Chapter 31

Yunlan stopped crying after hearing Lin Yuan's words and asked doubtfully, "Really?"

Lin Yuan smiled and said, "Of course, why would I lie to you?"

Tang Fan and Yunlan were both very happy. Lin Yuan said, "You two take your time eating. I'll go first. By the way, Reporter Tang, make sure to remember where she lives when you part ways."

This time, neither of them tried to stop Lin Yuan. Lin Yuan left the restaurant and saw many Japanese civilians marching in the streets. The banners read: "Refuse negotiations! Beat the Chinese until they submit!" "Overthrow the corrupt officials who negotiate!"

Lin Yuan walked around them and quickly returned to his residence. As soon as he got back, he said Tang Fan was fine, reassuring everyone. Shen Wanqing said, "I recorded it for you. When do you want to listen to it?"

Lin Yuan smiled and said, "Of course, now." He took the headphones from her and started listening.

An elderly voice sounded, and Lin Yuan guessed it was a professor. He said, "Commander, this is the photo of the mysterious ship you gave us." Lin Yuan thought, "It seems this mysterious ship refers to our aircraft carrier."

The voice continued, "In this photo, the Yoshino of our Combined Fleet is in the distance. Based on the distance between the Yoshino and the mysterious ship that you told us, we can calculate that the length of the mysterious ship is about 340 meters, the width is about 40 meters, and the freeboard height is about 12 meters. The estimated displacement is around 50,000 tons. Other ship form coefficients, such as the waterline area coefficient, cannot be deduced from this photo."

Lin Yuan thought, "With the shape data of known objects and the distance between known and unknown objects, calculating the shape data of the unknown object is easy. However, the photo can't capture the scene below the waterline. Who knows how they calculated the displacement."

Ito Sukenori said, "This mysterious ship is very fast. According to my observer's estimate, it can reach at least 30 knots when evading our gunfire."

Another elderly voice said, "30 knots, how is that possible! Based on a displacement of 50,000 tons and a speed of 30 knots, its kinetic energy would be 6.4 times 10 to the ninth joules. Everyone knows that ships face significant resistance during travel, such as wave-making resistance and frictional resistance in the boundary layer, which are proportional to the high power of the ship's speed. Wave-making resistance is proportional to the 4th to 6th power of the speed. Therefore, we can estimate that the entire ship would need to supply 2 times 10 to the tenth joules to maintain this speed. One ton of standard coal can release 30 megajoules of heat, so this ship would burn 15,000 tons of standard coal per second. Considering incomplete combustion, the actual coal consumption would be much higher, which is absolutely impossible."

Ito Sukenori said, "Can't they burn something else?"

"It's impossible. The only fuel with a higher calorific value than coal is oil, but how could oil be used as a ship's fuel?"

In Lin Yuan's era, using oil as fuel for warships was common, but in the 19th century, ships still used coal.

There was a moment of silence, and a voice said, "Commander, I mean no offense, but is there something wrong with this photo? This warship is too long. We know that the gravity and density of different parts of a ship cannot be the same, so if the parts are not connected, they will be at different vertical positions. In fact, a warship cannot be in such a state, so the keel of the warship will bear a great force. Moreover, with such a large displacement, what material is used for the keel?"

Ito Sukenori asked, "What do you mean?"

"Such load-bearing components can only be made of steel, and its yield strength will be over 400 megapascals. According to the current progress in materials science in various countries, no country has the smelting technology to achieve this."

Another voice said, "We don't know where this ship was built. With a displacement of 50,000 tons, building such a ship requires a shipyard capable of constructing such a large vessel. Such a large project cannot be kept secret anywhere."

After a long silence, Ito Sukenori sighed and said, "Let's put the ship aside for now and talk about those flying things. We'll call them aircraft. According to the experts, how do these things fly?"

A voice said, "These things really exist! According to our intelligence, the French have been secretly developing such flying machines. An engineer named Clément Ader flew an aircraft 50 meters off the ground in 1890. Since the French military has kept this a secret, few people know about it. This aircraft used a steam engine and a propeller for propulsion, but the aircraft in this photo has no propeller!"

The J-24 uses a low-bypass turbofan engine, so it doesn't need a propeller.

A voice said, "Since there is no propeller, it might use an unknown propulsion method, such as the one our project team is researching, which uses air for propulsion. We all know the principle of momentum. If this aircraft ejects a high-speed airflow backward, the aircraft will have a forward speed. Combined with the lift provided by the wings, the aircraft can fly."

Ito Sukenori asked, "How is your research progressing?"

The voice said, "To make the air cycle and do work, it must be pressurized and then heated, and then allowed to expand. This process seems simple, but it is fraught with difficulties. We know that a fan can move air, so we want to use a series of fan-like blades to rotate and pressurize the air. However, these blades are extremely difficult to make. First, the shape must be determined based on fluid dynamics to ensure that the blades can move the air and do work. To calculate fluid dynamics, we need to use the Navier-Stokes equations, which are nonlinear partial differential equations with no exact solution. We can only resort to numerical solutions, but the workload is enormous, impossible to complete. Second, even if we calculate the shape, it cannot be manufactured. According to our simplified calculations, these blades must be twisted, and no machine tool can process them. Casting them is even more difficult!"

Ito Sukenori sighed deeply and said, "Sigh, that's enough for today. Let's continue the discussion tomorrow." The meeting ended with a sigh.

Lin Yuan put down the headphones, feeling a wave of worry. He thought, "Our aircraft carrier is far beyond this era. If it needs to return to the factory for repairs, where will we go? After the treaty is signed, we must develop our own industry. Once it's developed, we'll turn all of Japan into a province of China!"

At this moment, Lin Yuan heard his stomach growl, realizing he hadn't eaten yet. Shen Wanqing laughed and said, "Hehe, our genius captain gets hungry too?"

Lin Yuan then noticed that Shen Wanqing had been by his side all along. He smiled and said, "You were just waiting?"

Shen Wanqing laughed and said, "How could I not be here? What if you broke my equipment?" She then walked out and quickly brought in a large plate, placing it on the table. "It's all your fault for insisting on listening just now. Now I can't even eat."

Lin Yuan looked at her pouting face, feeling a tickle in his heart, and joked, "Why don't we eat together? I'm hungry too."

Without waiting for her agreement, Lin Yuan sat down at the table. He noticed that Shen Wanqing had brought two sets of chopsticks and bowls, and he felt something. Shen Wanqing removed the lid from the dish, revealing a tempting pufferfish.

Shen Wanqing served rice and poured fish soup over it, then started eating. Lin Yuan asked, "What is this?"

She smiled and said, "It's pufferfish. Haven't you tried it? I love it. My mother often makes it for me."

Lin Yuan joked, "You have a mother?"

Shen Wanqing laughed so hard that she sprayed rice out of her mouth. "Why can't I have a mother?"

Lin Yuan laughed and said, "Aren't spies supposed to be orphans? That way, they can have no attachments when on missions and be ready to sacrifice for the country at any time!"

Shen Wanqing laughed dismissively and said, "You must have read too many web novels! Where are such spies? I've never seen one."

Lin Yuan said, "Look at us now, traveling back in time to fight the Japanese. This is something you'd only see in a web novel. I wonder if any writer would come up with this story."

After a while of joking, Lin Yuan became serious and said, "I have my eye on a girl."

Shen Wanqing, hearing this, felt a pang of jealousy and scolded, "What did you say?"

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