Due to some industry barriers, many people often think of it from a high-level perspective when it comes to engines.
But in fact.
In some aircraft model circles, homemade aero-engines are not a very unusual thing, and capital is always ranked ahead of technology.
Such as homemade turbojet.
There are a lot of related videos on Bilibili, and some geek websites still leave some data.
The number of homemade engines in many civilian homes can fill up half a room.
Of course.
Some people may ask, why are DIY engines so popular?
This has to be said as the source of all evil:
pantsrtShrekling.
In early 1998.
After countless failures, this engineer-level enthusiast finally allowed the first turbojet engine he designed to run successfully and have practical effects.
Ever since.
At that time, he published a book called "Gastur Bi Ne Engine For Air Raft Mo Del", which is called Aircraft Model Jet Engine in Chinese.
Among them, he published the parameters of an engine named FD3-64 in his book, and this engine became the ancestor of all future DIY engines.
Since then, the process for making homemade engines has been pretty much set in stone.
Just like a fishing rod.
With the development of the fishing industry, nowadays, the routines of how to install fishing reels, string hanging lines, and tie baits are all fixed.
The only difference is the drip wheel or the spinning wheel, which number of threads to put on, five grams or ten grams of bait, and which wet market to buy fish after the Air Force. These are just "parameter calculations".
True.
The industrial level of later generations was much higher than that of the Song Dynasty. For example, five-axis CNC machining centers and wire cutting were difficult to achieve.
But on the other hand.
As mentioned before, Xu Yunding's goals are very practical and he does not expect to reach the sky in one step:
First of all, the engine he designed will not reach mass production level in one step.
Secondly, this aircraft is intended to be used for the coronation ceremony, and its lifespan is only a few dozen hours.
There is no need to consider long-term durability, long-term deformation, popular processes and production lines.
With the support of Xiao Zhao, it is not unreasonable for a whole country to build an engine.
As for the engine Xu Yun is going to design this time?
It is a rotary cylinder engine. (Note: I was confused yesterday when calculating the thrust, so I wrote down the bypass ratio, which led some friends to think that I was going to build a turbofan)
A rotary engine, also called a radial engine, is actually a type of piston engine.
But it is different from the in-line piston engine block.
The rotary cylinder engine block rotates around the output shaft, while the inline piston engine block is fixed relative to the output shaft.
The engine template Xu Yun designed this time is Chujiao 6, which is a star-shaped air-cooled 9-cylinder engine.
However, it has been optimized in some aspects and is higher than the pulse jet engine in all aspects, such as increasing the curvature of the impeller, etc.
The specific parameters are as follows:
Compression ratio: 6.1±0.1.
Main connecting rod strength ratio: 1.0032
Working status: 2370rpm
Piston stroke: 130mm
Advance ignition angle: 29±2°
Maximum gas pressure value: 57.2kg/cm2.
Connecting rod length: 235mm
Neck rotation radius: 63mm
Piston diameter: 105mm.
Crankshaft deflection angle at the maximum pressure moment: 13° (Suppose the time from the beginning to the maximum of the gas explosive force is 4/1000, the first stage accounts for 12%, the pressure increase accounts for 20%, and the other dead center is 11°, I took the larger
Worth it, by the way, these are the parameters of an engine that I rubbed by hand 9 years ago and have actually tested)
Of course.
Parameters are parameters, and this is just a small part of the entire body design process.
There are also some data that cannot be completed by Xu Yun alone.
For example, cross-sectional thrust, reflected wave pressure from a vertical plate, etc.
Therefore.
Only then did he ask Xiao Zhao for help from Lao Jia and others.
Scientific research is never a matter of one person
One week later.
A vacant lot in the Manufacturing Bureau.
At this moment, there was a blast furnace similar to iron-making standing in the center of the open space, about four meters high.
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.
Beside the blast furnace.
Xu Yun first glanced at the sky to make sure there was no sign of rain, then turned to Siegfried and asked:
"Master Qi, how is the equipment prepared?"
Siegfried wiped the sweat from his forehead, calmed his breath, and said:
"Young Master Wang, don't worry. I checked it several times yesterday and tried to start it up once. Everything is normal."
Xu Yun looked at the blast furnace again and said:
"That's good, Master Qi. This equipment is the core of our research and development this time. It is the ear root in Fatty, the most important thing."
"So I thank you for your hard work these days and make sure nothing goes wrong."
When Siegfried heard this, he immediately puffed up his chest and said energetically:
"Don't worry, I'll be living here these days. I won't go anywhere. I promise to complete my mission!"
Xu Yun then nodded with relief.
