RM 75-01
Reflections and architecture
A celebration of contrast, the RM 75-01 Flying Tourbillon Sapphire perfectly embodies this dynamic. Blending the architectural grandeur of Gothic art with the mesmerizing fluidity of water, the collection reveals a sculptural dimension like never before.
RM 75-01 Manual Winding Flying Tourbillon Sapphire
CALIBRE RM75-01
Manual winding flying tourbillon movement with hours and minutes.
Limited editions
POWER RESERVE
Around 65 hours (± 10%).
BASEPLATE AND BRIDGES IN GRADE 5 TITANIUM
The RM75-01 movement embodies a fascinating paradox: minimalist in the purity and precision of its components, it reveals striking complexity through the boldness of its mechanical architecture. They are manufactured in grade 5 titanium, 5N gold and grey PVD treated.
Grade 5 titanium is a biocompatible, highly corrosion-resistant and remarkably rigid alloy, which enables the gear train to function effortlessly. The alloy is 90% titanium, 6% aluminium and 4% vanadium.
This combination further increases its mechanical properties, which explains its frequent use in the aerospace, aeronautics and automobile industries. As a consequence, the whole assembly is extremely rigid, with precise surface flatness, an essential for the perfect functioning of the gear train.
The skeletonised baseplate and bridges were subjected to separate and extensive validation tests to ensure they met rigorous strength requirements.
FLYING TOURBILLON WITH VARIABLE-INERTIA BALANCE
Positioned at 6 o’clock, the flying tourbillon is a complex regulating mechanism. The distinctive feature of the so-called ‘flying’ tourbillon is that its cage is assembled without an upper bridge, creating the impression of weightlessness and offering perfect visibility.
The free-sprung balance offers better reliability in the event of shocks or movement assembly and disassembly, and also guarantees better chronometric results over an extended period of time. The regulator index is eliminated, and a more accurate and repeatable calibration is possible thanks to 4 small, adjustable screws located directly on the balance.
WINDING-BARREL TEETH AND THIRD-WHEEL PINION WITH CENTRAL INVOLUTE PROFILE
The central involute profile of the winding-barrel teeth and Pinion provides an optimal pressure angle of 20°. This promotes effective rotary motion and compensates for possible variations in the engagement of the going train, thus ensuring excellent torque transmission with a distinct improvement in performance.
FAST-ROTATING FLYING BARREL (5.2 hours per revolution)
The fast-rotating flying barrel used in the RM 75-01 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.
The absence of upper bridges for these "flying" elements offers an aerial perspective of the movement, showcasing its volume and transparency in a unique way. This aesthetic choice, conceived from the very beginning, enhances the concept of skeletonization while maximizing architectural impact and ensuring exceptional durability.
MOVEMENT CHARACTERISTICS
Movement dimensions: 29.71 x 20.78 mm
Thickness: 5.45 mm
Jewels: 18
Balance: CuBe, 4 arms, 4 setting screws, moment of inertia 7.5 mg•cm2, angle of lift 50º
Frequency: 3 Hz (21,600 vph)
Balance spring: elinvar by Nivarox®
Shock protection: KIF Elastor KE 160 B28
Barrel shaft: nickel-free Chronifer® (DIN x 46 Cr 13 + S) with the following characteristics: stainless - antimagnetic – suitable for tempering
CASE
The entire case of the RM 75-01—bezel, caseband and caseback—is cut and milled from solid blocks of sapphire. No external structures are used to support the assembled parts. Sapphire is known as a particularly scratch-resistant material with a hardness of 2,000 Vickers. Made of aluminium oxide (Al2O3) crystals, it is transparent thanks to its molecular composition.
The creation of coloured sapphire crystals requires precise incorporation of metal oxides into the sapphire crystal. The colour is determined by the types and quantities of oxides present within the crystal structure. Coloured sapphire is very sensitive to the heating process and crystal growth rate: if the right temperature conditions are not respected, it can affect the way oxides diffuse into the crystal lattice and lead to the uneven distribution of colours or undesired hues. Similarly, too fast a growth rate can lead to uneven colour and the generation of bubbles within the crystal.
The machining of such components was another challenge faced by Richard Mille, one made all the more difficult as the sapphire machining process is exceptionally delicate. Although extremely tough, sapphire does not allow for even the slightest error during milling and cutting. Creating a case of this quality takes over 1,000 hours of machining, of which 430 hours are spent on preforming the case components and 350 hours on polishing the whole watch case. To ensure optimal optical properties, the front and back bezels have been treated with an anti-glare coating.
The tripartite case is water resistant to 30 metres, ensured by 2 Nitrile O-ring seals. The case is assembled using 24 spline screws in grade 5 titanium and abrasion resistant washers in 316L stainless steel.
UPPER FLANGE
Inspired by vaulted arches, the monumental microblasted and satin-finished gold flange rests on polished and satin-finished titanium pillars. It plays with contrasts between light and shadow, illuminating the movement in low light with touches of SuperLuminova. Its indexes echo the barrel's lines, reinforcing the overall harmony of the model and theatrically presenting the movement. It serves as the keystone connecting the movement to the case.
In 5N red gold with polished and microblasted steel markers.
Index points filled with approved luminous material.
Finishing
Movement
• Anglage and polishing by hand
• Hand-polished locking sections
• Sapphire-blasted milled sections
• Lapped and polished contact points
• Burnished pivots
Steel parts
• Sapphire-blasted surfaces
• Anglage and polishing by hand
• Burnished sections
• Satin-finished surfaces
Wheels
• Concave chamfering with a diamond tool
• Circular-finished faces
• Rhodium plating (before cutting the teeth)
• Minimal corrections applied to the wheels in order to preserve geometry and performance
Other features
CRYSTAL
Bezel side
Sapphire (1,800 Vickers) with anti-glare treatment (both sides)
Thickness: 2.30 mm
Caseback
Sapphire with anti-glare treatment (both sides)
Thickness: 2.30 mm
BARREL PAWL WITH PROGRESSIVE RECOIL
This device permits an appreciable winding gain (around 20%), especially during the start of winding. It is also helpful in ensuring even distribution of the mainspring’s internal tension.
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 unaffected by physical manipulation during assembly or disassembly and age well.