Russian Stratospheric UAVs La-251/252: The "Stork" We Missed
In the material from November 24, 2024 Stratospheric UAVs – pseudo-satellites: new horizons of high-altitude reconnaissance We talked about the prospects for the development of this area of unmanned aerial vehicles (UAVs), as well as about the prototypes that are being developed abroad.
In Russia, things are much sadder; the number of stratospheric UAV projects is significantly smaller, and they are inferior in scale to those being implemented in Western countries, and now in the East.
There is a feeling that over the years the topic of stratospheric UAVs in Russia is only deteriorating. Of course, one can assume that the best developments were classified and are about to "take off", but the author is not very optimistic.
Therefore, we will consider projects of domestic stratospheric UAVs in reverse chronological order.
2019
In 2019, the Central Aerohydrodynamic Institute (TsAGI) experimented with a large-scale stratospheric UAV demonstrator model, manufactured at a scale of 1:6, which was tested in the institute’s low-speed wind tunnel.
The prospective stratospheric UAV is supposed to use thin-film solar batteries, the flight at night will be carried out due to accumulator batteries for 10-12 hours. The target load is considered to be communication repeaters, photo and video equipment, as well as meteorological equipment.
Image by TsAGI
The aerodynamic design of the UAV provides for the placement of propellers at the ends of the wing, which should ensure lower energy consumption compared to other arrangement options.
According to the head of the aircraft aerodynamics department and missiles TsAGI Alexander Kornushenko, today the assessment of the flight and technical characteristics (FTC) of the demonstrator is preliminary - such parameters as the type of engines, the energy efficiency of the batteries and solar panels, as well as the weight of the structure, may vary as further development takes place.
There is no other information about this stratospheric UAV and the prospects for its development.
2018
In 2018, the dean of the facultyAviation Alexander Efremov, head of the Moscow Aviation Institute (MAI) Department of Aerospace Engineering, reported on the first flight tests of a prototype stratospheric UAV being developed for the Irkut Corporation. The prototype, weighing up to 25 kg and with a wingspan of over 5 meters, was tested without solar batteries and has already been manufactured jointly with the Central Aerohydrodynamic Institute (TsAGI).
No further information about him appeared in the open press.
2017
The website of the Foundation for Advanced Research (FAR) contains information about the development of a prototype of the stratospheric UAV "Sova".
UAV "Owl"
As part of the work carried out, a prototype with a wingspan of 9,5 meters, powered by solar batteries, was built, and a flight duration of 50 hours at altitudes of up to 8 kilometers was achieved. The "Owl" used a flexible wing, which, under the influence of turbulence, was supposed to bend and then return to its original state without collapsing.
The dimensions of the first prototype corresponded to 1/3 of the expected final stratospheric UAV with ultra-long-term operation and a wingspan of about 28 meters.
The second prototype, a flying laboratory with a wingspan of 28 meters, crashed during testing in 2018 after reaching a maximum flight altitude of 19 kilometers. The second prototype was supposed to be able to fly non-stop for 30 days at an altitude of about 20 kilometers.
Estimated technical characteristics of the stratospheric UAV "Sova":
- wingspan – 28,5 m;
- flight altitude – about 20 kilometers;
- maximum take-off weight – 100 kilograms;
- cruising flight speed – 150 kilometers per hour;
- maximum flight speed: 210 kilometers per hour;
- aircraft engine type – electric;
Apparently, after the accident of the second prototype, the project was closed.
Is that all?
2013-2016
No, back in 2013, the Lavochkin Scientific and Production Association developed and tested the La-251 Aist, an atmospheric satellite with an extremely long flight duration, which uses solar energy for flight.
The experimental La-251 was created as part of the research and development work that began in 2012 and was manufactured in just 9 months. During the tests, the longest flight duration was 72 hours, with a total of three flights.
The La-251 glider included a straight wing of large span (15 m) and a twin-boom tail unit, its power plant included four electric motors with tractor propellers. Solar-powered batteries could store 7 kilowatt-hours of electricity and ensure takeoff and flight in low-light conditions.
The takeoff weight of the La-251 was 150 kilograms, of which a third was the airframe, a third was the solar panel, and a third was the batteries. The payload weight was only 1 kilogram. The La-251 UAV reached its operating altitude of about 10 km on the second day after takeoff, and its cruising speed was 35 kilometers per hour.
Atmospheric satellite of very long duration flight UAV La-251 "Aist"
It was expected that in 2017, NPO Lavochkin would receive technical specifications (TS) and funding for the development and production of a larger stratospheric UAV, the La-252. (at this point, the FPI was already working on the previously mentioned “Owl”).
The La-252 under construction was supposed to be almost one and a half times larger than the La-251, and the same amount lighter, thanks to new photocells with an efficiency of about 24% from the Zelenograd enterprise Telecom-STV (by the way, this enterprise is “alive” and functioning to this day, at least their website is working).
The takeoff weight of the La-252 UAV was to be 116 kilograms, with a wingspan of up to 23 meters and a payload weight of up to 25 kilograms. It was to be kept in the air by a power plant consisting of two electric motors with a total capacity of 2,4 kilowatts.
According to the developer, the La-252 was supposed to be able to continuously stay in the air for up to 5 years (!) at altitudes of 18 to 25 kilometers, moving at a cruising speed of 30 kilometers per hour. The main limitation on the flight duration was the battery life of the UAV; at the first stage, it was planned to achieve an autonomous flight lasting 100 days.
The possibility of adapting existing models of optical and radar reconnaissance equipment, installing communications and relay equipment, and control via direct radio channel and satellite was considered for the Aist UAV.
Conclusions
The situation with Russian stratospheric UAVs looks sad, it feels like it's only getting worse. The Foundation for Advanced Research has closed its projects, some models are being tested at TsAGI, but when will there be a real result - a serial product?
But the same UAV "Aist", apparently, was a quite advanced development, but for some reason it was shut down without any continuation...
Now let's remember how much electric motors and batteries have progressed over the past 5-10 years thanks to electric cars, and the efficiency of solar panels is steadily increasing. Composite materials are becoming lighter and stronger, and the need for independent production of large composite parts for airliners in Russia after the introduction of sanctions allows us to hope for progress in this direction as well.
It can be assumed that the Aist La-252 UAV, if equipped with the most modern commercially available batteries, electric motors and solar panels, could show more than excellent results.
Now these machines could “hover” over the line of combat contact (LBC) in Ukraine, providing our soldiers with communications via repeaters, as well as intelligence data necessary for the functioning of reconnaissance and strike contours.
Such machines would also be useful in Syria, tracking in real time the actions of militants who simply do not have the technical capability to shoot down aircraft at an altitude of about 20 kilometers.
Well, for now all this remains fantasy for us.
There were all the prerequisites for Russia to be among the leaders in the field of stratospheric UAVs; in many ways, time has already been lost, but there is still hope – maybe it’s time to “blow the dust off” the old developments and bring them to serial production?
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