As the popularity of drones is continually growing by the day, it seems as though the applications for these little machines are growing at the same rate. Drones are being used in so many industries, it would require a post devoted specifically to identify them all! It is no secret that the range of applications is extensive though, so it is extremely important for people to understand the limitations, benefits, and differences between the two main types of UAVs; fixed wing vs. multi-rotor (a.k.a. multi-copter, quad-copter, etc.).
FIXED WING AIRCRAFT
Fixed wing UAVs, such as the AgEagle RX60 or the SenseFly eBee have an advantage over multi-rotor aircraft in that they are much more aerodynamic. These craft are usually thin and sleek, slicing through the air at between 30-60 miles an hour.
Battery life on a fixed wing tends to be longer, as these craft normally only have one motor, whereas multi-rotors can have anywhere from 4, 6, 8, or more propellers to keep them aloft. Each motor on a multi-rotor has to fight the forces of gravity while they push air down in order to remain aloft, however, fixed wings can be likened to a boat being pushed through the water by a single prop at the back. The lift generated by the aerofoil shape of the wing as it is pushed through the air is enough to keep it aloft, saving boatloads of power.
Since a fixed wing can fly faster and longer than a multi-rotor, it only makes sense that it can therefore cover more area in a single flight. The RX60, used for agricultural imaging of cropland, can cover around 500 acres in a single flight. When it comes to survey mapping using drones, the higher you fly, the greater the area you can cover. We have often flown at 500 ft. above ground level (AGL) which allows us to cover an entire section in one flight. Note: Transport Canada drone regulations no longer allow drones to operate above 400ft, even under an SFOC.
These things are great for navigating tight spaces. We have flown our DJI Inspire 1 through a stand of Jack Pine, carefully navigating between the tree trunks in Attitude mode. With "Atti" mode, you are flying without the aid of GPS positioning, which means the aircraft responds to the slightest movement of the joystick. It can be very difficult to master, however, you can get some amazing cinematic quality videos in this handy mode.
While the cost of drones has come down steadily over the past few years, it is still possible to easily drop $50-100k on a professional survey-grade commercial UAV. Though you can find very expensive multi-rotors that can carry heavy equipment such as large cameras and remote sensors, you are more likely to come across expensive fixed wing units. It is pretty standard at the time of writing this article, that fixed wing drones that can be used for agricultural, mining, forestry, and other survey applications, ranging from between $10000-50000, whereas you can get a high-end commercial grade multi-rotor from $2000-6000. No small chunk of change either way, but one is clearly an easier pill to swallow.
Due to the importance of maintaining an aerodynamic shape and balance, a fixed wing aircraft is very limited on what you can stick to it. Most fixed wing units have a small fuselage/equipment bay where you can place small cameras and sensors. A multi-rotor unit are sometimes capable of carrying more weight, and can be highly modular - meaning you can add equipment easily. We will often use a high-resolution camera on our Inspire 1 in addition to a 360 degree camera that we use to create Virtual Reality experiences. If you've ever wondered "what does it feel like to fly?" a virtual reality headset combined with a drones-eye view from 400 ft AGL is about as close as you can get without physically being there!
The final point we will mention is perhaps the most important point. When it comes to surveying/mapping, it is very useful, in the case of agriculture for example, to be able to fly right up to a spot in a field that you want to get a closer look at. With the NDVI (Normalized Difference Vegetation Index) crop health analysis that we provide our farming clients, once we discover a spot in a field that isn't growing very well in comparison to other areas, we will fly our multi-rotor right to that spot, and take several high-resolution pictures of the crops, from as close as just a few inches away. That way, we can get a view of the plant leaves and the soil surface to get a better idea of what the problem might be, without actually having to go out into the field. In this scenario, we would utilize the fixed wing UAV to map the field, and use the multi-rotor to get a closer look.
So, which type is best for you?
These are just a few of the major factors to consider when buying a new drone is the topic of the next board meeting. What do you need it for? What are you willing to spend? Would you just be better off going with a service provider?