What's Ticking Inside Your AVI-8? A Guide to Our Watch Movements

So you've got your eye on an AVI-8 — or maybe you already own one and you've found yourself staring at the dial wondering what's actually going on inside. What's making those hands move? What's the difference between an automatic and a meca-quartz? And does any of it actually matter? 

Short answer: yes. Long answer: let's get into it. 

You don't need to be a watchmaker to appreciate what's inside your watch. Think of the movement — or calibre, if you want to sound like you know what you're talking about at a dinner party — as the engine. The case is the body, the dial is the dashboard, but the movement is what actually makes the whole thing go. At AVI-8, we use five different movements across our lineup, and each one has been chosen for a reason. Here's everything you need to know, explained without the jargon. 

If AVI-8 had a workhorse, this is it. The TMI NH35 automatic movement is the heartbeat behind some of our most iconic watches — the Hawker Harrier HUD Automatic, the Spitfire Smith, the Spitfire Type 300, the Hawker Hurricane Clowes, the Baldwin, the Machbuster Automatic, and more. 

Here's what makes it special: it runs entirely on movement. Your movement. Every time your wrist moves throughout the day, a tiny rotor inside the watch spins and winds the mainspring — no battery, no charging, just physics doing its thing. It stores up to 41 hours of power reserve, so it'll keep ticking overnight and then some. Pull the crown out to set the time and the seconds hand stops dead — that's the hacking function, letting you sync it to the second. Push it back in and you're off. 

The NH35 has 24 jewels (think of them as friction-reducing bearings inside the movement), it can also be wound manually if needed, and it's built to last. For a first automatic watch, it genuinely doesn't get better value than this. There's something quietly satisfying about wearing a watch that runs on nothing but the energy of your day. 

Same DNA as the NH35, but with one seriously useful upgrade — a GMT hand. That's the fourth hand you'll spot on the Flyboy Airmaster GMT Automatic, the one that tracks a completely separate time zone independently of everything else. 

The NH34 is the movement for the pilot who's constantly bouncing between time zones, or frankly anyone who's tired of doing the mental arithmetic every time they call someone in a different country. It's automatic, self-winding, no battery required, and it does two time zones simultaneously without breaking a sweat. Simple, purposeful, brilliant. 

This one's our favourite to explain because it genuinely surprises people. Meca-quartz is a hybrid — part quartz, part mechanical — and it's what powers the chronograph side of our lineup. We're talking the P-51 Mustang Blakeslee, the Hawker Hunter Duke, the Hawker Harrier Matador, the Coningham, the Chadwick, the Machbuster Chronograph, and more. 

Here's how it works: the timekeeping — hours, minutes, running seconds — is handled by a quartz crystal. Accurate, reliable, battery-powered. But the chronograph, the stopwatch function, is operated by a mechanical module. Real gears, real springs, a physical clutch. So when you hit the pusher and start timing, that chrono hand doesn't tick — it sweeps. Smoothly. And when you reset it, it snaps back to zero with the kind of satisfying click that makes you want to time things just for the fun of it. 

It sounds complicated, but the result is actually simple: you get quartz accuracy for everyday timekeeping and the feel of a mechanical chronograph when you need it, at a price that doesn't require a second mortgage. The VK63 and VK64 are two versions of this movement — same great technology, just with slightly different subdial layouts depending on the watch design. 

The CVRT 3775A is a different kind of AVI-8. It was built in collaboration with Worn & Wound Creative Services as a compact, tool-first watch for enthusiasts who care deeply about what's inside. So naturally, it needed a movement to match — and that's where the Miyota 9015 comes in. 

Made by Citizen's movement division, the 9015 runs at 28,800 vibrations per hour, which is noticeably faster than the NH35's 21,600 vph. What does that mean for you? A seconds hand that sweeps so smoothly it almost looks like it's gliding. It's also slimmer — just 3.9mm thick — which is part of what gives the CVRT its clean, purposeful profile. Same core benefits as the NH35 (automatic, hacking seconds, manual winding, 42-hour power reserve), just turned up a notch. For the watch nerd who notices these things, it's a genuinely impressive movement at this price point. 

Not every watch needs to be automatic, and there's absolutely no shame in quartz. The Japanese quartz movement powers watches like the Hawker Hurricane Carey Dual Time, the McKellar Dual Time, the Spitfire Lock Chronograph, and the Hawker Harrier Farley Multifunction — and it does exactly what it says on the tin. Set it, wear it, forget about it. 

Battery-powered and accurate to within roughly ±15 seconds per month, quartz is the movement for people who want their watch to just work, every time, without thinking about power reserves or winding schedules. Change the battery every couple of years and you're done. For watches with more complex dual-time or multifunction displays, quartz is actually the smarter choice — fewer moving parts means fewer things to go wrong, and more brain space for actually living your life. 

Honestly, it comes down to what kind of watch person you are — or want to be. If you're just getting into watches and want your first mechanical piece, the NH35 automatics are the perfect starting point; there's a romance to wearing something powered entirely by your own movement that never really gets old. If you're a traveller or a pilot who lives across time zones, the NH34 GMT in the Airmaster is basically a superpower on your wrist. If you love the look of a chronograph and want that satisfying sweep when you hit the pusher, the meca-quartz models deliver the experience without the eye-watering price tag of a fully mechanical chrono. If you're a genuine enthusiast who wants the smoothest, most refined automatic in the lineup, the Miyota 9015 in the CVRT is worth every penny. And if you just want a watch that keeps perfect time with zero faff? Quartz is your friend — always has been, always will be. 

There's no wrong answer here. Every movement in the AVI-8 lineup was chosen because it fits the watch, the story behind it, and the person wearing it. The aviation world runs on precision, reliability, and purpose — and so does everything ticking inside our watches. 

At AVI-8, we believe the inside of a watch matters as much as the outside. The dials might pay tribute to the Spitfire, the P-51 Mustang, or the Harrier — but it's the movement that brings them to life. Whether you're drawn to the mechanical magic of an automatic, the hybrid brilliance of meca-quartz, or the dependable simplicity of quartz, there's an AVI-8 built for you. 

Now you know what's ticking inside. The only question left is which one ends up on your wrist. 

Explore the full AVI-8 collection at avi-8.com