Sunday, June 14, 2015

IWC Big Pilot’s Watch Ref. 5002 : Second largest wristwatch ever produced in the history of IWC

The Big Pilot’s Watch ref. 5002 , the largest professional pilot’s watch made by IWC in 2002, represents a high point in traditional watchmaking: with a Pellaton winding mechanism and a seven-day automatic movement.

Everything about it is out of the ordinary: the mechanical automatic movement, the seven-day power reserve, the solid case, the dial and the hands, and even the crown. This also makes it one of the most unusual watches of our time. The Big Pilot’s Watch, with its imposing 46 mm case diameter, 15.8 mm height and a take-off weight of 150 grams – including a leather strap and folding clasp – embodied a new dimension of professionalism in the market for oversize watches intended for aviation. It was also the second largest wristwatch ever produced in the history of the factory.
Externally at least, it traces its roots back to a navigation watch with a modified pocket watch movement produced for military pilots in 1940, which today commands record prices as a collector’s item. The heart of the Big Pilot’s Watch is IWC factory calibre 5011, an exclusive watch drive mechanism in the superlative class, the likes of which will not be seen again. Not in aviation, and not in ground-based watchmaking.

Pawl Winding Mechanism
The principle of the pawl winding mechanism already developed by the horological genius Albert Pellaton in Schaffhausen at the end of the forties has been revived in the calibre 5000 and its descendants. This technical solution, in which reciprocating pawls act on a toothed wheel and the smallest movement of the arm is also utilized for winding the watch, had for decades assured the technological superiority of IWC automatic watches. For example, this system is not subject to the familiar wear in the rotor bearings and reduction gear of other designs. The rotor itself is even spring mounted. The Pellaton winding mechanism is thus regarded as being unmatched to this day thanks to its robustness, ease of servicing and efficiency.
That is not all, however: a new addition to the calibre 5000 family is the layout of the spring, the barrel and the entire design of the full seven-day power reserve. All the parts, on which such spring forces act, are dimensioned accordingly. A long self-contained power reserve of this kind necessarily includes a clear power reserve display on the dial. This incorporates a special IWC feature: an integrated differential drive mechanism with a mechanical stop device arrests the movement before the force of the spring runs down fully, more specifically after precisely 168 hours or seven days. The watch could, in fact, continue to run for more than one extra day with the remaining spring energy. But it will be stopped after a week, if no kinetic energy is supplied to it, to ensure that the accuracy remains stable from the first to the last minute. Behind this intricate design lies the horological consideration that the physically unavoidable and unfavourable end torque of the mainspring must not be permitted to make its effect felt in this way. The power of IWC can thus be translated as: 168 hours’ accuracy.

Additional details, such as the screw balance with its Breguet spring, adjustment cams on the balance limbs and 18 000 semi oscillations, also identify this advanced school of precision watchmaking. A particularly intricate means of precision adjustment was adopted from the old “Ingenieur” watch. Even the escapement of this horological oversize calibre originates from the Mark XI which, as an official pilot’s watch, had previously passed all the quality and accuracy tests of the Royal Air Force for a “Navigator Wrist Watch”. All of this together endows the Big Pilot’s Watch with effortless chronometer accuracy.Without a certificate.

The design of the movement of this pilot’s watch was extended to include a date display at “6 o’clock” with quick changing in a forward direction and the central seconds hand that is essential for aeronautical use, the drive for which does not lie directly in the power flux of the train. Consideration was also given to small and important details: on the seventh day of operation of the power reserve or, to put it another way, after 165 hours, the date changes three hours before the movement is stopped mechanically, so that the change sequence continues to take place with entire reliability.

Optimal protection against magnetic fields for the movement
Professionalism in the case of the Big Pilot’s Watch naturally also includes optimal protection against magnetic fields, which extends far beyond the standard of 4800 A/m for antimagnetic watches. The Big Pilot’s Watch has been tested up to 32 000 A/m – while still retaining full efficiency. In order to achieve these fantastic values, use is made of a soft iron inner case of the kind already utilized by IWC in pilot’s watches in 1940, in the first “big” pilot’s watch, which provides all-round screening for the movement.This naturally also had its effect on the case dimensions. The dial, movement ring and a double back are all made from this ferromagnetic material, which absorbs all magnetic fields which may influence the watch and in so doing keeps them from the actual movement mechanism. The small date window is the only remaining minimal point of entry for magnetic forces. IWC had also attempted, in its early Ingenieur models, to close this opening with date display rings made of soft iron. However, the resulting new problems (weight) encountered when changing the date were not in an acceptable proportion to the additional protection afforded.

