Siheyuan: I eat melons while doing scientific research

Chapter 1336 From Deep Respect to Goosebumps (4k)

To the comrades at the Naval Equipment Bureau, this was perfectly normal; in fact, they had come all this way just to hear it.

Based on their understanding of Gao Zhendong, they knew that behind Chief Engineer Gao's "this won't work" was definitely a "very good" solution, and that was exactly what the comrades from the Naval Equipment Bureau were looking forward to.

However, Zhang and Wang were somewhat surprised to hear this. It seemed that this person not only knew about hovercrafts, but also had some knowledge of the hovercraft's lifting system, otherwise he would never have said such a thing.

They found it strange, though. Logically, after the domestic research on hovercraft ended its period of "a hundred flowers blooming" and shifted to concentrating efforts, the strongest research force in hovercraft in China should be here. They hadn't heard of any experts still scattered abroad.

But that matter is no longer important; what matters is the "this won't do" they heard. For a comrade so highly regarded by the Naval Equipment Bureau to say this, there must be a reason and a basis for his authority.

Even if we don't find a better solution, it's good to at least figure out why it doesn't work.

"Chief Engineer Gao, we have studied it. This ham-shaped airbag apron has good molding and stability. The apron will not wrinkle or turn outward. Relatively speaking, the jet air curtain of the nozzle also forms very well."

Gao Zhendong nodded repeatedly at what he said. He couldn't refuse, because he wasn't aware of these advantages, but since his comrades had done their research, there shouldn't be any major problems.

However, although Gao Zhendong was unaware of the advantages, he was very clear about another thing—the disadvantages of the ham design. After all, the relevant information on the final solution would definitely mention the disadvantages of the previous generation solution.

So after Gao Zhendong nodded repeatedly, all that remained were the drawbacks: "Yes, what you've said are indeed obvious advantages, but this thing also has obvious drawbacks."

"Disadvantages?" This is something the comrades haven't fully considered yet. After all, this ham-like thing is only in the planning stage and hasn't been put into practice. Before testing, the comrades basically can't know the disadvantages of this thing because the theory is still weak, and many problems can only be discovered through actual testing.

Moreover, compared to single-layer extended aprons, ham-style aprons are virtually without flaws. After all, single-layer extended aprons have far too many drawbacks, and with this counterpart in mind, the shortcomings of ham-style aprons are not immediately apparent.

"Yes, the downside. The problem with this ham-shaped thing, intuitively speaking, is that it's both its strength and its weakness. Its stability in forming is a bit too good..."

Gao Zhendong's words left the two hovercraft enthusiasts feeling a bit like Louis XVI—completely baffled.

"Is too much stability a problem?"

Gao Zhendong nodded: "Theoretically, the higher the stability, the better, but that's just theory. We can't forget that hovercraft are meant to operate on complex terrains such as water, beaches, and reefs. Too much stability isn't necessarily a good thing. Sidewall hovercraft have good stability, right? But sidewall hovercraft don't have all-terrain capability at all. This ham-type hovercraft has a bit of that in mind."

His example was so vivid and illustrative, and so relevant to the profession, that the comrades seemed to have grasped a little bit of the key points.

In terms of forming stability, the sidewall type is definitely better. After all, the two sides of this thing are two rigid bodies. Compared with the fully cushioned airbag, it doesn't deform at all. With the support of these two rigid bodies, the forming of the front and rear airbags is much easier to handle. However, Chief Engineer Gao is right. In terms of all-terrain capability, the sidewall type is really not good.

"So, what exactly are the drawbacks of the ham-style cooking method?" This is what Zhang and Wang are most concerned about now.

"The nozzles are prone to wear, have complex structures and high costs, and are difficult to replace after wear. They also have poor drag characteristics. Moreover, we must note that the hovercraft we originally planned to equip was designed for resupplying islands and reefs. The aprons are subject to significant wear and tear from the coral sand and other debris on the reefs," Gao Zhendong said, pointing to the ham apron on the blackboard.

