“Code-named W-99, theinvolved a supersonic cruise missile using a ramjet engine,” Kung wrote. “When reaching a certain altitude, the solid-fuelled booster of the engine allows the missile to travel at supersonic speeds of just over Mach 3 (3,675km/h or 2,284mph).
“The missile has excellent penetration as it comes down vertically and hits the target.”
The island’s military has long declined to confirm the institute’s development of the long-range Yun Feng missile – whose name means cloud peak.
Kung said the high-altitude supersonic cruise missile, with an operational range of more than 1,000km (621 miles), was difficult to intercept and would be a major deterrent to any enemy.
The missile was developed in the late 1990s during Lee Teng-hui’s time as the island’s president, Kung said.
Taiwanese news reports have said the Yun Feng project started soon after the 1996 Taiwan Strait crisis, when Beijing launched missile tests near the island to warn Lee against seeking independence.
Beijing regards Taiwan as its territory and has vowed to attack if it tries to declare formal independence from the Chinese mainland.
Given the sensitivity of the missile’s development, because it was designed to reach targets deep in northern and central China, flight tests were reportedly not disclosed to those outside the project and were carried out within other missile testing programmes.
The project was almost axed due to repeated failures in the tests during the first and second phases of development, but was saved by Lee’s successor,, who insisted on its continuation, Kung said, adding that the missile eventually passed operational tests and evaluation during his time in charge of the institute.
Kung did not reveal whether the missile had officially entered service. According to the Missile Threat website set up by the Centre for Strategic and International Studies, a US think tank, Yun Feng became operational in 2014 and the first batch of 20 missiles and 10 mobile launchers was rolled out in August 2019.
Kung said the development of the Hsiung Feng 2E land-attack cruise missile – whose name means brave wind – was also almost axed following five failed flight tests.
He wrote that in 2004, “defence minister Lee Jye said if the institute was not able to find out the cause of the failure before the end of that year, the project would be ended”, adding that it was the main task he was given after being made head of the institute in June that year.
He said a successful flight test was carried out in October 2004 after he replaced the project leader, and the result surprised the US.
Kung said there were two variants of Hsiung Feng 2E – one with an operational range of 500km and one able to travel 1,000km.
Maps show the first would be capable of hitting Shanghai, while the second would put Beijing within reach.
Kung said the institute also had a NT$6 billion (US$194.8 million) secret project code-named Ba Dan – target bomb in English – to develop a ballistic missile a metre in diameter and 10 metres tall, that involved 400 engineers.
Kung said Chen had been impressed when he inspected the missile test base, but after a successful trial launch of the missile, the– the de facto US embassy in Taipei – warned the island against conducting any more such tests.
“About 10 days after the trial launch, I was told the AIT director [Stephen Young, in office from 2006 to 2009] went to see president Chen and delivered him a memorandum of understanding, which roughly said we had conducted missile tests at a certain time and a certain place, and that was not permissible.”
The US had also tried to prevent Taiwan from obtaining some key components for locally developed missiles to force the island to buy US-made products, Kung said.
“When we were developing the Hsiung Feng 3 anti-ship missile, we applied to buy JP-10 high-density synthetic jet fuels, but the US notified us they would no longer sell those fuels to us,” he said.
Kung said the National Chung-Shan Institute of Science and Technology later declared that it had successfully produced its own JP-10 fuels, which prompted the US to immediately grant approval for the island to buy the fuels from Washington.
The island’s defence ministry and the science and technology institute declined to comment on Kung’s revelations, and the AIT did not immediately respond to a request for comment.
Observers said Yun Feng could be used to attack large fixed facilities in inland parts of mainland China, like fortified bunkers, joint combat operation command centres and ammunition depots.
But Chieh Chung, a security researcher at the National Policy Foundation, a think tank affiliated with the island’s main opposition Kuomintang party, said that “with limited resources and in the absence of nuclear warheads, it would be impractical” to rely on the missile as a major deterrent.
Su Tzu-yun, a senior analyst at the government-funded Institute for National Defence and Security Research in Taipei, said the science and technology institute appeared to have developed a second generation of the Yun Feng, which could enhance its deterrent effect.