Russia's Sukhoi developing single-engine stealth fighter: Reports

Russian news outlets reported early on Wednesday that the Sukhoi aircraft design bureau had started work on the country's first single-engine stealth fighter.

The Su-57 twin-engine jet is Russia's only stealth fighter to date, but its development has faced multiple delays since it first flew in 2010. Large air forces typically seek to have both single-engine and twin-engine fighters to meet varied purposes. Single-engine fighters are considered optimal for short-range air-defence and surface-attack missions, given their inherently lower maintenance costs on account of having just one engine and higher 'turnaround' time (time taken to equip aircraft for new mission). Twin-engine aircraft are considered more suitable for missions that involve long range and flying over water.

Russia has been lagging the US in development of stealth fighters for decades. The US inducted its first dedicated stealth air superiority fighter, the F-22, almost two decades ago. The US has not only inducted its first single-engine stealth fighter, the F-35, but has also exported the aircraft to numerous allies.

New project

Russia's TASS news agency gave some details of the new aircraft. "The Sukhoi company is developing a single-engine light tactical plane with the take-off weight of up to 18 tonnes. The plane’s maximum speed will be above 2 Mach. It will also have super-manoeuvrability and improved take-off and landing performance, thanks to a thrust vector control engine. The plane’s thrust-to-weight ratio will be above 1," TASS quoted a source as saying.

Thrust-to-weight ratio is the ratio of the aircraft's maximum thrust to its take-off weight. A high thrust-to-weight ratio means an aircraft will have high acceleration and rate of climb. An aircraft with thrust-to-weight ratio that is greater than 1 has a thrust greater than its weight, which means it can continue accelerating while climbing vertically. A high thrust-to-weight ratio confers significant advantages in aerial combat and also helps in evading surface-launched anti-aircraft missiles.

Russia's Sputnik reported the Sukhoi bureau had started work on the lightweight stealth jet "on its own initiative". "During the creation of the aircraft, it is planned to widely use the groundwork developed in the framework of the creation of the Su-57, including the state-of-the-art Product 30 engine, radio-absorbing coatings, on-board radio-electronic equipment, a weapon system," Sputnik quoted a source as saying.

Post-Soviet struggle

Since the collapse of the Soviet Union, Russia has only developed twin-engine fighters for its military. While the Su-57 and Yak-130 were new designs, the Russian military has also been inducting multiple derivatives of the Soviet-era Su-27 and MiG-29 fighters; all these aircraft have two engines. The decision to stick to twin-engine aircraft was attributed to the need to patrol and launch missions on Russia's vast borders, which meant having longer range.

In December last year, Sergei Chemezov, the chairman of the Rostec arms export conglomerate, claimed work had started on a new light "combat aviation system" that would be available in both manned and unmanned variants.

At the time, Chemezov claimed such a system was being developed primarily for the purpose for exports, though he added Russia's military could also purchase it. Talk of developing a new lightweight fighter has emerged occasionally from Russia over the years since the 1990s, though nothing concrete has resulted.

The latest statements on a new light single-engine jet appears to be motivated by the need for Russia to stay competitive in an evolving arms market. In recent years, developing countries have selected fighter aircraft like the Chinese-developed JF-17 and South Korean F/A-50, while more advanced militaries have opted for US and European systems.

India connection?

In 2018, Chemezov told IANS in an interview that Russia was open to developing a new single-engine aircraft with India.

“Russia is very strong in the production of various types of twin-engine aircraft, but at present we do not produce single-engine fighters. And our main twin-engine aircraft, both MiG and Sukhoi, are used by the IAF. But if India wants to develop its own one-engine aircraft, and if India is interested in international cooperation to develop this aircraft, Russia and Rostec will be open to cooperation. Thus, if we are invited to participate in the joint development of a single-engine aircraft, we are ready to do this, as it was done in the past with other Russian-Indian projects..." Chemezov had told IANS.