The
calibre 103.0 movement of the
SkyLife BENU Tourbillon represents a new concept with an array of surprising solutions. To translate into reality the aspirations of
Grossmann's
watchmakers with respect to precision, efficiency, and aesthetics,
classic principles of horological design were critically reviewed and
pivotal movement functions optimised.
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In particular, the
SkyLife BENU Tourbillon is characterised by the following new developments:
- The Grossmann three-minute tourbillon according to Alfred Helwig
- The flying tourbillon cage with a V-shaped balance cock for which a design patent is pending
- The patent-pending stop seconds with a fine-hair brush
- The asymmetric-arm lever escapement
- The new configuration of the Grossmann balance and hairspring with an overcoiled terminal curve
- The newly developed mainspring barrel jewel bearing
- The brake ring on the fourth-wheel arbor made of guaiacum
- The ARCAP alloy for the going train wheels
- The patent-pending dual minute display with an extension of the minute hand
The Grossmann three-minute tourbillon with stop seconds
Amply dimensioned, the oscillator with the
Grossmann balance is integrated in a unilaterally suspended, “flying” tourbillon cage according to
Alfred Helwig (
1886-1974). The famous watchmaker strongly influenced the evolution of Glashütte as a stronghold of German watchmaking.
Alfred Helwig was a teacher at the German School of Watchmaking from
1913 to
1954; in
1920, he applied for a patent for the flying tourbillon. In
1922,
he earned his master craftsman's credentials with a unilaterally
suspended five-minute tourbillon. Originally, the tourbillon served the
purpose of offsetting gravity-induced rate deviations in pocket watches
that were worn vertically. Today, a well-formed tourbillon ranks among
the genuine challenges for master watchmakers. As the author of the book
entitled “Drehganguhren”,
Alfred Helwig was a source of inspiration for
Grossmann's calibre designers while they were developing their three-minute tourbillon.
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The
tourbillon cage is freely suspended from a cantilevered, hand-engraved
cock made of German silver. Its design is totally new, resulting in a
distinctive manifestation of functional purity. The novel configuration
of the tourbillon, which has an unusually large diameter of 16 mm, is
beautifully showcased with a longer periodicity. Elaborately crafted,
the upper part of the cage is a V-shaped balance bridge that requires
only two posts, a significant hallmark for which a design patent has
been registered.
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The
lavish execution of the cage with two triangular posts is a
prerequisite for an additional complication. For the watchmakers at
Grossmann,
the ability to accurately set the time is a crucial precision
requirement for a tourbillon mechanism. To reliably immobilise the
balance, the stop device must bypass the cage frame posts. An elastic
human-hair brush can easily glide past the triangular posts and gently
brake the balance at the circumference of its rim. The patent-pending
stop-seconds solution completes this impressive implementation of a
Grossmann timekeeping instrument (the patent application is endorsed by
SIGNO, an initiative of the German Federal Ministry of Economics and Technology).
The asymmetric-arm lever escapement
Given the ambitious expectations imposed on a precise manually wound watch, the classic lever escapement was reworked for the
BENU Tourbillon.
Because of the use of a pallet lever with unequal arm lengths on a
shared locking circle, all entrance and exit adjustment points are on
the same lever arm, and even slight deviations can be precisely
rectified. The pallet lever is composed of two parts: a thin fork with a
blade-type guard pin, fashioned in the manner of Glashütte pocket
watches, and the lever body with the visible sapphire pallets. The
deflection of the lever is limited by a pin at the extension of the
fork, which significantly improves the lever's mass distribution and
equilibrium.
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The Grossmann balance
The
spatial configuration of the balance and hairspring in the tourbillon cage was optimised for the
BENU Tourbillon. The hairspring is attached upside down to the lower cage base beneath the
Grossmann
balance, resulting in an even more exquisite balance bridge design.
Optimised for artisanal manufacturing techniques, the design of the
Grossmann balance
improves the adjustability of inertia and achieves high kinetic energy
combined with minimised air resistance and the smallest possible mass.
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The
number of screws in the balance wheel rim was minimised, and the bores
in the rim are equidistant. This makes it possible to vary the moment of
inertia by inserting screws with different head lengths in the bores.
