Drone vs lightning
UOM life 10th April 2017
It’s not often you can get within ten feet of lightning and still walk away completely unscathed, but this is what happened when we visited The University of Manchester’s High Voltage Laboratory with YouTube film maker Tom Scott, whose 750,000+ subscribers get treated to videos of Amazing Places and Things You Might Not Know. In his latest video, he explores what happens when drones are struck by lightning.
So, how do you conjure up a bolt of lightning and get it to strike a drone? Short of using magic, our best option for on-command lightning was to head to our High Voltage Lab, the largest of any UK university, which houses a 2 MV impulse generator.
Our ‘on-call’ doctors, Dr Vidyadhar Peesapati and Dr Richard Gardner, set up the equipment ready for the test. After a few warm-up bolts we ended up with something that looked a little like this:
Pretty impressive, but not quite as impressive as we wanted; it was time to put a drone in the middle of that bolt to see what would happen.
We ran two tests; the first drone, tethered to the ground to prevent any mishaps should it wander off course, was shocked with over 1 million volts of electricity. The effect was immediate; the drone came crashing down with no signs of movement.
You can see from the video that the electricity passed straight through, flowing from one of the propellers to exit through the foot of the drone. Surprisingly there were no visible marks on the outside of the drone, but that doesn’t mean that the insides got away unscathed; as it turns out, the electricity took the path of least resistance and fried all the sensitive internal electronics. One of the team thought it might be repairable so took the drone home to investigate further.
We thought we’d be kinder to the second drone and try to protect it with a lightning rod made out of conductive copper tape; not necessarily the sturdiest lightning conductor, but a solid copper rod might have been more of a hindrance than a help. The scientists carefully wrapped the tape around the drone, leaving a fetching little tail of copper sticking up next to one of the propellers. Cue the lightning machine.
Sadly, this drone didn’t survive the strike either – in fact it was left in an even sorrier state than the first as the propellers were, well, propelled explosively away from the drone (this was caused by sheer force of the lightning strike).
The copper tape was intended to act like a lightning rod, much like the lightning rods you see on tall buildings. However, with the propellers of the drone still being one of the ‘tallest’ points on the miniature helicopter, they were equally attractive to a huge bolt of electricity. This is why, in the picture above, you can see streamers coming out from different places on the drone. So, whilst lighting rods have a higher chance of being struck, it’s not a guarantee they will be (don’t worry, you’re still pretty safe if you’re in a skyscraper in a thunder storm).
All this was very exciting, and certainly dramatic to watch, but there is some serious science that goes into experiments like this; and it all aims to answer questions and solve problems posed by exposure to highly charged environments.
One of the most pertinent questions we have had to answer in recent years is ‘what happens to aeroplanes if they’re struck by lightning’ (check out this podcast from the BBC World Service’s Science in Action programme for more information from the High Voltage Lab’s research on this topic). This research along with changes in the materials used in the aeronautics industry, has led to some careful engineering that ensures that planes stay in the sky when this happens.
But with the advent of drones and their increasing popularity, we have to be mindful of what happens if drone pilots end up flying their new gadgets in a lighting storm (we hope they don’t, from our experience it won’t end well). With our understanding of how aeroplanes behave in thunderstorms and how to provide protection for them, this knowledge could be applied to drone technology to ensure the drone and its pilot stays safe should they fly in adverse weather conditions.
To find out more about our day in the lab, you can watch Tom’s full video below:
Words and images – Enna Bartlett, Videos – the High Voltage Test Lab/Tom Scott