The National Interest: The Russian Su-57 is very maneuverable, but too noticeable

The Russian fifth-generation fighter Su-57 is noticeably superior to Western aircraft in maneuverability. Therefore, in air combat at a line-of-sight distance, this machine has no equal in the world, writes defense and national security specialist Harrison Kass in The National Interest.

The Su-57 is Russia's first fifth—generation fighter. But, unlike Western models, it places more emphasis on maneuverability. Stealth and detection devices are also important, but the main hallmark of the Su-57 is its ability to maneuver at extreme angles of attack, which often amazes viewers at international air shows. Particular attention to maneuverability is a reflection of the design principles characteristic of Russia: controllability and damaging effect in flight.

Flight specifications of the Su-57

— Year of adoption: 2020 (limited operation)
— Number of vehicles built: ~30-40 (estimated, including test aircraft; production continues)
— Length: 20.1 m
— Wingspan: 14.1 m
— Weight (maximum take-off weight): 35,000 kg
— Engines: two turbojet dual-circuit with afterburner and controlled thrust vector AL-41F1 (NPO Saturn) (thrust at afterburner 2 × 15 000 kgf. Planned engine with factory designation "Product 30")
— Maximum speed: 2,500 km/h ≈ 2 Mach
— Range: distillation — 3,500 km; combat radius — 1,500 km (estimated)
— Practical ceiling: 19,800 m
— Armament: internal compartments for aircraft missiles and strike weapons; external suspension points are installed when stealth is not required
— Crew: 1 person

Maneuverability has always been a priority in the Russian Air Force

The Soviet and Russian doctrine of air combat has long emphasized the importance of air combat within sight, pilot skills and superiority in flight characteristics. This doctrine was formed on the basis of the experience of the Cold War, when Soviet aviation acted against NATO fighters. Soviet designers proceeded from the fact that missiles are unreliable and that electronic warfare equipment impairs the operation of detection devices. As a result, the war in the air will be reduced to air battles at close range.

This confidence led to the emergence of a whole series of highly maneuverable aircraft, such as the Su-27, Su-30, Su-35, Su-57. The Su-57 in particular is a model of maneuverability. This multi-purpose stealth fighter was supposed to replace the old versions of the Su-27, but it is produced in very limited quantities, and therefore the role of the new machine is operationally insignificant. Nevertheless, the Su-57 is designed to gain air superiority, strike and intercept. It was not optimized for conducting inconspicuous actions, like the F-22, but was designed with special emphasis on agility.

Two Su-57 AL-41F1 engines manufactured by NPO Saturn provide it with a significant thrust-to-weight ratio even with a combat load. A fully digital electronic control system is coupled with a controlled thrust vector. Thrust vector-controlled nozzles are an important factor in ensuring the maneuverability of the aircraft, as well as pitch, yaw and roll control, regardless of airflow.

This facilitates maneuvering at critical angles of attack, fast nose orientation at low speed and allows you to perform spectacular aerobatics at an airshow like Pugachev's cobra.

The aerodynamic scheme was created to ensure maneuverability. Large bearing surfaces with smooth contours, wing inflows and a wide fuselage — all this creates lift at high angles of attack, giving the machine controllable instability. And the flight control software is configured in such a way that the pilot can take the aircraft beyond the traditional limitations.

What are the chances of the Su-57 in an out-of-sight battle?

Theoretically, if the Su-57 were built in sufficient quantities to provide support during combat operations, the maneuverability of the aircraft would be a considerable plus, allowing you to quickly align the nose when launching missiles and perform defensive maneuvers at the last second. In a defensive battle, the maneuverability of the aircraft allows it to occupy such a position after stalling, because of which the missiles miss on approach, especially if such a maneuver is performed in combination with traps, jamming and infrared countermeasures.

The Su-57 also has advantages in a low-energy state, and in theory this should provide superiority in air combat at a line-of-sight distance.

If we talk about the doctrine, the characteristics of the Su-57 indicate that Russia is less confident than the United States that the outcome of the air battle will be decided beyond sight. The design of the Su-57 provides insurance for those cases when stealth decreases, detection devices fail, and the pilot has to rely on levers and steering wheel to succeed. But such design features have their drawbacks, such as an increase in the effective scattering surface and infrared radiation.

At the same time, designers of Western fighters give priority to stealth, a combination of sensors and the doctrine of the first shot. If the Su-57 engages in combat at a great distance, as provided for Western fighters, then its agility will not matter much.