Unmanned aerial vehicles

Mykhailo Matiichyk, Cand. Sc. (Tech.), Associated Professor at the National Aviation University (Kyiv), Director of the Virage Unmanned Aircraft Research and Production Center.

The National Aviation University (NAU) has always devoted special attention to emerging technologies. Unmanned aerial vehicles (UAVs) are not the exception as evidenced by the UAV M-7D Sky Patrol successful launch in January 2011 (Fig. 1).

Figure 1

This is a fairly large twin engined UAV attributed to a group of tactical UAV Class CR (Lpol up to30 km; Tpol up to 4 hours; mo150 kg; Npol up to3,000 m) or class LADP (Lpol is more than250 km, Tpol about 1 hour, mo is250 kg, and Npol is up to9,000 m). Here we are talking about a solid piece of work on the development of an unmanned aerial vehicle, i.e. a prototype with increased size, weight, payload, fuel and other capacities.

However, it would be unfair for the author to consider UAV projects at NAU only in terms of their current status. Everyone understands there should always be background to the event...

The projects had obviously their beginnings in late 1970s when the proportional radio control devices Novoprop and Supranar replaced the RUM and Start models giving an impetus to not very "rich" model-makers for building and launching desirable radio-controlled planes and gliders despite the criticism over their quality. The author has trodden this path.

They started working in a club in 1970 begging the director, by hook or by crook, to allow a discrete Start, step-by-step mounting a device and practicing a launch of a “timer” along with a Rhythm first with turn signals, then with the ailerons, etc. somewhere in a wheat field.  Then came out our Pilot ...

Applied unmanned aircraft, i.e. drones useful for man, appeared later; many were drawn from the studies published in Interavia, Modelages of the Democratic Republic of Germany, Czechoslovakia, and Poland, and from our M-K and KR journals, etc. Face-to-face contacts, especially, at conferences and in competitions, broadened some knowledge on the matter.

In early 1980s we formed a student group which grew then into an inter-regional one. It would rather have looked like an inter-university group of students from Kyiv Institute of Civil Aviation, Ternopil Technical Institute and Lviv Agrarian Institute. The choice of such dissimilar institutes was the attempt to find solutions to the questions raised by the first launches of the so-called radio-controlled planes.  We encountered difficulties with the navigation software, traffic control beyond the zone of visibility, training of operators (now pilot – operator or RC – pilot), accurate calculations of useful substances emission overboard, etc.

Such natural "cooperation" encouraged the amateur association to work efficiently and develop an innovative product. For instance, they launched four devices between 1981 and 1987, and built dozen "trainers" for 2.5 cm3 to 10 cm3 engines. Among the group consisted of the following students: M. Matiichyk, V. Oleinyk, A. Sazanov, N. Horbulko, O. Ivanov and V. Ivanov, O. Shamryk, O. Berdychivskyi, O. Levchuk, and many others.

Then came "heavier" planes,  and by 1988 they had constructed two models of the "applied" M-1 and M-2 planes. They were built almost simultaneously for engines 10 and 20 cm3 based on MDS - 10 (Fig. 2 and Fig. 3).
  
Figure 2                                                    Figure 3

Both planes were designed for agriculture, in particular, to introduce Trichogramma. The M-1 project had a multi-channel Trichogramma emission along the wingspan, while M-2 emitted it from three points: one in the nacelle fuselage and two placed at wing tips.  Due to lack of engine (there must be a “dual” geared engine of  20 cm3) M-1 was not completed and remained as demo (demonstration copy). M-2 was successfully built and tested together with the Trichogramma emission metered devices. The designers were awarded USSR Inventor’s Certificate No 67516, and the plane with the entire research was then used to carry out dissertation experiments. M-2 was employed in aviation chemical works (АХР) in Lviv region in 1990s.

The need to increase the payload and switch to gasoline engines prompted the group in early 1990s to design and construct a 4.5-meter single-engine plane M-3 with a target load of30 kg(Fig. 4 and Fig. 4a).

