This realization sparked a hypothesis: could an autogyro (also known as a gyrocopter) serve as a suitable platform for such extreme environments? Autogyros, with their unique flight dynamics and ability to handle strong wind gusts, seemed like a promising candidate. To explore this idea further, we conducted a series of experiments.

Why Autogyros?

Unlike traditional fixed-wing aircraft or multirotor drones, autogyros use a free-spinning rotor for lift and an engine-driven propeller for thrust. This configuration provides several advantages:

• Wind Resilience: Autogyros are known for their stability and ability to fly in turbulent conditions, making them ideal for atmospheric research in stormy weather.
• Energy Efficiency: The single large rotor and flight powered by single large propeller requires less energy compared to multiple powered rotors, allowing for extended flight durations.
• Safety: In case of control or failure, autogyros should glide safely to the ground, a crucial feature for operations in unpredictable environments.

The Beginning: Setting Up the Auto-G2

With this in mind, we set out to modify the Auto-G2 gyrocopter, a small hobby-grade autogyro, and adapt it for autonomous flight using the PX4 autopilot system. What followed was a series of experiments filled with challenges, lessons, and breakthroughs.

When we received the Auto-G2 from HobbyKing, we quickly noticed some design quirks. Unlike traditional autogyros, the Auto-G2 had limited control over its rotor. It relied more on the tail surfaces—elevators and rudders—for stability and maneuvering. This made it deliberatery behave more like a fixed-wing aircraft than a classic autogyro.

We created a new “airframe” configuration in PX4. We modified the control software to suit the Auto-G2’s unique setup.

First Flight Tests: Learning the Hard Way

Our initial flight tests took place on a windy and rainy day (similar to thunderstorm conditions) at a small grassy airfield (LKSO). The Auto-G2 wasn’t designed for smooth takeoffs on grass, so we launched it by hand. At first, the autogyro climbed steadily and seemed to fly well. But soon, we noticed something wrong: in “Position Mode,” the autopilot struggled to control the motor, leading to an unexpected loss of stability.

We safely landed the autogyro and reviewed the logs. It turned out the autopilot’s default settings were not tuned for the unique flight characteristics of an autogyro. We went back to the drawing board, adjusting the parameters to improve how the system controlled the vehicle.

Upgrading the Rotor Head

After further testing, we saw that the Auto-G2’s original rotor head had limitations. It only allowed the rotor to tilt left and right, but we also needed it to tilt forward and backward for better control. To fix this, we designed and 3D-printed a new rotor head with full tilt capabilities.

But this introduced another problem. The rotor blades were too close to the tail, which risked collisions. To solve this, we moved the rotor head forward and removed the pre-rotator mechanism to reduce complexity. These changes improved the design, but they came at the cost of some convenience during takeoff.

Troubleshooting Failures

One of the biggest setbacks came during a test flight when the motor suddenly lost power. The autogyro drifted down into a tree. After a careful search, we recovered all parts of the aircraft, including the damaged electronics.

The failure was traced to overheating in the motor’s electronic speed controller (ESC). This highlighted the need for better cooling and possibly more powerful components. Vibrations from the rotor also caused issues with the sensors, making the autopilot less reliable. We realized we needed to improve vibration damping.

Breakthrough Moments

Despite the setbacks, we made steady progress. After countless hours of tuning the autopilot and refining the rotor head design, we finally achieved a stable flight. The Auto-G2 could now climb, turn, and glide smoothly, even in moderate winds.

This was a major breakthrough. It confirmed that the PX4 autopilot, when properly configured, could handle the complex dynamics of an autogyro. The onboard logs and video footage showed clear, steady performance, giving us confidence to move forward.

What’s Next?

The Auto-G2 experiment was just the beginning. We now plan to adapt larger, more robust autogyros for real-world atmospheric research. These vehicles could collect valuable data in harsh weather, where traditional UAVs often fail.

Our journey with the Auto-G2 shows how challenges can lead to innovation. We’re excited to share this story and inspire others to explore the potential of unmanned autogyros. With further development, these unique aircraft could play a key role in science, disaster response, and beyond.

Zároveň v roce 2020 začínala pandemie covidu, kde se ukázalo, že je velmi obtížné zrealizovat původní složení 5ti členého týmu, které bylo nutné k obsluze velkého TF-G1. Díky tomu se zrodil podstatně menší vírník TF-G2, který vycházel z rozměrů Autog-G2, který se osvědčil jako primitivní demonstrační model.