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Haute_Horlogerie_quer
All wound up

Before a mechanical watch movement can start moving, it needs an energy source to drive it. That energy source is the mainspring. And while there are some who enjoy engaging with the machine, lovingly winding it by hand, others take pleasure in the automatic mechanism, which will keep the watch running indefinitely, simply from the movements of the wearer's arm.

IWC Oils
Time That Runs Like Clockwork

Depending on the stresses and strains to which they are exposed, around 50 points in the movement are treated with oils and greases developed especially for use in wristwatches.

Test Lab

At IWC Schaffhausen, new watch models are put through a gruelling test program involving up to 50 separate stages that include long-term immersion in warm salt water and being locked away in an environmental chamber. All this guarantees that they will be equipped for everyday use – and much more – when they finally reach their future owners.

Sound_check_engine_AMG_972x426
Sound Check

How the engineers at Mercedes AMG in Affalterbach, southern Germany, create the right engine sound.

HALF_WAY_TO_THE_MOON_Trucks_972x426
HALF WAY TO THE MOON

For the MERCEDES AMG PETRONAS Formula One™ Team, following the Grand Prix circus means transporting 30 tons of material in 10,000 individual parts and at least 60 employees to venues on five continents. Of course, they have to ensure that everything arrives there on time what calls for a system and improvisation in equal measure.

Grande Complication Dial Explained
Small World

Time moves the world. The IWC Portuguese Grande Complication is an understated, beautifully designed way of summarizing time as the motor of all change: a time machine that shows a tilted globe on the dial.

89800 Calibre Movement
Eternity in Digits

The IWC-manufactured 89800 caliber, which made its debut in 2009, redefined the digital date display. The triple-disc mechanism in the perpetual calendar features large-format displays for the date and month and, slightly more discreetly, the leap year cycle. All are ingeniously synchronized.

Top Secret

In a small town in central England, over 500 specialists spend their time developing and building silver arrows for the MERCEDES AMG PETRONAS Formula One™ Team. Almost every one of the 3,200 parts in each car is custom-made.

Experiences

Flying high with big date and month displays

Text — Alexander Linz Date — 13 June, 2012

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Is it really appropriate for a top-class wristwatch to be equipped with an array of digital displays? Does this model mean we are witnessing the revival of the quartz watch? To answer these questions, probably the wisest thing to do is take a second look at this Pilot’s Watch from the Spitfire collection. For a start, there is not a sign of a battery or a digital display to be seen. What we do find are three numerical displays with digits. And this is where the difference lies: because a numerical display is not necessarily a digital one. If this seems like hair-splitting, it is intentional. To refer to the Spitfire Perpetual Calendar Digital Date-Month loosely as a watch with a digital display would be to do it an injustice. For ticking away under the dial is a complex mechanical movement comprising no fewer than 474 individual parts.

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The 89800 calibre is a chronograph movement featuring a calendar with large double-digit displays for both the day and month as well as a numerical leap year indicator. The calendar is mechanically programmed for all eternity. However, owing to the Gregorian calendar’s handling of the leap years, the mechanism will need to be corrected by one day in 2100. As is well known, every fourth year is a leap year apart from the one occurring every hundred years at the start of a new century. The exception here is every four-hundredth year (2000, 2400 etc.), which is likewise a leap year. For the succession of individuals who are likely to own our Spitfire in its long lifetime it means that the calendar display will only need to be advanced by one day every hundred years, with the exception of each four-hundredth year. Once the calendar has been advanced on 1 March 2100, for instance, it will require no further correction for the next century. This small adjustment and any other action necessary to reset the calendar – in the event of the watch stopping, for instance – is carried out using the rapid-adjustment mechanism activated by the winding crown. Anyone looking for recessed setting buttons in the sides of the case will be disappointed.

