Chapter 1402: Please explain to me, what is a surprise?

As the designer of the most important subsystem of an aircraft, Liu Yongquan had some knowledge of overall design. In addition, he had been influenced by Chang Haonan for a long time and had been deeply involved in several projects in cooperation with Dassault, so he was not unfamiliar with some basic concepts.

Looking at the infrared image in front of him that was as dazzling as a small sun, he certainly knew that the other party's concerns were justified.

In this case, even large areas of infrared decoys would find it difficult to lure away the missile's locked target.

But then again, infrared stealth is a big problem from a theoretical perspective.

Since infrared signals are actively emitted by the target and do not require electromagnetic echoes like radar signals, their essence is basically the same as visible light detection.

The difficulty of achieving it is comparable to optical invisibility.

As long as the basic logic of aircraft engines that "obtain reaction force by ejecting high-temperature and high-pressure combustion gas backwards" remains unchanged, it will be difficult to achieve effects like radar stealth.

In fact, due to the continuous increase in power levels, the infrared signatures of modern fighter jets are becoming more and more obvious.

On the other hand, infrared detection methods also have defects such as the inability to measure distance, and their application range in the air defense field is far less than that of radar.

In short, the attitudes of various countries in this regard basically highlight a Buddhist approach:

It’s best to do something if you can, but if you can’t, just lie down.

However, just as Liu Yongquan was about to say something, the countdown in the background system had returned to zero, prompting him to proceed to the next step.

He had no choice but to put aside the discussion about infrared characteristics for the time being and took over the command from Yang Wei:

"Start the tunable laser array and Mach-Zehnder interferometer to prepare to record the plasma distribution..."

The surface area of ​​an aircraft is too large to be measured directly with an invasive Langmuir probe as was done in Shengjing. Instead, a non-invasive measurement method is needed.

If it is the plasma in a nuclear fusion device, laser scattering is generally used directly to interact with the free electrons in the plasma, and the electron density and temperature are directly measured through the scattering spectrum.

However, the energy of the plasma generated on the surface of the aircraft by the aircraft engine is too low, and the error measured by Thomson scattering is higher than the electron density value itself. Therefore, we can only settle for the second best option and use tunable laser to excite particles of specific energy levels, measure the relationship between fluorescence intensity and spatial position, and use interference fringes to invert the electron density distribution.

Although the speed of each scan is very slow and only a set of two-dimensional density distribution images can be obtained, fortunately the spatial resolution can reach the centimeter or even millimeter level and the trigger threshold is very low. Repeating it several times can always give a very accurate result.

As new instructions were given to the front operating end, the robotic arm fixed to the ceiling quickly descended, projecting two parallel and relatively moving green bright lines on the surface of Unit 2003.

Wherever the light passed, the original lavender fluorescence immediately became intense, and then gradually returned to its original state.

It's like a layer of fluorescent waves that constantly move from both sides to the middle.

Taking advantage of this opportunity, Liu Yongquan resumed the original topic:

"I think the infrared signal problem won't be a big problem... at least not at this stage."

After feeling the other party's doubtful look, he further explained:

"When I was helping Snecma improve the M88-3 and M88-4 engines, I came across a large-scale release decoy in France that needed to be installed in a wingtip pod. It not only simulated the temperature of a fighter jet's tail nozzle, but also restored the complete fuselage signal to a certain extent. Moreover, after being launched, it would glide for a while instead of falling freely immediately. Dassault planned to use this thing to deceive the multi-component infrared seeker and even the infrared imaging seeker..."

Yang Wei seemed to understand what he meant:

"You mean, even if the infrared signature is more obvious, we can use new decoys to deceive incoming weapons to a certain extent?"

However, Liu Yongquan shook his head decisively;

"No...According to the test results of the French Air Force, even the Rafale F2 fighter, whose infrared signature is not particularly obvious, can hardly use this bait to deceive the latest generation of infrared guided weapons...So what I want to say is that the slight difference in infrared signature characteristics should not make a particularly obvious difference in actual combat. In comparison, the reasonable way to win is to use stealth, speed and maneuverability to stay outside the enemy's envelope at all times."

