Flying still generates emotions and provokes a unique feeling of freedom and pilot’s watches that evoke this high-altitude world are always on the radar. However, “pilot’s watch” is a broad definition that covers many styles. Even at Hamilton, the Khaki Aviation collection comprises military-inspired models, modern technical pieces and vintage-oriented watches. The brand’s latest addition is a proper flying instrument; it can perform technical calculations in conjunction with cockpit instruments. Its name is the Hamilton Khaki Aviation Converter collection and as the watches are now available, we take a closer look at the Automatic Chronograph Black & Gold model.
Hamilton is no stranger to the pilot’s watch. In fact, the brand has great legitimacy in this field – as well as other military fields. The brand, for instance, provided the first U.S. Airmail service with watches in 1918. Today, Hamilton still produces pilot’s watches with the Khaki Aviation collection, which comprises, for instance, the X-Wind watches supplied to air racers. What Hamilton is adding with the Khaki Aviation Converter is a collection of instrumental watches capable of performing flight calculations.
A look back at the Converter collection
Earlier this year, we introduced the Converter collection in an in-depth article covering most of the models, which are now being released. The difference between the Converter and a simpler 3-hand pilot’s watch is about purpose and functions. Classical pilot’s watches are often considered as observation tools, precise, often oversized and ultra-legible pieces to keep accurate track of the time. The Hamilton Khaki Aviation Converter Collection is a classic pilot’s watch that enables flying calculations to be performed on the wrist, with a so-called “slide rule”. As such, Hamilton has created a wrist computer.
The most noticeable element of the Converter is its slide rule bezel – a function also known as a “flight computer” or “logarithmic bezel” – a device that enables mathematical calculations while in flight. These bezels were first integrated into wristwatches in the early 1940s – to be precise, in 1940, with MIMO watch manufacture and Breitling almost simultaneously filing a patent. A slide rule was a crucial tool for pilots and is still used and taught in flight schools today. It is a mechanical analogue computer, used to primarily perform multiplications and divisions but also functions such as exponents, roots or logarithms. While modern avionics make the slide rule slightly outdated, back in the 1940s and 1950s, pilots needed it to perform calculations to track speed, fuel consumption, distance, rate of climb, or descent and flight time.
With the integration of the slide rule on watches, pilots could perform both timings and calculations on a single device. And the Hamilton Khaki Aviation Converter has a bezel that has been modelled after the famous E6B. The bezel is bidirectional and its logarithmic gradations interact with the fixed scale around the dial. It can be used to calculate distances, speeds and fuel consumptions, but also to carry out various unit conversions, such as kilometres/nautical miles or feet/metres, or currency conversions for those flying internationally. On the Hamilton Khaki Aviation Converter, the insert is made of K1 mineral glass (hardened glass with scratch-resistant coating) with graduations printed underneath, allowing for great contrast and good protection against scratches.
As for the watches themselves, Hamilton doesn’t much play on the vintage trend here, as the Converter isn’t a re-edition of a past model. Instead, it brings a classic, slightly retro-inspired feel to an instrumental watch focused on functionality. The cases, available in steel – with black PVD coating and gold-plated elements on some models – are modernly sized at 42mm or 44mm, depending on the movement. The construction is extremely solid, with great attention to detail, such as nice polished accents contrasting over the brushed surfaces, or well-designed notches on the bezel and crown, so the watch can be used with flying gloves. All the watches are rated 100m water-resistant.
The Hamilton Khaki Aviation Converter is available in three different configurations. The first is a 42mm time-and-date model, with a dial focused on legibility and function. Inside is a solid movement, calibre H-10, an upgraded version of the ETA 2824-2 equipped with a balance spring made of Nivachron alloy with anti-magnetic properties and a longer power reserve of 80 hours.
The second model features one of the most classic complications for a pilot’s watch, the GMT function, displayed via a central 24-hour hand and an additional track on the inner flange. This model, with its 44mm diameter, is easily recognizable, being the only one available with a blue dial. Inside its case is the calibre Hamilton H-14, which also comes with upgraded specifications, such as an 80-hour power reserve and anti-magnetic properties.
