Comparison Syma S39 vs Syma S108G

The minimum age for which this radio-controlled model is suitable. These recommendations are rather conditional, but it is still not recommended to deviate from them. "Adult" models 14+ with many adjustments, moving parts and power simply will not be able to master the baby. At the same time, models for the younger age category may not be interesting and boring for older children.

The number of control channels provided in the radio-controlled model.

Each such channel is responsible for a separate control function: the operation of the rudder, elevators, etc. For the simplest models, 2 – 3 channels are enough. Full control requires more channels. In advanced models, additional channels may be provided, the total number of which can reach 6 or more.

The capacity of the battery supplied with the electric motor model (see "Motor"). Indicated only for variants using branded batteries (see "Battery type"), measured in ampere-hours: 1 Ah corresponds to the capacity at which the battery is capable of delivering a current of 1 A for 1 hour.

The higher the battery capacity, the more time the helicopter can spend in the air, usually. However, the practical time of operation on a charge is largely determined by other characteristics of the machine — dimensions and weight, engine model and power, etc. Therefore, in most cases, this parameter plays a purely reference role, and only helicopters that do not have any significant differences in other characteristics (and even then very approximately) can only be compared in terms of battery capacity.

Operating time of an electric powered helicopter (see "Engine") on one battery charge or on one set of batteries. This parameter is rather conditional and approximate: it is usually indicated for optimal operating conditions, with a uniform low load on the engine (most often for hover mode), and when using replaceable cells — for high quality batteries. Accordingly, in fact, the operating time may differ markedly from that stated in the specifications. Nevertheless, this indicator quite reliably describes the battery life of the car, and different models can be compared according to it.

The frequency at which the helicopter control transmitter operates.

— 27.145 MHz. One of the frequencies used for radio remote control for a long time; in some CIS countries it is even reserved by state regulatory bodies for this very purpose. Such transmitters are relatively inexpensive, but suffer from one serious drawback: they do not provide channel separation when several consoles are operating in close proximity to each other. In other words, if the helicopter stays in the coverage area of two transmitters, the signals from them will be mixed, which is actually equivalent to a loss of control. This is most often unimportant in "recreational" flights; however, at competitions and other public events where several cars can be in the flight zone at the same time, very unpleasant and even dangerous situations can arise. You can avoid such situations by developing a common frequency grid and using interchangeable crystal oscillators for consoles — but such features are not always available. As a result, this frequency is gradually being replaced by the more advanced 2.4 GHz standard, not only among professional, but also among amateur models.

Separately, we note that transmitters with frequencies of 35, 40 and 75 MHz can also be found on the market; according to the main features, they are completely similar to the described 27.145 MHz and differ only in the operating frequency.

— 2.4 GHz. Today's most advanced communication standard used by remote control helicopters. Its main feature (and difference from the above options) is the possibility of normal operation of several transmitters of this format in close proximity to each other. To do this, various technologies are used that provide automatic distribution of receiver-transmitter pairs over their own channels (similar to how it happens, for example, in mobile communications). Theoretically, the 2.4 GHz band may be more prone to interference, as many modern electronics work in it (in particular, Wi-Fi and Bluetooth modules); however, thanks to the distribution of channels mentioned, such problems arise only in very unfortunate cases, but are solved easily and quickly. In addition, due to the coincidence in frequencies with the Wi-Fi standard, models for such remotes can be easily controlled from a smartphone (see below).

The greatest distance between the remote control and the helicopter at which the remote control transmitter is still able to guarantee normal controllability of the model. Note that official specifications usually provide data for perfect conditions: full battery charge, no obstacles in the signal path, extraneous interference, etc .; in fact, the range may be somewhat less. However, by this parameter it is quite possible to compare different models with each other.

The higher this indicator, the further you can let go of the helicopter from the remote control, the less often you have to move to keep control. However, a large range means not only a long range as such — it also speaks of a good signal penetration, its ability to pass through various obstacles. At the same time, powerful transmitters require appropriate power and large antennas, which affects the weight and dimensions of the console.

The type and number of batteries needed to operate the helicopter 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 remotes require several of these batteries — usually 2, 4 or 6.

— 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.

The frame is the base of the helicopter; it is on it that the engine, mechanisms, electronics and body are installed. It may have the following structure:

— Team. This category includes frames consisting of separate parts on detachable joints — for example, bolts. Other things being equal, they are considered less reliable than solid ones, because. connections are usually the "weak point" of the design; however, for simple flights, this reliability is quite enough, and prefabricated frames are somewhat cheaper. This option is found mainly in entry-level models, as well as in inexpensive middle-class cars.

— Whole. A frame that does not have collapsible joints and is made in the form of an integral structure. Theoretically, this option is able to provide high strength, making it suitable even for professional-level machines. However, in fact, a one-piece frame in itself is not an indicator of a high class model — it is found among helicopters of all price categories, and the quality of the structure, usually, directly depends on the cost.

The material used for the body of the helicopter.

The case, usually, is an external casing that covers the frame with the equipment installed on it (in whole or in part). It plays a decorative role, and also provides the necessary balance and aerodynamics of the model. High strength is not required for such a casing, since even during difficult piloting the loads on it are minimal, and accidental cracks, chips and other damage are not critical for the machine's performance.

In light of all this, plastic has become the most popular material for radio-controlled helicopter bodies. This material can easily be given almost any shape and coloring, while it is lightweight and inexpensive. Of the shortcomings, one can only note the susceptibility to scratches, but this moment mainly affects the appearance of the car, and not its flight qualities. Plastic is common among all categories of helicopters, from low-cost to professional.

Another option found in modern models is Lexan. This material is in many ways similar to plastic, but much more durable and wear-resistant. On the other hand, it costs accordingly, and therefore is used mainly in cars of the middle and higher price range.