TH9X (Turnigy 9x) FPV Ground Station

This is my solution to having an inexpensive FPV ground station. One of its greatest benefits is being able to easily redirect the direction of the FPV antenna without the need for an expensive antenna tracker. Keep in mind that this is made to be an inexpensive FPV platform.


Parts List:

[Qty. 1] 20cm Servo Leads

[Qty. 1] 15cm Y-Harness

[Qty. 1] Fly Sky TH-9X or Similar Radio

[Qty. 1] M3 20mm Socket Head Bolts

[Qty. 1] M3 Nuts

[Qty. 1] 1/4″ Aluminum Channel

[Qty. 1] 26 AWG Sheet Metal

[Qty. 1] 5.8 GHz 200mW TX/RX

[Qty. 1] 4.3″ TFT LCD or Similar LCD

[Qty. 1] 5.8 GHz Patch Antenna (Optional)

[Qty.1] Size M Power Plug


First I cut and drilled the panels for the mounting bracket.

Then I opened up my transmitter and drilled four 1/8″ holes for mounting the bracket through.

While the transmitter was opened, I wired the battery charging port on my radio to the +/- terminals of the pcb that lead to the battery pack. Although this consumes more of your radio’s power it is simple and allows the battery voltage of you FPV and radio equipment to be shown on the screen.

Finally I assembled the brackets together and wired up all of the components. There is very minimal wiring involved in this setup because I have created a universal futaba connection between all components that carries 12V, video signal, and ground. The power from the transmitter is wired through a futaba Y-harness that joins the video signal between the receiver and LCD as well as distributing power to each component. The power jack plugs right into the side of the 9X but it must be unplugged in order to prevent it from consuming power even when the radio is powered off.

Multiwii 1.9 Crius SE Flight Controller

The Crius SE Multiwii flight controller is a multicopter flight controller that uses Multiwii. The board can be purchased from GoodLuckBuy for $77.44. It performs well and comes packed with sensors and a FTDI basic programmer for an affordable price. This is a walk through of the steps I took to wire my Hexacopter and get it flying. Guides and additional information about this flight controller can be found at the rcgroups thread.


1 ) Solder  bullet connectors to each  speed controller.

2 ) Create a power distribution cable with six positive leads and six negative leads each with bullet connectors.

3 ) Wire two futaba terminals for auxillary power from the power distribution.

4 ) Wire and reverse wire the motors to each speed controller in accordance with the correct rotation of each motor.

5 ) Wire the futaba leads from each speed controller to the Crius board as follows:

6 ) Download Arduino v0023 and MultiWii 1.9.




7 ) Plug the FTDI adapter into the Crius and your computer.

8 ) Launch Arduino and open “MultiWii_1_9.pde” from MultiWii 1.9.

9 ) Select the “config.h” tab and uncomment (Remove the “//”) from the following lines of code:


“#define HEX6X” This will define the type of aircraft you will be using the board with

“#define YAW_DIRECTION 1” If the rotation of your props is opposite then choose “#define YAW_DIRECTION -1”

“#define I2C_SPEED 400000L”


“#define A0_A1_PIN_HEX” This will allow you to operate the hex with a standard receiver, no ppm sum signal

“#define RCAUXPIN8” or “#define RCAUXPIN12” if you want an additional mode switch, requires 6 channels

“#define FREEIMUv035_BMP // FreeIMU v0.3.5_BMP”


10 ) Save these modifications and upload the firmware to the board.

11 ) Close Arduino and launch MultiWii

12 ) Select the COM port for you FTDI adapter and press “start” and then “read”

13 ) Adjust your PID settings and modify your auxilary switches.

14 ) Calibrate the accelerometer on a level surface, the blue light will flash during this process.

15 ) Calibrate the magnetometer by rotating the board 360 degrees along each axis, you will have 30 seconds to do so as indicated by the flashing blue light on the board.

16 ) Bind your transmitter to the receiver and power on all of your equipment.

17 ) Check that your sticks are all centered around 1500, if not adjust the trim on your transmitter.

18 ) Check that the correct orientation including pitch and roll are indicated.

19 ) Remove the cable, attach the props and test fly. It may be a good idea to tether the mutlicopter to the ground for the first flight just to be sure that your wiring hasn’t resulted in any reversed motors. If it doesn’t try to flip then remove the tether and proceed, otherwise check your wiring connections between the motors and escs.

20 ) Adjust the PID setting to maintain stable oscillation-free flight.