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The ingeniously designed power source for the calendar mechanism is the IWC 89361 chronograph calibre, which comes with a mighty 68-hour power reserve. The energy needed to wind the barrel is generated by the double-pawl winding system, complete with shock absorber, designed in IWC’s own workshops. The balance has a frequency of 28,800 beats per hour, or 4 Hertz. Control of the chronograph functions is through a classical column wheel. The flyback mechanism allows a timing sequence to be reset and restarted rather than going through the usual three-stage stop, reset and start process. Simply depressing the reset button at “4 o’clock” terminates the current timing sequence, resets the chronograph mechanism and instantaneously restarts it. The flyback mechanism was originally developed for pilots who needed to follow approach and take-off instructions precisely. Basically, the brief was as follows: that one action should be sufficient to start the stopwatch again from zero. In the 89361 calibre, the display showing the aggregate timing of hours and minutes is extremely user-friendly. It takes the form of a small subdial positioned at “12 o’clock”, where the elapsed time can be read off easily in hours and minutes. The totalizers normally required for reading off stopped hours and minutes are superfluous, which in turn creates the space required for the numerical date and month displays.

Simply, ingeniously digital

The Spitfire Perpetual Calendar Digital Date-Month is the first Pilot’s Watch launched by IWC Schaffhausen to feature a perpetual calendar, a digital date and month display, and an innovative stopwatch display. The IWC-manufactured 89800 calibre provides a suitable drive.

The IWC calendar mechanism is mounted on top of the 89361 calibre directly beneath the dial. All in all, it comprises four large discs that display the date and month in figures. As is clearly visible in the diagram, the date is displayed on two discs with a different arrangement of numerals. During the first nine days of the month, the upper disc remains stationary so that the figure zero is visible in the far left aperture on the dial. The disc below it bears the figures zero to nine. At midnight, it advances by one step – or day – meaning that we see a combination from zero + one to zero + nine. On the tenth of the month, the upper disc is advanced by a single position and the combination one + zero to one + nine now appears as described above. On the twentieth of the month the upper disc advances by a further position; combined with the disc below it now shows the combination two + zero to two + nine. The entire spectacle is repeated on the thirtieth of the month. The upper disc advances one position and the disc below it now shows the combination three + zero and three + one. Another program disc informs the calendar disc whether it needs to show both the three + zero and three + one combinations or not. In months with only thirty days, the disc advances in such a way that the dial shows the combination zero + one at the start of the new month. And in February, the calendar knows whether the month has twenty-eight or twenty-nine days. This controls the combination of discs advanced and determines the necessary switching sequences. At the end of the month, as you would expect, the new month appears correctly in the aperture. Like the date display, it too consists of two discs. During the first nine months of the year, the upper disc remains stationary, displaying the figure zero in its rectangular window. At the end of the month, the lower of the two discs continues to advance from one to nine. On the dial, we see the figures zero + one to zero + nine. At the start of October (the tenth month) the upper disc advances by a single digit to cover the lower disc completely. The remaining months are now shown as ten, eleven and twelve. As miraculous as all this may seem, the technology itself involves no magic. The switching sequences are all controlled by the month cam, a single disc programmed with all the information required to keep track of the months in the four-year cycle, including the 29 days in February. The numerical disc display for the leap year cycle, clearly visible in the aperture at “6 o’clock”, is advanced only once a year. It shows either a figure from one to three or the letter “L” for leap year.

Spitfire Perpetual Calendar Digital Date-Month

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A watch movement is effectively a miniature engine with a limited amount of power. Ensuring that the basic 89361 calibre never runs out of steam despite the various switching sequences was a major challenge for IWC’s engineers. The mechanism was designed to ensure that the daily advance of one or two discs did not drain too much energy from the movement. This would reduce the balance’s amplitude and seriously affect the watch’s rate. But with the need for two disc mechanisms to advance synchronously at the end of the month and three at the end of the year, some assistance was called for. The aim was for the IWC-manufactured 89800 (89361 plus calendar mechanism = 89800) calibre to switch reliably without a noticeable drop in amplitude throughout its entire running time. To achieve this, the design engineers equipped the unusual movement with a quick-action switch comprising 19 individual parts. The assembly in question is a separate mechanical power reserve: over the course of a month, when the date advances during the night, a tiny amount of energy is tapped off and stored. It is then discharged later at precisely the moment when it is needed: in other words, at the end of the month when both the date and month-indicator discs advance simultaneously. Thanks to the sophisticated design, it was the first time it had been possible for a mechanical watch to have two unusually large, digitally inspired calendar displays. The technical details are as follows: the date change wheel, which completes a revolution every month, is fitted with a snail-shaped cam that rests on another advance lever. This cam raises the advance lever a tiny fraction every night until it reaches its maximum travel by the end of the month. At precisely the end of the month, the advance lever, which now rests on the highest point on the date change wheel cam, drops down over a raised step back to the point where it was at the beginning of the month. This releases the extra energy stored during the month, activating the quick-action switch and transmitting it to the month-indicator disc program wheels. A ratchet lever is also employed to ensure that only one month advances at a time and that the display does not simply run away with itself.

