"How many prototypes are there?"

？？？

Chen Ming didn't understand for a while, and subconsciously replied, "X frame." ”

"I'm afraid it's not enough." Li Zhan said.

Now the technicians of the R&D team are sweating down, and it is their turn to worry with complicated expressions. Oh my god, this is a fourth-generation aircraft, do you know how much it costs to build a prototype? The United States, which has a lot of money, has only built thirteen prototypes, of which the first two are demonstration machines in the research and development stage, and the last eleven are test machines in the engineering stage. Even began to enter the delivery phase, after which the last four went directly into service with the US Air Force.

Our model is about the same, touching the US military to cross the river. Therefore, the first few prototypes and the ones that came out of the back have changed quite a lot, and it can even be said that each one is different, from rough to delicate, and gradually to perfect. Li Zhan is now driving the earliest prototype except for the prototype used for static testing, and many test flight projects with a relatively high risk factor are carried out by this black ribbon.

However, Li Zhan's question really made the R&D team nervous, what are you going to do?

In the blink of an eye, the No. 01 black ribbon arched to 1XXXX meters, and everyone's hearts were raised, and they didn't have the heart to think about how many planes Li Zhan was going to fall.

Li Zhan still reports every 100 meters, and his voice is clear and calm. Everyone is not surprised by the strong psychological quality of test pilots, they all often deal with test pilots, and they have long been accustomed to it. You can't be a test pilot without a strong heart.

The enemy of a combat pilot is the enemy, and the enemy of a test pilot is his own fighter.

"I'm about to break through the two-word head." A technician wearing thick glasses muttered to himself, talking to himself in a very soft voice, but suddenly found that the entire tower was his voice, and he startled himself.

It was so quiet in the tower that everyone was holding their breath carefully.

Li Zhan's spirit was also highly concentrated, and most of his attention was focused on altitude and climb rate. The latter is very important, and if the rate of climb drops to a certain level, the aircraft is in danger of stalling and tailspin. However, Chen Ming and the others were surprised to find that Li Zhan seemed to be deliberately developing the plane in the direction of stall tailspin.

Is it deliberate?

Chen Ming didn't dare to communicate with Li Zhan rashly at this time, so as not to distract him. The No. 01 Black Ribbon has passed the design ceiling, and every subsequent advancement is significant, and the aircraft's corresponding performance data is crucial. It is true that relatively low requirements have now been put forward for the ceiling of fighters, and the high-altitude and high-speed requirements previously have been proved by actual combat to be unsuitable for modern warfare.

But from another point of view, if you can make the fighter have a higher ceiling and greater speed through a non-targeted design, why not?

Li Zhan suddenly said, "The ceiling envelope will come out soon!" The aircraft control system is normal, the power attenuation is serious, and the rest of the systems are normal! ”

With his report, the No. 01 black ribbon arched upwards for more than 200 meters with its last breath, breaking through the boundary of 20,000 meters in one fell swoop, and finally reached 2XXXX meters.

Everyone on the tower was seriously glowing and clenched their fists and threw their fists hard, and at this moment, the No. 01 black ribbon finally exhausted the momentum of climbing, and then began to fall straight down like a stone that had reached the critical point of a parabola.

"Stalled!" One of the technicians exclaimed.

Chen Ming hurriedly asked Li Zhan, "Dong Yu, report the situation!" ”

"Tower, I'm flying stall tail spin out of the situation, all systems of the aircraft are normal, over!" Li Zhan said steadily.

Everyone looked at each other, and any adaptive flight plan had long since become unrecognizable. Moreover, they had never met a test pilot who led the flight test program, and the tower that was supposed to call the shots was reduced to a submissive one. They didn't know much about Li Zhan, and they didn't know anything about Li Zhan's glorious achievements in the past, especially in terms of fighter jets' extreme flights and dangerous situations.

The No. 01 black ribbon swirled down, and the height fell very quickly. From an altitude of more than 20,000 meters, it began to fall vertically, as if it were a return capsule from a manned spacecraft.

Li Zhan in the cockpit rotated with the plane at high speed, turning sideways for a while and rolling for a while, and the tailspin was more serious than expected. It may be related to the altitude of entering the tailspin, or it may be related to the previous flight attitude. The tailspin caused by the stall is certain, and Li Zhan was pleasantly surprised at this point - the critical point of the black ribbon stall is very low.

That said, the minimum speed envelope data for the black ribbon is very good.

For example, if a fighter jet stalls at an airspeed of 220 kilometers per hour, then the Black Ribbon can achieve a stall envelope with an airspeed of 180 kilometers per hour. Just an analogy, of course. What Li Zhan can be sure of is that the minimum speed performance of the Black Ribbon is better than that of the Rafale fighter.

And he knew very well that the Rafale fighter could achieve a minimum airspeed of 195 kilometers per hour, which he had used to land on the Dai ship at that time.

Generally speaking, the maximum airspeed and the minimum airspeed cannot be combined, and it is difficult to achieve a larger airspeed for an aircraft to have a smaller minimum airspeed at the same time. Therefore, some high-altitude and high-speed fighters usually have a relatively small wing sweep wing angle (the angle between the trailing edge of the wing and the fuselage), and such an aerodynamic layout design is very suitable for high-altitude and high-speed aircraft.

For example, the J-8, the two wings are retracted backwards like a superman, and there is a sense of speed when you look at it, while the layout of the J-11 is decent. The J-27 series aerodynamic layout derived from the Su-11 is probably the pinnacle of conventional aerodynamic layout design.

Minimum airspeed is an important indicator of low-altitude and low-speed combat performance, and it is very important. At the same time, it means that the aircraft has a smaller turning radius and the nose is more agile.

During the high-speed rotation, many systems of the aircraft are alarming, which is an abnormal attitude. Black Ribbon has a very advanced warning system, and the flight control system has been trying to get the aircraft attitude back to normal. Li Zhan resolutely switched to pure manual control, and completely controlled the control of the aircraft, otherwise it would conflict with the automatic control system of the flight control system.

To the surprise of Chen Ming and the others, Li Zhan didn't seem to be in a hurry to change it, but let the plane fall down along the development of the attitude. He quickly understood Li Zhan's intention, and let the aircraft stay in the tail spin for as long as possible when the altitude was sufficient, so that more problems could be exposed, and more relevant data could be monitored.

The height of the clouds is about three thousand meters, and everyone's hearts fell on their throats, watching the height of the No. 01 black ribbon fall rapidly, and as time went by, more and more people's eyes were about to pop out, and they subconsciously clenched their fists and were highly nervous.

"Hole, hurry up and change it!" Chen Ming couldn't resist the pressure, seeing that the height was more than four thousand, he hurriedly gave Li Zhan an order.

Li Zhan said, "Change it out under the clouds, and pay attention to the attitude of the plane." ”

"Okay." Chen Ming could only agree.

The No. 01 Black Ribbon flew very high, but it didn't run very far, and its position was probably above the field, specifically above the runway. Li Zhan did not change his position because there were settlements around him, and if there was a crash and he could not control the plane, there was a possibility of threatening the safety of people's lives and property.

If you are high in the air directly above the runway, even if you want to fall, there is a high probability that you will fall on the outfield, and the loss is minimal.