To some extent, it is precisely because of its excellent forming stability that the apron deforms little when it comes into contact with obstacles or water surfaces. And the small deformation here means that the soft apron has to withstand these things hard, so its wear resistance is naturally not very good.

In fact, one of the main reasons why our earliest fully-cushioned hovercraft was not very practical was the lifespan of the apron.

Ham aprons offer advantages such as maneuverability and stability, but they also bring a huge problem: extremely short lifespan and extremely poor maintainability, both of which exist simultaneously.

The severity of the problem can be illustrated by one statistic: the lifespan of the nozzle connection line on the apron is approximately 1 to 2 hours, meaning that a large number of repairs are required after just one voyage.

Moreover, the repair of this kind of thread relies entirely on manual repair, and the combination of the two can be described as adding insult to injury.

We didn't have a truly usable fully-cushioned hovercraft until the late 70s. Before that, it wasn't that we didn't want to use them, but that we simply couldn't.

"Hiss... It seems there is such a problem. We only thought about making it well-formed, but we didn't expect that making it too well-formed would also be a problem." The two comrades admired Gao Zhendong very much. They believed that this comrade had definitely not actually installed the ham apron, but he was able to find out the problems of the ham apron just by using this kind of thought experiment method. This ability is not something that ordinary people can have.

Gao Zhendong's next sentence upgraded their admiration to profound respect: "Moreover, besides these problems, due to the existence of secondary resistance peaks, this kind of apron still experiences enormous water-lifting resistance when crossing peaks..."

This statement cannot be deduced solely from the intuitive inferences we just discussed. In fact, many comrades don't even fully understand what a secondary resistance peak is.

Seeing that the two colleagues from the Naval Equipment Bureau seemed somewhat hesitant to accept this, the comrades from the Naval Equipment Bureau added an explanation: "Chief Engineer Gao has profound expertise in fluid mechanics..."

They didn't know much about what happened on the plane, but at least they knew that the design of the medium-sized landing ship that was about to be completed was provided by Gao Zhendong. The hydrodynamics of air is fluid, and the same is true for water.

This ship design, while meeting the special requirements of landing ships for loading and beaching, also effectively balances economic efficiency and seaworthiness. No one in the Navy would believe that Gao Zhendong hadn't studied fluid dynamics. The words of the comrades from the Naval Equipment Bureau further heightened Zhang and Wang's admiration and surprise. Anyone who can study fluid dynamics, something so unpredictable, is extraordinary, let alone possess such "profound expertise." Although they didn't know why the comrades from the Naval Equipment Bureau said this, it was clear they had no reason to embarrass themselves on such a topic.

This made both comrades happy. Having such a comrade to help would undoubtedly be of great benefit to the development of hovercraft. No wonder the chief engineer of the National Defense Industry Committee said that it might even solve the technical difficulties. Now it seems that the chief engineer had a comprehensive grasp of the situation and was not joking after all.

"Chief Engineer Gao, what do you think is the best way to improve this?"

Speaking of this, Gao Zhendong was no longer sleepy. He stood up and began to draw a diagram on the blackboard: "We will do it like this, using this structural form."

—The finger-shaped apron, a truly mature apron widely used in fully padded hovercraft.

The two comrades stared in disbelief at Gao Zhendong's drawing. Not because it was too advanced, but because they found it far too simplistic!

The apron pouch has holes at the bottom, and the bottom is made of apron material forming triangular air pockets. That's all; it's extremely simple.

Besides being simple, this thing has a major problem at first glance.

"Chief Engineer Gao, isn't the air pressure loss in this air duct a bit too large? Will it affect the flight altitude?" They didn't believe that Gao Zhendong couldn't see this problem.

Gao Zhendong nodded: "Yes, you can see very clearly that because the air passage is made in the apron pouch, the air pressure loss is large, which affects the absolute flight altitude. But we need to consider one thing, which is whether we still care about that little bit of absolute flight altitude under these circumstances?"

"Don't care about flight altitude?" This statement is a bit hard for comrades to understand. Flight altitude is one of the most important indicators of a hovercraft. Just like the 100mm flight altitude of a rigid jet, it basically makes the hovercraft lose all all-terrain capabilities.