Figure 4                                                                             Figure 4a

The plane had an innovative layout scheme (probably under the influence of Soika and RQ), a good wing mechanism, and landing gears of various types. It was supposed to be employed in several areas, including aviation chemical works. The sketches planned a fertilizer (chemicals) disperse system with active (rotating) sprayers. The plane was 60-percent built. Later the M-3 plane was named Cordon. It is interesting to note that an air-cooled engine 2M - 220U was built especially for M-3 based on the components to the Ural chainsaws which were widely used in the CIS countries (Fig. 5).

 
Figure 5

The engine showed good performance, but the difficult situation in the country in mid-90s made the work on the plane and the engine come to a standstill.

The research study on M-1 and M-2 was presented on several exhibitions where former President of Ukraine Leonid Kuchma paid a higher compliment on them. Taking into account the UAV size, one cannot but remember the 01 engine project with a wingspan of 5 meters to have been developed in early 1980s for aviation chemicals work. 

Figure 6

The designers aimed to install a Voskhod (Sunrise) redesigned engine in the 01. The plane was projected as "flying tank" with a control system in front of the chemical tank in the engine cowling. However, the project failed to be set up, and as we see the Japanese successfully fly helicopters in the UAV segment for dispersing chemicals by air. Looking ahead, we can say that the UAV-system in terms of its application is still in its infancy, and hence it is hard to say today which carrier (airplane or helicopter) will be better (applied) to dispersing chemicals by air.
With regard to the control systems, the designers used the automatic radio control elements, such as individual gyroscopes (most probably accelerometers), final amplifiers, etc. In the beginning of 1990s the hardware was adapted under the Conrad, Futaba and Graupner systems. It is notable that the power units our group constructed (now referred to a power-box) were applied in domestic aircraft since mid 1980 due to large current flows through main tire receivers.

We also worked out separate power supply for receivers and servos, and developed a few high-power servos based on domestic components. Besides, we altered frequency bands and a modulation type. By early 1990s we had switched AM to FM, PPM and PCM. Also, we carried out the first research in airborne video surveillance composition.
In the turn of the century the primary group curtailed the work based on the imperfect experience of the previous years and a scientific vacuum our research and developments had turned out to be.

After a series of consultations and at the urgent request of Ya. Kozachok, vice-rector at the National Aviation University, the author moved to Kyiv.

Active participation of Vice Rector for Academic Affairs Mykola Kulyk (now rector at NAU) and Vice Rector for Scientific Work Volodymyr Kharchenko fostered creation of the first UAV staffing division.
After ending the initial stage it was necessary to bring together the previous developments and university’s great scientific potential. I would like to emphasize that the process was speeded up owning to internal readiness of the university leadership to such pioneering solutions against the background of a rather complicated situation in the aviation industry.
Among the new projects set up at that time I’d like to mention the M-4 plane that greatly contributed to the "coherence” between science and practice (Fig. 7).

 Figure 7

It is based on the traditional typesetting technology and is equipped with a Moki-75 gasoline engine. It looks like an amateur light aircraft. The purpose of its construction is to promote a new trend by participating in various air shows and using it as a "flying laboratory." The plane has 14 servos, a power-box, four batteries, an efficient muffler, mechanisms and underwing hinges, a 35-kilogram takeoff weight, and a 18-kilogram payload. The underwing rods designed for aviation chemicals work were attached to the regular nodes. The plane served to perfect the engine fuel feed system consisting of a two-way filling tap, a few fuel filters, a supply tank and a piping system. In addition, the engine has several Hall effect sensors to improve the ignition system.
The developers under the guidance of Professor S. Ischenko had equipped M-4 with various sensors and measuring instruments to study transient phenomena in aerodynamics.
In this connection it should be noted that many scholars at NAU (founders of scholar schools) welcomed Vice Rector Kharchenko’s idea to combine the results of engineers and scholars. Among the first was already mentioned Prof. Ischenko, Prof. Udartsev, Prof. O.Tunik, Prof. H. Yun, Prof. Dmytriev, and others.

The M-4 plane took part in demonstration flights at the AviaSvit XXI air shows in 2002-2006 (Fig. 8 and Fig. 8a, M-4 over the Sviatoshyn airfield).
 

