XL8 X4 Quad

By Dragunovgeorge on Oct 20, 2018

1  430  3

Right well this is my first build writeup and prompted by the lack of info on using the JR XBus receivers with Betaflight. The beauty of this setup for me is that with the following apps, I am able to set up & flash the flight controller, and configure the escs all from my Samsung S9 (which is with me in the field as a fpv monitor) using its OTG (on the go) functionality:
• Speedy Bee
• Drone Flasher
• BLHeli_32
I use an Eachine ROTG02 mounted on the back of my XG8 that plugs into my phone with the FUAV app to use my phone as a monitor to avoid taking extra powerpacks/monitors/receivers.

So my aim was to make a larger than 250 build (but smaller than my 650 DJI Tri-copter) running Betaflight that was light (auw of 550g with a 3S 2200mah), able to capture HD video, would work with my JR Pro XG8 and had a decent enough fc that it could cope with whatever I wished it to do.

• Matek F405-STD Flight Controller
• Matek FCHUB-6S PDB (ribbon cable connection to fc)
• JR XG612B XBUS Receiver
• Makerfire 35a Brushless ESC (4pcs) BlHeli/DSHOT (no bec)
• Crazepony 2205 2300kv Motor (4pcs)*
• ImmersionRC 200mW VTX
• RunCam Split Mini 2
• XL8 (360mm) Frame Set
• 7x3.5x3 HQProps

*I may swap out to a lower kv motor if I get the chance however I had these around

So here we go...

Receiver setup & wiring

On the XG8 transmitter (should be similar for others)
• System list > X.BUS > Bus Type: Mode.B

The RX is connect to the fc as follows:
• Signal - RX2
• Positive - 4v5 (from the sbus connection)
• Ground - G (again from the sbus connection)

In Betaflight:
• Ports > UART2 set to RX
• Configuration > Receiver > Receiver mode: Serial based receiver (Speksat, SBus...)
• Configuration > Receiver > Serial Receiver Provider: XBUS_MODE_B
use this for an official JR Receiver. The other Mode B is for JR DMSS compatible receivers

Now in Betaflight you will notice that none of your stick inputs match the channel outputs so this an be corrected as follows:

In Betaflight CLI tab:
• Enter 'MAP AER1T234'
• Enter 'SAVE'
• Exit CLI and reboot

If you should check the channel mapping again and see if the ranges are correct... both times I've done this they weren't so we can correct this. Note down the current ranges for your channels and then....

In Betaflight CLI tab:
• Enter 'RXRANGE' which will give the 4 current ranges
• Enter 'RXRANGE 0 0950 2049' only using the actual ranges you noted earlier for channel 1
• Repeat this replacing 0 with 1 for channel 2, 2 for channel 3, 3 for channel 4
• Enter 'SAVE'
• Exit CLI and reboot

Check the channel mapping which should all be sorted.

Motor setup & wiring

Now for the FCHUB-6S PDB wiring which I connected to the fc using the ribbon cable to avoid extra wiring & soldering.

If you position the pdb so that the battery connection is facing the rear of quad, the pdb motor positions match the Betaflight positions which are:

  1. Rear right
  2. Front right
  3. Rear left
  4. Front left
    The power is soldered positive, the signal to the signal pad, and the 2 negative both soldered to the negative pad. For the motor wires I soldered these in a way that looked tidy as I can reverse the motor direction through the BLHeli app as I don't any to run these bidirectional at the moment.

In Beaflight:

• Configuration > ESC/Motor Features > select the correct protocol which for me is DSHOT300
• Modes > Flip over after crash - zer to an Aux Channel (turtle mode available when using DSHOT)

VTX setup & wiring

The wiring of the vtx is fairly straightforward as is has 2 sets of connections, the 1st being the power for the device and the 2nd being the video signal. The pdb has 3 power out options
• G / 5V - this is a 5 volt supply
• G / Vcc - this is a voltage supply equal to the pack
• G / 10V - this is a 10 volt supply
Now simply put, match the supply to the requirements of your vtx. As I don't intend to use more than a 4S lipo I selected the Vcc. If I were to use 6S then I'd use the 10V. Just select the one that suits your setup.

If you wish to take use the fc's odd, then the final connections to make are the video/gnd inputs to the vtx which are wired to the VTX & G on the front edge of the fc.

Runcam Split Mini 2 setup & wiring

If you choose to use the 'soldering method', this camera has 5 connections:

  1. Video
  2. GND
  3. VCC (5-20V)
  4. TX
  5. RX
    The front edge of the flight controller has:
    • Cam - connected to Runcam Video
    • 5V - connected to Runcam VCC
    • G - connected to Runcam GND
    The final connections for the Runcam are
    • TX - connected to RX4
    • RX - connected to TX4
    These connections enable remote control over the camera. In Betaflight
    • Ports > UART4 set to Runcam Device
    This provides the following options that can be assigned to any available Aux signal.
    • Modes > Camera wifi (this is used to confirm selection in the cameras OSD menu - once i set everything up I no longer had this configured)
    • Modes > Camera power (is used to start/stop recording) and is the only option I still have configured)
    • Modes > Camera change mode (switches between camera & the menu options)

Betaflight settings

I'll be completely honest this section is mainly down to preference. The main one to consider is
• Modes > Arm > set to a free Aux channel (once the quad is armed it automatically enters Rate mode
Under the OSD menu I have most options disabled with the exception of voltage, horizon and mah drawn.

And that pretty much covers everything :)

I have only run a few packs though this but it has easily enough power, is stable and without pushing the packs I got 8 mins flight. My next flights will be monitoring the mah & battery voltage to see how long i can actaully get on a flight.

Anyway if you read through this all then well done, and I hope it can help a atleast one person.



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Zackthrills   Jun 13, 2021  

Hey my pilot name was Zackthirlls and I was sponsored thru JR radios when drones where first coming out and the xbus protocol is very fast just not used but I'm glade u figured it out or I would have been happy to walk you thru it. I have taken a long break from flying and racing and I am just now looking to get back into it and think I'm just going to go the common Taranis as it's just much easier and setup takes seconds but look forward to flying really soon

Mike V   Apr 28, 2019  

Dragunovgeorge, i plan to do the same thing....add some 2205/2300 extra motors to this frame, and move an old set up into it. What size battery are you using. After a year, any comments or changes to this build?


Dragunovgeorge   Oct 29, 2020 

hi Mike,
took a break from flying for a while due to other commitments.
I've changed now to using a taranis x7s with r9 module for better range

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