Finally, Hamilton also integrates a fully adequate chronograph function to this collection – indeed, the stopwatch function works really well in conjunction with the slide rule bezel (Navitimer owners will understand why…) This is the most robust version of the collection, with its 44mm case. The dial is complex, with multiple indications displayed, but still the same instrumental spirit. Inside the case is an upgraded Valjoux movement, but more details to come in the hands-on session below.
The entire Khaki Aviation Converter collection (9 references in all) can be discovered here, at www.hamiltonwatch.com.
The Converter Automatic Chronograph Black & Gold
In March, we got to know almost the entire collection, with the exception of the Black PVD-coated and gold-plated edition. Problem solved, as we have this chronograph on the wrist today, and this two-tone edition certainly is the model that shows the strongest character. Maybe more disruptive, bolder and less conventional than the classic steel on black dial version, but one that won’t fly under the radar.
Overall, even with its more fancy colour scheme, this black & gold edition of the Converter Chronograph retains its highly engineered look and feel. The case, which measures 44mm in diameter and about 14.5mm in height, has a great presence on the wrist and a cool instrumental style that fits perfectly well with the concept behind this collection. The black PVD coating, which is applied to all parts of the watch save for the bezel, crown and pushers, also benefits to the watch because it creates a more compact visual feeling. Despite its robust proportions, the case is well shaped and the curved lugs enhance the comfort of the watch on the wrist.
As an accessible-luxury brand, the gilt elements are not made from solid gold but plated in rose gold. The contrast with the black case makes for a striking look that won’t go by unnoticed, but (guilty pleasure), it certainly is the coolest of the Converter editions. The watch is worn on a thick and flat leather strap, in matte black leather with alligator embossing. Altogether, the feeling on the wrist is that of a high-quality watch that is ultra-durable and made for action.
With all its functions, the dial of the Khaki Aviation Converter Automatic Chronograph can seem quite complex at first, especially when combined with the equally information-packed bezel. There’s no denying that the watch needs to be explored to be fully understood – which is always the case with watches featuring a slide rule bezel. Still, thanks to contrasting colours, polished frames and generous luminous material, the multiple tracks and indications are well highlighted and practical to use. The central part of the dial is dedicated to the time, the calendar indications and the chronograph. To make them easier to read, the day-date complication, as well as the chronograph sub-counters, are both framed by metallic rings, here gold-coloured. Also, a nice touch specific to the chronograph models, the sub-counters have a gradient effect that not only adds depth to the whole dial but also enhance the visibility on the indications.
In addition to the classic indications, the Converter – hence its name – has multiple tracks and tools for calculations. From the centre to the periphery, the first one (next to the seconds track) is a classic tachymeter scale, which calculates speeds. Then, printed on the angled inner flange, and working in conjunction with the rotating bezel is the slide rule, a logarithmic scale based on the E6B “Whiz Wheel”. It can carry out various unit conversions. For instance, kilometres/nautical miles, pounds/kilograms, litres/gallons, feet/metres.
To power its latest collection, Hamilton relies on modern movements. This Converter Chronograph uses the calibre Hamilton H-21 Si. While its architecture is familiar, being the Valjoux 7750 with cam-lever system, Hamilton undertakes multiple updates to make this movement more efficient and more reliable. First, it is equipped with a high-tech silicon balance spring, which negates the effects of magnetism on the escapement – useful in a cockpit, but also in daily life. Second, the entire kinematic chain has been refined, from the barrel to the escapement, the mainspring has been improved to increase the power reserve from 42 hours to 60 hours, but the frequency has been kept at 4Hz for more precision.
Availability and Price
The entire Hamilton Khaki Aviation Converter collection is now available in stores and on the brand’s website. Prices start at EUR 1,045 for the time-and-date model in steel, up to EUR 2,045 for the present black & gold Converter Automatic Chronograph – a fair price for a watch of that quality and with a modern automatic chronograph movement.
More details about the collection and orders at www.hamiltonwatch.com.