Quadrocopter safety: calibrate the compass and hold it by hand

A month ago, we purchased a quadcopter DJI Phantom 3 Advanced. The device gives a lot of pleasure to the whole family, especially when you return home after the flight and view the recordings from a height on the big screen. But the strongest emotions we experienced when the drone lost control.

In general, when you buy such a neat, pretty and technologically advanced helicopter, your hands itch to launch it up immediately. I do not consider myself to be the most reckless experimenters, but all I initially wanted to learn from the instruction manual was how to start the engines and what the levers on the remote control affect. Since before that there was little experience in managing a small drone similar to Syma , with Phantom, it seemed, there should be no control problems.


Quite a lot is written about all sorts of different drones, including those on the GT. But, after a month of operation, I want to note that the articles usually do not meet the warm sensation that such a "pet" causes. He is really perceived as a rather obedient pet, which sometimes is capricious and gets into various troubles. Therefore, I will try to talk about how to take the drone on the handles, so that everyone would be calmer. If you read laziness, you can just watch the video at the end.

An interesting idea was expressed in an interview by one designer from our company. The bottom line is: all these gadgets and widgets around us form a different reality from the natural, in our opinion - augmented reality. If adults still somehow realize where and what, then the kids come into this world filled with drones, tablets and other equipment, feeling it, probably, to themselves completely integrally. Of course, I managed to dream about building a quadrocopter with my own hands. For my creation, I would hardly have left such a childish curiosity as arises from a complex Chinese craft. A DJI phantom arose in my life very spontaneously, like a hitherto unprecedented physical phenomenon that I would like not only to use for its intended purpose, but also to know it from the inside. It should immediately be emphasized that a kilogram machine with powerful propellers is really dangerous from all sides. However, the danger, as you know, is sharply reduced during the development of the apparatus, especially development on the verge of safety.

Naturally, the instructions will write, they say, do not fly up to people and animals. But they will not paint how to get out if the quadrocopter demolished people with an unexpected gust of wind. They will also write about what should not be launched in windy weather, but there may not be a downwind, and at a height of one hundred and fifty meters it will already be significant. So people, whatever one may say, are studying it all willingly. And the will, as experience shows, is much more effective and interesting.

Someone will say that the price of a flying gadget in itself limits the imagination for experiments, but even if this “someone” is in the majority, then the drones killed in the first flight will still not be returned. And anyway, is there any kind of despicable money that can cool the ardor of a real Russian naturalist? Moreover, the money already spent.

I was personally stopped by purely technical obstacles: the battery in the box was only 20% charged, and for some reason the DJI Go application did not show video from the camera on my elderly smartphone. While understanding the video, the battery has run out even more. So with the first flight, I didn’t come off the Phantom above one and a half meters from the ground.

Further picking with the video led to the thought of updating the firmware. Then night came, and after it - a working day. That's when I was fortunate enough to clear my brains of breathtaking traction rush into the sky in full sail.

So, before starting a new quadrocopter on dangerous three-dimensional travels, I strongly recommend not reading manuals, but watching the video of falls on YouTubeand other unpleasant situations with multicopter. I was just about to look at how people fly, or rather, pilot drones, but the eye itself caught on pictures with captions like “phantom crash”. After these videos, the instructions are no longer read, but as if reread in search of important information. Therefore, in the evening I was calm and balanced. Fly, as expected, began in beginner mode. And when he turned it off, at first it significantly limited the altitude and range.

Most impressed with the video showing how the Phantom is carried away into the unknown, picked up by a strong wind. There is some kind of anxiety and hopelessness in them that is not felt in the selection of funny falls and collisions. Only one thought reassures: “If the video was posted, it means that a drone with an onboard flash drive was found.” But again, another worries: “But what if someone else found him? But what if only the flash drive survived? ”Honestly, we also launched at significant speeds of air flow, but the drone, we note, resists them very confidently. It is hard to imagine which winds took place in the above videos. There, apparently, the operator himself was demolished, and he was still trying to control the drone. Although, once again, the upper air currents can be very different from the lower ones.