Yang Wei took off his work cap and rubbed his hair which was a little messy because he hadn't taken care of it for several days:

"I understand what you said. Currently, the only beyond-visual-range infrared air-to-air missiles equipped in large quantities are Mika and R27T. They are indeed not the main threat, but Party A did make relevant requests in the beginning..."

In fact, in addition to the requirements of the aviation force, he also hopes that the fourth-generation fighter jets born from his own hands can be as close to perfection as possible.

Due to the special nature of Project No. 10, Yang Wei was in charge of the work as deputy chief designer for a long time.

If nothing unexpected happens, by the time the fourth-generation fighter jet is finalized, he will be almost old enough to leave the front-line position and enter the management level of the Aviation Industry Corporation of China.

In other words, this is most likely the final work of his career.

However, Liu Yongquan had not yet realized this and only replied:

"Besides, the plasma generator is an accessory that the pilot can choose whether to activate or not. It is not a necessary equipment for maintaining normal flight..."

"From the perspective of written specifications, it belongs to the same category as the bomb bay and speed brake. You will not be allowed to open it when approving the indicators during the acceptance process. From the perspective of actual combat, the infrared guidance is basically used in visual range weapons. Even the range of Mika and R27T is terrible. Anyway, there is no need for radar invisibility during combat. Just turn it off before engaging the enemy within visual range..."

"..."

Yang Wei took a deep breath and wanted to refute something, but he had to admit that what the other party said seemed to make some sense...

But if this problem is not resolved, it will be like a thorn in the throat for a perfectionist.

I can’t say about the rest of my life, but at least I won’t be able to sleep well for the next year.

"call--"

Yang Wei shook his head, without giving a direct yes or no answer, but just raised his chin towards the test station outside the glass:

"Let's not talk about this for now. Let's wait and see the data."

Liu Yongquan also noticed some abnormalities in the other party at this time, but he didn't know what to say, so he had to turn his attention back to the verification aircraft that was glowing fluorescently.

For a moment, the atmosphere in the whole room became a little subtle.

About twenty minutes later, the first set of data directly above the aircraft was finally inverted and entered into the system.

The data analyst had already sensed the low pressure between the two bosses, but he could only bite the bullet and speak loudly:

"Report, the results have been uploaded to the server terminal!"

This sentence was like turning on a switch, causing Liu Yongquan and Yang Wei to take steps almost at the same time and walk to the control console.

From a qualitative perspective, it can only be controlled in one direction, and the plasma sheath distributed on the surface of the body in a semi-free form is bound to be unstable.

Therefore, the results presented on the two-dimensional graph are like jagged teeth, which is dazzling for a moment.

However, we can still see the overall trend that the electron density and infrared radiation intensity gradually weaken from back to front.

This is basically consistent with what we have observed with our naked eyes before.

Except for one extremely minor detail.

"Wait a moment."

Yang Wei's originally solemn expression suddenly changed from gloomy to bright, and he pointed to a position on the curve close to the tail nozzle of the aircraft.

The electron density there is no different from that at other locations, but the infrared radiation clearly shows an abnormal depression.

It is even close to the value in the middle of the plane.

Although the exact principle is unknown, it is clear that some kind of masking of the infrared signal is being performed.

The reason why it was not seen in the infrared imaging just now is probably because the spatial scale of this place is too small, only about 10 centimeters, so it is obscured by the ultra-high intensity infrared signals around it.

The results obtained by exciting fluorescence inversion will not be affected by normal optical interference and will still faithfully record the real situation.

"Old Liu, you can do it."

Yang Wei turned around and patted Liu Yongquan on the shoulder:

"This place probably corresponds to the transition from the engine casing to the tail nozzle. So you've been laying the groundwork for so long, are you planning to give me a surprise?"

However, Liu Yongquan was visibly as confused as he was:

"I'm not, I'm not..."