Into Unscientific

In the 21st century.

Due to some industry barriers, when many people mention engines, they often think from a high-level perspective.

But in fact.

In some aircraft model circles, self-made aero engines are not a very unusual thing, and the ranking of funds must be ranked ahead of technology.

Such as homemade turbojet.

There are a lot of related videos on Bilibili, and some geek websites still have some data left over.

The number of self-made engines in many Minke's homes can fill half a room.

Of course.

Some people may ask, why are DIY engines so popular?

This has to say a root of all evil:

Kurt Schreckling.

In early 1998.

After countless failures, this engineer-level enthusiast finally let himself design the first turbojet engine to run successfully, and it has actual combat effects.

Ever since.

He published a book called "Gas turbine engine for aircraft model" that year, and the Chinese name is Aircraft Model Jet Engine.

Among them, he announced the parameters of an engine named FD3-64 in the book, and this machine became the originator of all DIY engines in the future.

Since then, the process of building a homemade engine has been more or less settled.

Like a fishing rod.

With the development of the fishing industry, until now, the routines of how to install fishing reels, string hanging lines, and tie baits are all fixed.

The only difference is the "parameter calculation" of water drop wheel or spinning wheel, which line to use, whether to use five grams or ten grams of bait, and which vegetable market to buy fish after the Air Force.

Indeed.

The industrial level of later generations is much higher than that of the Song Dynasty. For example, five-axis CNC machining centers and wire cutting are difficult to achieve.

But on the other hand.

As mentioned earlier, Xu Yunding's goal is very realistic, and he doesn't want to reach the sky in one step:

First of all, the engine he designed will not reach production level in one step.

Secondly, the direction of use of this aircraft is aimed at the enthronement ceremony, and its lifespan is only dozens of hours.

There is no need to consider long-term durability, long-term deformation, popular technology and production line production.

With the support of Xiao Zhao, it is not whimsical to build an engine with the power of the whole country.

As for the engine Xu Yun plans to design this time?

It is a rotary cylinder engine. (Note: I was confused when I calculated the thrust yesterday, so I wrote down the bypass ratio, which caused some friends to think that they were going to engage in turbofans.)

A rotary cylinder engine, also known as a radial engine, is actually a type of piston engine.

However, it is different from the in-line piston engine block.

The rotary cylinder type is that the engine block rotates around the output shaft, and the in-line piston engine block is fixed relative to the output shaft.

The engine template designed by Xu Yun this time is Chujiao 6, which is a star-shaped air-cooled 9-cylinder engine

However, it has been optimized in some aspects, and it is higher than the pulse jet engine in all aspects, such as increasing the curvature of the impeller and so on.

The specific parameters are as follows:

Compression ratio: 6.1±0.1.

Main connecting rod strength ratio: 1.0032

Working state: 2370rpm

Piston stroke: 130mm

Advance ignition angle: 29±2°

Maximum gas pressure value: 57.2kg/square centimeter.

Connecting rod length: 235mm

Neck rotation radius: 63mm

Piston diameter: 105mm.

Crankshaft deflection angle at the moment of maximum pressure: 13° (assuming that the time from the start to the maximum value of the gas explosive force is 4/1000, the first stage accounts for 12%, the pressure increase accounts for 20%, and the other dead point is 11°, I took a large Value, by the way, this is an engine parameter that I rubbed my hands 9 years ago, and it has been in actual combat)

Of course.

Parameters belong to parameters, which is only a small part of the entire airframe design process.

In addition, there are some data that Xu Yun cannot complete alone.

For example, the cross-sectional thrust, the reflected wave pressure of the vertical plate, and so on.

Therefore.

That's why he asked Xiao Zhao for help from Lao Jia and others.

Scientific research has never been done by one person.

One night a week later.

In an open space in the Manufacturing Bureau.

At this moment, there is a blast furnace similar to ironmaking in the center of the open space, with a height of about four meters.

A pipe is connected to the side of the blast furnace, and a self-priming pump invented by Lao Su is placed on the pipe.

Blast side.

Xu Yun first glanced at the sky, and after confirming that there was no sign of rain, he turned to Ziegfried and asked:

"Master Qi, how is the preparation of the equipment?"

Siegfried wiped the sweat from his forehead, evened his breath, and said:

"Prince Wang, don't worry, Xiao Lao took people to check it several times yesterday, and tried to start it once. Everything is normal."

Xu Yun glanced at the blast furnace again, and said:

"That's good, Master Qi, this equipment is the core of our research and development this time, and it is the root of the fat man's ears, the most important thing."

"So thank you for your hard work these days, and there must be no mistakes."

Siegfried immediately raised his chest when he heard the words, and said energetically:

"Don't worry, I'll be living here these days, I won't go anywhere, I promise to complete the task!"

Xu Yun nodded in reassurance.