In this construction process, there are two links with the same name that are indispensable:
One is the donkey.
The second is aluminum.
That's right.
aluminum.
Aluminum and aluminum alloys are currently the most widely used aircraft manufacturing materials.
As we all know.
After adding a small amount of Cu and Mg to ordinary aluminum, a type of MgCu2 microcrystalline grain called the Ravis phase will be formed inside the aluminum.
Its dispersion in aluminum can increase the hardness and reduce the ductility of the aluminum material, forming so-called "hard aluminum", which is an important material for manufacturing aircraft fuselages and engine casings.
Of course.
From the perspective of convenience, the engine can actually be made of cast iron.
After all, cast iron engines are quite common in later generations, and the cost will be lower.
However, considering the technological 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, for performance reasons, Xu Yun is still planning to design with a combination of aluminum + ceramics to enhance some stability.
But then, a question arises:
Aluminum is an extremely rare metal in ancient times. It is difficult to find aluminum in nature.
According to normal history.
It was not until 1827 that Weller in Germany heated potassium and anhydrous aluminum chloride to produce metallic aluminum.
The method of producing aluminum in later generations mainly relied on electrolysis, that is, the cryolite-alumina molten salt electrolysis method.
Among them, molten cryolite is the solvent and aluminum oxide is the solute.
The carbon body is used as the anode and the aluminum liquid is used as the cathode.
After passing strong direct current, metal aluminum can be produced at 950℃-970℃.
However, this approach requires a large amount of direct current and a series of accompanying links.
Judging from the power of the generator that Xu Yun hand-made, it is impossible to achieve this effect.
So after much thought, he finally decided to use another way to make aluminum.
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:
At high temperature, 3Cu+Al2O3=3CuO+2Al.
CuO+C=Cu+CO in a closed environment.
Seeing this, some students may be surprised.
its not right.
Is this a reaction formula that violates modern chemical theory?
Because the chemical properties of aluminum are far more reactive than copper, it is impossible for aluminum to lose oxygen atoms and give oxygen atoms to copper, so this reaction equation is completely wrong.
Actually.
This reaction has preconditions:
In a sealed, high-temperature-resistant container without free oxygen, put copper and Al2O3 in it and heat it to raise the temperature to the boiling point of aluminum.
At this time, a small amount of Al2O3 can instantly lose oxygen and turn into aluminum vapor, which can escape from the surface of the molten copper and alumina mixture in time.
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 be flowed into another airtight container without oxygen without losing the opportunity, and then the temperature can be lowered to obtain aluminum in the elemental state.
Considering that the boiling point of aluminum is 2467°C, which is far higher than the 1600°C of an iron-making blast furnace, Xu Yun has used ethanol to produce acetylene these days.
You see, the initial alcohol and hydrochloric acid are useful again.
His eyes returned to reality.
After everything is ready.
Xu Yun looked at Siegfried and said:
"Master Qi, let's get started."
Siegfried nodded to him, walked to the stove himself, and lit a fire toward the low arch entrance.
The oxygen used for burning acetylene is still the same as when making iron, which is produced industrially by heating potassium permanganate.
Acetylene can reach 3600 degrees when burned in oxygen, so soon aluminum vapor will be produced in the equipment.
The aluminum vapor rises into the channel under the guidance of the self-priming pump invented by Lao Su, and the channel is surrounded by ice cubes for cooling.
Don’t ask where the ice cubes came from, do you still remember the original sour plum soup?
About half an hour later.
As the reaction progressed, something extremely rare in this era appeared in another container.
Metal aluminum.
However, the current aluminum metal is only a small lump, which is still far from what Xu Yun needs.
Therefore, after handing over the scene to Siegfried.
Xu Yun then said goodbye and left, arriving at another branch of the Manufacturing Bureau.
Note:
Do you still remember what I said at the beginning? Every item that appears will be used in the final stage. This is why the protagonist has such troublesome answers in front of me. Oh my god, it kills me.
There’s another chapter to come, it’ll be later.
Yesterday, someone said that rubbing a generator with your hands is ridiculous, but the problem is that I have actually rubbed it with my hands.
I have written down the principles and the process of making the materials so clearly. It’s okay to say I’m talking nonsense, but at least I should explain where I’m talking nonsense.
Some people just say that the plot is bullshit, and they can’t point out what’s wrong with it. Any concept that exceeds their own knowledge is bullshit?
The two reader groups combined have more than a thousand readers, four or five Ph.D.s, 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 ensure that the knowledge I output is correct, otherwise this book would not have the results it has now.
Speaking of results, let me tell you by the way, this book has been ordered for 6,500 yuan, which has increased by 1,000 this month~