21 ) Trim the accelerometer and gyro according to this chart:

22 ) Enable the barometric pressure sensor and magnetometer one at a time as you test and adjust the settings for each.

These are the PID settings that I am currently using, however, I have not completely tuned and adjusted all parameters:



Be sure that your props are balanced and the flight controller is well isolated from vibrations. In the following pictures you will see the amount of noise caused by vibrations without and with a foam pad under the board. Unbalanced props will have an even worse effect and cause the platform to randomly wobble and oscillate in flight.



Xaircraft Hexacopter

This is my Xaircraft Hexacopter. It is made of an extremely rigid and durable plastic composite with fiberglass panels. The frame is very light-weight and the kit includes many parts and mounts. The kit not only includes the oversize landing skids that are great for FPV, but it also includes regular claw shaped landing gear for each arm of the frame. With the claw shaped landing gear, the supplied yellow foam ball can be placed along a fiber rod between the two front arms in order to help maintain orientation. The kit also comes with a mounting panel and plenty of silicon standoffs for mounting your flight controller with. However, the hole spacing for the standoffs is 50mm and most 50mm flight controller boards have 45mm hole spacing, therefore I had to mount the board atop a dense 1/4″ piece of foam using zip-ties. The supplied motor mounts have both 16mm and 19mm spacing with M3x6 bolts for mounting various different motors. I used the 150W 1200kV Turnigy L2210C motors which fit perfectly into the mounts. These motors work excellent with 25A Redbrick speed controllers and 9x5x3 props. I went through three battery packs in about 20 minutes and the motors and escs were barely warm in 60 degree weather. Using a 3300mAh 40C LiPo I get over eight minutes of flight time even while powering 36 red LEDs and a 5.8 GHz 200mW video transmitter. It has no problem lifting a 5000mAh LiPo and a GoPro HD Hero with the protective poly-carbonate skeleton enclosure.

Hexacopter Bill of Materials

Programming the MWC Crius SE

Flight Video

$15 DIY three-axis GoPro gimbal

Assembled Xaircraft Hexa Frame

Turnigy L2210C 150W 1200kV Brushless Outrunner and GWS 9x5x3 / 9x5x3R props. Black aluminum alloy prop adapters are included with each motor as well as 3 pairs of 3.5mm gold bullets and a mounting bracket with bolts. The GWS props also come with shaft adapters for the prop adapter.

25A Red Brick ESCs with the red heat shrink removed and replaced with 30mm black heat shrink.

MWC Crius SE Flight Controller mounted on top of dense 1/4″ foam.

5.8 GHz 200mW video transmitter for FPV with standard antenna. Input to the tx is wired to a futaba connector with terminals for ground, audio, and video.

My TH9x receiver, MWC Crius SE Flight controller and 5.8 GHz transmitter are all mounted to the supplied mounting plate from the Xaircraft Hexa kit.

The Xaircraft Hexa Frame comes with a battery tray and two Velcro battery straps that attach to the loading pipes.

The included fiberglass landing skids are hollow with very thin walls. The pressure of snapping the rods into the skids was enough to slightly fracture them so I replaced them with 5/16″ dowel rods covered with black 10mm heat shrink.

Each leg of the landing skids is lined with 9 Red LEDs.

Cables for FPV and Telemetry including mini USB 5v charging cable to futaba, 4 conductor 2.5mm composite to futaba (Video, Audio, Ground) and Bluetooth Telemetry Module.

Simple FPV ground station with 5.8 GHz Receiver and a 4.3″ TFT LCD. Both the receiver and monitor are re-wired with a futaba connector for ground, power, and video.

Plano four pistol case for charging,  FPV, and radio gear.

Completed Frame with fixed GoPro Mount


X-Spider Hexacopter

This is a frame I designed to be used as an FPV platform. I never ended up using this frame because it was not very rigid so I decided to go with an XAircraft Hexa Frame. The build log for the Xaircraft frame can be found HERE.

Plans for this frame can be found HERE.

Each piece is cut from sheet metal, the edges filed, holes drilled, and the pieces flattened with a hammer.

The legs were creased in order to prevent them from folding.

Each arm was stained with Minwax Mahogany Finish and coated with polyurehane.

The frame and motors were bolted together with M3x20 bolts.

The power spider is made from several lengths of 16 AWG silicon wire. It distrubtes 11.1V to each ESC as well as two auxillary outputs for LEDs and the video transmitter.

Each ESC is mounted to the landing legs using two zip-ties.

This shows the partially completed wiring of the flight controller, power distribution, receiver, OSD, and video transmitter.