Hands-on Review: A Pair of Hamilton Khaki Aviation Converters

The H76635730 and H76726530, new from Hamilton

The Skinny

Khaki Aviation Converter Auto
Diameter: 42 mm
Thickness: 12.2 mm
Lug width: 20 mm
Movement: H-10 (80 hour power reserve)
Water Resistance: 10 ATM (100 meters)
Bezel: Logarithmic slide rule
Bracelet: calf leather
Price: $1,195

Khaki Aviation Converter Auto Chrono
Diameter: 44 mm
Thickness: 14.6 mm
Lug width: 22 mm
Movement: H-21-Si (60 hour power reserve)
Water Resistance: 10 ATM (100 meters)
Bezel: Logarithmic slide rule
Bracelet: calf leather (also available
on stainless steel bracelet)
Price: $1,995 on strap

The Elephant in the Room

Is it fair to call these new aviation watches from Hamilton “homages” to the Breitling Navitimer? While a number of watches from different makers use a similar style of logarithmic or flight computer bezel, the Breitling version is iconic and it’s impossible to avoid the comparison. And while on closer inspection there are some subtle differences – the edging of the bezel on the Breitling is beaded, for example, giving it a more luxurious feel – there is no denying the Hamilton is a less expensive version of the Breitling (at about a quarter of the cost.) Not a direct homage, but clearly riffing on that iconic watch.

L: Breitling Navitimer, R: Hamilton Converter.

It’s worth noting that while some Hamilton watches have had slide rule bezels in the past, the bezels themselves were not of this “E6B” flight computer style and the overall watch designs of the previous Khaki X-Wind and X-patrol did not mimic the Navitimer. Hamilton themselves told me that this line is a brand new approach and not a reissue.

I’m Not a Pilot

I’ve flown a plane once in my life. It was brief, exhilarating and made me extremely nauseous. As a 30th birthday present, my wife bought me a flight on a glide plane. I sat in the front of the cockpit with the pilot behind me. My first task, once we were off the ground, was to release the tether from the crop duster that had taken us up a several hundred feet. Then the pilot moved us to under some clouds so we could begin our slow, circular climb higher and higher. Once we reached 3000 feet, he offered me the controls. “Keep your eyes on the horizon,” he calmly told me, “and turn the plane very slowly.” Once I had control, two things happened simultaneously; I realized I had finally fulfilled a dream I’d had since I was 10 years old, watching Mark, the fearless leader of G-Force, piloting his single prop racing plane: I was flying. And I became more nauseous than I had ever been in my life. I relinquished control, and the pilot brought us safely down to earth.

Maybe one day I’ll fly again, but I doubt it. Even if I do, however, I will in no way need a slide rule bezel aviation watch to help me calculate air or ground speed, fuel use or any of the myriad other things they can do. Much like dive watches, these purpose built tools aren’t used for the purposes they were built for anymore. We have much better, more precise and more reliable tools now, and aviation watches, like dive watches, have become “lifestyle accessories.”

Which brings me to the new Hamilton Khaki Aviation Converter line of watches that seem to straddle the line between useful tool and stylish accessory.

[Image courtesy Hamilton]

The most obvious design feature on these watches is the slide rule bezel. While its layout is identical to the Breitling Navitimer’s, the Hamiltons feature more precise details, like markers to more easily calculate speed, distance and fuel usage. Hamilton states: “Calculate critical conversions and metrics at a glance with the Khaki Pilot Converter Auto Chrono’s bi-directional, rotating slide-rule bezel.” You’ve got to be kidding. No one, not a pilot, not someone just along for the ride, is going to use this for its intended purpose.

I once had a slide rule watch (a Seiko SNA411 Flightmaster) and while I did play with the bezel, it was for currency exchange on my last trip to the US (in January of 2020). Here’s an example of how it works: currently, a US dollar is worth about $1.30 Canadian. So I’d rotate the bezel so that the “13” on the outer bezel (representing $1.30) lines up with the “10” on the inner bezel (representing $1). All I have to do is compare any number on the fixed bezel (as US dollars) to the rotating bezel (CAD dollars).

Or I could just use my phone.