    
Figure 8                                                                                                         Figure 8a

To continue work on the M-2 project they set up a Skylark project for an M-6 plane construction (Fig. 9).

 
Figure 9.

M-6 Skylark (Pat. of Ukraine No 34952), a small plane with a maximum takeoff weight of 12 kg, has a Trichogramma emission system (Pat. of Ukraine No 43459) integrated into the design (Fig. 10).
 

Figure 10

The system was introduced to ensure the widest wingspan with the initial span of 1.7 meters. For this purpose we used air flow energy behind the propeller to straighten it into a special wing channel. The channel is fed by metered Trichogramma and the mixture received is spreading aside wingtips. The span width is 3.5 m, while that with Trichogramma searching radius is 5.5 m. 
The metering device (Pat. of Ukraine No 38142) is a biconical hollow bunker rotating on an electric driven axis (Fig. 11).
 

Figure 11

The M-6 carrier proved to be a very good plane. It smoothly flies in turbulent including in 2011 conditions and in the wind of 15 m/s. The tests took place in rain and during snowfalls. A number of flights were performed in winter in the air temperature of about minus 150C. In summer the temperature went up 350C. M-6 Skylark flew a total of 100 missions, including 2011 (one flight per 10 minutes).
M-6 Skylark consists of 3 parts required 10 minutes to be assembled. The sweep wing during a rough landing is its great advantage. Besides, the plane’s survivability is enhanced by the V-shaped tail unit. The plane has two engines, 2 to 4 HP, and is equipped with bike gears. It can take off with "hand" or from a special mast – launching device KP-1 developed as a mobile accelerator for UAVs up to 30 kg (Fig. 12).

 
Figure 12

KP-1 has a moving carriage fitted with a known amount of rubber bands. There are various methods and means of carriage movement. Therefore, using the KP-1 lead-in section the developers at NAU are working out other catapult accelerators for UAVs.

M-6 Skylark was subject to new requirements, and in 2007-2009 it was refurbished. 
First of all, the so-called “cheeks” appeared in the middle of the fuselage with a digital camera on a rotating platform behind. In addition, to transfer images in real-time a color video camera with its own transmitter and antenna in a radome was installed. Another purpose of the plane is to conduct a remote sugar beet germination survey with simultaneous mapping of sprout distribution. In doing so they used a ground control station that helped in piloting, data collection and processing of the data received (Fig. 13).
Today, we can assume that the Skylark project has an efficient M-6 carrier with a potential route distance of 500 km (1 kg payload) or 7 kg of cargo transportation on the route of 150 km. The National Aviation University is to launch a small-scale production of the plane (Fig. 14).

 
Figure 13

The group led by Prof. Tunik tested M-6 performance. The group led by Prof. Kondratiuk developed navigation software and avionics (Prof. Kharchenko as supervisor). The group headed by Prof. Yun made the UAV M-6 feasibility study. T. Lavryk, an employee at NAU, explored UAV M-6 application in aerial photography and researcher Rybalchenko dealt with its use in aviation chemical work. 

Figure 14.

The problem of improving UAV reliability affects its configuration. The two engines from this point of view are always better than one. In this regard, in 2005 the NAU leadership was offered the Sky Patrol project for a twin-engined UAV with a starting weight of 100 kg. Among the layouts they considered the most diverse ones, including a “tandem” as in Hunter. However, the choice was made in favor of the unexpected tandem, asymmetrical layout (Fig. 15).

 Figure 15

According to the developers, it should minimize an impact of the front power plant on the expensive target load in the nacelle. The plane was named the M-7 Sky Patrol (Pat. of  Ukraine No 33977). It took almost a year (2006 – 2007) to build it at NAU. It was launched in 2008 (Fig. 16 and Fig. 17).

 
Figure 16                                          Figure 17

The first tests showed that the designed layout along with many benefits does not provide high takeoff performance due to lack of power plant flow to the center wing. In addition, the power of existing engines was also insufficient. Despite the advantages in the initial cruise (almost "pure" wing), in 2009 the layout was changed to the traditional one with  puller prop engines on the center wing. The plane got an M-7D Sky Patrol index (Fig. 18).

