Fractal 75 Pro Max HDzero "Sophon One"

By hashslingingslasher on Jan 22, 2024

3  0  1

I went with the Pro Max version that allows for 45mm props with a 84mm wheelbase to help support the extra weight of the HDzero system. This thing has too much punch for me personally with the space and skill level I am working with for indoor use other than cruising around, but was made for the backyard and small nearby parks in anycase. Instead of the 1002 22kV motors used here, I would consider the 0802 25kV 1.5mm shaft motors that Fractal Engineering has on their site currently, to save some weight and potentially get even more out of the 45mm props. There wasn't any 1.5mm 0802 options when I originally bought the materials for this.

This is a tight built when using the Fractal HD hardware and there is some small pad soldering required for the HDzero whoop lite. Compatible FC's official used by Fractal BNF's are the Happymodel Cross F4 and Happymodel ELRS F4. I believe the X12 lite would work as well. I tried to originally use the HM CrazyF405 but due to the UART JST plug on the opposite side of the micro USB and motor plugs, it wouldn't fit.

Trying to make it work with that FC would've lead to the motor plugs being higher than the ducts, exposing them to more potential damage. Additionally, despite the datasheet saying the motors will pull 10amps, other people have said their 5A ESC's had no problem keeping up, so downsizing to the Cross F4 saved a bit of weight as well. That FC will make it onto the next microdrone build.

The FC/VTX stack included with the frame/HD kit are self tapping screws so that there's no head/nut poking through into the battery holder area, something to keep in mind if you wanted to use machine screws instead.

I originally made the BT2.0 pigtail too short, and became too difficult to pull the battery from the pigtail. I ended up taking the .75g penalty and adding on a little length without disassembling the rest of the stack.

I used Quicksilver firmware on the FC instead of BetaFlight, since the creator of the frame has tuned templates specfically for these builds. It was quite easy once the correct drivers were installed per the troubleshooting section of the install guide. The default was a props out configuration on the template and once that was setup properly, this thing immediately flew with control and power.



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Jodie Froster   Jan 24, 2024  


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