By now, it should be clear why it is simply not appropriate to refer to this timepiece as a digital watch. It becomes even more obvious when you turn the Spitfire round to admire the fabulous 89800 calibre through the screw-in sapphire glass back cover. Your attention is immediately drawn to the meticulous finishing and decoration, executed in various styles, as well as the uniquely shaped rotor. Designed as the three-dimensional silhouette of a Spitfire, it is the movement’s crowning glory. A top-quality mechanism like this, of course, calls for an equally prestigious case. The 46-mm, 18-carat red gold case complements the 474-part movement to perfection. With its convex sapphire glass featuring an anti-reflective coating on both sides, it also underscores the strikingly sporty, elegant style of the Spitfire collection. We should also mention in passing that the sapphire glass – as you would expect in any Pilot’s Watch worthy of the name – is secured against sudden drops in air pressure. With its brown alligator strap and 18-carat red gold folding clasp, the Spitfire Perpetual Calendar Digital Date-Month will hold an irresistible appeal for lovers of pilot’s watches and sophisticated technology. At this point, we can state once again, quite unequivocally: this model is the genuine high-flyer in the Pilot’s Watch collection from IWC Schaffhausen. And whatever your perspective, digital watches look completely different.

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Inside IWC

Flying High

It’s no flight of fancy that IWC Pilot’s Watches have become icons. Exceedingly popular, they represent IWC values, defining the entire genre of pilot’s watches within the Swiss watch industry.

Explore More Articles
Haute_Horlogerie_quer
All wound up

Before a mechanical watch movement can start moving, it needs an energy source to drive it. That energy source is the mainspring. And while there are some who enjoy engaging with the machine, lovingly winding it by hand, others take pleasure in the automatic mechanism, which will keep the watch running indefinitely, simply from the movements of the wearer's arm.

IWC Oils
Time That Runs Like Clockwork

Depending on the stresses and strains to which they are exposed, around 50 points in the movement are treated with oils and greases developed especially for use in wristwatches.

Test Lab

At IWC Schaffhausen, new watch models are put through a gruelling test program involving up to 50 separate stages that include long-term immersion in warm salt water and being locked away in an environmental chamber. All this guarantees that they will be equipped for everyday use – and much more – when they finally reach their future owners.

Sound_check_engine_AMG_972x426
Sound Check

How the engineers at Mercedes AMG in Affalterbach, southern Germany, create the right engine sound.

HALF_WAY_TO_THE_MOON_Trucks_972x426
HALF WAY TO THE MOON

For the MERCEDES AMG PETRONAS Formula One™ Team, following the Grand Prix circus means transporting 30 tons of material in 10,000 individual parts and at least 60 employees to venues on five continents. Of course, they have to ensure that everything arrives there on time what calls for a system and improvisation in equal measure.

Grande Complication Dial Explained
Small World

Time moves the world. The IWC Portuguese Grande Complication is an understated, beautifully designed way of summarizing time as the motor of all change: a time machine that shows a tilted globe on the dial.

89800 Calibre Movement
Eternity in Digits

The IWC-manufactured 89800 caliber, which made its debut in 2009, redefined the digital date display. The triple-disc mechanism in the perpetual calendar features large-format displays for the date and month and, slightly more discreetly, the leap year cycle. All are ingeniously synchronized.

Top Secret

In a small town in central England, over 500 specialists spend their time developing and building silver arrows for the MERCEDES AMG PETRONAS Formula One™ Team. Almost every one of the 3,200 parts in each car is custom-made.