Republic of China: Ace Pilot

Chapter 516 Propeller Shock Wave Phenomenon, Jet and Supersonic Seminar
After learning about the company's operations, Fang Wen prepared to head to the base in northern Myanmar.

Before leaving, he needed to resolve some minor issues he had brought from Guangzhou.

Sun Tianrui was assigned to study at an aviation school. He was somewhat talented and could teach himself to fly, but his foundation was weak, so he had to start by learning basic low-speed seaplanes.

If he performs as well in piloting as Fang Wen judged, Fang Wen would not mind taking him on as his second personal student.

In addition, there is the issue of the three orphans.

Although these three children have been arranged to attend a Chinese school, they still require adult care in their daily lives.

Although Gong Xiuneng cared about them a lot, he was, after all, an unmarried man and couldn't do many things well.

Fang Wen prefers to find a family to adopt them.

Therefore, he consulted some employees in the company who had families with children, and these employees were all willing to raise these three children with pitiful backgrounds.

Fang Wen originally planned to choose one of the couples, but who would have thought...
39 1 Month 10 Day.

Fang Wen is talking to a couple.

The man works in the company's finance department, and the woman stays home to take care of the children.

"How many children do you have?" Fang Wen asked.

“Two,” the man replied.

"If we leave the children in your care, can you raise five children well?" Fang Wen asked. He had no experience in raising children and just felt that it would be very difficult for a woman to raise five children.

“General Manager, I can do it. In my hometown, women all get through this,” the woman replied.

Fang Wenzheng was about to make a decision.

Fang Shouxin walked in from outside the door.

He interjected, "Young master, let me take care of the victory, the fight against the Japanese pirates, and the triumphant return."

The names Victory, Resistance Against Japanese Pirates, and Triumphant Return are the new names of the three orphans, representing hope and a desire for the children to forget the past and embrace a new life.

The name is very popular, and when the three children appear in the company building, many people often call their names.

Fang Wen looked at Fang Shouxin in surprise upon hearing his words.

He asked, "Uncle Fang, what made you come up with this idea?"

Fang Shouxin glanced at the couple, then hesitated, as if he wanted to say something but stopped himself.

Fang Wen understood that they had something to say, so he asked the two to leave.

After the two left, Fang Shouxin said, "My grandson is almost 3 years old. I plan to send him to Yangon to start kindergarten. My daughter-in-law has to work and can't come, so I'll take care of him myself. Taking care of one is the same as taking care of four."

Fang Shouxin's son Fang Shun's wife, although a Miao woman, was also a revolutionary. Now that the country is in crisis, she insists on staying at the Xiangxi Airport. However, the child needs a safe place, so it is only natural to send him to his grandfather's place.

"You're already so old, you're too busy managing the company, how can you take care of a child on top of that?" Fang Wen pressed.

Fang Shouxin was a little embarrassed: "I have a girlfriend who is from North China. Her husband was killed by the Japanese devils, and she fled to the Yellow River alone with other refugees. Later, when the company was hiring, she was hired as a staff member in the company's logistics department canteen. We were destined to meet, and we were from the same place, so we got together."

“Alright, Uncle Fang.” Fang Wen suppressed a laugh and decided directly, “Then I’ll entrust the three children to you.”

Afterwards, he and Fang Shouxin went downstairs to Gong Xiuneng's dormitory and took the three children to Fang Shouxin's house.

At Fang Shouxin's house, Fang Wen met the woman who was the same woman who usually served the main dishes in the cafeteria.

The other person seemed a little embarrassed; despite their age, their face was flushed.

Fang Wen smiled and explained the situation to the three children: "From now on, you will live at Grandpa's house. In a few days, another child will come over. The four of you will live together, go to school together, and help each other, okay?"

"Okay," the three children said in unison.

Only the youngest girl, Kaixuan, asked, "When is Mommy coming back to pick us up?"

The two older children had tears in their eyes. They had accepted the fact that their mother had been killed by the Japanese, but they didn't want to tell their younger sister and upset her.

Fang Wen sighed inwardly and explained, "Mom has something very important to do. She'll come back to you when she's done."

After saying that, Fang Wen handed the child to Fang Shouxin and left with Gong Xiuneng.

Because of the child's emotional state, he finally couldn't help but send a telegram to his wife.

[Mingzhu, it's been three months since we parted, and I miss you terribly. Our baby must be four months old by now; I miss him so much.]

After sending the telegram, Fang Wen did not linger and flew with Gong Xiuneng to the base in northern Burma.

