The clouds in the sky are high, smog warnings have been issued again, PM2.5 is exceeded, and people are wearing masks and trying their best to refuse to breathe in the dust and particles floating in the air. In the midst of such weather, at the end of the runway of a hidden military airport, China's self-developed Shenlong manned space plane is parked there, ready to take off.

Aviation fans will pay attention to the J-10, J-20, J-31, and even the J-7 Flying Leopard, but they will not care about this remote and isolated old air base, except for a few old J-7s, there is almost no movement on weekdays, and it is almost almost semi-abandoned. If it weren't for the perimeter fence and barbed wire warning lights still working, it would have become a favorite place for drag racers, and a 3,900-meter-long airport runway is undoubtedly the best place for drag racers to unleash their passion.

Of course, the drag racing party naturally can't get in. Although it is old, and it is rare to see planes taking off from this airport on weekdays, the patrol vigilance is not low, and the 4-meter-high fence also makes it not so easy for people outside the wall to see inside.

At one end of the runway, in the heavy haze weather, it was far away, and it was impossible to see the planes on the runway clearly. Three large turbine engines are already working, and they will be relied on for take-off and low-Mach speed flights.

After being towed to the runway by the tractor, there are still the final inspection procedures to be carried out before takeoff, and after confirming that they are all ready, Xia Yu began to contact the flight control center: "Command center, this is the Shenlong, the pre-takeoff inspection procedures have been carried out, and now it is on standby." ”

"The command center received that the Shenlong can take off at any time."

After getting permission to take off from the flight control center, Xia Yu and Wang Pengyu put their hands on the throttle push lever at the same time and slowly pressed forward. As the throttle output increased, the sound of the originally low and continuous turbofan engine gradually became high, and then began to drive the huge body of the Shenlong to glide down the runway.

Shenlong is the basic power configuration of turbine plus scramjet plus rocket, which is also the power combination chosen by most countries that are now studying aerospace aircraft. Because the scramjet engine cannot be ignited and started in a stationary state, only the aircraft can diffuse the air in the intake tract at a certain speed and generate shock waves, and then start working, so the low-speed performance of the scramjet engine is actually not good.

However, it does not need to carry a bulky oxidizer, and can produce four times the thrust of the rocket, plus the structure is simple, the weight is light, and the cost is less than half of the turbofan engine, so it can be regarded as the strategic development direction of future military and civilian spacecraft. Although the theory was developed earlier than the turbofan engine, and the engine itself has various advantages over the turbofan, the complex design of the air intake tract and combustion chamber, as well as ignition problems, have been one of the main reasons that plague the development progress of this excellent engine.

A supersonic combustion ramjet engine is one in which fuel is mixed with air above the speed of sound in the combustion chamber and burned, and finally ejected from an expanded nozzle to generate thrust. Just by the words 'mixed with supersonic air' you can imagine the difficulty, which is not fundamentally different from sliding a match in the middle of a huge tornado.

However, the progress of human science and technology will not be retreated because of difficulties, and many advanced theories have always been able to be verified under the influence of time, so human beings have a variety of inventions and scientific theories. Scramjet is just one of a myriad of problems, and the high-specific impulse nuclear fusion ion engine and so on, one day, the way humans send themselves into space will certainly not be so old and inefficient.

"Take-off speed." Wang Pengyu reminded. Today's take-off and landing were all taken over by Xia Yu, although he was the co-pilot, but the task was not easy. He needs to observe the dashboard in front of him at any time and report relevant readings, and is also responsible for radio contact with the flight control center according to the schedule, obtaining relevant information and other tasks, and then needs to compare flight information with Xia Yu, make various adjustments, and so on.

Wu Degao's seat is in the middle of the co-pilot, he is the second co-pilot, and he is also the first mechanic, the setting of various flight parameters and the switch of instruments, only the co-pilot is too busy, he also needs to participate in the actual flight control.

Du Junbao and Wu Min belong to the second and third mechanics respectively, although the two do not need to help too much in the flight parameter setting, but they need to monitor and confirm the control of the aircraft itself and during the flight, in addition to the weapon control, emergency treatment and inquiry in case of problems, etc., are also the responsibility of the two of them, all of them need to cooperate sincerely to complete the task.

Three high-thrust turbofan engines soon brought the Shenlong to an altitude of 18,000 meters, due to the haze, it can no longer be observed on the ground, fortunately, there are cameras in all parts of the Shenlong fuselage, so for the current state of the aircraft, the people in the flight control center are still relatively understanding.

After completing several sets of flight tests in turbine mode in the air, and after the Shenlong flew to the predetermined altitude and speed again, Wang Pengyu first confirmed the information with Xia Yu, and then began to contact the flight control center: "Group B test item one, scramjet engine starts, sub-combustion mode level flight, ask for permission." ”

"This is the command center, and you can start at any time by authorizing the Shenlong's test request for Group B item one."

"Shenlong understands, and is now ready to begin testing Group B item one." After getting the authorization of the flight control center, Xia Yu and the five of them glanced at each other, nodded, and began to prepare.

There are also many types of scramjet engines, including ordinary scramjet engines, as well as air-breathing pre-combustion chamber scramjet engines and jet scramjet engines, but there are really research progress, at present, there are only two kinds of dual-mode and dual-combustion chambers, of which the double-combustion chamber ramjet engine is more suitable for one-time aircraft such as **, and the real unmanned or manned space vehicle to be carried, at present, it is a dual-modal scramjet engine, which is used by Shenlong.

"The ignition procedure for the scramjet engine is ready." Wu Degao, the third mechanic, prompted two drivers.

"Understood." Xia Yu and Wang Pengyu nodded, and then Xia Yu spoke: "Prepare - ignition!" ”