Long Duration Flight Confidence gained

Posted on
September 11, 2024

Kitekraft has reached a technological inflection point though a test campaign completed over the past months. The flight test campaign showed a significant increase in flight duration and distance traveled. This technological proof point was achieved thanks to the various implementations and advancements of this year.

As shown in the diagrams below, Kitekraft has significantly improved its accumulated flight distance. While previous flights typically ranged below or around 5km, Kitekraft's engineers were able to push these numbers to consistent flights with distances averaging 120km. The longest flight clocking in 5:22h and over 420km, which was live streamed to YouTube (watch it here). This was possible thanks to a number of control software and redundancy improvements that were implemented over the course of 2024, which led to significantly improved flight stability and reproducibility.

Aim of this test campaign was to collect flights with a duration of around 1h and investigate the impact of the aforementioned improvements, the AI controller, and to generate learnings about the mechanical state of the system post-flight. All flights were intentionally stopped at certain time marks, even though no technical abort-reasons were present.

The diagrams of accumulated flight distance and figure of eights flown show a significant increase in 2024.

Refined control parameter validation thanks to full sensor redundancy

In the first half of this year, Kitekraft's current demonstrator system was upgraded to full sensor redundancy. Thanks to this more fault-tolerant setup, more consistent flights could be completed and control parameters refined and optimized. In combination with some control-model extensions, the flight behavior and stability were improved significantly. One outcome of these test flights was a good validation of Kitekraft's simulation/digital twin software, which is developed in-house. (We already touched upon these points in a bit more detail in another blog post)

Standardized and fail-safe flight management

The permit to fly into and during the night, was granted to Kitekraft by German airspace authorities (Luftfahrtbundesamt) this year. Kitekraft adheres to strict system operation procedures that guarantee flight readiness. Pre- and post-flight checklists ensure that the flying wind turbines are always in the required conditions for safe flight operations. While this establishes high safety standards, Kitekraft systems are designed in ways which effortlessly allow the completion of multiple flight cycles per day.

Kitekraft's flying wind turbined traces infinite eights over the night sky, in front of the milky way. Kite and ground station are illuminated by the Anti-Collision-Lights.

These pleasant test results were achieved with a system size which was intentionally kept small. On the one hand, fitting all required components on a kite with under 2.5m wingspan can be challenging and requires nifty implementations. (Note: a lot of components do not scale in weight and size with the wingspan of the system, for example the control electronics.) On the other hand, a small system size keeps development costs low and facilitates system handling and speed. Current development shows that Kitekraft's development strategy hit a sweet-spot between these two requirements.

Posted on
September 11, 2024
in
Technology
category

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