In the last year and a half, drones have become more popular than ever. More and more people are buying them for personal and hobby use, while countless industries have adopted them for day to day operations. When it comes to purchasing a drone, there are several features that consumers look for. One of the most important features to consider is just how safe the drone is. As drones increase in popularity, they are also being used to interact with people more. Everything from teachers using them in elementary classrooms to parcel delivery drones put people in close proximity to an unmanned robotic device with moving parts.

In 2016, a team of researchers from the Drone Research Lab at Denmark’s Aalborg University began running tests to see just how safe various drones were to people. The question they wanted to answer was what would be the severity of injuries if a drone were to collide with a person. The first thing the team needed to do was build a contraption that would allow them to monitor a drone’s speed and impact. The device they came up with is a catapult that a drone is attached to. The 9.8ft long catapult is more of a pulley system with a slide on an aluminum rail that travels at a rate of 49ft/second. Different drones can be attached to the slide to crash into a target at the end of the rail.

The next step was to choose a target to be impacted. At times the team used foam padding or pillows to absorb the impact, but these do not give a reliable comparison to what would happen when a drone hits a person. So the team turned to a local butcher for a better option, a slab of pork. While synthetically made skins are available, they can be costly and still not “feel” like real skin. For years, practicing doctors and tattoo artists have used pig skin to hone their craft before working on the real thing. Sinclair Research, a company that provides animal efficacy models for medical based research, published a paper explaining why pig skin is an ideal test material. “Pig skin is anatomically, physiologically, biochemically and immunologically similar to human skin,” the article states, “and the skin is ‘fixed skin’ like humans and unlike rodents or rabbits.”

So the researchers at the Drone Research Lab attached a slab of pig skin, complete with meat to be akin to muscle texture, at the end of the catapult. The team then ran more than 55 tests of launching a drone, or drone parts, along the catapult into a target. Documenting the process was a camera that captures 3,000 frames per second. Some of the tests were to see what would happen if just the body of a drone crashed into the target. Other times different types of rotors, still spinning, would be attached to the slide without a drone. Then the team would test drones, complete with moving rotors, positioned at different angles.

There was a wide range of test results. Sometimes the rotors would bend and cause very little damage to the pig skin. Other times the rotors would snap, lacerating or piercing the skin. However, the force of each impact was measured to determine the severity of each collision. These kinds of tests are not all that different than how motor vehicle companies use dummies to crash test vehicles. While the team has not published a paper on their findings, the video documentation shows that there are certain drones, and drone parts, that are less likely to inflict injuries than others. This research could be very valuable to drone manufactures to build the safest drones possible.