Ringplane: aircraft with a closed wing loop

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

An airplane with a closed wing loop cannot fly - it has been proven by time. Ringplanes have been attempted since the time of the Wright brothers, and no such structure has been able to stay aloft for several minutes. But the human mind doesn't give up. In 2007, after 100 years and more than 20 attempts, a similar device took off. And he proved himself to be a maneuverable, light and durable aircraft.

This story began in 1988, when things were already heading towards the collapse of the Union, but the hope for stability was still smoldering in the hearts of the leaders of the huge state. The technical creativity club at the Minsk Gear Plant received a creative task from a local agricultural structure: to design a maneuverable and light aircraft that can withstand strong side winds. The most popular "farmer" at that time was AN-2: he could take on board a lot of fertilizers and spray equipment. But the wind was his terrible enemy - in the endless Kuban fields, the AN-2, in terms of controllability, resembled a mad elephant. Aviation technician Arkady Alexandrovich Narushevich, pilot Anatoly Leonidovich Gushchin and several other people took up the case. After lengthy research, Narushevich came to an unexpected conclusion: it is necessary to build an aircraft with a closed wing contour, but not with a circular one, but an oval one. Several models were built, which flew quite successfully (I note that during our conversation Narushevich made a paper model in 15 minutes - and it flew!). Enthusiasts purchased materials and constructed an oval wing. And then 1991 crashed. The USSR remained in the past, funding ended in just a few days, and the remaining funds were withdrawn. The wing was sent for long-term storage, and the aircraft project was forgotten. But that was far from the end.

From Bleriot to Zhivodan

On December 17, 1903, a man took to the air for the first time in an airplane with an engine. The man was called Orville Wright, and the plane was called Wright Flyer I.

Despite the notable success of the Wright brothers, numerous inventors have come up with different wing configurations, according to their concepts, more effective than ordinary Wright planes. One of the pioneers of aviation was the French inventor Louis Bleriot, who built his first Ornithopter device back in 1900. True, only the 11th model, built in 1909, became the first truly flying airplane of Bleriot. We are not interested in it at all, but in the Bleriot III aircraft, designed in 1906 and never taken off. It was the first aircraft with a closed wing loop in the history of aircraft construction.

Bleriot was just experimenting - at random. He connected the ends of the wings of a conventional biplane in semicircles and installed the same design as the tail. True, the resulting seaplane "Bleriot III" never took off from the water on its own. Eyewitnesses described several flights - when the device was towed like a kite, but nothing more.

Today Blériot's mistakes are obvious: too heavy tail, high losses of lift due to an incorrectly chosen wing contour. But the fact remains - closed-wing aircraft began their journey in aviation.

In addition to Bleriot, several other designers from the beginning of the century experimented with the closed wing. The airplane of the French engineer Zhivodan, built by him at the Velmorel factory in 1909, was famous at one time. Everyone and everyone, including Scientific American and a number of respected publications, have written about the amazing machine that opens a new age of aviation. In Zhivodan's airplane, the role of wings was played by two ring-shaped figures, between which the pilot's seat was located. The engine weighed 80 kg and developed 40hp by rotating a 2.4-meter propeller. As you might expect, the strange structure, reminiscent of a pipe with a ripped out central section, did not rise into the air. It is worth noting that French model aircraft designer Emmanuel Fillon designed a working model of Zhivodan's aircraft in the 1980s. And the model flew beautifully. That is, its aerodynamic properties were not so bad. Excessive mass or low engine power may have prevented the original from taking off.

It is worth mentioning another amazing design - the so-called Gary-Plane by American William Pierce Gary. Gary's plane (1910) had a flat, ring-shaped wing with a diameter of 8 m - more than four human heights! True, Gary's airplane was notable for its terrible instability: all attempts to fly on it ended in overturning forward.

Late 1990s: second wind

In 1998 Anatoly Gushchin, Anri Naskidyants and a number of other pilots persuaded Narushevich to continue working on the plane. A certain private company became interested in the plane, the money was found, the half-forgotten wing was restored, and the team started assembling the fuselage. Everything was done from scratch. Unless the landing gear was taken from the Mi-1 helicopter, and the dashboard was taken from the AN-2. The car was designed for a potential consumer: seats for one or two pilots and three passengers in a semicircle. Instead of passengers, it was possible to place containers for storing fertilizers and spray equipment …

An important feature of Narushevich's aircraft was that the oval wing was not attached directly to the fuselage. It was located inside the wing on racks and suspensions. Thus, the lift was created over the entire wing surface.

