παμε στα ωραια :mrgreen:
Gyrotourbillon-I, The Superlative watch!
The preliminary idea of Gyrotourbillon was first discussed in October 2001 by Stephane Belmont of Product Development and Eric Coudray. The weather had just turned chilly, and both of them thought a super-complicated Spherical Tourbilon would be a challenge worth tackling.
If the unkempt Eric Couday in shorts and loose T-shirt doesn’t impress you, let me just say that this is the genius, who produced the new minute Minute Repeater mechanism in calibre 943 (1994) and the amazing Constant Force Atmos Mysterius last year. He is the best kept secret of Manufacture Jaeger-LeCoultre.
Before the cynics start to scream "Not another Tourbillon!" and "Thomas Prescher & Franck Muller copy-cats!", I do hope fellow members will be patient enough to hear me out.
The company founded by Antoine LeCoultre, is no stranger to making complicated watches. Since 1870, JLC has been making (or supplying the movements of) Minute Repeater, Chronograph, Grande Complication, Perpetual Calendar etc.
In 1938, the presentation of the retrograde calendar was a genuinely avant-garde event. The calibre 11U had a perpetual calendar complete with a retrograde date hand. Simple complications like alarm, GMT and worldtimer in watches were also not new to the factory in Le Sentier.
In modern times (since 1940), Jaeger-LeCoultre was probably the first to bring back tourbillon to the world in such quantity - 27 pieces of the legendary Calibre 170 three-armed tourbillon movement. This was considered an amazingly HUGE number of tourbillons at the time.
(MJLC Cal. 170 Tourbillon movement, winner of 1941 Neuchatel Observatory in 1941)
Jacques-David LeCoultre decided to throw the spotlight on the technical mastery of the manufacture by submitting the Cal. 170 for observatory competitions. Jaeger-LeCoultre immediately earned the highest distinctions, particularly from the Neuchatel Observatory in 1941.
(Many changes in the 2-1/2 years process)
This story is not new to MJLC, but there probably wasn’t a single Jaeger-LeCoultre Tourbillon in the 1940’s. Most of the JLC- made calibre 170 movements carried the engravings of famous top watch brands that come with non-JLC dials. The identity of the real manufacturer remains a shadowy secret to most consumers of "TOP" brands to this day.
Two years after the famous come-back piece that was 60eme in 1991, the legendary Gunter Blumlein decided to strategically introduce (probably) the smallest (volume) tourbillon movement in calibre 828 to maintain the momentum of success and to convert even the most stubborn JLC skeptics.
(The Calibre 828, used in the 1993 limited Pink Gold Reverso Tourbillon)
By the time the Platinum 2 Tourbillon was introduced last year, despite the platinum case, 18K solid grey gold movement and fine decorations, for JLC, it was probably a lot less of a challenge.
(The 2003 Platinum-2 Tourbillon, Grey 18K solid gold movement, Platinum case)
While I need not explain to fellow PuristS why the traditional tourbillon doesn’t correct horizontal positions (when watch is faced up or down), Eric Coudray (technical) and Magali Metrailler (aesthetic) knew this project was going to be a big challenge for them, and they quickly put their minds to work.
By January 2002, the first drawing of the face of this exceptional timepiece was out. After many months of intense work, Eric had the mechanisms all figured out.
(One of the Gyrotourbillon-I movement being assembled, the Spherical tourbillon cage is already fully functional in this particular piece)
As in the conservative tradition of Jaeger-LeCoultre, the manufacturer probably made the mistake of not quickly launching the Spherical tourbillon watch. Instead they choose to file for new patents to protect this technology. The 3 separate patents were granted by end 2002.
The 3 patents granted are for these breakthrough mechanisms:
(1) Spherical tourbillon
(2) A new Double Retrograde Date
(3) An entirely new Perpetual Calendar Mechanism
Spherical Tourbillon:
Based on my visual inspection, the new spherical Tourbillon Calibre 177 is the most graceful implementation of the Dual-axis tourbillons so far. The three dimensional rotation of the balance-wheel are at the very heart of an extraordinary horological invention. The ultra-light external cage makes a complete turn about its axis every minute. The internal cage which supports the balance wheel, spiral and escapement, rotates far more rapidly – every 24 seconds to be exact, hence completing 2.5 turns per minute. As a matter of fact, the speed of 20 seconds per rotation was tested in an early prototype for a considerable period, but for most of the time, the balance-wheel was not as visible as desired. Hence it was deemed not attractive enough.
(Exciting Gyrotourbillon-I prototype on Magali’s table, so close, and yet so far!)
To be clear, Jaeger-LeCoultre’s master-watchmakers did not settle on this unusual rotation speed by mere chance. In fact, this means that the solid gold balance wheel will appear once every minute in all its glory before the eyes of the observer, before continuing its tottering progress, as though weightless, but following a carefully pre-planned course through the microcosm of the spherical tourbillon. The total weight of the 90 part rotating body is only 0.035grams.
