Comparison WL Toys V931 vs Nine Eagles Solo PRO 228P

Helicopter rotor(s) diameter. In fact, this parameter primarily determines the dimensions of the machine in the working position; this is especially true for three- and four-bladed models, where the propeller cannot be deployed along the fuselage, reducing the width of the space occupied (although the blades can be folded, which eliminates this drawback). Otherwise, the diameter of the rotor is of secondary importance: it is selected by the manufacturer in such a way as to provide features corresponding to the class of the machine, and it is worth focus primarily on the general purpose and price category of the helicopter, and not the size of the propeller.

The diameter of the tail rotor in machines of the classical scheme (see below). This parameter is of practical importance only in professional aircraft modeling sports, and even then quite rarely; relevant moments are described in special sources.

The number of blades provided in the design of the main rotor of a helicopter. When calculating this number, all rotors are taken into account — this means that in the coaxial circuit models (see above), the total number for both screws is indicated. Actually, in such machines 4 blades are used as standard — 2 per screw, there is usually no need for more; but in the classical scheme, this number can be different — from 2 to 3 — 8(technically, more is possible, but in fact this is rare).

The fewer blades provided in the design, the simpler and cheaper the screw (ceteris paribus), but the faster it must rotate in order to provide the necessary lift; this puts forward corresponding requirements to the engine. However, the number of blades is usually chosen by the manufacturer in such a way as to provide the machine with flight characteristics corresponding to the price and class. Therefore, this parameter can only be of practical importance for professional models designed for complex aerobatics; You can read more about this in special sources.

A method of transmitting torque to the tail rotor of a helicopter. Note that such a screw can also be used in coaxial machines (see above).

— Val. Transfer of rotation from the main engine using a shaft located inside the tail boom. This option is very convenient for those cases when the screw needs to be rotated constantly, but is not suitable for periodic inclusions. Therefore, it is found only among models of the classical scheme. The main advantage of this type of drive is considered to be high precision in control, however, it is also quite expensive.

— Belt. As the name implies, the link between the tail rotor and the engine in this case is provided by a belt drive. Like the shaft described above, this option is used in classic helicopters; it is less precise in control, but is also suitable for aerobatic models. Of the obvious disadvantages, one can note the need for periodic adjustment of the belt tension — in order to avoid slippage.

— Motor. In such models, a separate miniature motor is provided to rotate the tail rotor. This option is very convenient for coaxial helicopters, where the tail rotor is switched on periodically for pitch control; however, it can also be used in classic models (usually low-cost level). The motor is cheaper than the rotor and belt, and the design of the machine itself is simpler; control accuracy, however, is usually low, however, given...the class of machines where such a drive is used, this disadvantage can hardly be called critical.

— Missing. The complete lack of tail rotor drive is found in low-cost coaxial models; the screw itself, however, may be present — as a decorative dummy.

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 presence in the design of the helicopter of a stabilization system in the form of a so-called servo axis (flybar) located on the axis of the main rotor (above it or below it). A spun flybar tends to keep the plane of rotation in one position, thus ensuring a stable position for the entire helicopter. This has a positive effect not only on resistance to wind gusts, but also on the quality of control: without a flybar, the helicopter would react too sharply to commands from the remote control, and with a stabilizer, control becomes soft, smooth and accessible even to beginners. On the other hand, the higher the stability, the lower the accuracy and responsiveness of the control; therefore, in professional flight machines, a flybar may be absent — its role in such cases is played by an electronic stabilization system.

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 voltage of the battery supplied with the helicopter. For models for AA cells (see "Battery type"), this voltage is not indicated — the specification of such cells assumes a common voltage standard, about 1.5 V. In other cases, this data is not particularly important for everyday use, but it may be useful if you you need to pick up a charger, a spare battery or a battery to replace a damaged one, but you don’t have data on the battery model (see below).

Model of the original battery (see “Battery type”) for which the helicopter is designed. Most often, such a battery is supplied with the device. Data on the battery model may be needed if it is out of order and needs to be replaced, when looking for a spare battery or when selecting a charger (usually, charging capabilities are already provided in the standard package, but it is possible that a separate device will be required).