By 2004, the first field tests of the received machine were carried out. She made several flights in calm and crosswind conditions. The inventors discovered that the device has very unusual aerodynamic properties. Firstly, an airplane with an oval wing (we will call it further SOC) did not react at all to gusts of side wind up to 13 m / s. Secondly, for a takeoff run, 150 m was enough (for the AN-2 - 180 m, for other aircraft of the same class sometimes even more). But the main thing turned out to be the practical ratio of the payload and the total curb weight of the aircraft - 0.45! So far, no one has come close to such a coefficient. The plane could be safely shown to future investors.

Today the strange "ovaloplane" by Louis Bleriot seems absurd: too many mistakes were made by the French designer during its construction. But Bleriot acted at random: in 1906, no one knew which wing configuration would be winning.

Vertical take-off rings

Among the German projects of the Second World War, many were absolutely amazing in their courage and originality. Thus, the vertical take-off and landing fighter-interceptor "Lark" (Lerche) designed by Ernst Heinkel (1944) had a closed nine-sided wing and two independent Daimler-Benz 605D motors, each of which rotated its own propeller. Both propellers were located inside the wing. For that time, the plane was unusual in that it meant vertical take-off and landing.

It's hard to say what Heinkel would have done if Lark were embodied in metal. In 1945, Heinkel also developed LercheII, there was not enough time for the first, and the project disappeared into obscurity. However, everyone has the opportunity to fly the Skylark - in the computer game IL-2 Sturmovik: Forgotten Battles. 1946.

But the French in 1959 found the opportunity to embody their ring-winged masterpiece in metal. The amazing SNECMA C-450 Coleoptere jet even took off. True, he landed quite hard, almost burying the pilot under him. In fact, SNECMA developed the ring-wing unmanned aerial vehicle even earlier, in 1954. It was given the lyrical name Atar Volant C-400 P-1 (Flying Star) and made more than 200 successful test flights. Like the German Lark, it was a vertical take-off and landing aircraft. The next step was the creation of a manned vehicle, which became the C-450. The eight-meter fighter was successfully launched, but during the transition from vertical flight to horizontal flight, it demonstrated a complete inability to maintain altitude and plunged like a stone. The pilot ejected, and the expensive project was immediately closed.

SNECMA C-450 (1959) He could only fly vertically. When the pilot tried to switch to horizontal flight, the experimental structure fell down like a stone. The closed wing aircraft project was immediately closed.

SNECMA C-450 (1959)

He could only fly vertically. When the pilot tried to switch to horizontal flight, the experimental structure fell down like a stone. The closed wing aircraft project was immediately closed.

The last attempt to create a vertical takeoff ringplane was the American project Convair Model 49 (1967). Convair is now well known for its submarine design and a number of other insane designs. The Model49 was a hybrid of an airplane and a helicopter. Its ring-shaped wing concealed an arsenal that an entire artillery regiment could be proud of. Machine guns, grenade launchers, cannons and rocket launchers - "49th" could single-handedly give battle to a full-fledged army. If it was made. The crazy project was wisely rejected by the US government.

Closed wing new life

In 2006, experts again became interested in the topic of the oval wing. At one of the Minsk enterprises, experimental design work (R&D) was organized to restore an aircraft with an oval wing, test it and study its aerodynamic features. The chief designer of the ROC was Alexander Mikhailovich Anokhin, a former military pilot with a solid 35-year experience. Narushevich and Gushchin became members of the design bureau. In 2008, Doctor of Physical and Mathematical Sciences, Professor Leonid Ivanovich Grechikhin was involved in the work. He worked on the aerodynamic properties of rockets with the famous Korolev, and now he consults and lectures at various institutes of the CIS. As a result, a team was formed, which continues to work on this topic even now.

The problem was that the plane had not taken off into the sky since 2004 and had become practically unusable. But the work was in full swing. The aircraft was modified, prepared for flights and removed from the hangar. The tests began. The configuration of the vehicle remained the same, but the fine-tuning was serious - right up to the change in the wing profile. Significant work (which continues now) went to Grechikhin: an airplane with an oval wing was built, but no one had previously calculated it in detail!

Technical features

What is SOC today? This is definitely an airplane. But in terms of its qualities in the air, it differs markedly from ordinary machines with flat or rounded wings. An ordinary flat wing is characterized by inductive resistance: air from the high-pressure zone under the wing tends to flow into the vacuum zone on the upper surface through the wing tips. In this case, end vortices are formed behind the aircraft, the formation of which also consumes energy, which is the value of the inductive resistance.

