By advanced flyer at oscarliang.com
This Blog comes from https://bit.ly/3nd0dlF
11th August 2021
Here’s another 1S 3inch micro FPV drone powered by 18650 Li-ion battery cell by DarwinFPV. The frame itself is almost a direct copy of the HGLRC Rekon3 I reviewed but with different components. Is it better? Let’s find out.
In case you are not familiar with this type of quads, they are not for freestyle or acrobatics. They are for long flight time cruising only. The other advantage is that they are much safer and quieter to fly around than those that are powered by LiPo battery as the power is heavily reduced. You can still do a flip and roll here and there with them, but it will struggle to recover from acro moves due to the lack of thrust.
Where to Buy?
In the box there’s the quad, a set of propellers and screws for the props, that’s all.
The whole frame of the DarwinFPV 18650 is 3D printed in Nylon (multi jet fusion) including the battery tray. Printing quality is excellent. It’s also pretty strong, though it still flexes a bit when you try to bend the arms, not as stiff as the Rekon3. But considering the low power of this kind of quad, it doesn’t seem to be a problem.
The motors are slightly smaller than the Rekon3, they are 1103 12000KV.
The Darwin 18650 3-inch doesn’t come with a receiver. I think it’s designed for the Frsky R-XSR as shown in the manual, and should be plug and play, however the cable they soldered to the FC is a weird one with 4 pins, and it’s too small for the R-XSR. In the end I had to cut the connector off and soldered it directly to the receiver. Note that the FC has a SBUS pad which can take Frsky’s inverted SBUS signal.
The VTX antenna is a bit short to be honest, it barely sticks out of the frame.
The USB connector on the FC is really deep inside the frame, you will need a small USB cable to reach it.
Weight is about 60g without battery, with a 18650 it’s 106g.
One huge advantage of the DarwinFPV 18650 3-inch over the Rekon3 is the more powerful FC.
There are also just 2 UARTs in this FC, UART1 is used for receiver while UART2 is used for SmartAudio (VTX). But you can definitely hook up a GPS module to this quad if you want, which is not possible in the Rekon3. You can remap either S5 (motor 5), or LED_Strip to Softserial and use that for Smart Audio to free up UART2, and use UART2 for GPS. There’s also Buzzer pads if you want to use a buzzer.
You will also need a 18650 Li-Ion cell to fly the Rekon 3, ideally something with high discharge rate. The recommended battery is Sony VTC6, VTC5A also works but with slightly less capacity.
How to Setup
FC board: MTKS/MATEKF411, Betaflight firmware version 4.2.5. You can find the original CLI dump here
Here’s how I set it up for first flight:
- Solder and bind RX to your transmitter, receiver works right away without any configuration changes, I am using Frsky XM+
- Setup arm switch in modes tab
- Setup OSD (NTSC) to display voltage and timer
In power tab, voltage warning and minimum voltage should be set much lower (e.g. 2.9V, 2.7V), but they were all left at default.
Out of the box it definitely flies a bit smoother than the Rekon3 that gave me some vibrations. But flight performance and handling are more or less the same, the smaller motors don’t actually make a noticeable difference when I am flying.
Flight time is similar to the Rekon3, about 12-14 minutes depending on how aggressive you fly. Nothing out of the ordinary really, it flies just as you would expect from a 3″ quad powered by 1S 18650.
What Can Be Done Better?
It’s $30 cheaper than the Rekon3, which is a good deal given that the specs are similar between the two. The DarwinFPV 18650 is nowhere near perfect, but between this and the Rekon3, I’d probably pick the Darwin because you have to spend just as much time and effort to set it up and it does fly a bit nicer.
I only wish they offer receiver options such as Crossfire and ExpressLRS, which would make it easier to setup and have great range. Also it would be nice to use a CP antenna for the VTX. With the current setup and a Frsky receiver, the range is only about 400-500m. After all the idea behind this setup is long range.
Finally, Betaflight settings are mostly left at default, things like voltage warning and OSD should be set specifically for this quad.