The stealth fighter’s performance is hampered by the failure to produce a suitable engine and this may limit its ability to use directed-energy weapons. The advanced systems, which include lasers and sound waves, are being developed by a number of militaries

China’s ambitions to arm its most advanced fighter jet with hi-tech weapons, such as lasers or particle beams, may be frustrated by its underpowered engines, according to military analysts.

An increasing number of countries are researching cutting-edge directed-energy weapons (DEW), including the United States which is looking into their use to target hypersonic missiles and gliders.

The J-20, which is central to the country’s plans for military modernisation, would be an obvious choice to be armed with these weapons – which can attack a variety of targets from long-range using highly focused energy such as lasers, microwaves, particle beams, and sound beams.

But Chinese engineers have struggled for years to produce engines powerful enough to allow the J-20 – a fifth-generation stealth fighter also known as the Mighty Dragon – to reach its peak performance and match the likes of the US F-22.

Last month, military sources said the People’s Liberation Army would start upgrading its engines, but work on a purpose-built engine has repeatedly fallen behind schedule.

Wang Mingliang, a professor at the Air Force Command College, told state broadcaster CCTV that he was optimistic about the fighter’s future development.

“I have expectations for this aircraft. And I believe China’s industrial progress can make these expectations into reality,” Wang said.

“These can include many cutting-edge innovations … for example, the J-20 might be equipped with directed-energy weapons.”

However, Ridzwan Rahmat, principal defence analyst at military publisher Janes, said directed-energy weapon systems required large amounts of energy to be effective, and the limited thrust from the J-20’s WS-10 engines, initially designed for earlier generations of fighters, might be a major constraint.

“There are lingering questions over whether China has managed to achieve the thrust required on the J-20 on current payloads with the locally produced WS-10 engines,” Rahmat said.

“As such, loading the aircraft with more payloads, such as power systems for DEW, will have an effect on the aircraft’s range and manoeuvrability.

“Additionally, it is unclear how DEW systems will perform in high-speed environments. When an aircraft comes close to the speed of sound, it produces shock waves and aero-optics flow disturbances that degrade the quality of the lasers in use in DEW systems.”

He also said that a more pressing requirement was for the J-20 to develop the ability to operate in tandem with an escort of pilotless aircraft – also known as manned-unmanned teaming (MUM-T) operations – given current developments in contemporary warfare.

Song Zhongping, a former PLA instructor, said directed-energy weapons might become a default for future Chinese fighter jets, since they could be used discreetly and for an infinite time, but added: “The J-20 needs more thrust and stable power generation to fully utilise directed-energy weapons.”

Last year, China’s state-owned Poly Group demonstrated a ground-based active denial system during the biannual Zhuhai Air Show, which used microwaves to deter people from getting too close.

The United States Navy has already installed a directed-energy system – the Optical Dazzling Interdictor, Navy (Odin) which confuses drones rather than destroys them – to some of its warships.

But these hi-tech weapons also have their drawbacks. According to a report by the Lexington Institute, a US defence think tank, laser beams are weakened by water vapour, dust and other obscurants, while radio-frequency emissions can be absorbed by any conductive material placed between the weapon and the target.