RM 74-02
Uniquely appealing and technically complex
The RM 74-01 and RM 74-02 In-House Automatic Tourbillons offer two new versions of the fully in-house automatic tourbillon calibre. These two striking models, both with the same ultra-skeletonised heart, are distinguished by the materials used for their cases as well as by their aesthetics, making them fraternal twins with unique personalities.
RM 74-02 Automatic Winding Tourbillon
IN-HOUSE CALIBRE CRMT5
Skeletonised automatic-winding tourbillon movement with hours, minutes and variable-geometry rotor:
Power reserve : around 50 hours (± 10%)
BASEPLATE AND BRIDGES MADE OF GOLD
The baseplate and bridges of the RM 74-02 are machined from 18K 5N red gold and 18K 3N yellow gold respectively, both microblasted and bevelled by hand.
The skeletonised baseplate and bridges were subjected to intensive and complete validation tests to optimise their resistance capacities
FREE-SPRUNG BALANCE WITH VARIABLE INERTIA
This type of balance wheel represents the ultimate in innovation. It guarantees greater reliability when subjected to shocks and during movement assembly or disassembly, hence better chronometric results over time.
The regulator index is eliminated, and a more accurate and repeatable calibration is possible thanks to 4 small, adjustable weights located directly on the balance.
VARIABLE-GEOMETRY ROTOR
Rotor specifications:
• Heavy outside edge and heavy edge ring in 18K red gold
• Weight segment in platinum
• Automatic OneWay® winding system in ceramic with ball bearings
• Bidirectional winding system
This variable-geometry rotor has been incorporated within the in-house CRMT5 calibre, making it possible to set the rotor according to the owner’s activity level.
The setting is modified by adjusting the two moveable weights into the correct position and fixing them in place with spline screws. The inertia of the movement is increased when the two weights are closer together; the barrel then rewinds more quickly. If the weights are positioned at the extremities of the rotor, the inertia is decreased and the barrel winds more slowly.
MOVEMENT CHARACTERISTICS
- Movement dimensions: 30.70 x 23.70 mm
- Thickness: 6.20 mm
- Number of jewels: 23
- Balance: CuBe, 4 arms, 4 setting weights, moment of inertia of 7.5 mg.cm2, 50º angle of lift
- Frequency: 28,800 vph (4 Hz)
- Balance spring: AK 3
- Shock protection: INCABLOC 908.22.211.100 (transparent)
CASE IN GOLD CARBON TPT®
The design and execution of the watch demonstrate a holistic approach to conception of the movement, case and dial. As a result, everything has been constructed according to extremely rigorous specifications. For example, a casing ring is no longer used, and the movement is fixed by titanium screws.
Gold Carbon TPT® is a high-tech material comprising some 600 layers of parallel filaments obtained by separating out carbon fibres. The layers, no more than 30 microns thick, are impregnated with a black matrix. They are then assembled on a dedicated machine, which stacks the layers, varying the orientation of the fibres by 45° between layers and alternating them with 24K yellow gold leaf layers. As gold is a noble material in chemical terms, it was very difficult for the NTPT and Richard Mille engineers to ensure it ‘fused’ correctly with carbon. The composite is then heated to 120°C at a pressure of 6 bars in a kiln similar to that used for the production of aeronautics parts, after which it is ready to be machined at Richard Mille.
This process accentuates the specific characteristics of these materials, which in turn enhance the contours of the cases they adorn thanks to the unique play of light they create and their extremely attractive graduation of golden tones. The caseband is made of 18K 5N red gold.
The tripartite case is water resistant to 50 metres ensured by 2 Nitrile O-ring seals. The case is assembled with 20 grade 5 titanium spline screws and abrasion-resistant washers in 316 L stainless steel.
Finishing
Movement
• Hand-polished anglage
• Hand-polished stepped bevelling
• Microblasted milled section
• Microblasted sinks
Steel parts
• Satin-finished surfaces
• Hand-polished anglage
• Hand-polished sinks
• Burnished sections
Wheels
• Diamond-polished sinks
• Circular decorations on the front surfaces
• Rhodium plating (before cutting the teeth)
• Minimal corrections applied to the wheels in order to preserve geometry and performance
Other features
FAST-ROTATING BARREL (5 hours per revolution instead of 7.5 hours)
This type of barrel provides the following advantages:
- The phenomenon of periodic internal mainspring adhesion is significantly diminished, thereby increasing performance.
- Provision of an excellent mainspring delta curve with an ideal power reserve/performance and regularity ratio.
GEAR TEETH PROFILE
The entire going train of the watch, the primary transmitter of power through the movement, utilises a special profile for the teeth of the wheels. Developed specifically for Richard Mille’s in-house calibres, the wheels employ a 20° pressure angle. This system equalises any discrepancies that might arise between the centres of each wheel, for instance, during thermal changes and normal use, and promotes excellent torque transmission to the balance wheel, thus supporting excellent chronometric characteristics.
SPLINE SCREWS IN GRADE 5 TITANIUM FOR THE BRIDGES AND CASE
This permits better control of the torque applied to screws during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well.