To achieve this weight, the aluminium ball-shaped external body is supported by titanium parts. If steel were to be used, this same element would weigh around 0.11grams. Aluminium, used in aeronautics and high performance engines due to its exceptionally low density, high resistance to corrosion and ability to be mirror polished, is perfectly suitable for this tourbillon.
In any case, this is not the first time JLC has used this metal. In their ongoing pursuit for innovation, they had successfully experimented with prototypes made entirely of aluminum in the 1940s.
(The amazing complete gyrotourbillon-I escapement)
Because a high moment of inertia is required for the oscillation mechanism, the balance-wheel and the setting screw is made entirely of 14K solid gold.
The calibre 177 is also equipped with two barrels mounted in series. In order to limit the effects of friction, for the first time ever, the lid and base of the spring barrels are made of sapphire crystal, making it also possible for the observer to gaze on the springs that guarantee a power reserve of 150 hours.
(Testing the Sapphire crystal main spring barrel, a first in the industry)
A steel gearwheel attached to the tourbillon’s external body locks into the slant-toothed “roué de moyenne”, catching up all the different areas of activity into a single circular clockwise motion.
In order to reduce the height of the movement, JLC decided to have the tourbillon cage angled downwards by about 37 degrees. In my opinion, this subtle slant further improves the visibility of the mechanism and makes this the most graceful 3 dimensional tourbillon ever. Another wheel, placed at the same angle and with similarly slanted teeth, rotates the internal cage through 360 degrees.
The indispensable link between the oscillation and escapement system, is provided by a second wheel situated within the aluminium ball and the gearwheel of the anchor wheel.
(For journalists who were invited to Le Sentier on February and March this year, an autographed copy of Magali's initial Gyrotourbillon-I drawing was given – spot the difference)
The circular motion of the internal cage automatically transmits a similar motion to the anchor wheel. The anchor then passes this energy on to the balance-wheel and its Breguet spiral in order to maintain the rate of vibration at 21,600 oscillations an hour. Going in the opposite direction, the escapement ensures that the wheel mechanism only advances in small, finely calibrated steps that can be represented by the second and minute hands. Yes, despite considerable difficulties with a three dimensional sphere, the watch still has a very attractive second hand, in the form of a small pointer designed for that very purpose, positioned on the external part of the aluminium cage.
The regulation of the oscillation system can be carried out once the mechanism has been put together. In order to do this, Jaeger-LeCoultre’s master-watchmakers alter the balance-wheel’s inertia by means of the outlying screws under the serge. Of course, the factory and major service centres will have the custom design tools to help regulate the watch quickly and easily.
Most of us think of a tourbillon as a delicate object that needs to be stored carefully; a mechanical marvel that was only to be brought outdoors with utmost care. While we hobbyists should still treat mechanical watches with respect, perhaps it is time a tourbillon need not be deemed excessively delicate and fragile. To withstand normal shock, JLC has equipped the watch with six anti-shock devices: two in the aluminium cage, two in the internal revolving titanium and aluminium cage and two in the balance-wheel.
(Many versions of Gyrotourbillon drawings on Magali’s table)
As this great autonomy of self- function can make one forget to rewind the movement, on the side of the dial there’s a power-reserve indicator which is quite simply impossible to ignore. But this is by no means the watchmakers’ final word where indications are concerned. The new movement has further surprises up its sleeve.
Patented Double Retrograde and Double Retrograde mechanism:
If one finds most complicated wristwatch dials too busy and illegible, both Eric Coudray and designer Magali Metrailler want this super complication to be simple, legible and yet able to indicate all functions clearly. One of the difficulties for Magali is that she also wanted to be faithful to the classic system of analogue display of the hour and minutes.
Thinking a traditional Date and Month indicator may be too busy, the product development team decided to stretch the date scale from left to right in a splendidly smiling arc, across the whole dial. But to make this work, the traditional date change disc mechanism has to be abandoned.
(The lovely Magali, designer of the exceptional looking Gyrotourbillon-I!)
The patented Double retrograde mechanism works in a most exciting manner. One small triangle hand is responsible for the first half of the month and another hand for the second half. While the hand on the left attends to its business, the tip of that on the right remains in its waiting position. The changeover takes place on the 16th of each month, when the two hands are briefly united. Then the pointer on the left takes up its waiting position while that on the right advances by one position on the stroke of midnight each day. As large and small jumps alike require a great deal of energy, throughout the day, the mechanism accumulating small amounts from the movement, storing it in the springs and liberating it in a concentrated force at 00:00 hrs. This makes it an instantaneous date change or what is commonly called “The Whip”. Such ingenuity ensures that the calendar functions fluently without affecting the oscillations of the balance-wheel or the dynamic movements of the tourbillon.
(Experimenting with different dials and see how they look)
If this is not interesting enough on paper, watching the followings date changes should be visually exciting:
(1) On the midnight date change from 15th to 16th, you will see the left indicator jump from “15” to “16”, while the right indicator jumps simultaneously from the empty space right of “31” to “16”.
