Limited edition of 75 pieces made from Graph TPT™.RM50-03 Calibre:
manual winding tourbillon movement with hours, minutes, split-seconds chronograph, 30-minute totaliser, and power-reserve, torque and function indicators.Dimensions:
44.50 mm x 49.65 mm x 16.10 mm.Power reserve:
Around 70 hours (±10%), displayed on a numeric scale at 11 o’clock.Ultralight tourbillon calibre in titanium and carbon TPT™
The RM50-03 calibre weighs just 7 grams. This record-breaking weight was obtained by using high-tech materials and by skeletonising its components as far as possible.
The baseplate and bridges in grade 5 titanium are highly resistant to corrosion and remarkably rigid, enabling the gear train to function effortlessly. This alloy (90% titanium, 6% aluminium and 4% vanadium) enhances the mechanical properties of the latter.
Some of the bridges of the split-seconds chronograph are made from Carbon TPT™, as is the transverse carriage that supports the entire calibre together with the barrel and tourbillon bridges. Attached to the caseband, this carriage circumvents the need for a casing ring, allowing the movement to be ideally integrated into the case.
All of these technical solutions give this complex calibre, with its extreme weight to resistance ratio, an impressive resistance capacity, tested in our workshops to shocks of 5,000 g.New Split-Seconds System
The RM50-03 calibre introduces a latest-generation split-seconds mechanism developed by the Richard Mille engineers. The new column wheel operates the different levers of the split-seconds function and optimises the chronograph’s operation. While previous Richard Mille chronographs have traditionally featured a wheel with 8 columns, the one equipping the RM 50-03 now only has 6 columns to ensure optimised simultaneous movement, maximal function locking, and greater adjustment durability. In-depth studies carried out on the function of clamps also led to a new clamp design. The helical spring has also been replaced by a blade on the split seconds wheel of the RM 50-03, a technical decision that reduces the variation in torque when the split-seconds function is activated.
All of these developments have considerably improved the timekeeping performance of this tourbillon calibre and have halved the chronograph’s energy consumption while reducing friction on the arbors.
Use: the pusher at 8 o’clock starts or stops the seconds hand of the chronograph. The pusher at 4 o’clock stops the split seconds hand and allows an intermediary time to be read off while the chronograph is engaged. When this pusher is pressed again, the split-seconds hand catches up with the chronograph hand and simultaneously continues its course. The pusher at 10 o’clock resets the hands.Torque indicator
This function indicates the tension of the mainspring and makes it possible to optimise the winding of the watch. Under 53 dNmm, the spring is too slack. However, over 65 dNmm, the excessive tension could affect the operation of the mechanism, or even damage it. (These indications appear on the numeric scale to the right of the barrel).Function indicator
When the crown is pulled out, the hand indicates winding, hand setting or the neutral position, similar to the gearbox on a car. A hand at 4 o’clock displays the selected mode: W (Winding) – N (Neutral) – H (Hand Setting). Free sprung balance with variable inertia
This type of balance ensures greater reliability in the event of impact and during the assembly and disassembly of the movement. The watch’s long-term precision is therefore improved. The regulator index has been removed and more precise and repeatable inertia adjustment can now be made using four adjustable weights. Fast rotating barrel
(6 hours per revolution instead of 7.5 hours)
This type of barrel has the following advantages:
Barrel pawl with progressive recoil
- The phenomenon of periodic internal mainspring adhesion is significantly diminished, thereby improving performance.
- Excellent delta of the mainspring curve with a power reserve that ideally balances performance and regularity.
This device permits an appreciable winding gain (circa 20%), especially at the start of winding. It also helps to distribute the internal tension of the mainspring correctly.Teeth of barrel and third wheel pinion with central involute profile
The central involute profile of these teeth exerts pressure at an optimal angle of 20°, which enhances the efficiency of the gear train and compensates for any potential variations in penetration. This results in excellent torque transmission and a noticeably improved performance.Modular hand setting mechanism on caseback
This presents the following benefits in terms of longevity and maintenance:
Spline screws in grade 5 titanium for the bridges
- As this module is assembled outside of the movement, it can be replaced without touching the baseplate during a procedure or maintenance operation.
