IWC Schaffhausen Ingenieur Constant Force Tourbillon (Ref. IW590001)

Unveiled at SIHH as the part of IWC Schaffhausen’s 2013 Ingenieur collection, the spectacular Ingenieur Constant-Force Tourbillon integrates the patented constant-force mechanism in a tourbillon.

Haute horlogerie and Formula One™ motorsport have one thing in common: only if the engineers adjust the individual parts to interact perfectly can they get the most out of their machines. And only then, whether they’re designed for the wrist or the racetrack, will their performance be spot on.

While V8 engines are built for extreme acceleration and braking power, the hand-wound mechanism of a mechanical wristwatch should ideally supply energy at as constant a rate as possible. But because the mainspring in a conventional hand-wound movement is under more tension when freshly wound than when running down, the amount of power it generates varies constantly.

IWC’s team of engineers, watchmakers and designers sought an answer to the problem for 10 whole years. The result of their efforts is a highly complex constant-force mechanism integrated in a tourbillon. And in 2013, IWC’s invention makes its way into the Ingenieur watch family for the first time in the form of the Ingenieur Constant-Force Tourbillon (Ref. IW590001) in a platinum and ceramic case.

IWC Schaffhausen Ingenieur Constant Force Tourbillon (Ref. IW590001)

Positioned at “9 o’clock”, the impressive constant-force tourbillon provides a fascinating view of its layered construction. Connoisseurs of precision mechanics will particularly enjoy watching the complex interaction of the springs, wheels and pallets. The striking black tourbillon bridge is calibrated to facilitate reading off the seconds and, like the black screws, underscores the dial’s high-tech look.

As a captivating contrast to this we see the delicate, gold-coloured Glucydur®* beryllium alloy balance with its high precision adjustment cam on the balance arms. The tourbillon revolves around its own axis once every 60 seconds to offset the influence of gravity on any positional error in the balance and its adverse effect on the rate.

Down in the depths of the tourbillon we see the constant-force mechanism, the true heart of the watch. This intricate assembly allows the escapement to be uncoupled from the gear train, which keeps the amplitude of the balance – and thus the watch’s rate – virtually constant. The energy is stored temporarily in a balance spring and dispensed to the escape wheel. This balance spring is put under tension once a second, as we can see from the one-second advances made by the tourbillon hand.

IWC Ingenieur Constant Force Tourbillon Ref. IW590001

After every five beats of the balance, the stop wheel and the tourbillon cage are also released. The stop wheel turns and causes the tourbillon cage to rotate with it, which puts the balance spring under tension again. After about 2 days, the watch moves from constant-force mode into normal mode. Now, the seconds hand advances smoothly every one-fifth of a second. The constant-force tourbillon guarantees a regular and precise rate over a period of at least 48 hours.

IWC Ingenieur Constant Force Tourbillon Ref. IW590001

The new 94800-calibre basic movement was developed entirely internally by IWC. It features two barrels, which provide the energy for the higher torque required to drive the constant-force tourbillon. It also provides the moon phase module with the necessary power. IWC’s hallmark double moon display for the northern and southern hemispheres also makes its debut in the new design. If its position on the dial is a bold statement in itself, the incredibly realistic depiction of the moon is even more daring.

IWC used a special 3-D laser technique to render the surface as authentically as possible. As a result, even tiny craters are visible to the naked eye. The countdown display on the outer ring of the totalizer shows the number of days remaining before the next full moon. A new departure for IWC is the retrograde design of the power reserve display between “4” and “5 o’clock”, which has a triangular indicator to show the power remaining. The connecting bridge was designed in such a way that the IWC logo is not concealed at any point during the watch’s 96-hour run time.

The three totalizers protruding into the bezel were inspired by dashboard instruments and underscore the watch’s sporty character. In keeping with the cool, technically inspired look are the finely nuanced shades of black on the dial, the black, high-tech ceramic lugs and the solid crown protection in platinum. In the inner circle is the traditional pattern consisting of interlocking capital “I”s with elongated serifs. The letter stands for Ingenieur and lends an unusual depth to the relief.

If we look at the Ingenieur Constant-Force Tourbillon from the movement side, it’s like peering into a sports car’s engine compartment. Complementing the bores in the bezel on the front side are five titanium screws with ceramic heads, which secure the sapphire-glass back firmly to the case.

IWC Ingenieur Constant Force Tourbillon Ref. IW590001

On the bottom plate, the lively interplay of blasted and satin-finished surfaces combined with polished edges is reminiscent of a high-performance Formula One™ racing car. Perforated sections reveal the intermeshing gears, while engravings provide the technical details. All the design elements are meticulously harmonized and radiate power and pure dynamism.

Technical details

Model: IWC Ingenieur Constant Force Tourbillon, Ref. IW590001

Mechanical movement – Power reserve display – High-precision moon phase display – Double moon phases for the northern and southern hemispheres – Countdown display showing phases until next full moon – Tourbillon with integrated constant-force mechanism – Glucydur®* beryllium alloy balance with high-precision adjustment cam on balance arms – Screw-in crown – See-through sapphire-glass back

Calibre 94800
Frequency: 18,000 A/h / 2.5 Hz
Jewels: 43
Power reserve: 96 h
Winding: hand-wound

Case, dial & strap
Materials: Platinum and ceramic case, black dial, black alligator leather strap, pin buckle in platinum
Glass: Sapphire, flat, antireflective coating on both sides
Water-resistant: 12 bar
Diameter: 46 mm
Case height: 14 mm

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