Long Range FPV Plane – Ardupilot in the Talon Pro

This is the largest autonomous model airplane I’ve built so far, I’m using the airframe of a Talon Pro which you can find here. I’ll show you how I did this project and put together all the components and firmware to make it fly.

Project Outline

Autonomous flight is an interesting topic, this project will make use of the readily available and cost-efficient technology to make an autonomous airplane, the idea is to reach the farthest distance with little human pilot intervention as possible but at the same time implement some failsafe protocols to avoid accidents.

Firmware side

We’re going to use Ardupilot software, an open-source autopilot project as powerful as any other commercial autopilot software, Ardupilot is completely free, and it works with many unmanned vehicles, for our airplane, we’ll use the Arduplane branch of the project. We need to install Mission Planner in our computer to flash the firmware and configure the whole system. An alternative firmware you could flash in your flight controller is iNav it’s much more simple to configure but some features Arduplane has will be missing in it. If you’re a beginner I recommend using iNav but in this project I’ll go with Ardupilot for more options and complexity.

Airframe - Talon Pro
talon pro joyplanes ardupilot
  • 1350mm
  • 828mm
  • 3-4kg
  • EPO
  • Medium
What you'll need

The following is a list (links) of what you’ll need to complete this project, this will include the FPV system to allow you to see the real-time video feedback, for me the project was cheaper since I already had many of the components and equipment being used, like the radio control, camera, receiver, batteries, etc. If you’re completely new to the hobby, you’ll also need tools and other supplies like glue, tape, and others. The glue I recommend for this airplane is UHU Por.

Wiring the flight controller

The F405 Wing is a good flight controller to start with, the wiring is actually easy, you just need to know in advance what sensors you’re going to use to know the ports you’ll be using from the board. Here’s a schematic of how I did it.

f405 wing

I recommend you visit the manufacturer’s website to read more information about it, in my case, my receiver with CRSF protocol can only be connected in Serial1/USART1 , so be careful with this type of details.

Download image

And for the servos, that’s the easy part, all green dots represent the PWM out and then there are the voltage and GND rails.

f405 wing servo out
Installing the peripherals

In this project, I’m using the digital airspeed sensor and a GPS with a magnetometer (compass), the rest of the sensors are built in the flight controller. The airspeed sensor is an interesting one, it uses a pitot tube that I decided to place in front of the nose of the aircraft, it goes connected to clear flexible tubes and at the other end, they connect to the actual sensor.


How do you know what cables are going where?

Since this system is using different brands there’s no standard connector, what I do is make my own JST connector or simply solder the cables directly to the board, but, how do I know which one is which? Well, every sensor includes labels for every pin on the PCB, if they’re not visible simply google {the model of the sensor} pinout, and you’ll see some pictures, that way you know what cables go where.

For UART ports, you should connect the TX of the sensor to the RX of the FC, and the RX of the sensor to the TX of the FC, the rest is the same: VCC to VCC and GND to GND, etc.

airspeed sensor
Airspeed sensor (digital)
GPS BN880, good price, enough precision.
The software side

There are two different parts, the computer software, and the firmware we flash into the flight controller, Ardupilot is what we’re going to use, it’s a complete autopilot solution for our autonomous RC plane, first, we need to install Mission planner to our computer, it will help us flash the firmware and do all the configuration by connecting the FC to the computer via USB. The configuration can be daunting, there are so many options, the best about Ardupilot is the amount of documentation available, I really encourage you to read the documentation to understand every part of the process.

mission planner ardupilot
Mission planner screen
ardupilot firmware
Firmware installation screen
The flight

After finishing the plane now it’s time to fly it, the most critical part, if you followed the Ardupilot documentation regarding all the steps you should follow then it should not be a problem, but problems always arise, even after doing the calibration and checking that everything works. It happened to me during this project, the maiden flight was a disaster, as you’ll see in the video below. The main issue was the configuration of the V-tail, changing the  MIXING_GAIN parameter to a higher value fixed it.

The video below will show you the process.

The project's video

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