Colonel-General Bondarev said that work is currently underway on a new project whose goal is to significantly increase the maximum speed of helicopters. Already have an engine that will allow to carry out this project. The technologies and technical solutions currently being studied in the future will increase the maximum speed of helicopters 1,5-1,8 times. Thus, for promising rotary-winged cars, this parameter can exceed 350-400 km / h, which will provide them with higher flight characteristics in comparison with the existing technology.
The details of these works and the approximate dates for their completion are still unknown. Some features of the new project can be found out from previous statements by Russian officials. So, in February of this year, Deputy Prime Minister Dmitry Rogozin spoke about the development of a promising high-speed helicopter, which is supposed to be used for transport purposes. This machine will be designed to replace the deserved, but obsolete Mi-8. In addition, the possibility of creating a combat modification of the helicopter was not excluded.
The development of new high-speed helicopters is one of the most promising areas in the field of helicopter. Such projects are engaged in all the world's leading manufacturers of such equipment. Russian helicopter builders, who have been studying this topic for the past few years, are no exception. It is known about the existence of three projects of domestic design bureaus, the purpose of which was to study the appearance of helicopters with a high flight speed. These developments are known under the indexes Mi-X1 (MVZ them. ML Mil), Ka-92 and Ka-90 (JSC "Kamov"). Similar projects exist abroad, and some of them were able to reach the prototype testing stage.
In fact, to create a high-speed helicopter, engineers need to solve only one problem, but this solution turns out to be extremely difficult. The fact is that as the speed of horizontal flight increases, the flow around the propeller blades gradually worsens. Upon reaching a certain speed associated with the characteristics of the screw of a particular helicopter, so-called occurs. stall on the retreating propeller blade. This means that the end part of the blade, moving to the tail of the helicopter, develops supersonic speed relative to the air with subsequent disruption of the flow and a sharp drop in lift. Over the past decades, aircraft designers have been trying to influence this process and “delay” the disruption before the helicopter reaches the required speed.
The existence of the Mil project under the designation Mi-X1 became known at the end of 2007. A few months later, the helicopter builders shared some of the details of this development. Within the framework of the project several different measures were proposed at once, aimed at increasing the flight speed, as well as at eliminating the disruption of the flow at the required flight conditions. For this it was proposed to optimize the aerodynamic appearance of the car, to use the so-called. system of local suppression of stall on the retreating blade, as well as use an additional pushing propeller.
An interesting fact is that all modern projects of promising high-speed helicopters involve the use of additional pulling or pushing screws. The main reason for their appearance is the need to unload the rotor and reduce its speed, which allows you to expand a number of modes where no disruptive phenomena are observed. In addition, the pushing / pulling screw in comparison with the bearing has a much greater efficiency in the role of propulsion in the horizontal plane. In certain modes, the main rotor can be used exclusively as a source of lift, and the pushing / pulling is able to perform the functions of the steering compensating reactive torque.
On the available photos of the layout, made in the framework of the Mi-X1 project, the general features of the perspective machine are visible. It should have a streamlined fuselage with a sufficiently large cabin for cargo or passengers. Above the cab, space is provided for the power plant and the main rotor is mounted, the sleeve of which is covered with a radome. The tail plumage is the basis for the pushing screw, enclosed in an annular channel.
According to reports, the Mi-X1 project allowed creating a multi-purpose cargo-and-passenger helicopter with a normal take-off weight of about 10 tons and a maximum up to 11-12 tons. on emergency mode. When using such a power plant, a promising helicopter could take on the 2500-2700 tons of cargo or 3-4 passengers. The estimated cruising speed of the Mi-X20 reached 25 km / h, the maximum - 1 km / h. Practical ceiling - 475 m, range - over 520 km.
At the exhibition HeliRussia 2008 representatives of the cost center for them. M.L. Mile argued that with the timely completion of all the work, tests of an experienced Mi-X1 helicopter could start in 2014-15. However, information on the construction of the prototype of this machine is not available. Probably for some reason the project stopped at the stage of research or design work and has not yet reached the stage of building a prototype.
