Recently, jiuzhou Yunjian "Lingyun" 10-ton liquid oxygen methane rocket engine has completed multiple starts + depth variable thrust two-in-one test runs. This test was carried out at the 100-ton double-station test base independently constructed by Kyushu Yunjian. The test was a complete success.
This test has the following characteristics:
① It marks the first time that my country has made a breakthrough in mastering the three-time start-up technology of the liquid oxygen methane rocket engine, becoming the first country in the world to realize the three start-up of the liquid oxygen methane rocket engine;
② When the engine is throttled to 40% before shutting down, the "Lingyun" engine has fully verified the engine's variable thrust performance after multiple starts, and meets the engine's variable thrust requirements before the rocket is recovered and landed;
③ This test covers the mission profile requirements of the target rocket's flight test. "Lingyun" engine has been started multiple times + deep variable push two-in-one test run

What is the multiple starts of the liquid rocket engine?
Multiple start refers to the ability of the liquid rocket engine to achieve more than 3 ignition starts during a mission. Due to the limitation of the starting method, the traditional liquid rocket engine can achieve 1-2 starts, while the new generation of commercial launch vehicles put forward higher requirements on the starting ability of the engine, which requires more than 3 starts, and the engine timing is set. Come to challenge. Through the innovative starting method, the starting ability of the engine can be effectively improved to meet the recycling demand.
Why do I have to start multiple times?
The liquid rocket is reusable through vertical recovery, which can significantly reduce the cost of a single launch, and at the same time has a broader prospect for derivative applications. At present, the key bottleneck restricting the development of my country's vertical recovery rocket is the liquid rocket engine. The vertical recovery rocket needs to experience at least three ignition and start processes of ground igniting and take-off, reverse thrust deceleration in excessive wind area, and reverse thrust deceleration during landing, in order to make the rocket recover and land according to the established trajectory. Therefore, the engine's ability to start more than three times is a necessity for the vertical recovery launch vehicle.

"Lingyun" liquid oxygen methane rocket engine ignited
Ji Fenglai, CEO of Kyushu Cloud Arrow, said:
The "Lingyun" engine is the first domestic liquid oxygen methane engine that truly realizes reusable, multiple-start and deep variable thrust technology. It has passed the deep variable thrust hot test in 2019. The "Lingyun" engine is in the development process. A series of bold and difficult explorations and attempts have been made in terms of low-cost and rapid use and maintenance of the engine, multiple start-up capabilities, wide-range variable thrust adjustment technology, control technology, and key assembly adaptability technology. This hot test is a complete success The success indicates that the "Lingyun" engine has further refined its products and core technologies. After the reliability accumulation is completed, it will soon enter the stage of industrialization.
Kyushu Yunjian Engine Technical Director Huang Shiqi said:
This time the "Lingyun" engine multiple start + depth variable thrust two-in-one test run has verified that the "Lingyun" engine multiple start sequence settings are accurate, the main and auxiliary dual-circuit torch electric ignition system works reliably, and the thrust adjustment system works stably and responds. Excellent characteristics; each core component of the engine has good adaptability to multiple starts and large-scale variable thrust. It laid a solid foundation for the engine to participate in the customer's first flight.

jiuzhou Yunjian 100-ton double-station hot test base
At present, the "Lingyun" engine has completed the cumulative test run for thousands of seconds, and technologies such as multiple starts, deep thrust adjustment, and low-cost maintenance have been verified. The subsequent "Lingyun" engine will continue to carry out engine reliability accumulation work and large-scale continuous changes. Thrust test, working condition pull-out test and other tasks have solidified the technological innovation and reliability of the engine. In addition, the "Lingyun" engine innovation results can be transplanted to the high-thrust "Longyun" engine and participate in the follow-up test run assessment.

"Lingyun" and "Longyun" liquid oxygen methane engine