Having trouble installing the DJI O4 Wide Air Unit in your drone? These mounting adapters and CNC cases could make things much easier. They essentially convert the O4 Wide into a form factor more similar to the O4 Pro, making it compatible with a wider range of frames.
The CNC cases also double as heatsinks, helping to reduce overheating while offering additional protection in crashes.
In this review, I compare options from Flywoo, DeepSpace and RunCam, looking at mounting compatibility, cooling performance, size, weight, camera adapters and extension cables to see which one might suit your build best.
Further Readings:
Where to Buy
Flywoo O4 Wide Kit
Flywoo O4 Wide Air Unit set (Includes the CNC case, camera adapter and other accessories)
DeepSpace O4 CNC Case
DeepSpace CNC Case
Runcam O4 CNC case
Runcam CNC Case, Camera Adapter, extension cable etc
O4 CNC Case: Which Brand Is Best?
Mounting Pattern
Left: DeepSpace; Right: Runcam
Left: DeepSpace; Right: Runcam
Flywoo CNC Case
The O4 Air Unit (both the Lite and Wide versions) is designed primarily for micro quads and only has a 25.5×25.5mm mounting pattern. This can make installation in larger frames less convenient. A CNC case is effectively a mounting adapter as well, providing both 20×20mm and 25.5×25.5mm threaded mounting holes, which makes it much easier to install in a wider range of frames.
All mounting holes use M2 screws.
| 20x20mm Mounting | 25.5×25.5mm Mounting | |
| Flywoo | One side | Both sides |
| DeepSpace | One side | Both sides |
| Runcam | Both sides | One side |
Cooling Performance
All 3 cases are made from CNC-machined aluminium alloy. Apart from providing extra protection in crashes, they also act as heatsinks.
This is particularly useful because the O4 Air Unit can overheat quite quickly when powered on without airflow. If you leave it sitting on the bench or ground, it may shut down after only a couple of minutes.
With these heatsinks installed, overheating is much less likely.
All tests were performed on my bench at an ambient temperature of around 25°C, with Low Power Mode set to Auto.
| Shutdown Time (minutes) | |
| Without Heatsink | 1:25 |
| Flywoo | 11:00 |
| DeepSpace | 8:30 |
| Runcam | 4:50 |
To keep the O4 as light as possible, it does not come with a heatsink. As a result, it can overheat quickly when there is little or no airflow. That is why it is generally a good idea to take off as soon as possible after plugging in the battery rather than leaving the quad sitting powered on for too long. When the O4 starts overheating, it first displays a warning on screen. If the temperature continues rising beyond its protection threshold, the Air Unit can shut down, and you will lose video.
Putting the O4 Air Unit inside one of these CNC cases significantly extends the shutdown time, although there are noticeable differences in cooling performance between the 3.
Apart from differences in case design, I think the heat conducting material used between the Air Unit and case makes a major difference. Both Flywoo and DeepSpace use thermal paste, and they performed noticeably better in my testing. RunCam uses thermal pads, which did not perform quite as well, but still provided a substantial improvement over running the Air Unit without a heatsink.
Thermal paste can be quite messy when you need to remove the case. Thermal pads, on the other hand, are much cleaner and easier to work with. If you regularly remove the O4 from the case and are happy with the 4-minute shutdown time, RunCam’s solution may be more convenient. However, if your priority is the best possible passive cooling performance, thermal paste is definitely better.
Flywoo CNC Case
DeepSpace CNC Case
Weight and Size
| Size | Weight | |
| Flywoo | 29.5×29.5×12 | 6.22g |
| DeepSpace | 31.5×31.5×10 | 8.02g |
| Runcam | 33x33x10 | 10.49g |
There is quite a difference in both size and weight.
Flywoo’s case is the smallest and lightest of the three. However, if you are installing one of these cases in a 5-inch quad, you probably will not notice the difference in flight. Even on a 3-inch build, a few grams may not matter much unless you are already pushing a strict weight target.
Camera Adapter
Both Flywoo and RunCam offer camera adapters for the O4 Wide camera.
These increase the camera width to 20mm, effectively converting it into a mounting format similar to the O4 Pro camera.
The designs are similar, although the mounting-hole arrangements are slightly different. Both should work well with FPV frames designed for the O4 Pro.
There is a small weight difference between them, with the RunCam adapter being about 1g lighter. Again, not a big deal for anything larger than a 3-inch quad, unless you are trying to keep the build under 250g and are already very close to the limit.
Camera Extension Cable
The original O4 camera cable is only around 5cm long. For micro quads, that is usually enough, but on larger 4-inch, 5-inch or 7-inch builds, the short cable forces you to install the Air Unit near the front of the frame. If you want to mount the Air Unit further back, you’d need a longer camera cable.
RunCam offers 15cm, 20cm and 30cm cables: https://shop.runcam.com/compatible-dji-o4…
RunCam offers 15cm, 20cm and 30cm cables: https://flywoo.net/products/compatible-dji…
Conclusion
RunCam offers a useful range of accessories for the DJI O4 Wide Air Unit, including CNC cases, camera adapters and longer camera cables. These accessories make the O4 Wide compatible with a much wider range of existing FPV frames that were originally designed around other Air Units and camera sizes.
Flywoo offers similar accessories, but some of them are bundled with the O4 Wide Air Unit as a kit. Flywoo also offers a version using the MP66 gyro instead of the original 1469D, which may be of interest if you want more reliable image stabilisation. You can read more about the stabilisation issue here: https://oscarliang.com/dji-o4-pro-gyro-stabilization-issue/
When it comes specifically to the CNC cases, Flywoo and DeepSpace performed best in my cooling test, likely helped by their use of thermal paste. Flywoo is also the smallest and lightest of the three. RunCam still performed significantly better than using no heatsink at all, and its thermal pad approach is cleaner and easier to remove.
All three work well as mounting adapters, but the dimensions and mounting-hole layouts are slightly different, so make sure you choose one that suits your frame.
For very small builds such as the BetaFPV Meteor75 Pro, I would generally avoid these types of CNC cases because the added weight is relatively significant. However, for larger builds such as 3-inch, 4-inch and 5-inch quads, they make much more sense. The extra weight becomes relatively insignificant, installation is much easier, and you gain both physical protection and improved cooling.
For many pilots, the O4 Wide may also be a more affordable alternative to the O4 Pro, especially when paired with the right mounting accessories.
