What remains of a drone after it was fired at a wall using a customized testing unit. Photo used with permission from Fraunhofer EMI.

Since being introduced to the market, commercial drones have rapidly grown in popularity. An increase in the number of unmanned aerial vehicles in the sky, year over year, has also created an uptick in reports of collisions and near misses with manned aircraft. While some drone sightings, including high-profile incidents at Gatwick and Heathrow airports, have yet to be confirmed, others such as the 2017 collision with a Canadian passenger aircraft make one thing clear: bird-strike tests for aircraft are mandatory.

Currently, an equivalent standard test procedure for collisions with drones doesn’t exist. The Fraunhofer Institute for High-Speed Dynamics, based in Germany, is aiming to change that by building a test bench for recreating various collision scenarios. The test bench will measure the consequences of a collision between a drone and airplane by firing a drone toward a wall at a speed of 500 miles per hour.

A lithium-ion battery, weighing roughly 700g, used in one of the drones Fraunhofer EMI tested. Photo used with permission from Fraunhofer EMI.

In the U.S., alone, the commercial drone market is forecast to triple in size by 2023. For Germany, an 80 percent increase from 169,400 unmanned aerial vehicles to 847,000 by 2030 is expected. German police have warned of a credible threat to both helicopters and airplanes posed by irresponsible use of drones. While all manned aircraft are required to undergo a standardized test to assess their tolerance to a bird strike, drones are not subjected to these regulations. Experts believe a collision with a drone would cause more damage to a manned aircraft than a bird strike.

‘From a mechanical point of view, drones behave differently to birds and also weigh considerably more,’ explains Dr. Sebastian Schopferer, a scientist working on this project. ‘It is therefore uncertain, whether an aircraft that has been successfully tested against bird strike, would also survive a collision with a drone.’

It is imperative for the drone industry to obtain accurate data surrounding collisions as it will inform the future of regulations regarding flight around airports. Varying opinions have been published over the years on the potential damage caused by a drone colliding with an aircraft. However, these theories are limited because they are based on computer simulations or assessments derived from outdated testing methods. The Fraunhofer Institute is creating numerous scenarios with a variety of both amateur and semi-professional unmanned aircraft models weighing 2.5 to 6.5 pounds.

‘Using compressed air, we accelerated these two components to speeds ranging from 115 to 255 meters per second and fired them at aluminum plates up to eight millimeters in thickness that were mounted in a test bench,’ said Dr. Sebastian Schopferer, a scientist working on the project.

The institute has already started performing initial impact tests with these drones, their batteries, and motors. ‘Using compressed air, we accelerated these two components to speeds ranging from 115 to 255 meters per second and fired them at aluminum plates up to eight millimeters in thickness that were mounted in a test bench,’ said Dr. Sebastian Schopferer, a scientist working on the project. ‘There was substantial deformation and indentation of the plates, and the drone battery and engine were completely destroyed.’

Ultimately, the underlying goal of the institute is to provide in-depth assessments to aircraft manufacturers and aviation authorities regarding the potential danger to aircraft posed by drones. ‘We will be able to investigate the impact and fragmentation of complete drones during collision with both rigid and flexible targets and thereby study the presumably catastrophic effects of a drone strike for an aircraft,’ Schopferer explains. ‘Tests in this weight class of drone have never been carried out before.’