For an oval wing, the problem of inductive resistance is not relevant, since it has no tips. In addition, the incoming air flow, passing through a closed loop, is directed downward, creating additional lifting force. The larger the angle of attack of the wing, the stronger this effect is. And the angle of attack of such a design can be unprecedentedly large.

The flow stall occurs when the air jet, with an increase in the angle of attack, ceases to smoothly flow around the upper surface of the wing and breaks away from it with the formation of vortices. In this case, the lift on the wing immediately disappears and the apparatus loses control. The oval wing allows an angle of attack of the wing of up to 50 °, while its closest competitors reach a maximum of 20-22 °. The air inside the closed wing makes it difficult to stall the flow from the upper surface of the lower part of the wing. And when the flow leaves the closed loop, due to ejection (the process of mixing two media, when one medium entrains the other), it "sucks" the air passing along the upper surface of the upper part of the wing. These data were not obtained empirically - the oval wing was "spilled" in the water channel.

Before incarnating in metal and taking off into the air, the Belarusian aircraft with a closed wing loop went through three “reincarnations” - its construction began back in 1988.

The ability to fly at extremely high angles of attack, coupled with the flow deflection effect, allows the aircraft to fly at extremely low speeds without the use of flaps. The SOK lacks wing mechanization, which does not prevent it from taking off and landing reliably. Unprecedented stall resistance allows the aircraft to fly steadily and reliably over the widest speed range.

Many qualities of SOC are surprising. He manages to accelerate, fly up and land on an uneven grassy track only 400 m long, with the engine off, he plans well and generally behaves very stable in the air. The oval wing makes the aircraft more maneuverable and fuel efficient. In addition, the closed loop gives the wing extra strength. According to Grechikhin, aircraft with classic wings will soon run out of steam. It's very simple: the larger the plane, the heavier and more powerful its wing, the more difficult it is to maintain its rigidity. Essentially, the plane carries a mass of "useless" load - the weight of its own spars. And the oval wing is twice as light for the same lift.

Traditional problems

The main problem is that the Belarusian laws on aviation do not provide for the creation of aircraft on the territory of the country and their flight operations at all. Recently, Midivisana has created a specialized design bureau for the development of unmanned aerial vehicles under the leadership of Anokhin. Among the employees are both Narushevich and Gushchin. The established team of enthusiasts does not lose hope that at least in an unmanned aircraft they will be able to realize their invention - a closed oval wing.

Ringplan Sukhanov

Attempts to create a ringplane were also made in the USSR. In 1936, a student at the Moscow Aviation Institute Sukhanov presented a project of an airplane with an annular wing for defense as a thesis. The wing diameter was 3 m, and the design speed of 600 km / h was to be provided by the 800-horsepower Hispano-Suiza engine. By 1940, the diploma had become a full-fledged project of a short take-off and landing fighter-interceptor and was considered at the scientific and technical council of TsAGI. But the war came, there was no time and money for the construction of the aircraft, and even more for its testing. In 1942, in Novosibirsk, Sukhanov built a working model of the ringplane. Model tests have shown that the aircraft can withstand angles of attack up to 43 °, has a high power-to-weight ratio, anti-spin properties and excellent maneuverability. Sukhanov received the author's certificate, carried out all the calculations, but the ringplan, due to the war and devastation in the country, never saw the light of day.

The wing shows its properties only at a certain ratio of the axes of the ellipse to each other, the length of the chord of the wing to the minor axis of the ellipse and other nuances of the wing profile. The designers applied for a patent and received priority certificates for this wing shape in Belarus and Russia. Now, it seems, no one will be able to repeat their success, because all the available "corridors" of advantageous wing parameters have already been staked out.

For the period from the start of development to the construction of the first production model of a light-engine aircraft, about $ 12 million is needed, says Alexander Anokhin. “We can even make a hang glider with such a wing. Can you imagine? Hang glider, not afraid of the crosswind! The main problem is not even financing: as soon as SOK gets to MAKS, for example, investors will be found. The problem is in the Belarusian legislation, according to which an aircraft created on the territory of the country is extremely difficult to register, and in this case it is simply impossible, since it does not belong to the known aircraft classes. However, there is already an agreement with the Voronezh airfield, which is planned to be used for further testing of the vehicle.

What's next? Let's see. The fact remains. For the first time in the history of aircraft construction, a closed-wing aircraft took off. Maybe we are on the verge of new discoveries. Or maybe it's just a curious aircraft, an isolated incident. Time will tell.