I’ll be sincere: I really like my drone. I imply, I at all times had remote-control autos again once I was a teen. And naturally essentially the most spectacular RC automobile was the gas-powered helicopter. But it surely was costly and exhausting to fly. Now, with a quadcopter, it is a breeze. On high of that, it takes photos and movies.
Since I’ve this fascination with drones, it is solely logical to take the following step and use it for some physics. How about an evaluation of the aeronautics of this explicit drone, the DJI Spark. Drones, physics—what may very well be higher?
So I used my cellphone to report some slow-motion movies of the Spark transferring first vertically after which horizontally. This is an instance beneath. After which I used one in every of my favourite instruments, the Tracker video-analysis app, to plot the place of the drone in every body. Armed with that knowledge, it is only a hop, skip, and a leap to derive efficiency specs like acceleration and thrust.
On the Ball
The video basically offers me a sequence of time-stamped snapshots of the drone because it strikes, however I have to know the body fee to calibrate the time scale. My cellphone says it data slo-mo at 240 frames per second—or, in different phrases, at 4.17 millisecond intervals.
Simply to double-check that, I’m going to run a take a look at evaluation on one thing I already find out about: the acceleration of a ball tossed straight up into the air. An object in free fall, the place gravity is the one pressure engaged on it, has a vertical acceleration of about –9.81 meters/second2.
So if I put a meter stick within the video body (it’s that horizontal stick subsequent to my hand), I’ll know each the gap scale and the vertical acceleration. From that, I can determine the true body fee. This is what the ball toss seems to be like:
I ran the Tracker software program on this clip and adjusted the listed body fee till the becoming equation offers me a vertical acceleration of –9.81 m/s2. After enjoying round a bit, I acquired a time interval of 4.28 milliseconds—so truly about 234 frames per second. Right here is the trajectory with the adjusted body fee: