If you want to make money flying drones commercially, or even if you are having fun just flying them around in an open field; you had better understand how weather can affect the operation of your flying machine. It isn't a "little thing." Weather is the number one reason people have accidents with their drones.
"MY PHANTOM'S BATTERY POWER DROPPED FROM 70% TO 20% IN A FEW SECONDS!"
"IT FLEW INTO THE BUILDING ON IT'S OWN, I DIDN'T EVEN TOUCH THE JOYSTICK!"
"MY DRONE JUST FELL FROM THE SKY!"
Why did my drone crash?
Transport Canada mandates that you must have UAV Ground School Training which teaches you the Knowledge Requirements for Pilots of Unmanned Air Vehicle Systems - UAVs 25 kg or Less, Operating Within Visual Line of Sight. You can find that document online (just click the image to go to the link on the Transport Canada website to download it) - however, it is not simply enough just to read it, you must pass an exam (with 60% or more) that proves you know the material. You can learn more about the course here.
Part of the course, a good chunk, focuses on weather and how it affects the operation of UAVs. I'm going to tell you about the 3 most critical points that could save the life of your drone someday.
Probably the most obvious factor. If you go outside, and your brain says "hey, its pretty windy out here, maybe we shouldn't fly right now...?" - you should probably trust it. Wind increases with altitude. If you see the wind is blowing at 40 km/h on the ground - it could be blowing at 50 or 60 km/h at 100-400 feet above the ground.
As wind blows across the surface of the Earth, it gets hung up on trees, houses, hills, and even just the gently undulating ground. It slows down considerably due to the increased friction. But if you go up, even just a matter of a couple stories off the ground, you can already feel a difference in how fast the wind is blowing.
A drone uses much more energy by flying two or three times as hard just to maintain its hovering position. When a drone is flying in high wind, it is going to drain the battery faster than it would on a calm day! So beware of the wind my friends!
The DJI "Phantom" series Lithium Polymer "Smart Battery" can discharge energy automatically if left for a long period of time.
Heat can affect your drone in several ways. When the sun beats down on the ground during the day, it heats it up quite a bit. You can see how hot the ground can get when you go to the beach and the sand burns your bare feet! So to cool off you run into the cool water. Well, in a similar fashion, the air doesn't like to sit around on the hot sand either and it goes UP to get away, creating what is called a "convection current." Hot air rises, and cold air that was sitting on top of the cool water rushes in to take its place. Due to this natural phenomenon, you could experience a drop in altitude when flying your UAV from land to water on a hot day. If you're trying to get that nice shot flying at just a couple feet above the water - you might end up losing everything!
Heat can also affect batteries, both during storage and in-flight. Most of the batteries that are used to power UAVs are Lithium Polymer (LiPo). LiPo's are a highly energetic, compact battery that lasts a relatively long time compared to some other types. The problem with the LiPo is that they are super volatile. Their integrity can be compromised very easily. You can learn more about caring for your LiPo's in an upcoming post. My point here is that heat can have a negative affect on battery life and can cause them to become dangerous to use.
Example: Hot day. 35 degrees Celsius. Batteries have been kept in the big black box along with the drone, in the back of the truck, with the sun beating down on it for an hour. They feel almost hot to the touch. This is a cause for concern, because the drone will cause them to heat up further during use, and the potential for a dangerous situation to develop is HIGH.
Picture this: You are out for a walk on a really cold day (Canada cold) and you pull your phone out of your pocket to check the time, but it is off, and won't turn back on. You could have sworn that when you left the house you had around 80% battery life... You've just been bitten by the battery sapper!
Cold has an extremely negative effect on the life of batteries. Some drones say that they are capable of flying in temperatures reaching -10 degrees Celsius. But this is IF the batteries have been stored in a warm place, and then loaded into the machine and flown right away before they get a chance to cool down. The UAV will generate some heat when using the battery, but lifespan will still be affected. It is commonplace for people to report that their drone fell from the sky because the voltage meter went from 50% down to 5% in a matter of seconds.
I've flown before with my DJI Inspire 1 when the thermometer was showing -8C using warm batteries, and the flight time went from the standard 17-18 minutes down to about 7 minutes.
I left out rain in this article because, unless you have deep pockets, or a drone that is waterproof (they DO exist), you are probably not going to fly your $1000+ tool in the rain. The general rule of thumb is: drones can't fly in the rain.
Weather is always changing, and thus it is on the UAV operator to ensure they know the current, and forecasted weather conditions before they head out for their day of flying!
It is a good idea to ensure that you have proper drone training from a Canadian ground school course provider. You will learn a great deal about safe drone operations. Until next time, fly safe!