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MB&F Gilds the HM9 Flow

A year after MB&F introduced its hyper-aerodynamic Horological Machine No.9 Flow, the pioneering independent maker expands the HM9 series with the HM9 Flow Red Gold.

MB&F made the debut HM9 series in two titanium editions of thirty-three pieces, and likewise this new variation comes in two limited editions, but only numbering eighteen pieces each, all with a new, rich red gold aura.

Echoing the original HM9, the new red-gold editions split their personalities based on dial style and accents. Each eighteen-piece red gold edition is either an HM9 Air or an HM9 Road. Where the Air version features an aviation instrument style, a darkened movement and rhodium-plated dual balance wheels, the Road version shows its colors with a classic speedometer, a rhodium-plated movement and red gold dual balance wheels.

Dual regulators

The MB&F HM9 movement is one of very few dual regulator calibers in any case shape to feature two fully independent balance wheels. But unlike other multi-balance movements, the HM9 engine deliberately avoids a resonance effect (a type of harmonic mind meld among two linked oscillators) in favor of a system using the two balance wheels to obtain “discrete sets of chronometric data” translated by the differential to produce one stable averaged reading. The balances are individually impulsed and separated to ensure that they beat at their own independent cadences of 2.5Hz (18,000 bph) each.

Echoing the dual-regulator style of the MB&F Legacy Machine No.2, the HM9 features a consciously more aerodynamic profile, with two satin-finished air scoops seamlessly mounted alongside the two balance wheels, each set within sapphire-topped pods. Between the pods, the movement’s unusual planetary differential gear ensures that the dial, showing hours and minutes, remains precise, even though the dial is set at a 90-degree angle to the movement.

You might recall that due to its unusual aerodynamic shape, Busser and Friends needed to divide the watch’s 57mm-wide titanium case along two axes and devise an unprecedented three-dimensional gasket. The gasket solved one of several conundrums for MB&F during the design phase for HM9, which several case makers originally deemed impossible to construct.

But despite that hesitation, company founder Maximilian Busser told iW earlier this year that the final HM9 design was nonetheless true to his initial idea.

“I am so proud of the team because the final piece is practically identical to my initial concept design,” Busser said. “That usually never happens. I guess either the engineers were even smarter than usual, or I was just more difficult and adamant not to allow modifications.” The price for the HM9 Red Gold is $198,000.

Specifications: MB&F Horological Machine No. 9 Flow, red gold

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 now available in titanium (two editions of 33 pieces each) or in red gold (two editions of 18 pieces each)

Movement: Manual-winding with two fully independent balance wheels with planetary differential, frequency of 18,000bph, single barrel with 45-hour power reserve, hours and minutes on vertical dial display

Case: New limited editions in 57mm x 47mm x 23mm red gold assembled in three segments with patented three-dimensional gasket, 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), water resistant to 30 meters, five sapphire crystals

Strap and buckle: Hand-stitched brown calf-leather strap with custom-designed titanium or red gold 5N+ folding buckle

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