Independents

219
3826

• Show profile
• Show other posts

A race strategy.

Greubel Forsey were putting their watches where their claims were! That they could show that the Double Tourbillon 30 degree (as described: one cage rotating at a four minute cycle; one cage rotating at a one-minute cycle; and the escapement inclined at 30 degrees to the vertical) improved the chronometric performance of the watch throughout the five measuring positions. Added into the mix would be the anti-magnetic and shock tests that previously had not been part of the Observatory tests, but now had to be accommodated in regulating a watch for the MIH Chronometry Competition.


[The winning team: left: Olivier Steiner – Project manager and Head of the ‘Labo’ (Laboratory); middle: Stephen Forsey (Robert Greubel and Emmanuel Vuille are missing); right: Frédéric Rüfenacht - Precision timing specialist].

The degree of difficulty in the tests gives weight to different aspects of watches performance under different conditions. First, there is the variation in location. The first test is held at Besancon, the second at Bienne (COSC), the watches are then delivered to an engineering school for the shock and magnetism tests, and given they are still running, they are delivered back to Bienne (COSC) for a final third set of (15 day) timing tests. The complete set of timing tests are in the five positions for the watch on the wrist over a total of 45 days.


[The ‘Labo’ room at Greubel Forsey]

The nature of the tests are such that a variation of +/- 2 seconds a day would be sufficient to see the watch finish so far down the list that it would never win. Alternatively, another way of gauging just how accurate the watches need to be, a single variation of 5 seconds a day (at any point over the course of the tests) would be sufficient to knock the score down to an unrecoverable position. Out of 1000 points that you start with, it is the watch that loses the least points, that is the winner. The time variation of +/- 2 seconds a day (throughout the course of the tests) would be sufficient to see the watch lose approximately 700 points and be placed far down the list. The winning score for the Greubel Forsey Double Tourbillon Technique in 2011 was 915. What does that translate into the variation in seconds (on average) across the 45 days of the testing? It translates into a variation of +/- 0.3 to +/– 0.8 seconds a day. To put that number in perspective, it is the kind of variation quoted in the more accurate of the quartz chronometers when worn normally on the wrist (with no abnormal or adverse shocks or other treatments). An astounding degree of accuracy!

This message has been edited by 219 on 2013-03-28 14:32:29