And then it happened again. I have been rather impressed with my first DJI O3 machine, the 5" SpeedyBee, and generally very impressed with the whole O3 system - everything really feels next level, it's kind of amazing. So I felt that I needed a smaller machine, and something without any signs of props in view.

I ended up going for a 3.5" frame as I felt that might give a bit more oomph and stability over just a 3". And, moreover, I found this Cloud-160 frame that had a nice set of O3-specific features - Air Unit mounting point with a heatsink built into the frame, pre-printed TPU parts to hold various antennas and such, and TPU soft side mounts for the camera - although I suspect that the effect of the latter is minimal as the TPU is in full contact with both camera and frame. So it was the right size, looked like it would offer a clean build, and has the camera far enough forwards that no props should be seen. As such, it seemed a good choice.

When it came to it, I actually redesigned and reprinted all the TPU parts in grey, as that worked better visually with the silvery camera cage, and I had some ideas that I wanted to get into the build - rear mounting an LED buzzer board, and creating an internal tray to hold both the RX and keep all the leads tidy and out of the way. This tray does, however, mean that some leads had to be fed through it and then components soldered together, so taking this build apart will be something of a pain. But the tray has kept everything a lot tidier, so that's the price I am willing to pay.

The build was relatively easy, there was plenty of room in the frame and everything fitted nicely. The only problem that I really encountered was that when I came to set up the firmware, I discovered the ESC was BLHeli_S, not BLHeli_32 as I had assumed - this was a 20x20 stack that has been sitting in my spares box for a while and as it was F7, I presumed that it would be the latest and greatest of everything, but not so - another case of failing to RTFM. And this of course meant that I could not set up RPM filtering or switch the ESC PWM frequency away from 24kHz - both of which would be beneficial for the O3 EIS.

So my initial hover test was very disappointing. I engaged the Rocksteady EIS, hovered about in the back yard, unloaded the Air Unit video, and discovered it was completely unusable - a mass of bounces and tics. Just terrible. And very disappointing for a fancy new build. But I went online and did a little digging, and discovered this excellent resource: https://esc-configurator.com/ I used this site to flash my ESCs to Bluejay firmware, which in turn enabled me to switch on RPM filtering, and to change the PWM frequency to 48kHz.

When I took the machine out for another back yard hover test, the results were night and day - the Air Unit video is now smooth and stable and looks fantastic, with nary a hint of prop in view. I do love software fixes to complex hardware problems, so much easier...

Unfortunately, when I took the machine out for my initial flight tests, whilst the video looked great, the motors were just a little bit too slow for the 4S packs I had intended to use with it, and so the machine was a bit sluggish, the handling lacked snap, and because I needed to keep the throttle just a bit too high, the flight time was short. I thought about swapping out the motors for something a little faster, but decided to pick up some 5S packs first to see how that worked out.

And I would say it worked out pretty well. The machine is now way faster, it's much snappier - if anything I might need to drop the rates a touch as I was over steering in my flips (but again, this is a new machine, so still getting a feel for it). There is a bit of rattle and bump getting through to the EIS, which I had feared as the camera is pressed pretty tightly against the metal cage, despite a small amount of TPU isolation, but it's not terrible - and anyhow, I might be able to tune more of that out.

Overall, this is looking like it's a solid build, and as such is a nice, compact, poweful little 4K camera rig with no props in view. That works for me.