Monochrome Watches
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Chocks Away With The Hamilton Khaki Aviation Converter Auto Chrono

A very capable aviation chronograph for proper pilots (and enthusiasts).

| By Robin Nooy | 4 min read |

If you’re at all familiar with Hamilton’s portfolio of tool watches, you’ll know about its various Khaki collections designed and built to tackle adventures in the water, on land and in the air. The company has a long history in all three fields of tool watches and is very capable of offering good, reliable timekeeping instruments with a purpose at sensible prices. Presented in 2020, the Khaki Aviation Converter collection fits the bill perfectly. It comprises time-and-date, GMT and chronograph watches with a very clear purpose; Flying. The clue is in the name of course, but each one comes fully equipped with a slide rule bezel construction allowing for precise calculations ‘on the fly’. We now bring you the Khaki Aviation Converter Auto Chrono in blue, a variation added to the collection a couple of months ago.

With over a century of aviation-related watchmaking under its belt, Hamilton sure knows a thing or two about the subject. It was Hamilton after all, who first provided the U.S. Airmail services with watches in 1918. This was not that long after the successful flight of the Wright brothers, to give you a sense of the timeframe. The outbreak of the First World War certainly accelerated things, and in the years that followed, the pilot’s watch became a staple for many brands. This history is reflected in Hamilton’s Khaki Aviation collection of pilot’s watches in both vintage and contemporary styles.

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The Khaki Aviation Converter Auto Chrono is the most purposeful watch in Hamilton’s line-up. The 44mm wide steel case, nicely finished with brushed and polished sections, feels robust and sturdy enough for the task at hand; taking flight. With a height of 14.60mm, it is a pretty sizable watch, but not much bigger when compared to standard chronographs. Modern features such as a sapphire crystal on both sides and 100m of water resistance are standard. It is topped with a bidirectional rotating slide rule bezel that, together with the scales on the inside, is based on the principle of the E6B flight computer first developed in the late 1930s and is still in use today.

An E6B flight computer commonly used by student pilots. These flight computers are used during flight planning (on the ground before takeoff) to aid in calculating fuel burn, wind correction, time en route, and other items. In the air, the flight computer can be used to calculate ground speed, estimated fuel burn and updated estimated time of arrival. source: wikimedia

It is basically a mechanical, analogue computer to perform timings and calculations in a single device, a crucial tool for pilots. As explained in our hands-on story when the collection was released in 2020, the slide rule lets you calculate distances, speeds and fuel consumption but also unit conversions such as kilometres to nautical miles, pounds to kilograms and feet to meters. Provided you have come to grips with the user manual, of course, as it’s quite complicated to use. But for trained pilots, and perhaps hardcore enthusiasts, this should be known territory.

This new edition comes in a cool blue colour scheme, both for the bezel and the dial. The sunray brushed finishing plays with the light and despite the many indications on the watch, it remains fairly easy to read (pretty important in a pilot’s instrument!). The dial has an inner slide rule scale on the sloping outer flange, with a tachymeter scale on the outside edge of the main dial. The hour markers are applied, and finished with Super-LumiNova, as are the hands. The central chronograph seconds hand stands out thanks to its bright red tip, a colour also found on the slide rule elements. The three subdials are recessed into the dial, with a polished bevel around the outside of the ones for the chronograph. The third one, positioned at 9 o’clock is for the running seconds. Finally, the day-date window has a silver frame, with Hamilton’s logo just above it and the word “Converter” just below. All in all, it feels busy but balanced.

You need a reliable engine in circumstances where you want to be able to rely on your wrist calculator, and the Khaki Aviation Converter Auto Chrono certainly delivers. We’re already acquainted with the H-21-Si automatic chronograph movement from the previous versions, including the Air Zermatt limited edition, and it’s based on the tried-and-tested ETA/Valjoux 7750. This robust movement has been improved to provide a 60-hour power reserve. It also comes with an anti-magnetic Nivachron hairspring. It can be seen through the sapphire crystal caseback, although the large rotor hides most of it.

The very capable Hamilton Khaki Aviation Converter Auto Chrono comes on a leather strap with the typical H-shaped pin buckle or a stainless steel bracelet with a folding clasp. And although the practicality of such a tool on a bracelet can’t be denied, there’s something about the combination of blue and cognac that just works wonders on the wrist. Also, at EUR 2,245, it’s certainly not too expensive for a very reliable and focused automatic chronograph. The steel bracelet ups that price to EUR 2,295, which is extremely reasonable in terms of the price difference between the two.

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1 response

  1. Hamilton seems to be borrowing from the Breitling’s Navitimer and some of their other pieces resemble the Top Time. Hamilton has always been on of the best values around for a daily use piece or one that you can wear to knock around but now that they’re doing this I would be less incline to put one on my wrist.

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