Monochrome Watches
An online magazine dedicated to fine watches

IWC Ingenieur Perpetual Calendar Digital Date-Month

| By Frank Geelen | 4 min read |
IWC Ingenieur Perpetual Calendar Digital Day-Date

In 2009 IWC created the Da Vinci Perpetual Calendar Digital Date-Month (ref. 3761). It was the first flyback chronograph with a perpetual calendar and digital leap year display as well as a digital display for the month and date with large numerals. This development was a tour de force that has paid off: the result is a very clever way to combine a perpetual calendar and a chronograph, while maintaining the legibility of all functions. Monochrome goes hands-on with the IWC Ingenieur Perpetual Calendar Digital Date-Month.

This is probably one of the most innovative perpetual calendars on the market, because of its digital display of day, month and leap year. And totally befitting the brand and its innovative and technical character, it’s presented in a watch case made of titanium aluminide. Titanium aluminide is used widely in motorsport, because the alloy is lighter and more robust than pure titanium. The black parts of the case are made of zirconium oxide, which is another material typically associated with motorsport.

IWC Ingenieur Perpetual Calendar Digital Day-Date

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The digital displays for both the date and the month features large numerals. These large numerals require more rotating disks with numerals printed on them, more gears, more levers, springs and cams. Simply conclusion: this type of display is much more complicated that one simple date or month disk, which makes one full rotation every 30/31 days or every 12 months.

Of course, the more parts, the more can go wrong. Simple as that. However this construction also requires more power, and while this might look like nothing for us, relatively speaking these powers are enormous. Especially when both month and date discs have to switch at the end of the month. In order to make both discs switch at once, power is accumulated, in a quick-action switch that was specially developed for this purpose, over the course of the entire month. At the end of the month, the energy is released and the discs advance once that power is released.

IWC Ingenieur perpetual calendar digital date-month

The leap year indication (the leap year has a 4-year cycle) also has a digital display: the disc with 1, 2, 3 and L is positioned at the lower end of the dial. The aforementioned quick-action switch generates the energy needed to advance the numeral discs. Every night, when the date display moves forward, it taps a little of the energy, stores it and then discharges it precisely at the end of the month or year. The switching of the digital leap year display is instantaneous and at the same moment when the date and month switch, which is a great improvement over old-style perpetual calendars.

What’s another improvement, is that the perpetual calendar can be set easily using just the crown. No small push-pieces in the case-band, no tool is required. And it will not need any intervention by a watchmaker until 2100, because in that year the conventional 4-year cycle will be broken and 2100 will not be a leap year. No worries about that today, it’s 86 years from now.

IWC Ingenieur Perpetual Calendar Digital Day-Date

The chronograph has a useful fly-back function, making it possible to reset the registers to zero without first having to be stopped. Hours and minutes recorded by the stopwatch can be read off on the totalizer at 12 o’clock, while the central hand shows elapsed seconds. This is similar to the chronograph register on the IWC Portuguese Chronograph Classic that we reviewed recently. The IWC-manufactured 89800 calibre comprises 474 individual parts and has a 68-hour power reserve when fully wound. The rotor, which takes the form of a light alloy wheel rim, can be seen through the sapphire-glass back.

IWC Ingenieur Perpetual Calendar Digital Day-Date

On the wrist, this complicated Ingenieur feels light, wears light and with the black rubber strap with alligator leather inlay, it also wears very comfortable. Usually we’re not the biggest fans of watches with a diameter exceeding 44mm. In this case we make an exception, due to the soft and shaped strap, the light case material and ultra short lugs, which all contribute to the watch’s comfortable wearing experience.

The IWC Ingenieur Perpetual Calendar Digital Date-Month is a rather unique wrist watch with both a perpetual calendar and a fly-back chronograph. It looks sporty and technical at the same time, and because of its superb wearability, it makes a very good all-round watch that you can wear at almost all occasions. Retail price is around € 44.000 Euro (depending on the vat/tax percentage) or CHF 48.000 in Switzerland.

IWC Ingenieur Perpetual Calendar Digital Day-Date

Specifications IWC Ingenieur Perpetual Calendar Digital Date-Month

  • Case: titanium aluminide case, 46mm diameter, 17mm in height, 120 meters (12 bar/ATM) water resistance, flat sapphire crystal with anti-reflective coating on both sides, see-through sapphire-glass back, screw-in crown
  • Movement: IWC-manufactured 89802 calibre (89000-calibre family), 51 jewels, 68-hour power reserve when fully wound, perpetual calendar, large double-digit displays for both the date and month, leap year display, flyback chronograph, small hacking seconds
  • Strap: black rubber strap with alligator leather inlay

More info at the IWC website here.

2 responses

  1. Great article! One question though, is it possible to accurately measure elapsed time in seconds between the 10 and 20 seconds mark? In the pictures it looks like the scale has a gap there, maybe not important, but strange design decision given that the scale is complete in the other 89800 watches (to my knowledge).

  2. That’s correct Tor Skare. There are no index markers between 10-20 and 40-50. It looks like overall design prevailed over usability.

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