Figure 18

The aircraft has two engines of 15 HP and a takeoff weight up to 150 kg. The fuel capacity of 20 liters allows flying about 800 km at a cruise speed of 190 km/h. The increased wing span and its area, modern equipment (slotted flap) and a slotted flaperon ensure a takeoff from problematic and short runways. During the 2010 tests in winter conditions (air temperature was about minus 100C, and the snow cover of about 10 cm) the plane with the takeoff weight of 80 kg ran up 17 m before the liftoff (the flap was minus 200). The projected takeoff run of a fully loaded aircraft is about 38 m; the target load is 50 kg. An autopilot based on the integrated SNA / SINS, on-board redundant power supply components, ground-based devices, etc. are under development. 
The final stage in the Sky Patrol project ended by preparing a package of documents in early 2011 for building an M-7V5 plane, takeoff weight of 200 kg (Fig. 19).

 
Figure 19

The plane is designed for flights of up to 4 units of load factor on about 1,500 km. Depending on the target load (20-70 kg), the distance can range 1, 200 to 2, 700 km with a flight duration of 7 to 15 hours. The plane will have two engines with a total capacity of 50 HP.  In particular, the plane will be equipped with a ballistic parachute system. Like the previous model (M-7D), M-7V5 will have a high take-off /landing performance. The design takeoff run of the fully loaded airplane is about 75 m; the wing has a large retractable slotted flap and slotted flaperons.
A few words about prototypes of our UAV. As known, aeronautical equipment goes through a complex process from first sketches to serial production. At the stage of validating layout decisions it is useful to have a relatively simple testing tool, for instance, radio-controlled prototypes which are used in the National Aviation University. Here are the examples of the radio-controlled prototypes which helped put into operation airplanes with direct and inverted V-shaped tail units (Fig. 20 and Fig. 21).
 

 
Figure 20                                                                                Figure 21

It should be noted that the preliminary plan of the above said M-7 Sky Patrol project included the M-7A plane with a inverted V-shaped tail and two power plants with ring propelling devices (Pat. of Ukraine No 40288) (Fig. 21).

 
Figure 21

The unmanned aerial vehicles designed at the National Aviation University are currently in the Virage Unmanned Aircraft Research and Production Center. It was established in 2010 after reorganizing the Research and Training Center created in 2007. We are pleased to emphasize on active participation of Maksym Lutskyi, a Verkhovna Rada deputy, first vice rector of the National Aviation University, in Virage creation.

Virage is provided with an advanced composite small-scale production of UAVs and their components. But Virage is famous for its team of young scientists, engineers and technicians whose average age is about 25 (Fig. 22).
The majority of them are the people devoted to aviation. It is worth mentioning the works of talented designers O. Rybalchenko, M. Makarchuk, K. Kryvenko,

Ye. Doroshenko and O. Sytnyk. The skilled workers, S. Olekseyenko, O. Plakhotniuk and others have built up a well-deserved reputation at the production facilities. Women do not fall behind the men. Media coverage is successfully provided by I. Kachalo and documentation management by A. Demchenko.
 

Figure 22

Design is carried out with the help of modern tools - Compass, AutoCad, Solid Worcs, etc. If necessary, Virage employs the aerodynamic complex (TAD-2 and UTAD-2 pipes) and pressure chambers with appropriate scientific and methodological support.
As our UAVs are supposed to be used in the airspace of Ukraine, we are preparing appropriate certification documents. In developing UAV vital systems Virage involves specialists and scholars of relevant departments of the National Aviation University, especially, the department of air navigation systems chaired by Volodymyr Kharchenko, Doctor of Technical Sciences, Professor, Honored Scientist of Ukraine, laureate of the State Prize of Ukraine in the field science and technology (reference to the article).
Technologically our planes are entirely composite products. The Virage Research and Production Center is oriented to a high-grade closed loop product with warranty service, as well as to personnel training.
In conclusion I want to say that the future plans in Virage are  to design a carrier with an electric power plant,  a carrier with a target loading capacity of 200 – 250 kg, and noteworthy and beneficial unmanned aerial vehicles (drones) for our national economy.