Introduced in 2018, the Horological Machine N°9 ‘Flow’ timepiece by MB&F is inspired by the dynamic profiles of automotive and aviation mid-century design. Horological Machine N°9 ‘Flow’ is audacious in its design, not simply because of its unconventional form, but because of the extremes to which it takes this form. Mould-breaking, transgressive case shapes are nothing new to the MB&F Horological Machine collection, but HM9 has rejected all limits. Its extreme curves and acute angles required new manufacturing standards and techniques to obtain a complete milled and finished case. This timepiece is now available in two new versions (Road & Air) in 5N pink gold.
Reminiscent of a jet engine, a highly complex case in alternating polished and satin finishes encloses an equally complex manual winding movement, developed fully in house. Independent twin balance wheels beat at a leisurely 2.5Hz (18,000bph) on each flank of Horological Machine N°9, visible under elongated domes of sapphire crystal. A third pane of sapphire crystal on the central body reveals the gearbox of the HM9 engine: a planetary differential that averages the output of both balance wheels to provide one stable reading of the time.
Sitting perpendicular to the rest of the HM9 engine is the dial indicating hours and minutes, driven by conical gears that ensure precise engagement even when motion is put through a 90° planar translation. The winding and setting crown is located on the rear of the central body, its deep fluting providing ergonomic grip as well as aesthetic coherence with the overall design.
Two satin-finished air scoops are mounted alongside the pods containing the oscillating balance wheels, evoking the raised vents that allow continuous airflow to high-performance motor engines.
HM9 Flow treads the path first opened by the HM4 Thunderbolt and subsequently by the HM6 Space Pirate, utilising a geometrically complex combination of milled case elements in both sapphire crystal and metal (grade 5 titanium and 18k red gold). However, HM9 goes beyond its predecessors, redefining what was thought to be possible in case design – illustrated for example by a patented three-dimensional gasket ensuring water resistance.
Quite naturally, HM9 Flow was therefore declined in two versions, drawing their inspiration from the two main sources: A “Road” version with a speedometer-style dial; an “Air” version with an aviator-style dial.
The Horological Machine N°9 ‘Flow’ was launched in 2018 in two limited titanium editions of 33 pieces each: the “Air” version with darkened movement; the “Road” version with pink gold treated movement.
In 2019, MB&F presents two new limited editions in 5N+ red gold with 18 pieces each: the “Air” version with blackened movement and rhodium-plated balance wheels; the “Road” version with rhodium-plated movement and red gold balance wheels.
The result of three years of development, the HM9 engine was created entirely in-house, with the accumulated experience that came with MB&F’s 13 years in existence (in 2018) and previous 14 different movements.
Long-time MB&F collectors and fans will recognise the mechanical pedigree of the HM9 engine. Its double-balance with differential is descended from the similar system in Legacy Machine N°2, albeit in vastly different aesthetic form. Whereas LM2 emphasised design purity and the hallucinatory effect of its suspended oscillators, HM9 is exultant in its celebration of expressive design.
The twin balance wheels of the HM9 engine feed two sets of chronometric data to a central differential for an averaged reading. The balances are individually impulsed and spatially separated to ensure that they beat at their own independent cadences of 2.5Hz (18,000bph) each. This is important to ensure a meaningful average, just as how a statistically robust mathematical average should be derived from discrete points of information.
Two balances beating within the same movement will inevitably bring up discussions of resonance, the mechanical phenomenon that describes linked oscillators in a state of mutual harmonic excitation. As with the LM2 engine, HM9 deliberately avoids inducing the resonance effect. Its purpose in including two balance wheels is to obtain discrete sets of chronometric data that can be translated by a differential to produce one stable averaged reading. This purpose would be defeated by two balances oscillating perfectly in phase, giving the same chronometric data at every point.
HM9 further calls out the MB&F Legacy Machine collection with the curved arms anchoring its balances. The polished appearance finishes contrast vividly with the movement bridges.
Model: HM9 Flow
Horological Machine n°9 ‘Flow’ is available in two versions:
– ‘Road’ version with a speedometer-style dial;
– ‘Air’ version with an aviation-style dial
Each version is available in titanium (two editions of 33 pieces each) or in red gold (two editions of 18 pieces each)
Manual-winding in-house movement
Two fully independent balance wheels with planetary differential
Frequency: 2.5Hz (18,000bph)
Single barrel with 45-hour power reserve
301 components, 52 jewels
Hours and minutes on vertical dial display
2 launch editions in titanium grade 5, limited to 33 pieces each, with a NAC movement (“Air” version) or red gold (“Road” version); and limited editions in red gold 5N+ of 18 pieces each, with a NAC movement and rhodium-plated balance wheels (“Air” version) or rhodium-plated movement with red gold balance wheels (“Road” version)
Dimensions: 57mm x 47mm x 23mm
Titanium editions: 43 components, red gold editions: 49 components
Water resistant to 3ATM (30m); assembled in three segments with patented three-dimensional gasket
Five sapphire crystals treated with anti-reflective coating
Strap and buckle
Hand-stitched brown calf-leather strap with custom-designed titanium or red gold 5N+ folding buckle