Comparison JJRC H31 vs WL Toys Q212

Additional sensors provided in the design of the quadcopter.

— Heights. A sensor that determines the flight altitude of the machine. Such sensors can use the barometric or ultrasonic principle of operation. In the first case, the height is measured by the difference in atmospheric pressure between the current point and the starting point (that is, the sensor determines the height relative to the initial level); in the second, the sensor acts similarly to sonar, sending a signal to the ground and measuring the time it takes to return. Barometric sensors are not very accurate, but they work well at high altitudes — tens and hundreds of metres; ultrasonic — on the contrary, they allow you to accurately manoeuvre at low level flight, but lose effectiveness as you climb. However, in some advanced models, both options may be provided at once. Data from the height sensor can either be used by the quadcopter “independently” (for example, when hovering or automatically returning), or transmitted to the operator to the remote control or smartphone.

— Optical. A sensor that allows the quadcopter to "see" the environment in certain directions. One of the simplest variants of such a sensor is a downward-facing camera that allows the device to “copy” the surface under which it flies. Due to this, the machine, for example, can navigate indoors, where the signal from GPS satellites does not reach. In...addition to such a chamber, "eyes" can also be provided from different sides of the machine. Note that optical sensors have certain limitations in their use — for example, they lose their effectiveness on dark, shiny or uniform (without noticeable details) surfaces, as well as at high speeds.

— GPS module. A sensor that receives signals from navigation satellites (GPS, in some models also GLONASS) and determines the current geographical coordinates of the machine. Specific ways of using position data can be different: returning home, flying by waypoints (see below), recording a flight route, etc.

— Gyroscope. A sensor that determines the direction, angle and speed of the machine's rotation along a specific axis. Modern technologies make it possible to create full-fledged three-axis gyroscopes of very compact dimensions, and it is with such modules that quadcopters are usually equipped. On the basis of gyroscopes, automatic stabilization systems usually work, returning the car to a horizontal position after a gust of wind, collision with an obstacle, etc. At the same time, such equipment affects the cost of the device, and in some cases (for example, during piloting), automatic stabilization is more of a hindrance than a useful feature. Therefore, some low-cost, as well as advanced aerobatic quadcopters, are not equipped with gyroscopes.

The range of the drone is the maximum distance from the control device at which a stable connection is maintained and the device remains controlled. For models that allow operation both from the remote control and from a smartphone (see "Control"), this item indicates the maximum value — usually achieved when using the remote control.

When choosing according to this indicator, note that the range is indicated for perfect conditions — within line of sight, without obstacles in the signal path and interference on the air. In reality, the control range may be somewhat lower; and when using a smartphone, it will also depend on the characteristics of a particular gadget. As for specific figures, they can vary from several tens of metres in low-cost models to 5 km or more in high-end equipment. At the same time, it should be said that the greater the range of communication, the higher its reliability in general, the better the control works with an abundance of interference and obstacles. Therefore, a powerful transmitter can be useful not only for long distances, but also for difficult conditions.

The number and type of batteries used in the quadcopter control panel.

— AA. Replaceable batteries, colloquially known as "AA batteries". They are available not only in the form of disposable batteries, but also in the form of rechargeable batteries, are produced under various brands that differ in price and quality (which provides freedom of choice), and finding such elements on the market is usually not a problem. The power and capacity of AA elements are relatively small, but in most cases they are quite enough for normal operation of the transmitter for quite a long time. Usually, modern consoles require several of these batteries; in the most high consumption this number can reach 8.

— AAA. Also known as "pinky". In fact, a smaller version of popular AA elements (see above); has the same key features, but differs in more compact dimensions and, as a result, somewhat reduced power. This option is typical for low-cost class models, with a small range of the remote control.

— 3s. This marking does not describe the size of the battery, but its operating voltage and technology. It denotes a lithium-ion or lithium-polymer battery (see "Battery type"), assembled from three cells with a standard voltage of 3.7 V each, and thereby delivering an operating voltage of 11.1 V. The advantages of such a power supply are high power and capacity, which allows you to use the remote control for a long time without recharging. At the same time, batteries of thi...s type can vary significantly in size and weight, and not every model marked 3s will be compatible with the remote control. In addition, finding a spare battery is more difficult than a set of cells of a standard size.