The profile of the Khaki Aviation Converter Auto Chrono

Which leaves us with modern aviation watches as style items. And, of course, there’s nothing wrong with that, especially when they are well executed. While all those extra red markers on the bezel are supposed to help with calculations, what they also do is bring visual harmony and interest to the entire dial. But while these new Hamilton watches are, in my opinion, exceptionally well executed, they aren’t to my taste. The Khaki Aviation Converter Auto (H76635730) for example, is well finished and a pleasure to look at. But I have to admit the addition of rose gold plated bezel edge and crown make it too blingy for me. And the chronograph while, again, stunning in its appearance, is just too bulky and tall – 44mm wide and almost 15mm thick – for my wrist.

Khaki Aviation Converter Auto

I have to admit, the first moment I looked at this watch, I was put off by the rose gold bezel. But for someone more comfortable rocking gold on a large tool watch, the execution is remarkable. I love the general design and look of the watch, with its classic flieger shape, lugs flowing out instead of attached to the case. The bezel itself is so satisfying to use. Not the slide rule calculation stuff, but just moving it back and forth: there’s enough tension that you can position it precisely and it shouldn’t move with a light touch. The crown, also in gold tone, is solid and satisfying to wind. Speaking of winding, though, I was a little surprised that I could hear the rotor spinning around occasionally while wearing the watch, not something I particularly enjoy.

The dial itself is exceptional. The finishing is superlative, with no blemishes or poor execution at all under a loupe. I enjoy the subtle things on such a busy watch, like the hour numbers in a dark grey. And while I’m not a fan of the rose gold, the nickel accents on the indices and hands make them nicely stand out. Plus, that red tip to the seconds hand is perfect, tying together all the red highlights on the watch. However, of what Hamilton offers, I think I’d prefer the simple stainless steel version H76615530. Simpler and more classic. Or better yet, in the style of the blue GMT version. Hopefully they’ll offer it some day.

At just over 12mm tall, the watch is thin and light enough, with curved lugs, to wrap and wear comfortably on the wrist. But the croc-style calf leather strap, while comfortable, is flawed. On my model, as well as another I saw at a virtual presentation, it squeaks as you move the strap back and forth, even while wearing the watch. It seems that either the straps are a bit too wide for the lugs or there’s a bit too much edge dressing added to the strap. Either way, Hamilton is aware of this issue and looking into it.

The movement that powers the Converter Auto is the H-10, Hamilton’s version of the ETA C07.111. It beats along at 21,600 with an impressive power reserve of 80 hours and is the movement you’ll find in many, many Hamilton three-handers, with or without a date, including the Khaki, Jazzmaster and Railroad lines.

Khaki Aviation Converter Auto Chrono

Now this is a proper aviation chronograph. Even though it is too bulky (heavy and tall) for my liking – at 44mm wide and almost 15mm thick – it looks stunning and feels like a solid tool watch. The chronograph pushers, which require some force to depress, have a satisfying click to them. Like the other Converter, the bezel action has just the right amount of tension. The version I reviewed was on a leather strap (22mm wide at the lugs, which didn’t squeak, by the way) but I’d personally go for the stainless steel bracelet option, which looks even more badass (and you can always swap in a strap). Also like the other Converter, this chrono is very well finished, without a single flaw under a loupe.

I particularly like the design choices made on the dial. While the seconds subdial is black, the two chrono subdials feature a grey circular gradient and polished edges, that really sets them off. I also noticed something on this watch, actually, that I didn’t on the black version (even though it’s also there): the outer edges of the lugs are beveled and polished. This makes the lugs look even thinner than they are, tapering in slightly. A lovely touch. And while the dial is clearly riffing on the classic Breitling Navitimer (more on that later) this is a fantastic alternative.

There were a couple of oddities I noticed, but I’ll chalk them up to this being a sample watch and not the final version: the chrono seconds hand doesn’t line up perfectly at 12 o’clock; and the movement is finished differently, with the production version not having the brick pattern on the plate you can see in the photo below.

As to the movement in the Converter Auto Chrono, it’s the H-21-Si found in other Hamilton chronographs in the Khaki, Jazzmaster and Broadway lines. Based on the ETA/Valjoux 7750, it beats at 28,800 and has been modified to improve accuracy and increase the power reserve from the standard 42 to an impressive 60 hours. Hamilton also states that the state-of-the-art silicone balance spring “negates the powerful magnetic forces found around airplane cockpits and flight decks.” Which matters not one bit to the many of us, myself included, who spend next to no time around cockpits and flight decks.

So while I still haven’t found the right aviation watch for me – not for racing around in a single prop plane, by the way, but for building plastic models – these are two solid entries from Hamilton if you’re a fan of the Navitimer aesthetic.