"Yes, let's look at the advantages of this structure first." Gao Zhendong put aside the matter of flying at high altitudes and began to analyze it for his comrades one by one.

"Everyone can see at a glance that this thing has a simple structure and is very easy and inexpensive to manufacture." The comrades didn't seem to have any objections to this, as it was almost obvious to the naked eye.

"The nozzle does not directly contact obstacles, resulting in less wear, and it is very convenient to install and maintain. In this respect, the ham-style apron cannot compare at all." The airflow nozzle of this method is raised high, away from the water surface and obstacles, so there is no direct wear problem at all. What comes into contact with the water surface and obstacles are those triangular sac-like fingers, which are not afraid of wear at all, and are simple to manufacture and easy to repair.

"The most important point is that this structure has excellent obstacle-crossing and wave-taming capabilities, and generates very little water resistance." Gao Zhendong analyzed it for his comrades point by point on the blackboard.

"The water resistance is really not much!" The comrades finally understood what the comrades from the Marine Equipment Bureau meant when they said that Chief Engineer Gao had a deep understanding of fluid mechanics. At least when he analyzed the resistance of the apron, his theory was solid and his reasoning clear, making him more knowledgeable and convincing than they, who specialized in hovercraft. At least in his analysis of water resistance, the two of them couldn't see any problems; the water resistance of this apron was indeed that small!

Only then did the two comrades understand what Gao Zhendong meant by "not caring about that little bit of flying altitude".

Such low water resistance can cover up and solve many problems.

To some extent, if water resistance is reduced, the power required for forward movement can be reduced, leaving more power available for other purposes.

However, they still hadn't expected that Gao Zhendong hadn't even considered this kind of robbing Peter to pay Paul approach. Regarding the altitude, he had other considerations: "Moreover, comrades, is the absolute altitude really that important here? Once the apron forms a closed space to create an air cushion, the absolute altitude isn't that important anymore, because the closed space created by the apron has already raised the hull. At this point, whether the absolute altitude is a little higher or lower is no longer important compared to the hull raised by the apron."

For rigid jets, flight altitude is crucial, directly determining the distance the hull is from the support surface and its obstacle-crossing capability. However, for apron-type fully-cushioned hovercraft, this indicator is relatively less important, because the hull's flight altitude is actually determined more by the apron's inflation height.

"Yes!" Both comrades became excited. This is a dead end that senior technicians can easily get stuck on. They are too familiar with the matter and can't get out of it.

"This finger-pouch apron is actually quite promising!" In fact, this was also John Bull's invention. While John Bull didn't accomplish much in this area during the 60s and 70s, his ideas were incredibly innovative and effective. Aside from small things like hovercraft, even the most iconic structure of modern aircraft carriers—the angled flight deck—was their invention. However, after inventing the angled flight deck, their planned fleet carriers were "sunk" by their navy's biggest enemy—the Labour Party—ultimately benefiting the Americans.

Several years later, we somehow obtained basic information on fingerless aprons, but it was undoubtedly inferior to the comprehensiveness of the set Gao Zhendong had. After all, Gao Zhendong's set came from hovercraft design textbooks from the 80s and 90s.

Moreover, Gao Zhendong's goal is not just to solve a "simple" problem like aprons, but to develop a practical theory of padding based on the form of aprons.

There is no complete theory, nor is there ever a complete theory. For something as practical as a hovercraft with complex working conditions, we can only develop a practical theory based on experiments and specific applications. That is basically the limit.

Fortunately, Gao Zhendong could copy a set of theories without experimentation. These theories were originally the result of research and summaries by comrades who worked on hovercraft twenty years later. The fact that they could be returned to their rightful owner so early in such a peculiar way gave Gao Zhendong a very strange feeling.

"If you comrades think this pouch-style apron is good, then I have a set of padding theory that I came up with in my spare time not long ago. Although it is not very mature, I think it should be helpful to you comrades."

A complete theory of stabilization? The comrades were not just filled with awe, but also felt a chill run down their spines.

(End of this chapter)