Limited edition of 30 timepieces in TZP ceramic and carbon nanotubes.

Caliber RM052: manual winding tourbillon movement with hours and minutes.

Dimensions: 42.70 mm x 50.00 mm x 15.95 mm.

Power réserve: Circa 48 hours (±10%).

Baseplate of the movement in Grade 5 titanium
The RM 52-01 Skull features the skull as its key symbol. It is a fascinating creation from an artistic point of view, but even more so from a technical point of view. The baseplate has been crafted from grade 5 titanium, 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 boosts the mechanical properties of the material even further, which explains why it is often used in the aerospace, aeronautics and car industries.
The upper and lower jaws hold the jewel of the tourbillon carriage. The “Jolly Roger” comes to life thanks to the 4 bridges that link the movement to the case.
The skeletonised baseplate and bridges have been subjected to comprehensive testing in order to optimise their resistance capacities.

Free sprung balance with variable inertia
A free sprung balance with variable inertia and a terminal-curve spring guarantees greater reliability in the event of impacts and during movement assembly and disassembly. It also guarantees better chronometric results over an extended period of time.
The index is eliminated, thereby allowing a more precise and repeatable adjustment using 4 setting screws.

Fast rotating barrel (6 hours per revolution instead of 7.5 hours)
This type of barrel has the following advantages:

• The phenomenon of periodic internal mainspring adhesion is significantly diminished and performance is thus enhanced,
  
• It provides an excellent mainspring delta curve. The choice was determined by the ideal power-reserve/performance/regularity ratio.

Barrel pawl with progressive recoil
This device offers significant winding gain (approx. 20%), especially at the start of winding. It also ensures an ideal distribution of the mainspring’s internal tension.

Winding barrel teeth and centre-wheel pinion with central involute profile
The central involute profile of the winding barrel teeth provides an optimal pressure angle of 20°, which promotes effective rotary motion and compensates for possible variations in the operation of the going train. This, in turn, ensures excellent torque transmission and a distinct improvement in performance.

Spline screws in Grade 5 titanium for the bridges
These screws enable better control of the torque applied to the screws during assembly. Hardly affected by physical manipulations during assembly and disassembly, they also age well.

• Movement dimensions: 32.80 mm x 30.90 mm - Thickness: 6.87 mm
  
• Tourbillon diameter: 10.90 mm
  
• Balance wheel diameter: 9.12 mm
  
• Number of jewels: 19
  
• Balance wheel: Glucydur, 2 arms, 4 adjustment screws
  
• Moment of inertia: 11.50 mg.cm2, angle of lift 53°
  
• Frequency: 21,600 vph (3 Hz)
  
• Balance spring: in ELINVAR by Nivarox®
  
• Shock protection: KIF ELASTOR by KE 160 B28
  
• Barrel arbor: in nickel-free Chronifer (DIN x 46 Cr13 + S),
  with the following characteristics:
  stainless, non-magnetic, tempered.

Case
TZP was chosen for the RM 52-01’s bezel and case back. This low-density material (6 g/cm3) is highly scratch-resistant and has a low thermal conductivity coefficient.
Made from 95% yttrium-stabilised zirconium, TZP has a pronounced grain that provides the perfect finish. The bezel and case back can therefore be microblasted and the corners hand-polished.
For the case middle, Richard Mille decided to use carbon nanotubes for their proven ability to protect the tourbillon movement nestled in the centre against impacts. Bonded to a black polymer, the carbon nanotubes case middle helps to reduce the watch’s weight.
The RM 52-01 case is water resistant to 50 metres. It is assembled using an average of 20 spline screws in grade 5 titanium and abrasion-resistant washers in 316L stainless steel.

Spline screws in Grade 5 titanium for the case
These screws enable better control of the torque applied to the screws during assembly. Hardly affected by physical manipulations during assembly and disassembly, they also age well.

Torque-limiting crown
This additional security system prevents from accidental overwinding, which could cause damage to the winding stem or putting extreme pressure on the mainspring barrel.

Interior flanges
Upper flange in carbon, lower flange in grade 5 titanium with DLC coating.

Crystal

• Bezel side: in sapphire (1,800 Vickers) with anti-glare coating (on both sides).
  Thickness: 1.50 mm
  
• Case back: in sapphire with anti-glare treatment (on both sides)
  Thickness: 1.20 mm in the centre and 2.04 mm at the outer edges

Movement

• Hand-polished bevelling
  
• Microblasted milled sections
  
• Drawn or polished outer faces

Steel parts

• Microblasted surfaces
  
• Satin-brushed surfaces
  
• Hand-polished bevelling
  
• Long strokes
  
• Matt ”brouillé“ strokes
  
• Long strokes on the sides
  
• Polished sinks

Profile-turning

• Lapped and polished ends
  
• Burnished pivots

Wheels

• Diamond-polished sinks
  
• Circular decorations on the front surfaces
  
• Rhodium-plating (before the teeth are cut). Minimal corrections are made to the wheels to preserve their geometry and overall performance.