Upon arrival in northern Myanmar, Fang Wen disembarked and went directly to the Taishan Research Institute.

In the office he had reserved for himself at the research institute, he pondered and summarized the Battle of Guangzhou.

The battle of Guangzhou once again proved the importance of information warfare.

Once the enemy's command structure is compromised, the complete coordination of the entire region's armed forces is lost.

As long as our side maintains the information advantage, we can definitely achieve victory with fewer troops.

However, this kind of special operations is more about tactical effects.

China's current overall military strength is insufficient to achieve what Germany did: a large-scale blitzkrieg-style surprise attack in Europe.

Therefore, the sophistication of military equipment is also very important.

Without man-portable rockets, gunboats, and aerial bombs, Japanese warships would have been an insurmountable nightmare.

I shook off the jumbled thoughts.

Fang Wen crumpled the paper with writing on it into a ball.

This is not something I should be thinking about right now.

His thoughts drifted back to the time of the battle in Guangzhou.

During the high-speed dive attack of the Qinyuan, he discovered the problem with the Taishan's first-generation aircraft.

When the flight speed reaches 700 kilometers per hour, the fuselage will shake violently and make a very piercing sound.

He discovered the problem immediately through mechanical perception.

That was the noise and vibration generated by the high-speed rotating propeller.

What is the reason for this situation?

Based on his understanding and the principles of airplane operation, Fang Wen wrote it down on paper.

[Propeller shock wave phenomenon]

When an airplane is in flight, the propeller rotates, and the speed of the propeller tip is the vector sum of the airplane's flight speed and the velocity generated by the rotation. Therefore, even if the airplane's flight speed does not reach the speed of sound, the fastest moving part of the propeller tip may already be traveling at a speed exceeding the speed of sound.

At this moment, the air in front of the propeller tip is rapidly compressed, and collisions between gas molecules become more frequent and violent, leading to increased air density, pressure, and temperature, thus forming a localized shock wave.

After a pause, Fang Wen added another sentence.

Although it was only a localized shock wave, its wide application is enough to prove that the upper limit of piston-engine propeller aircraft is 700-1000 km/h, and it is impossible for them to exceed the speed of sound.

So how can we increase the speed to above the speed of sound?

This is also the military technology leap that Fang Wen has always wanted to achieve.

If we continue with existing engine technology, even if Pratt & Whitney successfully develops its dual-engine system, it will only double the kinetic energy.

Such a super radial engine should be able to increase the speed of the aircraft to 700 kilometers per hour or even higher, but it would be impossible to reach speeds of 1000 kilometers per hour or higher.

Because the speed of sound is 1224 km/h, the closer to the speed of sound, the more obvious the shock wave phenomenon of the aircraft, and the higher the risk of flight.

To overcome this limit, we must abandon piston engines and switch to jet engines.

Fang Wen stood up and tried hard to recall his future memories. With the help of his powerful mental strength, he found some information about jet engines deep in his memory.

He then made a side-by-side comparison of the two different types of engines.

Piston engine.

[Through the reciprocating motion of the piston within the cylinder, the chemical energy of fuel combustion is converted into the mechanical energy of crankshaft rotation, which in turn drives the propeller to push air, generating thrust.]

[Bottleneck 1: Power Density Limitation: The power of a piston engine is limited by the number of cylinders, displacement, and rotational speed. When the flight speed approaches the speed of sound, shock waves are generated at the tips of the propeller blades, causing a sharp drop in efficiency. It is estimated that the speed limit of propeller-driven fighter jets equipped with piston engines will not exceed 700-1000 km/h, and the speed of excellent fighter jets will be around 700 km/h.]

[Bottleneck 2, High-altitude performance degradation: As altitude increases, air density decreases, significantly reducing the intake air volume and combustion efficiency of piston engines, making them unable to meet the demands of high-altitude, high-speed flight, limiting their service ceiling to below 10000 meters.]

Jet engine

[Principle: A power device that uses the reaction force generated by a high-speed jet of air to propel an object forward. Its core principle is based on Newton's third law (action and reaction forces) and gas dynamics.]

[Taishan Military Industry has made preliminary applications of propulsion generated by reaction force in man-portable rocket launchers.]

How does it work?

Fang Wen stopped writing. This kind of matter involves the entire system and should not be studied by one person alone.

He then convened relevant personnel from the Taishan Research Institute to participate in the research discussion.

The rocket research groups 1 and 2, and the aero-engine research group of Taishan Research Institute all received a notification to come to the conference room to participate in a research discussion meeting.

Fang Wen, as the host, explained the situation.