- The assembly and disassembly of this module from the back does not require the removal of the hands nor the dial.
The design of these screws permits better control of the torque applied during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well.
CASE IN GRAPH TPT™
- Dimensions of the movement: 31.10 mm x 32.15 mm
- Thickness: 9.92 mm
- Diameter of the tourbillon: 12.40 mm
- Diameter of the balance: 10 mm
- Number of jewels: 43
- Balance wheel: Glucydur, 2 arms and 4 setting screws
- Inertia moment: 10 mg.cm², lift angle 53°
- Frequency: 21,600 vph (3 Hz)
- Balance spring: elinvar by Nivarox®
- Shock protection: KIF Elastor KE 160 B28
- Barrel shaft in nickel-free Chronifer (DIN x 46 Cr 13 + S) with the following properties:
stainless – antimagnetic – suitable for tempering
The bezel and case back feature Graph TPT™, an Carbon TPT™ whose physical properties have been considerably improved by the injection of graphene, a revolutionary nanomaterial that is six times lighter than steel but 200 times more resistant.
Thanks to the collaborative work between The University of Manchester, McLaren Applied Technologies and North Thin Ply Technology (NTPT®), Richard Mille has succeeded in producing a watch case machined in an improved form of Carbon TPT™. Numerous control and validation tests conducted by McLaren Applied Technologies have made it possible to develop the solutions that resulted in the production of Graph TPT™, a material employed exclusively by Richard Mille in the domain of watchmaking.
With its distinctive, wavy graphic structure, Carbon TPT™ is made up of 600 layers of parallel filaments obtained by separating out carbon fibres. These layers, each a maximum of 30 microns thick, are impregnated with a graphene- containing resin. They are then assembled using a specific machine, which stacks the layers by varying the orientation of the fibres by 45° between two layers. The composite is then hardened in a kiln heated to 120°C with a pressure of 6 bars.
At the Richard Mille manufacturing facility dedicated to machining movement parts and cases – were tasked with machining the Graph TPT™, following many hours spent developing programmes and producing adapted cutting tools to give a machining precision accurate to the nearest micron.
The case of the RM 50-03 is water-resistant to 50 metres thanks to two Nitril O-ring seals. The case is assembled with 20 spline screws in grade 5 titanium and abrasion-resistant washers in 316L stainless steel. Spline screws in grade 5 titanium for the case
This permits better control of the torque applied to the screws during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well.Torque limiting crown
This additional security system prevents accidental overwinding, which could cause damage to the winding stem or put extreme pressure on the mainspring barrel.Upper and lower flanges
In Carbon TPT™ filled with an approved luminescent coating.Dial
In grade 5 titanium with black galvanic treatment.Bezel and case back
rubber strap injected with graphene
- Bezel side: sapphire crystal (1,800 Vickers) with anti-reflective treatment (on both sides)
- Thickness: 1.10 mm
- Case back side: sapphire crystal with anti-reflective treatment (on both sides)
- Thickness: 1.00 mm
Thanks to Richard Mille’s partnership with BIWI SA, a Swiss company specialised in very-high-precision moulding of vulcanised elastomers, graphene was injected into the rubber strap of the RM 50-03 in order to improve its rubber-like behaviour and thus its resistance to wear.Movement
- Hand-polished bevelling
- Hand-polished locking-sections
- Sapphire-microblasted milled sections
- Lapped and polished contact points
- Burnished pivots
- Wire-drawn and microblasted surfaces
- Hand-polished bevelling
- Concave chamfering with a diamond tool
- Circular-decorated front surfaces
- Rhodium-plating (before cutting the teeth)
- Minimal corrections made to the wheels to preserve their geometry and overall performance