In a display of true awesomeness, researchers from the Drone Research Lab at Denmark's Aalborg University have built a catapult that fires hobby drones at a pork roast. This display of porcine projectile piercing is not only high on the list of conversation starters, it also has the serious goal of finding out more about the safety hazards the tiny aircraft pose to people and property.
Anyone who has given their kids a toy drone knows that they can and will crash into just about anything. The problem is, how much damage potential do various hobby drones pose and what kind of injuries can they inflict? To work this out, the Drone Lab and the Aalborg University Hospital came up with a motorized catapult and high-speed camera system that can make precise measurements of both the speed and the force of drone impacts.
Despite its name, the catapult doesn't hurl drones across the room like bean bags. Instead, the drones or drone parts are attached to a slide and are pulled along an aluminum rail by an electric motor until they slam into a variety of targets at the other end, such as a pork roast standing in for an innocent passerby.
According to the team, the 3 meter-long (9.8 ft) catapult shoots a 1-kg (2.2-lb) drone at 15 m/sec (49 ft/sec) while the camera records the mayhem at 3,000 frames per second. Meanwhile, the force of impact is measured over time to ascertain the severity of the injuries.
The rationale behind the Aalborg catapult is the same as most modern safety testing and goes back to the early days of aircraft safety. It may seem strange to shoot drones at pork, but in 1943 Westinghouse Electric started shooting dead chickens at aircraft at 200 mph (322 km/h) using a compressed air cannon (a technique that was used well into the jet age), to test the effects of bird impacts on windscreens and engine intakes.
The researchers say that the catapult is still in the early stages of development as the team works to refine the mechanics and electronics, as well as the camera and lighting setup. As the experiment progresses, the catapult will be tweaked to fling larger drones at higher speeds.
The top video below shows the catapult taking on a pork roast in slow motion, while the one below shows the same impact at normal speed.
Source: Aalborg University
Elsewhere in today's issue there is an article about drone racing. If it is going to be successful, it will need to be in close proximity to the spectators. If any drones need guarded rotors it has to be those taking part in this sport.
Drones, with minimal practice and skill, excel in their ability to easily hover and be controlled compared to model helicopters. This quality allows them to be used by amateur from almost any starting point. This maneuverability is their strong point. The flyer's goal for the most point is to fly in a deliberate way as to capitalize on this ability, not to race with them as would be the case erroneously depicted here attempts to represent. Again, "popular small hobby drones" cannot even come close to speed represented here without a huge tail wind. Can "popular small hobby drone[s]" race? Of course. But the 33 MPH scenario of this staged situation is far from probable.
Real world momentum is an unknown factor in this test. If we formed a hollow hatchet out of aluminum foil and could sling it at you at 33 MPH, vs. slinging a three pound puffy feather pillow at you at 33 MPH, which would cause more damage? The puffy feather pillow would do the most harm. We don't know the power output of what is being used as the acceleration source of the "Test Sled" or if it was still under forward power at impact, or the weight of the "Sled".
Things move when impacted which tends to minimize destructive results. That's why cars have and rely on "Crumble Zones". In this "test" the pork is part of the chassis of the test fixture and incapable of movement. That is the equivalent of the pork placed against of a concrete wall and hit with a three pound sledge hammer rather than the piece of pork being swatted and allowed to move across the grass. I can assure you that when the three pound pillow makes contact with you at 33 MPH that you will be knocked down, and if it wasn't for that, your face would receive the same tenderizing that the pork against the concrete would have.
There are many other all too obvious misinterpretations that an unrealistic "apples and oranges" comparison like this unrealistic demonstration will unfortunately lead to.