— Proprietary battery. Powered by an original battery that is not related to any of the options described above. Such batteries can be much more powerful than replacement cells, making them well suited even for remotes with high power consumption. Their main advantage is the difficulty with quick replacement: the design of the remote control is at best poorly suited for this, and at worst the battery is generally non-removable. Also, finding the right replacement battery can be a major hassle.

The type of motors used in the quadcopter.

Modern copter drones are traditionally equipped with electric motors (usually one for each propeller), and by type, such motors are divided into relatively simple collector and more advanced brushless ones. Here is a detailed description of each variety:

— Collector. In motors of this type, a collector is used to switch the current between the windings — a mechanical device in the form of a ring mounted on the motor shaft and divided into separate sections. The current to this ring is supplied by a pair of fixed contacts — the so-called brushes. Such a design is very simple and inexpensive, moreover, it is repaired without much difficulty. On the other hand, collector motors have a relatively low efficiency, and brush contacts wear out and fail quite quickly due to constant friction (especially with frequent operation at high speeds). Therefore, the main scope of their application are relatively simple and inexpensive quadcopters — in more advanced technology, the brushless motors described below are often used.

— Brushless. In such motors, current switching between windings is carried out using electronic circuits, without the use of moving parts. This complicates and somewhat increases the cost of the design, but it gives a number of advantages over collector units. First of all, brushless motors are more efficient and experience less wear when running at full po...wer. In addition, it is easier to adjust the actual power in them, the range of such adjustment is wider, the accuracy is higher, and the reaction to changing the settings is almost instantaneous. With all this, modern technologies make it possible to create relatively inexpensive and affordable brushless motors, the cost of which is often only a small part of the price of the entire copter. So this option is quite popular in modern drones, it can be found even among relatively inexpensive models.

The name of the engine installed in the quadcopter. Usually, knowing this name, you can easily find information about the features of the engine — both official manufacturer data and reviews from users — and determine how much you are satisfied with its characteristics. This can be very important when choosing a high-end professional model.

The capacity of the battery supplied with the quadcopter.

Theoretically, a larger battery can provide a longer charge time. However, keep in mind that this time also depends on the power consumption of the copter — and it is determined by the power of the engines, dimensions and weight, as well as a number of other features. In addition, the actual battery capacity is determined not only by ampere-hours, but also by its nominal voltage. Therefore, only quadcopters with the same battery voltage and similar operating characteristics can be compared by amp-hours; and it is best to evaluate battery life by directly claimed flight time (see below).

The operating voltage of the battery supplied with the quadcopter. This information is not particularly important for everyday use, but may be useful in some specific cases — for example, if you need to pick up a charger or a spare battery. In addition, voltage data is needed for a correct comparison in terms of capacity (see above): recall that only batteries with the same voltage can be compared by ampere-hours, with a different number of volts, you need to use a special formula.

Battery model for which the quadcopter is designed. Most often, such a battery is supplied with the device, and data on the battery model is not needed for everyday use. At the same time, such information can be useful, for example, if the battery or "charging" to it is out of order and needs to be replaced, or if you are looking for a backup battery.

The term "protected housing" in drone copters usually refers to protection for propellers; sometimes it also covers the fuselage, but the key point is precisely the covered blades.

The specific design of such protection may be different. The traditional option is characteristic rings or arcs that cover each screw of the copter on the sides; however, there are also more exotic options — for example, a lattice "shell" that covers the entire apparatus. Anyway, in the event of a collision, the protective devices prevent the rotating blades from contacting the obstacle, protecting both the propellers themselves and the objects surrounding the copter from damage; of course, such protection is not absolute, but at least it reduces the likelihood of serious accidents. And solid rings around the screws can also increase their traction. On the other hand, the additional "kit" increases air resistance, especially when driving at high speed; therefore, in many drones (especially advanced ones), protection is made removable — primarily for flights in open areas, where there are no obstacles and the risk of collisions is minimal.