The soft iron cage and the associated extreme protection against magnetic fields is no “ideological” whim of the IWC engineers, but has since become a quality feature of all particularly durable watch production. This was an absolute must in the confined surroundings of the cockpits of older aircraft in particular with their numerous electrical devices. In our everyday lives, in which we are surrounded by more or less strong magnetic fields from countless electrical devices, such screening of the watch movements is an important condition for accurate running.

All technical features of this watch thus adhere uncompromisingly to a single requirement: airworthiness. And this means robustness, reliability and full functionality, including under the most unfavourable conditions. The dial and indices are coated with Superluminova. The sapphire glass is specially protected against a sudden drop in air pressure and is anti-reflecting, in order to ensure legibility of the watch under all conditions. In a modern interpretation of the specification, a top-class pilot’s watch includes the aforementioned date display with quick setting, large seconds hand, screw-in back, screw-in crown and tested water-resistance to 60 metres.
Historical references

The Big Pilot’s Watch from IWC has a similarly named predecessor with a wartime past. It is a legend among connoisseurs, because between 1940 and 1945 there were only a few hundred of these watches in their grey stainless steel case with the modified, gold-plated precision calibre 52 S.C. (for Centre Seconde) pocket watch movement. This “oversize device” produced for the German Air Force according to the criteria for military observation watches (B watches) was, with a case diameter of 55 mm, a height of 16.5 mm and a weight of 183 grams, the largest “wristwatch” ever produced by IWC. Its long leather strap allowed it to be worn by the pilot in an easily readable position on top of his flying suit. And the above-mentioned principle of a movement completely encapsulated in soft iron was used here for the first time in a wristwatch. Yet it was neither water resistant nor shock-proof.

The Big Pilot’s Watch adheres to the tradition of the navigation watches and observation watches in pocket watch format for navigational purposes (calibre 52, calibre 67, and calibre 71) that were already being produced by IWC for the German and British Admiralties at the start of the twentieth century.

Its characteristic protection against magnetic fields also has its roots in early railway watches and, in particular, a pocket watch with a soft iron inner case first produced for the Berlin tramways between ca. 1920 and1930. As a pilot’s watch with particular specifications it can be traced back to the first pilot’s watch, the Mark IX from1930, and naturally to the first “big” pilot’s watch, several hundred examples of which were supplied to the German Air Force from 1940 onwards.

Of the 1200 calibre 52 S.C. (for Centre Seconde) movements produced, a proportion was fitted in an additional oversize observation watch and a smaller number in pocket watches for military use. This “navigation watch” (observation watch, Class I) produced by IWC in line with military criteria, each of which was subjected to individual testing at the German Marine Observatory, was the first IWC wristwatch to incorporate a ferromagnetic inner case as protection against magnetic fields. The case dimensions (diameter 55 mm, height16.5 mm) conformed to the requirements of the military procurement office. Apart from IWC, only A. Lange & Söhne, LACO, STOWA and Wempe manufactured this particularly demanding type of pilot’s watch.

A movement component with a critical role in the escapement of the 2002 the Big Pilot’s Watch was also adopted by the next generation of post-war pilot’s watches (Mark XI): this was the screw balance with adjusting cams and Breguet balance spring beating at18 000 semi oscillations. The Mark XI (1948-1984) has passed all the “navigator’s wrist watch” tests with flying colours.

Significant references to the past are combined in the Big Pilot’s Watch and are associated in particular with the development of a distinctive automatic movement at the end of the forties by the Technical Director of IWC at the time, Albert Pellaton. His patented design for a winding mechanism operating via a cam disc, ruby ferrules and click springs established the 85 family of calibres, which continued to be improved and developed until the mid seventies culminating in the legendary calibre 8541. This watch drive mechanism helped the Ingenieur range in particular, but also the Yacht Club and other models, to achieve considerable success. The revival of this patented and proven mechanism, exclusively identifiable with IWC, was an important objective of the new family of calibres developed by IWC.

