At the Moscow Air Show held recently, Su-47 fighter forward swept wing test machine was unveiled in a static display. This is the second demonstration of Su-47 fighter after its public appearance at the Moscow Air Show in 2007.
Chinese military observer Fu Qianshao introduced that Su-47 fighter, as a rare forward-wing aircraft, made its first flight in September 1997. The aerodynamic characteristics of the forward swept wing are superior to the swept wing, but there are also problems such as the wing being easily upturned and twisted.
Generally speaking, the aerodynamic characteristics of the forward-swept wings are better. The transonic speed is small when the flight is low, and the speed-up ratio is high. The operation at low speed and high angle of attack is more flexible. However, the forward swept wing also has shortcomings.
The time of the invention of the forward swept wing was similar to that of the swept wing invention. It was invented by the Germans in the late World War II, but most of the aircraft used swept-wing wings without the forward swept wing, mainly because the lift between the wings causes the wing to bend and deform, causing severe tremors, and even the upturned torsion causes the wings to break.
After the 1970s, with the development of aviation technology, this problem has basically been solved. Composite materials can be used to replace aluminum alloys, and aeroelastic tailoring technology is used for composite design, which can greatly improve the forward swept wing. The resistance to bending and torsion is to avoid serious problems such as upward bending and twisting.
Because of its high mobility, Su-47 fighter was once considered to be the benchmark for Russia’s future fighters, but it was not put into mass production. Chinese military observer Fu analyzed that the reason is that when Su-47 fighter was born, the warplanes of the world began to develop in stealth direction, and Su-47 fighter lacking stealth performance could not meet the needs of Russian military combat missions, so it only stayed in the technical verification stage.
The birth of Su-47 fighter marks the ultimate in the high maneuver that the Soviet or Russian aircraft designers pursue, and its mobility is superior to many conventional fighters at the time.
But in the process of designing Su-47 fighter, Russian aircraft designers ignored one of the most important indicators – stealth. Of course, they did not deliberately ignore it because they had very few stealth techniques at the time. They believed that as long as the aircraft was maneuverable, it was coated with a certain stealth paint on its surface, and then some wing body fusion design was made. The radar cross section was small enough, so the designers didn’t design the fighter completely according to the stealth shape, but only emphasized the ability of maneuverability, short-range takeoff and landing performance and so on.
In the development stage of the fourth-generation fighter, the most important indicator is the stealth. In this respect, Su-47 fighter is insufficient, so the Russian Air Force was not satisfied with the flight test and test results of this fighter, so it was aborted. And a state-of-the-art fighter with stealth capability was re-developed. That is the Su-57, the fourth-generation stealth fighter that appeared later.
Fu Qianshao believes that after a lapse of 12 years, Russia once again exposed Su-47 fighter, and it still appeared in a well-maintained state, which means that the Russian forward-swept fighter program has the possibility of “resurrection”.
For the work done by the former Su-47, although many of its techniques can be transplanted to the Su-57, there are some techniques that cannot be transplanted, such as the forward swept wing. Some of the advantages of the forward swept wing have certain appeal to the world’s air forces, especially for the small and medium-sized national air forces.
Of course, appearance of Su-47 fighter again at the Moscow Air Show may reflect an intention implicit of the design department. It might hope that the Russian Air Force will continue to invest in this high-mobility fighter that has been invested a lot of manpower and resources. Give attention; they might hope to continue to develop this type of aircraft in some places that do not emphasize stealth, and finally get applied. Therefore, this appearance of Su-47 is for the Russian military to see on one hand, and on the other hand, it is for some third-world countries in need, in order to strives to raise funds to make this aircraft resurrected.
