the escapement. The amount of energy transferred to the escapement thus is always the same, it is constant. The energy is transferred to the escapement through an axis.

The escapement mounted on this axis is a Tourbillon. The Tourbillon is a special escapement. It is also one of the most complicated components known to watchmaking. In a Tourbillon, the whole escapement including the balance rotates typically once a minute.

The idea behind the Tourbillon is that the balance, despite its name, is never perfectly balanced. This means that it oscillates slightly differently, depending on its position in space.

When the Tourbillon was invented by Abraham Louis Breguet in 1801, men wore pocket watches. A pocket watch is carried vertically, and the balance always oscillates on a horizontal axis. This means that gravity pulls more on any part of the balance which is thicker or heavier.

Andreas Strehler Trans-axial® Remontoir Tourbillon

Now, by rotating the whole escapement and hence the balance once a minute, it did not matter if the balance was slightly imperfect: Gravity would still pull heavier on the thicker part of the balance. But, by its rotation, this effect would even itself out.

The balance would, for one part of the rotation of the Tourbillon, work uphill, so to speak. But for the other part of the rotation of the Tourbillon, it would work downhill (and for the rest of the time in neutral).

Andreas Strehler Trans-axial® Remontoir Tourbillon

In his quest for perfection, Andreas Strehler has designed, constructed and built a movement where internal influences on the already pretty linear power supply from the epicyclically limited twin mainspring barrels is filtered through a Remontoir d’égalité and transferred to a Tourbillon escapement mounted on the same axis to eliminate the influence of gravity on the escapement.

Andreas Strehler Trans-axial® Remontoir Tourbillon

The Trans-axial® Remontoir Tourbillon escapement is hand wound, using Andreas Strehler’s own true conical gear wheels.

Andreas Strehler Trans-axial® Remontoir Tourbillon

To show the power left in the two mainspring barrels, the movement has a power reserve indication using an extremely small differential gear, another speciality of Andreas Strehler.

The Remontoir d’égalitéis mounted on three roller bearings and powers a separate jumping seconds indication. The Tourbillon is held in position by two gold chatons.

Andreas Strehler Trans-axial® Remontoir Tourbillon

Technical details

Trans-axial Remontoir Tourbillon

  • Impulse: Double main spring barrel, energy regulated by a remontoir d’égalité
  • Plates and bridges: Three 18k gold bridges, Central Main Plate and bridges are decorated to the highest standards, edges bevelled and polished by hand, fully decorated movement
  • Escapement: swiss lever escapement designed by Andreas Strehler
  • Regulating system: Free-Sprung balance with Breguet overcoil and eight adjustment screws
  • Frequency: 3 Hz / 21’600 A/h
  • Number of jewels: 37, 3 gold chatons
  • Number of individual parts: 250
  • Size: 32.0 x 30.0 mm
  • Height: 7.01 mm (without Tourbillon)
  • Power reserve: 78 h, limited by a differential stop works
  • Functions: Hour, minute, small jumping second, constant force, Tourbillon, power reserve indication (micro differential gear train)
  • Winding-mechanism: Hand winding with conical gear wheels
  • Speciality: Constant force Tourbillon, Remontoir trans-axial underneath the Tourbillon, special roller bearing for the remontoir.

Arnold & Son Constant Force Tourbillon (Royal Collection)

Swiss luxury watch maker Arnold & Son pushes precision chronometry ever further with the Constant Force Tourbillon, featuring a patented constant force device with 60-second tourbillon and true beat seconds.

The symmetrical movement architecture of the Constant Force Tourbillon movement pays tribute to Arnold & Sons’ historic marine chronometers. At the top, two visible mainspring barrels and the constant force device provide optimal power to the tourbillon at the bottom of the dial.
Arnold and Son Constant Force Tourbillon watchThe Constant Force Tourbillon watch is part of the Royal Collection and, like every other model from Arnold & Son, features an in-house mechanical movement.

John Arnold (1736-1793) was constantly searching for higher precision in his timepieces, as the more accurate the chronometer, the more precise the calculation of longitudinal (east/west) position at sea. Arnold and his son were the first to develop and produce technically superlative (but reasonably priced) marine chronometers in significant quantities.

Constant force is an essential element in the quest for higher precision because it is difficult regulating a consistent output, e.g. isochronal time when the power input from the mainspring is constantly changing.

To maximize power consistency in the Constant Force Tourbillon, Arnold & Son began at the beginning, i.e. the mainspring barrel, as this is the source of the movement’s power. Instead of using just one mainspring barrel, which would produce significantly different amounts of torque between fully wound and nearly empty, the Constant Force Tourbillon has two symmetrical barrels in series, visible dial side at 10:30 and 1:30.

The first mainspring barrel alone powers the gear train, while the second barrel tops up the first whenever its torque output drops below optimal. This ensures that the power to the regulator flows as constantly as possible.

Arnold and Son Constant Force Tourbillon

The Constant Force Tourbillon features a patented constant force mechanism. Instead of power from the mainspring feeding directly to the escapement/tourbillon, it charges a small hairspring which in turn releases a consistent amount of power to the escapement/tourbillon once each second.

The device also drives the true-beat seconds hand (also known as jumping seconds or dead seconds), a highly cherished Arnold & Son complication. When the power from the mainspring drops below that required by the constant force mechanism, the movement stops rather than running at lower precision.

The constant force device rotates once per minute in increments of one second, visually mirroring the rotation of the constantly rotating tourbillon cage. The bridges supporting the constant force regulator and tourbillon are also symmetrical, both horizontally with each other and vertically with the barrel bridges.

While the constant force mechanisms optimize precision with the movement in stable positions, the 60-second tourbillon averages out gravitational errors on the escapement by constantly rotating it through 360°. The difference between the rotating tourbillon and rotating constant force device is that the former turns continually while the latter steps in increments of one second.

Arnold and Son Constant Force Tourbillon watch with red gold case and Anthracite open dial

The Arnold and Son Constant Force Tourbillon watch is a limited edition of 28 timepieces, and is available in a 46 mm 18-carat red gold case with anti-reflective sapphire crystal and sapphire display back for viewing the superbly hand-finished movement.

Technical details

Model: Constant Force Tourbillon, Royal Collection
Limited edition: 28 timepieces
Reference: 1FCAR.B01A.C112C

Calibre: A&S5119, Exclusive Arnold & Son mechanical movement, hand-wound, 39 jewels, diameter 36.8 mm, thickness 6 mm, power reserve 90 h, double barrel, 21,600 vibrations/h
Functions: hours, minutes, true beat seconds, tourbillon, constant force
Movement decoration: nickel-silver and steel movement, palladium treated bridges and NAC grey treated main plate with Haute Horlogerie finishing: hand-chamfered bridges with polished edges and brushed surfaces, screwed gold chatons, screws with bevelled and mirror-polishedheads
Tourbillon cage: mirror-polished with hand-chamfered polishededges and circular satin-finished surfaces

18-carat red gold, diameter 46 mm, cambered sapphire with antireflective coating on both sides, see-through sapphire case back, water-resistant to 30 m

Anthracite open dial

Hand-stitched brown bottier alligator leather with patina