"I'd like to remind everyone in advance that this research discussion will be held at an irregular pace until a theoretical breakthrough is achieved. Furthermore, this research project is top secret; participants are strictly prohibited from disclosing it. Violation of this rule will be treated as military leaks, and in serious cases, as treason. Is everyone clear?"

The researchers in the three research groups, all engaged in military-related research, understood this principle of secrecy and unanimously agreed.

No one withdrew from the research discussion.

The discussion then began.

Fang Wen continued, "I am preparing to research a brand-new aircraft engine whose efficiency will far exceed that of existing engines, potentially increasing the speed of aircraft to near or even beyond the speed of sound."

This opening is stunning enough.

Researchers all know what the speed of sound is.

At standard atmospheric pressure, the speed of sound at 15°C is approximately 1225 km/h (340 m/s).

This speed is already the limit of current technology.

Only bullets can reach that speed.

One question after another was raised.

"Are the materials used in the aircraft capable of withstanding supersonic flight?"

"What kind of engine can produce enough power for a multi-ton aircraft to fly at such high speeds?"

"Is the pilot capable of flying at such high speeds?"

The questions they raised were very practical, and Fang Wen replied:

"I can't give you the answers to these questions. The joy of scientific research lies in understanding and solving the unknown. I hope to create miracles together with everyone. But I do have a draft regarding the engine."

As he spoke, he tore the cloth off the blackboard.

"This is the preliminary design of the new engine. It uses propulsion rather than propeller lift. Its principle is the same as the rockets we are researching, which is why rocket groups one and two are involved in the discussion."

Jiang Wenjin, the leader of the second rocket team who had been silent until now, looked surprised.

As a physicist specifically recruited by Fang Wen, he has a better foresight.

He then asked, "If it uses propulsion, the engine should convert the chemical energy of the fuel into kinetic energy through an 'intake-compression-combustion-expansion-exhaust' process, using the reaction force to propel the object forward. If such an engine can be developed, it can be used not only in aircraft, but also in our rockets and even other weapons. Theoretically, the operability of such engine components in weapons is better than that in aircraft."

To prove his point, Jiang Wenjin gave an example.

Jiang Wenjin walked to another blackboard and drew a diagram with chalk: "As you can see, due to their size, existing rockets can only provide single-pulse power, which limits their range and trajectory change capabilities. But if we can miniaturize this new type of engine, we can completely transform it into an adjustable 'power heart'."

He picked up a model rocket and pointed to the tail fin, explaining, "Take the Taishan fighter jet rocket we are developing as an example. After being equipped with this engine, it can adjust its attitude through multiple ignitions at the end, allowing it to hit the target at a higher speed and with greater accuracy."

A murmur of discussion arose in the conference room. Fang Wen hadn't expected that Jiang Wenjin would turn the discussion to missiles, a strategic weapon.

But now, missiles face far more problems than jet aircraft, and controlling range, course, and accuracy are all issues that need to be addressed one by one.

After all, Germany's V2 missile is still only at the blueprint stage.

Fang Wen quickly spoke up: "The rocket proposal is very good. Your group can follow up. Now let's continue discussing the engine."

He uncovered another blackboard and continued.

"The theory is similar to what Jiang Wenjin described, mainly involving energy conversion and reaction force. It consists of three steps: 1. Energy input and gas compression: Air is drawn in and compressed, increasing its pressure and temperature, converting mechanical energy into gas internal energy. 2. Combustion and energy release: The compressed air mixes with fuel and burns, generating high-temperature, high-pressure gas, further enhancing internal energy. 3. High-speed exhaust and reaction force generation: The gas is accelerated and ejected through the nozzle. According to Newton's third law, the rearward-ejected airflow generates a forward reaction force on the engine, propelling the aircraft forward."

"My original design concept was a turbine engine, in which the gas passes through a turbine to drive a compressor and is then expelled from the tail nozzle, with the thrust mainly coming from the high-speed exhaust. The efficiency is high at supersonic speeds, but fuel consumption is high at subsonic speeds. However, this design has a problem: it is very difficult to operate and has low practicality. Therefore, I think we can compromise and build a jet aircraft first, sacrificing some speed."

Fang Wen set the tone for this seminar.

The main discussion focuses on practical jet engines.

As for what kind of practical jet engine is needed?

He chose two options: turbofan engine (for future commercial airliners) and turboprop engine (for future regional jets).

These two types are better than the primitive turbine engines being researched by Germany and Britain, easier to implement than ramjet engines, and safer than pulse jet engines.

(End of this chapter)