The
Grossmann balance interacts with a Nivarox 1 balance spring.
Its terminal curve is overcoiled according to calculations performed by
Glashütte regleur
Gustav Gerstenberger.
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The barrel bearings and the Glashütte stopwork
An extremely rare solution was chosen for the barrel bearings in the
calibre 103.0 movement.
The bilateral jewel bearings are located on the ratchet wheel and main
plate sides. A gold chaton on the ratchet wheel carries the upper jewel
for the mainspring barrel and tastefully complements the traditional
finissage of the ratchet wheel. As customary, the lower jewel is
embedded in the main plate. The mainspring barrel arbor extends through
the hollow core to the chaton in the ratchet wheel; the barrel is
perfectly stabilised with a maximised distance between bearings.
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A
modified Glashütte stopwork secures the tension of the mainspring.
After winding, it allows the ratchet wheel to reverse somewhat and
slightly relax the mainspring. The stop click is firmly secured with the
addition of a steel cover.
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Special facets of the wheel train
The train configuration of the
Grossmann three-minute tourbillon exhibits several unusual features.
To
reduce the kinetic energy of the tourbillon and the exposure of the
lever escapement to stress, the periodicity of the cage was extended to
three minutes with an additional wheel.
The pinion for the
seconds is segregated from the power flow of the wheel train and driven
with reduced torque. To prevent arbor and seconds-hand backlash, the
pinion is constantly braked by a spring.
Grossmann's watchmakers
designed this function in a sustainable and maintenance-free manner by
choosing guaiacum spp., an oily wood species, for the brake ring of the
fourth-wheel arbor. It is classified as “rock-hard” and has good
long-term tribological properties. This solution was inspired by the
extremely dependable marine and tower clocks that
John Harrison (
1693-1776) crafted with great success in the
18th
century. As a master carpenter, Harrison accrued considerable
experience with various types of woods, especially the very durable ones
he selected for his marine chronometers.
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Grossmann's contemporary precision timepieces stand for
HERITAGE IN TIME beyond our era. It was also a key objective to preserve the beauty of the wheel train of the
BENU Tourbillon,
with its precious decorations and polishes, by precluding oxidation and
damage to coated surfaces. The train wheels are made of
ARCAP, a
copper-nickel-zinc alloy coveted for its long-lasting brilliance.
Crafted from beryllium bronze, the balance has a stately presence above
the silvery going train.
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The unmistakable frame
The pillar movement with the main and
2/3 plates, a typical hallmark of
Grossmann watches,
embodies the traditions of Glashütte pocket chronometers. A balanced
ensemble of components in untreated German silver with different types
of finissage and two pillar spacers constitutes the tiered calibre that
accommodates the separately removable winder. The graceful engravings on
the movement parts are all fashioned by hand.
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The Grossmann winder with pusher
The watchmakers at
Grossmann addressed
the requirements imposed on a manually wound watch by focusing on
improved convenience and greater functional reliability. The
Grossmann
winder with pusher incorporates a refined handsetting mechanism that
eliminates two unwanted phenomena: it prevents the ingress of particles
into the case during the setting process as well as unintentional hand
position changes when the crown is pushed home again. When the user
briefly pulls the winding crown out, this mechanism switches to the
handsetting mode and stops the movement. Although the crown immediately
returns to its home position, it can now be turned to precisely set the
hands. Afterwards, the movement is restarted with the pusher adjacent to
the winding crown without altering the positions of the hands. At the
same time, this action switches the mechanism back to the winding mode.
The hallmarks of the Moritz Grossmann brand
The
BENU Tourbillon also unites the traditional characteristics of
Grossmann-style horological prowess with modern watchmaking elements and the typical features of the new brand:
• Pillar movement with
2/3 plate and frame pillars in untreated German silver
• Hand-engraved
2/3 plate and tourbillon cock
• Wide horizontal Glashütte ribbing on the
2/3 plate
• Modified Glashütte stopwork with backlash
• Separately removable clutch winder
• Raised gold chatons with pan-head screws
• Screws annealed to brown-violet
• White sapphire bearing jewels
• 3-band snailing on the ratchet wheel
• Manually crafted steel hands, annealed to brown-violet
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RUAG Aviation is a leading supplier, support provider
and integrator of systems and components for civil and military aviation
worldwide.
