219's in-depth review of the Richard Mille RM038 offers a fascinating look into the engineering challenges of creating a tourbillon watch for professional golfers. This article highlights the extreme forces a watch endures during a golf swing and Richard Mille's innovative approach to shock resistance and material science. It provides valuable context for understanding the RM038's design philosophy and its connection to ambassador Bubba Watson.
[Bubba Watson at the French Open this year wearing the RM038 prototype on one of its first outings.]
About a year ago, I learned that Richard was about to enter the world of golf. It seemed a strange departure after Formula 1 and tennis, but as with all of Richard's ventures into sponsoring a sport ambassador, the proof was going to be in the watch and who was wearing it. And while part of the thought was: another sports watch: so what? There is also the fact that this is the first watch specifically designed for a golfer to wear in play. Being a Richard Mille tourbillon I knew that there would be more to the watch than meets the eye.
While some of the forces acting on a watch as part of being worn by a tennis player are also there for the golfer, there is a difference in the impact force for the watch as part of the wrist. A tennis racquet connects with a ball that is essentially soft, with netting that also has an ability to ‘give’ at the point of impact. This still does not negate the fact that about 400G’s are impacted on the watch mechanism each time a backhand is played on the wrist of Rafael Nadal.
For golf, the forces are less frequent, but arguably more severe. In a drive, a golf club plus the wrists holding it accelerate to when the club head connects with a solid(ish) ball the impact force on the club is transmitted through the club and hands to the wrist and watch. Once the ball is hit, there is the de-acceleration of the club to the top of the swing. The watch had to be comfortable on the wrist, lightness, and with extreme shock resistance. If ever there was a need for an impact resistant escapement that could also cope with the changes in forces, then who better to design that than Richard.
[The titanium back plate of the RM038 mechanism with winding gear in place.]
The mass of a golf ball is just less than 46 grams and the standard acceleration of a golf club by a professional player is about 100 mph or 44.73 m/s. This speed of the club, when it connects with the ball, produces a speed for the golf ball which on average is about 170 mph or 76.08 m/s. The moment of impact lasts for 5 milliseconds, or about 0.005 seconds. With me so far!? One way to measure the force of the impact is to express it as a Newton. A Newton is equal to the amount of net force required to accelerate a mass of one kilogram at a rate of one meter per second squared; or to put it another way 1 N is the force of Earth's gravity on a mass of about 100G. Running through the calculations, the force applied to the ball (through the driver) is around 695 Newtons; or the equivalence of approximately 1400 earth’s gravities. Although that is not the entire force of the club on the watch, the watch would feel part of the impact through the golf club and wrist. It would represent a significant 'jolt' to the mechanism. That is probably more than the original design of a mechanical watch mechanism was designed to withstand; with or without a tourbillon escapement!
For that reason, Richard set out to design a watch that could cope with such forces. For the watch case, Richard returned to what he had learned developing the RM009 and RM027. The cases for the latter two watches were built for different purposes. For the RM009, the objective was a light metal capable of withstanding direct impact if necessary (although hopefully not!). For the RM027, the casing had to be even lighter, although the impact properties were not as severe as the ones required for the RM009.
For the RM038, Richard employed another esoteric metal alloy that allowed other properties of case manufacture to be explored. Magnesium lithium alloy is a cast alloy and this made it easier to deal with as the basic tonneau shaped parts could be cast and then machined into the iconic Richard Mille case shape. Magnesium is the lightest structural metal and magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Cast magnesium alloys are used for many components of modern cars, and magnesium block engines have been used in some high-performance vehicles. The designation AZ91 means that it is a magnesium alloy where roughly 9 percent of the magnesium alloy is aluminium and 1 weight percent is composed of zinc.
The coating given to the watch casing was electro-plasma oxidation treatment named Titalyt II (R); the white colouring was from the cristalline oxide ceramic with a high ratio of high resistant composites such as MgAl2O4 spinels. It all sounds very technical and cutting edge, but the practical applications of this process are that it improves both the hardness and scratch resistance of this alloy: its wear resistance and corrosion resistance. The MgAl2O4 spinel is a more technical way of saying that the atomic structure of the coating is a very regular hexagonal pattern. Material bonding that has such a regular hexagonal shape is very tough as the bonds between atoms are very strong in such a lattice structure. What appears hyperbol and marketing speak actually has a very real application: a very tough and durable coating to the metal that becomes part of the metal itself.
For the RM038, the purpose of the coating was two-fold. First, the coating gave the watch a distinctive look. Usually, the cases for Richard Mille watches, the case had been a finished precious metal, titanium, or some form of alloy or composite that was dark (read black or grey) in colouring. For golf, a decision was taken to produce a sports watch that was different; something that would be distinctive and match the more colourful attire favoured by golfers. Second, the coating was highly scratch resistant and bio-compatible: this would make it hypo-allegenic and not feel metallic against the skin. The material eschews moisture making it comfortable on the wrist. It was the ideal coating for a sports watch.
As with most of Richard’s innovations, the original inspiration came from auto engineering at the front end of the science. Usually such finishing (Titalyt) is found on the outside of pistons (the coating is almost self lubricating) to reduce friction. However, we also use such coatings on more mundane everyday household good as irons (the underside of the iron that is in contact with your clothing) or the coating of outer shells on mobile phones.
For the baseplate and bridges Richard returned to using titanium. Titanium was chosen over the other esoteric metals Richard had used in the past as the bridges in particular had to be rigid and strong enough given the sudden pressures that would be applied to the mechanism. In particular, a special lattice bridge was designed and manufactured to not only hold the mechanism in place but to also hold the pin for the hour and minute hands.
Basically, the design of the lattice bridges at the front of the mechanism is a '3-bridges' design. There is the top bridge to hold the winding barrel, the bottom bridge to hold the tourbillon escapement, and the middle bridge holds the hours and minute hand pin in place. But it is the design of the bridges to allay the forces acting on the watch mechanism that makes the RM038 different. On the left hand wrist of the right-handed golfer the dynamics of the bridges form a ‘wedge’ against the forward motion and impact of the golf club. The middle bridge holds the hours and minute hand pin in place (against the forward motion); the top and bottom bridges form the same pattern. All are anchored against the ‘back wall’ of the case.
Never one to shrink from the challenge, the RM038 was Richard’s answer to the problem of employing a watch on the wrist of the player with the hardest hitting swing in the game of golf in on the professional circuit today. Bubba Watson has distinguished himself on the professional golf circuit, with victories in a number of tournaments, but one of his claims to fame is that he has the longest hitting drives. Self taught, and with something of a 'healthy' attitude towards accepted paradigms, he is one of the few golfers not to mind a watch being worn during play. Admitting that the closest he had been to a watch in the past was only ones with a battery in it. Bubba has since become something of a Richard Mille watch enthusiast buying other Richard Mille watches by choice.
Over the past 6 months the RM038 has been worn continuously by Bubba in practice and match play conditions and the watch has been ‘tweaked’ by the watchmakers to understand how the pressures on the watch have affected the mechanism. There have been no problems and recently, when at Richard Mille in Les Breuleux, the RM038 watches were being made. The movements are just about finished; each one undergoing timing tests. Once cased, the watches will undergo further testing for shock resistance, after which some lucky Richard Mille collectors will have the chance to enjoy a ‘white’ RM038 Christmas!
[The RM038 movements being made and tested]
Andrew H
This message has been edited by AnthonyTsai on 2011-11-29 13:55:04 This message has been edited by AnthonyTsai on 2011-12-20 12:36:39 
