In the field of vertical take-off and landing aircraft, the undisputed leadership belongs to helicopters. However, the search continues for alternative schemes that may have real prospects. In particular, right now Russian specialists are studying the concept of the so-called. cyclolet or cyclocopter. As part of the Cyclone program, bench models and a prototype aircraft have already been created and tested, and a full-size aircraft is expected to appear in the near future.
Free takeoff
In 2017, the Russian Foundation for Advanced Study (FPI) launched the Free Takeoff competition. His task was to find alternative schemes for vertical / ultra-short take-off aircraft that could compete with the helicopter. One of the applications for the competition was submitted by the company "Flash-M" (Krasnoyarsk), which united representatives of the creative group "Arey" and the Institute of Thermophysics of the Siberian Branch of the Russian Academy of Sciences (IT SB RAS).
"Flash-M" came up with a proposal to create a so-called. cyclolette. Scientists of the IT SB RAS have been working on this concept for a long time and conducting theoretical and experimental research. A large amount of data was collected and a bench sample of a promising cyclic propulsion / cycloidal propeller was demonstrated. The Flash-M proposal interested FPI, and it was this organization that became the winner of the Free Takeoff.
In 2018, FPI launched the Cyclone project, during which it was planned to continue work on the cyclolette theme, as well as build and test the first prototypes. Also, within the framework of this project, issues of further production, implementation and operation of full-size equipment suitable for real use are being studied.
In July 2020, "Flash-M" conducted the first flight tests of an experienced unmanned aerial vehicle. The apparatus weighing 50 kg received four original cyclic propellers. Its capabilities for vertical takeoff and landing, level flight and maneuvers were confirmed. In addition, they demonstrated some of the capabilities not available to helicopters. Shortly thereafter, another experimental drone called Cyclone 2020 was shown at the Army 2020 forum.
Plans for the future
In April of this year, the start of a new stage of work was announced. Now the goal of the Cyclone project is to create a full-size optionally manned aircraft weighing up to 2 tons with a payload of 600 kg. Such a "Cyclocar" is planned to be put on trial next year. In the medium term, mass production and introduction of such equipment may begin in various fields.
The Cyclone developers plan to create a whole line of equipment based on common principles and technologies. Loads weighing up to 20 kg will be carried by a 60-kg UAV "Cyclodron". Larger cargoes, incl. passengers will have to carry a 2-ton Cyclocar. In the distant future, a heavy Cyclotrack may appear, which with a take-off weight of 10 tons will be able to carry up to 4 tons of cargo.
It is assumed that new types of cyclolets will find application in the field of cargo and passenger transportation. Also, the military, rescuers, etc. may be interested in them. In some areas with special requirements, such technology can replace helicopters. Its advantages are considered smaller dimensions and weight, as well as higher maneuverability and stability.
To fulfill orders for equipment, it is planned to create a new aircraft building plant. The development organization already has a business plan, and it is reported that there are investors who are ready to ensure its implementation.
Technical features
Within the framework of the Cyclone program, a universal scheme of a cycling aircraft is being studied and tested, which will then be used in all planned projects. This scheme lends itself to scalability, as a result of which the compact "Cyclodron" and the heavy "Cyclotrac" will be similar to each other.
The proposed scheme provides for the construction of an aircraft with four cyclic propellers, located in pairs on the sides of the streamlined fuselage. The design proposes the widest possible use of plastics and composite materials, which will increase the weight perfection.
Cyclelets will receive a hybrid or all-electric power plant. In both cases, the rotation of the propellers is provided by electric motors. A fly-by-wire control system with maximum automation is being developed. She will have to work completely independently or follow the pilot's commands, unloading him.
The main innovation of the project is the so-called. cyclical mover. This device is a set of five blades of limited length, installed between the side discs. The blades have the ability to rotate freely around the longitudinal axis; a special mechanism - similar to a swashplate on a helicopter - sets their common and cyclic step.
When the propeller rotates, the blades move along a circular path. In its upper and lower parts, the control mechanism exposes them to the angle of attack, which ensures the creation of lift. A similar principle is used to create horizontal thrust. The simultaneous use of four such propellers creates ample opportunities for vertical and horizontal flight, various maneuvers, etc.
The design of the cyclic mover can be of different sizes. Thus, a product with a diameter and width of 1.5 m has already been tested at the stand. A propulsion device of this size is intended for a Cyclocar weighing 2 tons. This means that one such device creates a thrust of 500 kg. According to calculations, such a device will be able to reach speeds of up to 250 km / h and fly 500 km. The length and width of the product will be at the level of 6 m.
Benefits and perspectives
The main advantage of the cycloopter / cyclocopter over the helicopter is the smaller size of the key units. With the same thrust indicators, the cycloidal propeller turns out to be much smaller than the propeller. The propeller of the cyclolet is constantly working in one position; the absence of the need for tilting allows it to create horizontal thrust without reducing the vertical.
An aircraft with several cycloid propellers is capable of generating thrust in different directions and, due to this, performing various maneuvers, incl. inaccessible to a helicopter. By improving the systems for setting the angle of the blades, it is possible to expand the permissible pitch angles in flight. In particular, thanks to this, a cyclolet, unlike a helicopter, is capable of taking off from inclined surfaces and landing on them.
The developers note the safety of the aircraft. Cycloid propellers are easy to equip with guards. For example, at the exhibition "cyclodron" a device consisting of a pair of disks with jumpers between them was used. A propeller was placed inside this device. The Cyclocar in the published images is protected by a grid. In addition, the device will not be noisy: in this respect, it should not differ from a regular car.
However, the original scheme has certain drawbacks, which are quite difficult to get rid of. First of all, this is the lack of extensive experience in the development, construction and operation of such equipment. Research and development of new solutions will take a lot of time, and only after that the cyclolettes will be able to count on any place in cargo transportation. Helicopters, by contrast, are already well studied and mastered, which to a certain extent simplifies both development and operation.
The experience problem is aggravated by the fact that a cyclolet is technically more complex than a helicopter. So, in the scheme from "Flash-M" and IT SB RAS, four original propellers are used at once. Each of them is not distinguished by simplicity, and their combined use leads to the need to solve new engineering problems in the field of power supply and drives, aerodynamics, control, etc.
The medium-sized cyclone of the Cyclone program is considered as a mass model capable of taking on the role of an “air taxi” in the future. A new challenge follows from this: developers and regulatory bodies will have to determine the rules for the operation of such aircraft, work out safety issues, etc. The project participants are said to be addressing these issues already.
Technology for the future?
It should be recalled that the Cyclone project from FPI, Flash-M and IT SB RAS is not the first of its kind. The idea of a cycling / cyclopter was proposed at the beginning of the last century. In 1909 the Russian engineer E. P. Sverchkov built a "wheeled orthopter" - an aircraft with two "paddle wheels". The product did not take off due to not the most perfect design and due to a lack of engine power.
In the future, new cyclolets were repeatedly developed and built in our country and abroad. However, even the most successful projects did not progress beyond the flight tests of the models - the complexity of the concept and the imperfection of the designs affected. In addition, unusual aircraft could not compete with the already familiar helicopters.
In recent decades, cyclolettes have been remembered again. Modern scientific methods, technologies and materials make it possible to study and implement such a concept at a new level. In our country, such work is carried out within the framework of the Cyclone project, which has already passed through the mock-up stage and is approaching the testing of a full-size manned / unmanned vehicle. Whether scientists and engineers will be able to cope with all the challenges ahead will become clear in the near future. The first flight of the Cyclocar will take place next year.