Servicing aircraft and helicopters throughout their
entire life cycle, the company’s core competencies include maintenance, repair
and overhaul services, upgrades, and the development, manufacturing and
integration of subsystems.
RUAG is an authorised service centre for OEMs of
renown, such as Airbus Helicopters, Bell, Bombardier, Cirrus, Cessna, Diamond,
Dassault Aviation, Embraer, Leonardo-Finmeccanica, Piaggio, Sikorsky, Piper,
and Mooney, as well as a service centre for 328 Support Services, Hawker
Beechcraft, Viking und MD Helicopters. RUAG Aviation is also a partner to the
Swiss Armed Forces and other international air forces.
The company is also the manufacturer (OEM) of the
Dornier 228, a versatile aircraft for challenging special missions and
passenger and cargo operations.
RUAG Aviation is an approved Part 21/J EASA Design
Organisation, Part 21/G EASA Production Organisation, and Part 145 EASA
Maintenance Organisation.
------------------------------
Contact for Corporate
Information: Jiri Paukert, RUAG media spokesman
Tel. +41 79 758 47 77, jiri.paukert@ruag.com
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TECHNICAL SPECIFICATIONS
Moritz Grossmann – SkyLife BENU Tourbillon Gold Special Edition
Reference:
MG-001173 -
Argenté Blue Dial –
Only available for aircraft owners
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Other Versions:
Reference:
MG01.G-02-A000004 -
Argenté Silver Dial
Limitation 50 watches
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--------------------------------------------
Reference:
MG01.G-02-A000779 -
Argenté Black Dial
Limitation 50 watches
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Movement
Manufacture calibre 103.0, manually wound, adjusted in five positions
No. of parts: 245 (wheel train
186, cage
59)
No. of jewels: 30, 4 of which in screwed gold chatons (wheel train 17, cage 13)
Escapement: Lever escapement
Movement dimensions
Diameter: 38.4 mm, height: 7.1 mm
Oscillator: Grossmann three-minute tourbillon with stop seconds; shock-absorbed
Grossmann balance with 4 inertia and 2 poising screws, suspended Nivarox 1 balance spring with No. 80 terminal curve,
Gerstenberger geometry
Cage diameter: 16.2 mm
Cage speed: 1 revolution in three minutes, anti-clockwise when viewed from dial side
Balance diameter: 14.2 mm, frequency
18,000 semi-oscillations per hour
Power reserve: 72 hours when fully wound
Functions / features
Flying three-minute tourbillon with screw-secured driving wheel and
V-shaped balance bridge (design patent pending)
Sweep minutes, off-centre hours and seconds with stop seconds,
replacement of the missing minute scale segment from 25 to 35 minutes
with a separate scale swept by the extension of the minute hand on the
opposite side (patent pending)
Stop seconds at the balance wheel rim with a pivoting fine-hair brush (patent pending)
Asymmetric-arm lever escapement with counterweight and lever banking pin
Grossmann balance with suspended balance spring, adjustable with poising screws in the rim
Newly developed mainspring barrel jewel bearing
Brake ring on the fourth-wheel arbor made of very hard, oily guaiacum
ARCAP train wheels
Grossmann winder with pusher to deactivate the handsetting mode and start the movement
Modified Glashütte stopwork with backlash
Pillar movement with
2/3 plate and frame pillars in untreated German silver
Hand-engraved
2/3 plate and tourbillon cock
Broad horizontal Glashütte ribbing
3-band snailing on the ratchet wheel
Raised gold chatons with pan-head screws
White sapphire bearing jewels
Separately removable clutch winder
Operating elements
Crown in
750/000 white gold to wind the watch and set the time,
pusher in
750/000 white gold to start the movement
Case dimensions
Diameter: 44.5 mm, height: 13.8 mm
Movement dimensions
Diameter: 38.4 mm, height: 7.1 mm
Case
Three-part, in
750/000 White Gold
Dial
Argenté
