DJI Snail Review
The world leader in drone technology DJI has entered the Drone Racing market with the new DJI Snail racing propulsion system. The DJI engineers optimized the motors, electronic speed controllers (ESC) and propellers for the needs of the FPV racing pilots. I am going to review the propulsion system, make some thrust tests and finally share my flight experience.
What´s in the package:
4 x 2305 2400kv Motors (2 CW and 2CCW)
4 x 430-R ESC (incl. additional heat-shrink tube)
M3 5mm and 6mm mounting screws
Manual and safety instructions
DJI Snail propellers as well as the ESC programmer are optional. You can choose between normal mount propellers or the DJI quick-release propellers. The last are using the same quick-release system as the DJI Mavic Pro or the new Phantom 4 Pro.
The build quality of the 2305 motors is superior. Motor is very smooth and there is no vertical play in the bell. The quick release system of the CCW motors is marked with white dots, so you can pick the right propeller while mounting it.
Mounting holes pattern is standard M3 19 x 16mm. The holes are protected, so there is no way to short and burn the motor while using longer mounting screws.
The Snail 430-R racing ESCs are rated for maximum 4S LiPo battery and maximum continues current of 30A. It features the well known OneShot125 signal protocol as well as regular throttle signal. Currently there are even faster protocols available (OneShot42, MultiShot) for BLHeli firmware based ESCs, but DJI decided not to use these for some reason.
Active Braking function is available (known as Damped Light on BLHeli ESC) and helps for better motor response while decelerating.
3D mode with the 6048 3D propeller is possible after activating it in the DJI Assistant 2.
On the picture above you can see the DJI microcontroller chip (MCU) with integrated gate driver running at 100MHz. Most of the current ESCs on the market use MCU (max 50Mhz) and dedicated gate driver chip. The better clock speed of the MCU could lead to better overall performance of the ESC, however I am not sure if it will be a significant and noticeable difference.
I have used a 4S 16.000mAh LiPo battery for the thrust test of the 2305 motor. Attached was the quick release 5048S Tri-blade propeller.
|ESC signal (µs)||Thrust (gf)||Voltage (V)||Current (A)||Electrical Power (W)||Efficiency (gf/W)|
Maximum thrust was 1183g. I couldn´t achieve the 1.35kg thrust that DJI measured, because the battery voltage dropped to almost 16V and I am not at sea level. I haven´t tested another 2400kv motor, so I can´t make a real comparison, but the almost 1.2kg thrust looks very promising.
In order to test the Snail propulsion system in flight I need to build another quadcopter. I have used my SG Acro frame with 4mm carbon arms and 210mm distance between the motors.
First of all I have mounted all four Snail motors on the arms and cut the cables. Next I soldered the 430-R ESC to the motors by reversing the cables of the CCW motors. You can reverse the motor direction using the DJI Assistant 2, but you need the ESC programmer.
Next step was soldering all 4 x ESCs power cables to the Realacc power distribution board (PDB).
I am using the AirBot Flip F4 flight controller flashed with Betaflight 3.0.1.
Note: If you are also going to use Betaflight make sure you reduce significantly (about 50%) the standard PID values. I got some strange oscillations when making a flip/roll or tilting the quad more than 45 degree before decreasing the PID.
The quad is very responsive. I can´t make any noticeable difference with one of my other racing quads using BLHeli ESCs. The mini drone weighs about 430g with a 4S LiPo battery and is super powerful with the 5048S Tri-blade propeller.
What impressed me a lot, was how quiet the propeller were. I also think, that the flight time was significantly more, but for now I can not confirm.
I like the build quality of the complete DJI Snail racing propulsion system (after 4-5 crashes no broken propellers so far). Performance is also very good and at the same level as current racing propulsion systems. Manual is good and contains notes how to build your drone using the DJI Snail. The package costs 89$, which is a very good price for 4 x motors and 4 x ESC. A set of 4 quick release propellers cost 4$.
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