At the HeliRussia 2009 exhibition, Kamov OJSC presented its version of a high-speed helicopter called Ka-92. In terms of its architecture, this aircraft was largely reminiscent of the Mi-X1, but it was proposed to build it using a number of technical solutions typical of Ka-brand helicopters. The overall layout of the Ka-92 is the same as that of the Mi-X1. The fuselage is given for the placement of goods or passengers, and in its upper part there is a volume for the power plant. In the tail of the car, it was proposed to install a pushing thruster.
Like other Kamov helicopters, the high-speed Ka-92, had to have coaxial rotors with characteristic hub fairings. In the same way, it was suggested that the tail pusher be made. The tail of the Ka-92 was to consist of an arrow-shaped stabilizer and two puck keels at its ends. The screws were to be located on the tail fairing of the fuselage, the annular channel was not provided.
It was reported that two Ka-92 engines could be installed on Ka-2500 helicopters, but the possibility of using the prospective VK-3000 with a power over 3000 hp was not ruled out. A new model helicopter could fly at a cruising speed of about 420-430 km / h, if necessary, developing to 500 km / h. Flight range was set at 1400 m. With a maximum take-off weight of about 16 tons of Ka-92 had to take on board up to 30 passengers.
Like the Mi-X1, the Ka-92 helicopter was demonstrated several times at exhibitions solely in the form of layout and promotional materials. Any information about the further implementation of the project is missing. Probably, the work stopped at one of the early stages of the project, before the start of preparation for the construction of the prototype.
The high-speed helicopters Mi-X1 and Ka-92 even look like a vehicle that can ascend into the sky very soon. Another project of Kamov, Ka-90, led to the appearance of a mock-up of an unusual futuristic look and a few bold ideas. Moreover, some features of this aircraft do not allow to unambiguously classify it as a helicopter. Perhaps the widespread adoption of such a concept (if, of course, it happens) will lead to the emergence of a new term for the designation of such a technique.
The Ka-90 high-speed helicopter should take off with a propeller, like all other cars of this class. In case of horizontal movement at low speeds, the main rotor should be used as a propulsor. With further acceleration of the car is proposed to include a turbojet engine mounted in the rear fuselage. After reaching a certain speed, the relatively wide rotor blades should stop and turn back, taking up a position along the fuselage. Further flight at high speed was proposed to be carried out without the use of a rotor.
According to the information provided, the Ka-90 aircraft at speeds up to 400 km / h should have used the rotor, and in a configuration with folded blades could accelerate to 700-800 km / h. This concept of a promising aircraft, capable of taking off and landing on small platforms and flying at a high cruising speed, is of some interest and also raises some questions.
The main issue is the mechanism for creating a lift on a cruise flight mode with the propeller folded. The lack of clear information on this matter may cast doubt on the whole project. In this context, we should recall the fantastic film “6 Day” (USA-Canada, 2000, dir. R. Spottyswood), which used Whispercraft aircraft with a foldable rotor. Fictional film engineers solved the problem of screw removal and providing the required lift force in an original way: when switching to cruise mode, the wide rotor blades turned to the desired position and turned into a swept wing.
The appearance of promising high-speed helicopters, presented by domestic designers in recent years, allows us to build some assumptions about the future of this direction. Apparently, the new equipment of this class, which is to be built and tested in the foreseeable future, will be created on the basis of the Mi-X1 and Ka-92 projects. The original and interesting Ka-90 is still too bold and difficult to translate into metal and testing. The perspectives of the scheme used in the Mi-X1 and Ka-92 projects can be expressed by the statements of Colonel-General V. Bondarev on the approximate flight speed of the promising technology.
It is possible that shortly the testers will have to fly the Mi-X1 and Ka-92 helicopters. In addition, we can not exclude the possibility of creating new projects based on these developments. With confidence, we can only say that work in this direction is underway and one should already wait for the construction of experienced helicopters capable of accelerating to record speeds.
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