The experiment uses the University’s High Voltage Lab, which has a 2-megavolt impulse generator that can conjure up a lightning strike on demand. The U of M’s Dr. Vidyadhar Peesapati and Dr. Richard Gardner set up the lab to create a lightning strike rated at more than 1 million volts of electricity.
For the first experiment, the drone was tethered to keep it in place but otherwise flew as the Phantom would under normal conditions. A bolt of lightning strikes, and the drone instantly drops from the sky. There is no visible damage to the exterior, but the team said all of the internal electronics were fried since the electricity took the path of least resistance. In slow motion, you can watch the lightning enter one end of the drone and shoot out of the bottom.
But what if the drones was a bit more protected, perhaps with a lightning rod to divert the brunt of the damage away from the quadcopter? The team rigged a second drone with a piece of conductive copper tape as a sort of makeshift lightning rod, becoming one of the tallest points on the drone.
They reset the lightning machine, zapped the new drone — and the propellers blew completely off. While the first experiment only damaged the drone on the inside, instead of taking to the copper tape, the lightning favored the propellers. The group said the sheer force of the strike took the propellers off before taking a path through the drone’s internal circuits, leaving the second “protected” version worse for wear.
While the experiment is incredible to watch, it also carries scientific significance. The group says that similar research has led to changes in piloted airplane design, but little has been done to see how unmanned aerial vehicles fare in a lighting storm. Small drones typically don’t fly in storms because the wind seriously drains their already short battery life; as waterproof variations begin popping up, drone flight during storms and rain may become more common.
The team’s recommendation? Keep ’em grounded during lightning storms if you don’t want a few thousand dollars worth of equipment to go up in one zap.
