Chapter 1310: Fast and Slow, Far and Near 1

half a month later.

In a conference room in Huairou Science City.

As soon as Han Chenfeng walked in from the back door, he was stunned by several name tags placed in front of the long conference table.

In addition to several well-known names in academia and engineering, there are also several high-ranking representatives from the military.

Combined with the previous speculation, he was basically certain that today was not just a simple technical meeting, but probably also included decision-making parts such as development routes.

Of course, Han Chenfeng was here only as an observer, so he had no right to speak and could only watch the whole process.

A few minutes later, Chang Haonan entered from another door in front of the conference room, but did not sit at the head of the conference table with his name tag. Instead, he walked directly behind the small podium where the computer was placed.

With his appearance, the meeting room, which had been a little noisy, suddenly became quiet.

The only sound left was the fan noise from the on-site equipment when dissipating heat.

Xing Muchun, who was following behind Chang Haonan, sat directly in the first seat on the left and acted as temporary host.

Of course, I am the host, but in fact, this kind of internal meeting doesn't require any pomp and circumstance, so I just say one sentence as an introduction:

"Everyone, we just spent some time preparing the pneumatic model. Now the meeting officially begins..."

As soon as he finished speaking, Chang Haonan on the stage pressed the page-turning pen and switched to the first page of the PPT.

“Thanks to the commissioning of the new hypersonic wind tunnel and the efforts of all the comrades involved in the project, we completed the testing and data collection of several types of waverider standard models two months ahead of schedule, confirming that the waverider configuration can achieve an extremely high hypersonic lift-to-drag ratio in the atmosphere and near space…”

All the people sitting here today, including the military representatives, were not complete laymen, so after a brief opening, he directly showed several densely packed data charts:

"In addition, during this process, we have also successfully expanded the design freedom of the waverider in the longitudinal and span directions within a certain range through the cone-guided theory based on the three-dimensional axisymmetric flow field. The mean square error between the calculated parameters and the measured results is less than 0075, which has laid the foundation for the next step of specific hypersonic aircraft development..."

"..."

After summarizing his work, Chang Haonan paused for a moment to make sure the audience had no questions about what he had just said.

Then he changed the subject and entered today's main topic:

"However, although the data in the main topic is in line with expectations and meets the basic requirements, it can still be seen that since the principle of the waverider is to prevent the lateral flow of the fluid on the lower surface, thereby limiting the high-pressure area under the aircraft, it is equivalent to using shock waves to maintain flight. Therefore, different flight conditions, mainly speed and angle of attack, are extremely sensitive to the shape, and the optimization range is extremely narrow."

"Take the classic single-stage compressed cone-guided waverider as an example. At the design point of 0° angle of attack and speed Ma=12, the flow coefficient is as high as 4.083, and the inviscid maximum lift-to-drag ratio is greater than 3.75, which completely exceeds our performance requirements for gliding hypersonic missiles."

"But if the angle of attack is adjusted to -5° and the speed is reduced to Ma=9, although the changes are not large, the above two parameters will still drop sharply to 1.970 and 1.85, which will seriously affect the flight trajectory and effective gliding distance. Of course, the same is true in reverse. A waverider designed at -5° and Ma=9 will also find it difficult to adapt to the flight conditions of 0° and Ma=12..."

His tone was quite sad when he said this, as if the project could no longer be carried out, which made several military representatives present at the meeting look at each other in bewilderment.

After confirming that his understanding was correct, one of them spoke hesitantly:

"But Academician Chang, this is what we knew before we chose the waverider..."

"Also, the air-breathing type maintains a relatively stable flight speed and attitude throughout the entire process. It only turns into a dive at the end, and at this time, it does not need any lift... Although the glider type is decelerating overall, it will also be at the end when it slows down to Mach 9, so it will not affect the actual tactical effectiveness... right?"

By the end, you could clearly hear that he was a little bit unconfident.

But I really couldn't think of any problem, and I couldn't figure out why Chang Haonan was dissatisfied with the result.

"Of course, of course..."

Chang Haonan raised his hands, then pressed them down, signaling everyone to calm down:

"If it is just to meet the basic requirements of a hypersonic weapon, then the current research stage is indeed sufficient. However, even for an air-breathing hypersonic weapon, a large part of its range still comes from lift gliding, and it cannot flexibly adjust its flight speed and flight attitude, which means that it is impossible to significantly adjust the predetermined range, which has a great impact on the tactical flexibility of the weapon..."

Although Chang Haonan's future goal is to enable aircraft to achieve hypersonic flight and cross the Pacific or Atlantic Ocean within an hour, as Han Chenfeng had guessed before, this idea is indeed a bit too long-term. In addition, the current research is still carried out in the name of weapons, so he chose to obtain further support within the existing framework.

However, the problem he just mentioned is by no means groundless.

"Although in theory it is possible to develop a series of different types of weapons to deal with the ranges of different key targets, the Second Artillery Force has limited funding and staffing. If too many similar but different types of equipment are dispersed, the density of firepower against specific targets will be insufficient..."

Sure enough, Chang Haonan was well prepared.

When he mentioned "insufficient firepower density", several military representatives below showed slightly uneasy expressions.

Although China's equipment development has advanced by leaps and bounds in recent years, the worry about insufficient firepower has long been engraved into the soul of this army...

It was at this time that Chang Haonan gave a well-prepared solution:

"So, over the past period of time, I have verified a new conjecture..."

He turned the PPT to the next page again.

Above is a design diagram that may seem a bit confusing at first glance.

However, experts can quickly see that this is a series of common-reference cone waveriders designed based on cone-derived theory.

"When the upper surface of the waverider free flow remains unchanged, the design requirements of different incoming flow Mach numbers can be met by changing the compression surface, that is, the aerodynamic shape of the lower surface... Of course, this is the result of the design based on the cone guide theory, which cannot provide uniform compressed airflow for the scramjet engine, but the principle of the tangential cone waverider used in the air-breathing hypersonic engine is the same..."

"..."

Later, in order to prove the feasibility of this theory, Chang Haonan also demonstrated a relatively complete design and calculation method.

However, this is the part that only core technical personnel can understand.

It was not the focus of the military representatives on the scene.

"Keep the upper surface unchanged and change the compression surface..."

The Air Force representative was obviously more familiar with this kind of gameplay and was the first to react:

"Just like the Kh31P missile switches its seeker according to the different bands of the target radar?"

Chang Haonan shook his head:

"You don't even need to go through the trouble of replacing the entire warhead... You just need to replace the corresponding compression surface fairing according to the target distance before launching."

This time, everyone understood instantly.

"In other words, we only need to equip one type of basic warhead to meet different mission requirements from 1000 kilometers to 10000 kilometers?"

The representative of the Second Artillery Force sat up straight instantly.

"Almost the same. Of course, intercontinental weapons require a larger boost stage, so for cost considerations, it may still be necessary to equip both long-range and short-range models. However, the warhead can indeed be combined into one."

Chang Haonan switched to another rendered picture that was easier to understand:

"In fact, if future ramjet engines can also adapt to a wider range of working ranges, then we can even make a two-stage glide-cruise waverider design, that is, use different waveriders in the glide and cruise stages. The glide stage waverider can be transformed into a cruise stage waverider by discarding the fairing midway, thus achieving free crossing between the atmosphere and near space..."