Researchers at the Micro Aerial Vehicle Laboratory (MAV) have made a drone that takes off and lands vertically and that can fly for hours horizontally like an airplane. It does all this on hydrogen.
The drone weighs 13 kilos, has a wingspan of three metres and is fitted with 12 engines (and 12 propellers). The researchers tested the aircraft from a Royal Navy ship at sea. The drone can fly dozens of kilometres, far beyond the horizon, and thus outside the radar radius of the Navy. This makes it a very advanced observation tool.
The researchers have been working on this aircraft for a couple of years. One and a half years ago, they succeeded in landing the drone on a bobbing ship. That was not an easy job and it needs a high degree of manoeuvrability from the flying robot. “It’s not only the movement of the vessel that makes this manoeuvre complicated,” explains Project Leader Bart Remes, “but as naval vessels are made of metal, the compass went crazy. We had to reset all the sensors and align them to each other.”
Once the aircraft is flying horizontally, it draws all its power from hydrogen
And that was just the first step. The second step, which is now completed, involved aligning the electric propulsion from the battery and the energy generated by the hydrogen cell. When the aircraft takes off, both forms of propulsion are needed as take-off is so energy intensive. Once the aircraft is flying horizontally, it only uses the hydrogen cell.
The drone can be compared to a hybrid car, but a hybrid car that flies and uses hydrogen instead of petrol. Just like with hybrid cars, the drone’s battery charges while it is on the move. “We had to get used to this,” says Remes. “Normally, batteries empty quickly during flights. Now it’s the opposite.”
So what is the link to more sustainable passenger aviation? Airplanes do not take off vertically. “True,” says Remes, “but when passenger aircraft take off, they consume a lot of energy and would need to draw that energy from the batteries. Once they are at cruising altitude, they could easily just use hydrogen cells. So the technology that we are developing is definitely of interest to civilian aviation.”