Produced in a stainless steel and a limited series of a 500 pieces in platinum.

Technical details
Specification
professional pilot’s watchwith automatic movement, patented Pellaton winding mechanism, barrel drum for a theoretical 8.5 day power reserve after being fully wound, with power reserve display, date, hour, minute and large seconds hands, mechanical stopping of the movement after 168 hours, or 7 days, to prevent variations in the escapement caused by the effect of the end torque of the spring. Reference: 5002, The Big Pilot’s Watch of IWC

Movement
IWC calibre 5011, year of manufacture 2001
Movement dimensions: 38.2 mm x 7.44 mm at the centre
Number of parts: 334 component parts in 53 sub-assemblies
Number of functional jewels: 44 functional synthetic rubies, including35 different jewel bearings.
Train: 57 interconnections, special feature. Seconds wheel situated beneath the escape wheel, and the train with one additional wheel (eight-day wheel) compared with a conventional train; indirect large seconds and indirect minute, i.e. the drive for both pinions does not take place in the direct power flux of the train.

Spring barrel: barrel made of Aluminium S-Korofestal (AIMgSi1), artificially aged, anodized, teeth screwed on separately, mainspring with bridle made of Nivaflex1, spring barrel – minute wheel multiplication 1:15, spring barrel ca. 13.6 revolutions when fully wound. One revolution of the spring barrel = 15 hours power reserve. Theoretical power reserve: 13.6 x15 hours = 204 hours (8.5 days). Ca. 12rotor revolutions = 1 hour power reserve.

Power reserve display: differential gears with inputs for winding up and running down and output for power reserve display. Mechanical stopping of the movement after 168 hours (7 days).

Winding mechanism: Pellaton pawl winding system, identical with the winding mechanism used in IWC calibre8541, via a spring-mounted rotor, cam disc, ruby ferrules and 2 pawls on a pawl wheel; reduction: 175:1.

Escapement: two-armed screw balance with 16 adjusting screws and 2 adjusting cams on the balance arms (IWC special feature), in the form of a “sage leaf” (or bird’s tongue) arm. Balance wheel, pallet fork and escape wheel identical with IWC 89 calibre. Nivarox 1 balance spring with Breguet curve, “chronometer” quality,18 000 semi oscillations: per hour 18 000 A/h= 2.5 Hertz (Hz).

Shock-absorber: Incabloc system
IWC precision adjustment: stud carrierand regulator stem are adjusted  with cams, identically with IWC calibre 8541.

Date: conventional jump-type date change(ca. 1 hour), quick change forwards via crown, last date change is possible until in conjunction with the movement running down after 165 hours.

Movement decoration: bridges and bottom plate nickel-plated, engraving gold plated, decoration of the “circular rib” type, bridge edges diamond-cut, typical IWC rotor (without gold medallion) with gold-plated “Probus Scafusia” engraving, main plain edges, crown wheels, ratchet wheel, spring barrel cover and differential wheel with sun pattern finish.

Case
Special steel with screw-in back, anti-reflecting sapphire glass
Case variant: Platinum with screw-in back and anti-reflecting sapphire glass
Protection against magnetic fields: soft iron inner case (dial, movement ring and inner back), effectiveness up to 32 000 A/m without loss of function tested by the Straumann Institute (standard value for antimagnetic watches: 4800 A/m).
Crown: screw-in, especially user-friendly crown for winding the movement (after stopping), date change forwards and hand setting with seconds stop function.
Security: minimum water-resistance up to 6 bar = 60 metres, shock resistance to NIHS standard.

Dial
matt black, Arabic numerals, white indices, luminous, executed in Superluminova C1 (dark blue dial for the platinum variant).
Hands: original arrow shape of the first“big” pilot’s watch from 1940, skeletonized, inlaid with Superluminova C1.

Straps
Buffalo, dark brown, with rivets as in the first “big” pilot’s watch strap from 1940, (Platinum: buffalo, dark blue, without rivets), in each case with secure button closure.

Weight
Total weight of the watch with strap and button closure
- Stainless steel model: ca. 150 grams
- Platinum model: ca. 220 grams.

Production limits

Stainless steel version: unlimited
Platinum variant: 500 pieces.

Recommended service interval
5 years

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