Watching videos with beating and deflating quadrocopters, I once noticed a simple recommendation: calibrate the compass before flying- this will allow the Phantom to return to the take-off point without any problems. Indeed, returning “home” is almost the most important function of the aircraft. Because when you climb 150 meters above the ground, even in a clear daytime sky, it is already not easy to see. And if you do not know the approximate sector of the solid angle, then just do not make out. If the drone takes off at 250 meters and horizontally moves away at 500, then there is no way to visually control it. In an unfamiliar monotonous landscape, you can’t navigate the video from his camera either. I suspect that at the dawn of copter engineering, more than one vehicle was lost in the sky in this way. And we are lucky. Smart Chinese have built in such functionality that the quadrocopter returns home not only when asked, but also in case it loses the signal from the remote control. By the way

But back to the calibration. Once we went into the courtyard of our own housing complex and calibrated the compass. The quadrocopter status table disappeared from the tablet screen, the engines started, and the copter soared into the sky. Sixty centimeters somewhere ... Immediately after take-off, he led somewhere to the side, into a tree. The operator was able to correctly respond and remove the machine from a collision. But the crazy drone continued its hooliganism: at first, it nearly knocked out the operator along with the audience, and then safely crashed into another tree and fell upside down on the grass. Again, we must pay tribute to the Chinese: the screws did not break, and in general, everything remained intact, except for a couple of scratches on board.

The mistake was that the instructions should be read even more carefully. When calibrating the compass, the copter should be kept at least a meter above the ground, while I usually turned it, barely lifting it. But I found out about the correct method later. And then I thought that somewhere below the ground lies a magnetic anomaly. There, generally speaking, is parking, so, in principle, there can be a lot of electromagnetic interference. We simply moved to another place and, barely restraining the trembling in the knees, again launched the beast. This time successfully.

But not quite usual. Off hand. In my opinion, it is useful to know that the DJI Phantom 3 starts without problems if you hold it with one hand by the foot. It may come in handy when starting on some field with tall grass. At the end of the video under this article, we show how to land in this way, that is, taming. Well, it’s just useful to know the gravity and strength of the quadrocopter just in case. When I first started it from my hand, I simply succumbed to gas to hang the drone in the air and, without fully unclenching my fingers, was convinced that it was not blowing anywhere.

In addition, after the first hit on the tree, we immediately acquired a protective framework for the propellers. They, of course, make the structure bulky and unsuitable for quick disassembly, but they are calmer. By the way, on the same YouTube there are such videos where quadrocopters suddenly rush into a wall or into people for no apparent reason. This did not happen to us, but during the shootings near tall buildings, the apparatus does sometimes sometimes unpredictably talk. Tryndit, like a burnt merchant ... I suspect the point here is in complex air vortices, which locally can be very swift (a vivid example is a tornado). So let him be better off in defense.

Thus, before each launch, we calibrate the compass. Unfortunately, I still have not understood how the failed calibration status is displayed in the DJI Go application. In any case, first I take off about thirty centimeters above the surface, check the controllability and only then send the gadget on a long flight. Now, at least, I can easily catch and hold him in a demolition situation.

In the process of studying the flight characteristics of the drone, we had the idea to make a short film about the life of these aircraft. The tale, of course, is a lie, but it turned out funny. (Watch with sound.)



Update Many interesting comments formed, for which I am very grateful. Of course, the article did not claim to be the ultimate truth, but personally, for my taste, it did not lose its value due to criticism. As for the calibration of the compass and, in general, accurate take-off, there is an extensive commentary from the experienced fly4546 copter guide . It seems to me too much, but interesting for reference. The other day, he took off from a car parking on the roof of a building: Phantom refused to take off from the floor, because surrounded by such an amount of iron, the compass was demolished, but it calmly took off from the hand and behaved absolutely predictably. I think the Phantoms' brains are getting better, so a great deal of caution from previous generations is losing relevance.