In this construction process, two links with the same name are indispensable:

One is donkey.

The second is aluminum.

That's right.

aluminum.

Aluminum and aluminum alloys are currently the most widely used aircraft manufacturing materials.

well known.

After adding a small amount of Cu and Mg to ordinary aluminum, a kind of MgCu2 tiny grains called Lavis phase will be formed inside the aluminum.

Its dispersion in aluminum can increase the hardness and reduce the ductility of aluminum, forming the so-called "hard aluminum", which is an important material for manufacturing aircraft body and engine casing.

Of course.

From the perspective of convenience, the engine can actually be barely dealt with with cast iron.

After all, cast iron engines are quite common in later generations, and the cost will be lower.

However, considering the technical level of the Song Dynasty, the performance of the machine body has been reduced a lot, and it has reached a very crude level.

Therefore, out of performance considerations, Xu Yun is still planning to design with a combination of aluminum + ceramics to enhance some stability.

But in this way, a problem arises:

Aluminum is an extremely rare metal in ancient times, and it is difficult to find aluminum in nature.

Follow normal history.

It was not until 1827 that Weller in Germany co-heated potassium and anhydrous aluminum chloride to produce metal aluminum.

The method of producing aluminum in later generations mainly relies on electrolysis, that is, cryolite-alumina molten salt electrolysis.

Among them, molten cryolite is the solvent and alumina is the solute.

The carbon body is used as the anode, and the aluminum liquid is used as the cathode.

Metal aluminum can be produced at 950°C-970°C after a strong direct current is applied.

However, this approach requires a large amount of direct current, and also requires a series of accompanying links.

In terms of the power of the generator produced by Xu Yun's hands, this effect cannot be achieved at all.

So on second thought, he eventually decided to make aluminum another way.

This process is based on the smelting of copper and iron, and requires the use of copper, carbon and bauxite.

Its main chemical reaction formula is:

3Cu+Al2O3=3CuO+2Al at high temperature.

CuO+C = Cu+CO in a closed environment.

Seeing this, some students may be surprised.

its not right.

This is a reaction formula that violates modern chemical theory, right?

Because the chemical properties of aluminum are much more active than copper, it is impossible for aluminum to lose oxygen atoms and give oxygen atoms to copper, so this reaction formula is completely wrong.

Actually.

This reaction has a precondition:

Put copper and Al2O3 in a closed high-temperature-resistant container without free oxygen, and heat it up to the boiling point of aluminum.

At this time, a very small amount of Al2O3 can instantly lose oxygen and become aluminum vapor, and escape in time from the surface of the mixture of copper and alumina in a molten state.

At this time, the copper in the molten state will have to accept oxygen and become copper oxide.

Therefore, if the small channel above the airtight container can be opened in time, the aluminum vapor can flow to another airtight container without oxygen without losing the opportunity, and then the aluminum in the elemental state can be obtained by cooling down.

Considering that the boiling point of aluminum is 2467°C, which is far higher than the 1600°C of the iron-making blast furnace, Xu Yun used ethanol to produce acetylene these days.

You see, the original alcohol and hydrochloric acid are useful again.

The line of sight returns to reality.

After everything is ready.

Xu Yun looked at Siegfried and said:

"Master Qi, let's start."

Siegfried nodded to him, went to the stove himself, and lit a fire against the low arched entrance.

The oxygen for the combustion of acetylene still comes from the industrial production of heating potassium permanganate as in iron making.

Acetylene can reach 3600 degrees when burned in oxygen, so soon, aluminum vapor is produced in the equipment.

Under the guidance of the self-priming pump invented by Lao Su, the aluminum vapor rises into the channel, and there are ice cubes around the channel to cool down.

Don't ask where the ice cubes come from, do you still remember the sour plum soup?

About half an hour later.

As the reaction progressed, another container emerged, which is extremely rare for this era

metal aluminum.

However, the current metal aluminum is only a small group, which is far from what Xu Yun needs.

So after handing over the scene to Siegfried.

Xu Yun took his leave and left, and came to another courtyard of the Equipment Manufacturing Bureau.

Someone said yesterday that hand rubbing generators are ridiculous, but the problem is that I have really rubbed them with my hands.

I have written the principle and the preparation process of the materials so clearly, it’s okay to say I’m nonsense, but at least I’ll tell you where.

Some people open their mouths to say that the plot is nonsense, and tell them to say where there is a problem but they can’t say it. Co-authoring any concept that exceeds their own cognition is bullshit?

The two readership groups add up to more than 1,000 readers, four or five PhDs, and twenty or thirty graduate students. They often chat with me privately to discuss some issues.

I dare not say how good my writing is, but at least I can guarantee that the knowledge I output is correct, otherwise this book will not have the current results.

Speaking of grades, let me tell you by the way, this book has already been ordered for 6,500, and it has increased by 1,000 this month~