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The new testing ground for mechanical watch movements

The new testing ground for mechanical watch movements
Two watch manufacturers from opposite ends of the price spectrum, each with a sister company that makes balance springs and escapements, are taking to the skies to test their movements on so-called parabolic flights that create short periods of zero gravity.

On Tuesday 22 September a handful of lucky individuals had the chance to experience brief moments of weightlessness on the first parabolic flight to take off from Switzerland. Those on board the specially fitted-out Airbus A310 of French company Novespace enjoyed repeated climbs at a pitch angle of 50 degrees – much, much steeper than the take-off angles that the frequent traveller is accustomed to – followed by high-speed descents at an angle of 30 degrees, which is again far steeper than normal. The initial acceleration creates twice the force of gravity, but just before the aeroplane reaches the apex of this rollercoaster ride there is a period of around 20 seconds of micro-gravity (0.01g), which is close enough to a zero-gravity environment to allow the scientists on board to frantically rush to carry out their experiments and for some of the lucky passengers to experience momentary weightlessness.

What is interesting is that two watch brands, each of which is associated with a sister company that produces balance springs and escapements, have decided to use the flights to pioneer a new type of test on watch movements. H. Moser & Cie. and its sister company Precision Engineering were first off the mark with the first parabolic flight ever to take off from Switzerland on 22nd September, while Hamilton and ETA are close behind, scheduled to take off from Merignac, France on 5th October.

Checking theory against practice
As much as images of CEOs and watch movements floating around an aeroplane cabin make for great publicity, there is also a genuine research side to these tests. At the heart of both test programmes are two industry-standard Witschi M10 testing machines, each of which can monitor 10 watches simultaneously. The identical choice and configuration is interesting, since Witschi worked closely with H. Moser & Cie. on their tests, while Hamilton and ETA organised their tests independently. As Martin Schürch, Chief Marketing Officer at Witschi Electronic AG, explained to WorldTempus, the big challenge was securing the test equipment in the plane, “everything has to be fastened down securely and protected with rubber foam to meet the security guidelines. Furthermore, the movements are sealed inside an insulated box to shield them from the aircraft noise.”

There are some subtle differences between the two tests and their objectives. For H. Moser & Cie. and Precision Engineering, the aim was to test an entire range of hairsprings and escapement materials, including a new prototype paramagnetic hairspring, as well as a series of entirely new movements that will equip a forthcoming new product line. The objective was to observe changes between the zero gravity environment and normal gravitational forces by measuring amplitude and optical observation using a camera. As Dominique Lauper of Precision Engineering explains, “it is difficult to learn things if you are using the same testing protocols as everyone else.” As a safeguard, the Precision Engineering tests organised with Witschi incorporated an extra recording channel on each machine to record sound alone, in case of any problems with their testing equipment, which relies on audio measurements taken from the watches by high-precision microphones.

Hamilton and ETA will be testing the H-10, H-21 and H-20-S movements, as well as the ETA 2671, which is one of the few self-winding mechanical movements on the market that is small enough for ladies’ watches. The objective of these tests will be to test the movements in the zero-gravity environment but also during the acceleration and deceleration phases as part of a broader commitment to testing its watches in the range of 0g to 10g. “The parabolic flight, which covers the range of 0g to 2g, is the first stage of these tests,” says Hamilton CEO Sylvain Dolla, “and will be followed by tests in a centrifuge from 2g to 10g.” Hamilton’s tests in the Zero-G A310 will also incorporate accelerometers to measure changes in g-force during the flight.

For the Swatch Group’s ETA division as one of the world’s biggest movement producers, the tests will also be a chance to test their in-house theoretical models in a real-world simulation. As Hamilton CEO Sylvain Dolla explained to WorldTempus, “when the watch is in a vertical position, the effects of gravity on the balance spring are well known because of the imbalance of the balance wheel or spring. When the watch is in a horizontal position, however, the effects of gravity are much less clear. As far as we know, there is no theoretical model that describes the effects of gravity in a horizontal position. ETA has developed a model describing these effects and is using various methods to corroborate it. The parabolic flights are one of the ways of checking the theory against practice.”

The “seventh position”
Mechanical watches are usually tested in six positions (crown right, crown left, crown up, crown down, dial up, dial down). Each of these positions, even the two horizontal ones, is subject to the effects of gravity. The zero gravity flights effectively introduce a “seventh position” in which gravity is absent and the movement’s going rate can be measured independently of its effects.

With each period of micro-gravity lasting just 22 seconds, however, for a total of just several minutes of micro-gravity per flight, is this enough to establish a reliable measure? Sylvain Dolla thinks so: “This is sufficient to have a reliable measurement of the going rate. The only risk is that the amplitude may not stabilise completely, but the rate and amplitude are measured every two seconds, there will be enough data to allow for this.”

The conclusions from the Hamilton/ETA tests will be applied to the development and optimisation of performance of mechanical watches for two different user categories: users on the ground with weak gravitational variations and thrill-seeking extreme sportsmen and sportswomen. Precision Engineering, on the other hand, will be using the findings to improve those crucial components that are the very heart of every mechanical watch: the balance spring and escapement.

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