'Magic Wings' Helped Revolutionize the Soviet Air Force

The variable-sweep wing design met the technological challenges of the 1960s, revolutionizing Soviet aviation.

Special features of the swing-wing design

On July 9, 1967, spectators at the Moscow Air Show saw for the first time the brand new MiG-23 and Su-17 swing-wing fighters. These were considered revolutionary third-generation fighters that would shape the Soviet aviation industry for decades to come, according to Sputnik.

"The variable-sweep wing principle applied to these two aircraft types allowed Soviet designers to solve a series of difficult problems," said military analyst Andrei Kotz.

Previously, fighter models had only two basic wing designs: straight wings and swept wings. Straight wings give fighters a high coefficient of lift, allowing pilots to take off easily, especially when the fighter is fully loaded with ammunition and fuel, as well as providing stability at subsonic speeds, but this design creates a lot of drag when the aircraft reaches supersonic speeds. Meanwhile, the design of swept wings at an angle to the length of the fuselage can help fighters achieve high speeds and have better resistance to air turbulence, but their lift when taking off is not high.

The variable-sweep wing design, also known as the "magic wing", combines the advantages and eliminates the disadvantages of both principles above, bringing many advantages to the MiG-23 and Su-17, creating a breakthrough development for the Soviet military aviation industry.

The design of the swing-wing wing includes the wing hinge shaft, the inner wing, the center wing and the rotation mechanism. When taking off and landing, the pilot puts the wings in the straight-swept position to maximize lift, shortening the take-off and landing distance. During flight, the wings will gradually retract to reduce drag, and the high speed of the fighter will compensate for the lift lost due to the swept wings. When reaching supersonic speed, the wings will be in the maximum swept position.

Wing spread and retract mechanism on MiG-23 fighter. Photo: Wikipedia.

The disadvantage of this design is its large mass, making the fighter heavier than those with fixed wings. The complex structure of the variable-sweep wing also makes it difficult to repair and maintain at field airfields, which have less infrastructure than large air bases.

However, the advantages of variable-sweep wings along with many advanced aviation technologies at the time compensated for these disadvantages.

"A MiG-23 carrying full weapons and fuel weighing 20 tons only needs 450 meters of runway to take off, much shorter than a modern MiG-29 fighter of equivalent weight. The maximum speed of the MiG-23 when its wings are folded is up to 2,500 km/h, equivalent to many modern fighter aircraft," expert Kotz affirmed.

The high maneuverability, modern weapons and electronic systems of the MiG-23 helped Iraqi pilots win more than 30 air battles with Iranian fighters between 1980 and 1988. FighterF-4, F-5 and F-14 produced by the US in serviceThe Iranian air force at that time only won 9 battles, even though the F-14 model also had a swing-wing design.

Mr. Kotz said that the US military also appreciated the MiG-23 design. In 1980, the US had about 12 MiG-23s of Egyptian origin.

American pilots and technicians studied the MiG-23s closely. They disassembled them into the smallest pieces, then reassembled them and used them until 1988 for air combat training. American pilots praised the MiG-23's excellent acceleration, speed characteristics and comfortable cockpit design. They considered it aThe MiG-23 performed exceptionally well in close combat, but was inferior in long-range duels.

MiG-23 demonstrating swept and swept wing modes.

However, American technicians have to use the word "terrible" to describe the repair and maintenance of MiG-23 fighters. This may be the reason for their high accident rate. Since being put into service in 1970, more than 100 MiG-23s have crashed out of a total of 5,047 aircraft built.

For the Su-17 attack aircraft and the export version Su-20/22, the swing-wing design effectively supports ground attack and infantry support missions. In addition to shortening the take-off and landing distance, the swing-wing design also allows the Su-17 to attack ground targets at medium speed, giving pilots more time to identify and aim at targets more accurately.

This advantage is significantly superior to its predecessor, the Su-7B, which used a fixed-sweep wing design, had too high a cruise speed, and was ineffective in ground support.

The experience from the MiG-23 and Su-17 was an important step forward for the Soviet and Russian aviation industries. They were an important premise for the Soviet Union to design the MiG-27 attack aircraft, the Su-24 tactical bomber, the Tu-22M/M3 strategic bomber and the Tu-160 strategic bomber. The Su-24, Tu-22M3 and Tu-160 are still in service with the Russian Air Force, directly participating in attacks on terrorist groups in Syria.

The wing sweep mechanism of the Tu-160 bomber.

Today, variable-sweep wing technology is only suitable for bombers, where combat effectiveness depends largely on the amount of weapons it can carry. Modern fighters such as the Su-27, MiG-29 and their upgraded versions are built in a different direction, applying the blended wing body design.) to form a uniform raised surface.

The wing-body principle allowed Soviet and Russian aircraft designers to retain all the advantages of variable-sweep wings without complicating and increasing the mass of the airframe. This solution also allows modern fighters to possess super-maneuverability, reaching supersonic speeds without using afterburners, one of the main requirements for today's fighters.

Variable-sweep wing technology, introduced more than 50 years ago on the MiG-23 and Su-17, successfully met the challenges of the 1960s and provided insights for Soviet and Russian aviation designers decades later, Kotz concluded.

According to VNE