Happymodel Crux3 is an ultralight 3 inch micro quadcopter capable of running 2s and 1s batteries. It ships with multiple on board and external receiver options including FRSKY, DSM and now TBS crossfire as well.
Happymodel have been quiet recently with their own brand so it is good to see them with a release again in a evolution of the ultralight micro class. This started with the Sailfly-x and Larva-x which were both in the 2.5 inch / 65mm class. The Crux3 steps up to a full 3 inch blade and uses all of their past learnings on making things lightweight in what I feel is more of a finished package.
At the heart of this lightweight quad is the CrazybeeX AIO board which houses an incredible amount of gear: F4 flight controller, 5a 1-2s BLHeli_S ESC, 25-200mW VTX and in some versions and SPI receiver (although I've chosen a model with an external receiver here). This is an evolution from the excellent board used on the mobula 6 but adds 2s capability and increased VTX power, both a welcome bonus. The nature of this board means that all you need to do is plug in a camera, motors and battery and you are away - no messing around with small wires for 5v, ground, UARTs etc. It also makes manufacture and assembly much easier for the manufacturer BUT if something fails you are up for a whole new board.
Frame
There is quite literally not much to the Crux3 frame. It is ultra-minimalist and will surely be relying on the low weight of the craft to avoid damage in a crash. Be wary if you fly over hard object or a frequent crasher. If you do wish to swap for another frame this would not be difficult given this components are very simple.
Motors
Happymodel have opted for the EX1202.5 motor here which is no doubt inspired by KababFPV's 1s babytooth 3 inch ultralight quad however the choice of 6400kV suggests this has been designed for 2s rather than 1s. Motors are mostly typical of happymodel but good to see improvement over time - standard 4 screw mounting and I can see they have now gone with curved magnets and a tighter magnet-stator gap which should make for better power. Shaft size is 1.5mm which is typical for the category (although KababFPV has gone with 2.0mm for his micro motors)
Camera
I'm impressed by the specs of this little camera - the Caddx Ant camera used here is a screw mounted 14mm wide unit that weighs just 2g. More impressive is that fact that it has 1200TVL and is fully controllable via the included remote for fine tuning. I'm looking forward to seeing how it stacks up in use. Nice to see that the canopy has four mounting points which should solve the Jello issues from the Mobula 7 and it's canopy with only 3 mounting points.
Assembly
Assembly overall is super simple since components just plug in to the AIO board - it must make assembly a dream for Happymodel. Since I opted for an external receiver this had to be wired in but there is a perfect spot that is easily accessible through a large hole in the frame - plenty of room for the larger of micro receivers, namely Crossfire Nano and FRSKY XM+. A slim, foam battery pad goes over this to lock it all in place.
So pleased they chose to go with a rubber band battery hold rather than a more bespoke and limited 3d print. It just makes so much more sense on a quad this size - cheaper, lighter, more durable and way more versatile to run any battery size.
Video performance
The Caddx ant lite actually produces a pretty good picture albeit a bit oversharpened as is typical with Caddx. With that said colours were crisp and it certainly looked good in the goggles (and obviously better than DVR below). These setting can be fine tuned via the (included) remote if required.
Flight performance
This is a VERY lightweight 2s quad, around 70g with a 2s 450mah battery. I think for this weight they have their motor choice spot on - the EX1202.5 motors are as small as they could have chosen without sacrificing the ability to manage these lightweight 3 inch Gemfan 3018-2 props. I believe 6400kV is exactly the right kV option for 2s based on my experience with 5000kV on my TP3 build being a little slow on 2s and too much for 3s.
So it's a fairly quick little quad but not as fast as a heavier, higher powered micro that runs a higher cell count. If I were to put a number on it I'd say the same as a TP3 build on 2s or about 80% of the speed of a TP3 on 3s. This board is obviously limited to 2s max but it isn't really about top speed, it's about control and efficiency
Conclusion
Two things really stuck out for me, the ease of flying right out of the box as result of clever hardware choice and a very good tune and the efficiency. On the efficiency in particular I have never seen anything like it - over 6 minutes on an old 2s 450mah battery. Sure you could fly harder than I did above but this puts it well ahead of anything I've ever reviewed especially with the not unsubstantial power this has.
As a result of the main AIO board that has ESC, flight control, VTX and SPI receiver this truly is a simple, no fuss quad. FPV performance is pretty good and overall this comes across as an excellent little package that should please everyone from the beginner-intermediate range right up to an experienced pilot.
Want to learn more? Check the official page for the latest discount.
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