On October 17th, 2015, Dirk Brunner took his drone to a field in Munich to prove what he already knew: that his drone could ascend to a height of 100m faster than any other drone in the world.
At the field, Brunner met with a small group of doctors and professors studying drone flight who’d been invited to witness Brunner’s second attempt at breaking the record. Only a few days earlier this same group of friends and colleagues had gathered to watch his first attempt, which failed after the drone entered an uncontrolled spiral and crashed to the ground. Fortunately, the necessary repairs were minimal and the group of onlookers seemed happy to watch the second attempt. One even told Brunner that the sound of the propellers accelerating was still stuck in his ears from the first attempt.
In order to ensure the safety of those present, all were instructed of the possible dangers and told to stay in a “safety zone” during the actual flight, strong lighting was added to the drone to make it easier to see, a fail safe was added to shut off all the engines in case of failure, and police and officials were notified ahead of time.
With help from these witnesses, Brunner first set up an a fluorescent pink circle used to make optical height measurements. A barometric sensor wasn’t going to work, because most of these sensors would be too sensitive to vibration and not nearly fast enough to keep up with the rate of acceleration. So instead a camera would be used to record the flight. By comparing the size of the pink circle in pixels in the image against the known diameter, Brunner and witnesses could confirm the height using math. Once the diameter of the circle was confirmed it was time get to the safety zone and begin flying!
The record to beat was an ascent of 100m in 5 seconds, though Brunner admits “I think it was not really done and only a starting number for this new [record] category.” After a few short warm up flights, Brunner brought the drone to a hover just above the ground then hit the acceleration making the drone rocket up into the sky and into the Guinness World Records.
The final stats of this record breaking drone flight: It took 1.3 seconds for the drone to accelerate to a speed of 100 km/h, reached a maximum climb speed of 189 km/h (119 mph), and took a total of 3.871 seconds to reach a height of 100m.
Becoming a Record Breaking Drone Maker
Dirk Brunner made his first quadcopter over 20 years ago. At the time, nobody thought his model would fly. And while it did have major problems — instability, batteries so heavy that they had to be placed on the ground and connected to the quadcopter with a flexible cable — it did make it off the ground.
“I’ve been flying drones for about 5 years (the first one 20 years ago does not really fly). Compared with other guys, I am a normal pilot not a pro,” Brunner says modestly.
Still, during that five year period Brunner has been doing lots of research on drones — making calculations, creating mathematical and physical models, testing mechanics, electronics, software, and components — and he says he often hears from drone professionals things like “I don’t know anybody with such good mathematical/physical models of a drone.”
Brunner’s interest in not only making drones, but making the fastest drone comes from his desire to develop existing technologies to their absolute limits. Other projects include another record setter: the world’s smallest R/C submarine. The idea to break the record for fastest drone ascent came as he worked on another project where speed was key.
Making the Fastest Drone
Making an extremely fast drone is not a simple matter of buying the best of each component (i.e. the biggest engine, the largest power source, the fastest motor controllers). On his website, Brunner details many of the considerations he made designing and testing this drone. A careful balance of speed, weight, and power usage was needed to ensure a good flight. The motor controllers need to be able to withstand the extreme acceleration. The engines couldn’t be too heavy or too weak.
Finding a combination of motors, engines, and propellers that worked most optimally with each other proved to be one of the most challenging aspects of this build. Special consideration also needed to be given to the propellers, the tips of which would be reaching a speed of 200m/s (faster than the projectile of a strong air rifle); so, not something you want to break at a critical moment of acceleration.
Testing was key to predicting the effectiveness of the drone’s ascent speed. For this Brunner had several test stands set up to test and record data. For example, to stress test a motor he would essentially feed it more power until it burned out. In his video, you can see some of the testing take place (as well as his record breaking ascent).
Brunner doesn’t suggest hacking your store-bought drone to make it faster if you don’t know what you’re doing. His website, however, hosts lots of good information for learning more about drones if you’re willing to learn. As a simple tip, he offers this advice: “Good motors, ESC, and battery are essential.”
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