(2) On the midnight date change from 16th to 17th, you will see the left indicator jump from “16” to the empty space before “1” and at the exact same moment the right indicator jumps from “16” to 17”
(3) At the turn of the month, the left indicator jumps from the empty space before “1” to “1” while the right indicator will at the exact same moment jump from either “28”, “29”, “30” or “31” to the empty space right of “31”
Such sights are guaranteed to make all PuristS skip a heart beat, certainly a moment to be treasured.
(The Date Change mechanism diagram)
And because Eric Coudray refused to add on just a perpetual calendar module to the calibre, he designed an entirely new patented mechanism where the calculations are based on 572?? days per year and will be complemented by the necessary correction to the right day, date and month in every day of the year, in a four year cycle.
(Eric Coudray, aka Peter Jackson of JLC, an unassuming genious)
EQUATION OF TIME:
“What time is it?” To this seemingly simple question, one should made a no less simple an answer. Since time is relative rather than absolute, it can only be what it says on the face of a watch. With this bold affirmation, Albert Einstein, one of the greatest mind acrobats of all time, initiated a whole series of experiments and studies which hardly made an impression on the ordinary person’s perception of time.
Everyone knows that our system for measuring time is based on the earth rotating around the sun. One complete turn is therefore logically called a solar day, which humans have divided into hours, minutes and seconds. Up to this point, everything seems clear. But there is a problem: The earth follows an elliptical course around the sun. Moreover, the earth’s axis is at an angle. As a result, the length of each day is always changing, in a slight but nonetheless measurable degree. The temporal difference between the shortest and the longest solar day is exactly 30 minutes and 45 seconds in a year – far too great a span to not have an impact on our daily activities. So, as a way out of this impasse, humankind calculated an average solar time, defining the length of a day as 86,400 seconds, 1,440 minutes or 24 hours. It’s this notion of time that the hands of 99.9% of watches indicate.
The actual but largely ignored difference between the mean time we commonly assume to be correct and true solar time, is represented by the time equation. The annual cycle can be shown in mathematical form, reaching its maximum points of differences on 10 and 11 February (+14 minutes and 24 seconds) and 3 November (-16 minutes and 21 seconds).
Four times a year (15 April, 13 June, 1 September and 25 December) true solar time is identical to mean time. Though it plays virtually no part in most people’s daily lives, astronomers are strongly dependent on true solar time in order to observe cosmic events.
(Translation, 2nd. Cage wheel / anchor bridge / seconds index / stud holder / balance wheel in gold / screws / fixed wheel for 1st. cage / antishocks / escapement bridge etc...).
Since the end of the seventeenth century, there were complicated clocks that displayed true solar time as well as mean time.
In this unusual complication, there are basically two different accepted systems of solar time indication. The first illustrates the value of the time equation at a given time on a scale ranging from –17 to +15 minutes. A good deal of cerebral gymnastics is thus required to determine the true time. Jaeger-LeCoultre has refrained from imposing such a brain-teasing puzzle on the owner of its Gyrotourbillon I. Instead, an equation hand, or what I would like to term as the solar minute hand, which has a tip adorned with a small sun, alongside the watch’s mean (normal) minute hand.
The solar minute hand will sometimes overtake it, or lag behind the mean minute hand. And for four times a year, they will synchronise almost perfectly.
Tied to the perpetual calendar, the solar minute hand will indicate astronomical data exactly. A simple glance is thus enough to see, for example, that it is 10:10 according to mean solar time, but 10:20 in true solar time without the need to take out a calculator necessary for other Equation of Time wristwatches. Impressive!
Another exciting change is that I feel this manufacture has now posted her first notice for what I think is a long overdue change in design aesthetic. When “grumpy old men” complained that the Compressor range is too un-JLC, my only complain on this great new range is that the Compressor is still “too JLC”.
Although Magali is relatively young for a watch designer, the new compressor range she designed has been commercially accepted. Despite hoping for more radical changes, I did like the product and noticed a glimpse of her vast potential.
It is obvious to me that Jaeger-LeCoultre has always possessed the technical prowess and the ability not just to launch technically superior prototypes, but actually construct the production-piece (as opposed to the prototype) for actual delivery to the end user.
No doubt each Gyrotourbillon-I will be assembled by a single watchmaker, atelier style, but Jaeger-LeCoultre is confident to actually produce around 15 pieces of production models a year.
Despite a launch which comes one year later than both Thomas Prescher and Franck Muller, I dare say that Jaeger-LeCoultre will be the first to actually deliver a real production piece (not just a prototype) to a retailer.
Certainly, due to the total limited production of 75 pieces in 5 years, Jaeger-LeCoultre will not distribute this product through every authorised JLC retailer. The watch will only be retailed at selected exclusive retailers who have proven their ability to serve haute horlogerie technical collectors.
Cynics may still claim they don’t want another tourbillon, but I am pretty certain this Spherical tourbillon, Perpetual Calendar, equation of time, double retrograde date, retrograde month and retrograde power reserve should be the piece de resistance of SIHH 2004.
πηγη thepuristpro