FPV gear makers Axis Flying are known for quirky products, but their CNC upgrade kit for the DJI O4 standard airunit—also called the lite air unit—might just be the practical mod no one expected but many need. It offers protection and cooling for the barebones board DJI shipped, which can overheat faster than you can say “thermal shutdown.”
Why This Matters
The DJI O4 release split the airunit crowd: the hefty Pro model wrapped in aluminium and dual antennas, and the barebones standard (or lite) version. The lite unit is lightweight and voltage-flexible but comes naked—no casing, no cooling, no protection. That’s fine for tiny whoops, but anyone pushing it in bigger quads or wings faces overheating and damage risks.
Axis Flying’s Solution: CNC Metal Heat Sink and Camera Housings
Axis Flying offers a full CNC-machined metal casing for the airunit and metal housings for the camera. Both aim to protect and cool the components. The camera housings come in 14mm and 20mm options, letting you fit the lite cam into standard FPV frames, a welcome upgrade for those unwilling to spring for the Pro.
Heat Sink Details
The heat sink is a precision-machined aluminium block designed to meet key ICs on the board—the RAM chip and main processors—via thermal grease supplied in the kit. It clamps around the board, leaving USB-C, antenna, and bind button accessible. The casing also offers some physical protection, especially around the antenna.
Camera Housing Build
The camera case includes a protective glass lens and is CNC-machined to touch the back of the camera sensor for heat dissipation. It supports traditional mounting patterns (14mm or 20mm), has cable exits, and comes with screws and thermal paste. The housing adds bulk and weight but offers thermal benefits and frame compatibility.
Thermal Testing: Barebones vs. Heat Sink
Testing under a thermal camera reveals the bare DJI O4 lite airunit runs hot—even in standby mode, it hits 80+°C on key chips and quickly throttles or shuts down. The RF chip area heats up but isn't the main culprit; the processors and memory generate the most heat.
Without cooling, the unit overheats in seconds, making it impractical for anything but very short flights or low-power modes. The heat sink changes the game. Mounted with thermal paste, the unit runs significantly cooler, maintaining stable temperatures in standby and recording modes for several minutes without overheating.
Recording Mode Stress
When recording at 1080p and max bit rate, the heat sink keeps temperatures manageable for over two minutes before the unit finally hits thermal shutdown. This is a marked improvement over the bare unit, which overheats almost immediately under the same conditions.
Camera Thermal Performance
The camera housing slightly raises the temperature on the back of the sensor (around 55-56°C), but the protective glass prevents lens damage. There's a minor risk of lens flare from the extra glass, though it can be removed if needed. Overall, the housing balances protection and thermal management well.
Weight and Mounting Considerations
The combined weight of the air unit, camera, antenna, and housings is about 20.7 grams—heavier than the bare unit but still reasonable for non-ultralight setups. The heat sink retains the original 25x25mm mounting pattern, so it fits standard FPV frames. Standoffs and screw holes allow mounting with airflow in mind, crucial for fixed-wing or ground vehicles.
Who Should Buy This Upgrade Kit?
If you want to run the DJI O4 lite air unit in anything bigger than a tiny whoop, this kit is a no-brainer. It offers physical protection and thermal mass to keep your air unit cooler and running longer. However, it won’t let you run the unit entirely without airflow—you still need some breeze or a fan for sustained use.
The camera mounts let you use the smaller lite camera in traditional rigs without hacking, a practical plus for those wanting to avoid the Pro’s bulk and price.
Pricing and Availability
Axis Flying keeps the kit affordable: the 20mm camera housing costs $4.90, the 14mm version $11.90. The air unit CNC heat sink is $11.90. You can buy components separately or as a set for around $16-$20, making this a budget-friendly upgrade with real-world benefits.
Final Thoughts
Axis Flying’s DJI O4 CNC upgrade kit turns the barebones lite air unit from a hot mess into a much more manageable piece of kit. It’s simple, effective, and cheap. For anyone running the lite air unit in bigger quads, wings, or ground rigs, it’s worth serious consideration.
Just remember: no heat sink can fix physics. You’ll still need airflow or a fan to keep things cool during extended flights.
FAQ
- Does the heat sink allow the DJI O4 lite air unit to run without airflow?
No. The heat sink improves thermal dissipation but airflow or a fan is still necessary for sustained operation. - Can the camera housing cause lens flare?
Potentially yes, due to the added protective glass, but the glass can be removed if needed. - Will this upgrade kit fit in standard FPV frames?
Yes. The camera housings come in 14mm and 20mm mounting patterns compatible with traditional frames, and the heat sink retains the 25x25mm mounting pattern. - Is this kit compatible with the DJI O4 Pro air unit?
No. It is designed specifically for the DJI O4 standard (lite) air unit. - How much does the upgrade kit weigh?
The combined air unit, camera, antenna, and housing weigh approximately 20.7 grams.
Takeaway Box
- Axis Flying’s CNC heat sink cools the DJI O4 lite air unit, preventing rapid thermal shutdown.
- Metal camera housings (14mm/20mm) protect the lens and enable mounting in standard FPV frames.
- Without airflow, the air unit still overheats, but the kit extends operational time considerably.
- The upgrade adds ~20.7g weight but offers valuable protection and cooling for bigger quads or wings.
- At $12-$20 for the kit, it's a cheap, practical mod for DJI O4 lite air unit users.
This article was based from the video Axis Flying DJI O4 Airunit CNC Upgrade Kit - Cool & Protect!
