In the 21st century.

Due to some industry barriers, whenever people mention engines, they often think of them in a grand and upscale way.

But in reality.

In some model aircraft circles, making your own aircraft engine is not a very rare thing, funding is positioned behind technology.

Take DIY turbojets for example.

A quick search on Bilibili will yield a lot of related videos, and some geek websites still have some data left.

The number of engines made at home by many amateur scientists can fill half a room.

Of course.

Some may ask why DIY engines are so prevalent?

This cannot be explained without mentioning a source of all evil:

Kurt Schreckling.

In early 1998.

This engineer-level enthusiast, after countless failures, finally got his first designed turbojet engine to successfully operate and it even proved effective in actual combat.

Thus.

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

In it, he disclosed the specifications of an engine named FD3-64, which became the ancestor of all future DIY engines.

Since then, the process of making engines was pretty much set.

Like a fishing rod.

With the development of the fishing industry over the years, how to install the reel, string up the line, and bait the hook are all standard routines.

The only differences are whether to use a baitcasting reel or a spinning reel, what line to use, and whether to use five grams or ten grams of bait, and which market to buy fish from if you come back empty-handed, just "parameter calculations" really.

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 before, Xu Yun's goal is very practical and he doesn't intend to leap ahead:

Firstly, the engine he designs won't immediately reach mass production level.

Secondly, the intended use for this aircraft is precisely for the enthronement ceremony, and its lifespan is only a few dozen hours.

No need to consider long-term durability, long-term deformation, popularization processes, or production line manufacturing.

With Xiaozhao's support, creating an engine with the power of the whole country is not a fantasy.

As for the engine that Xu Yun wants to design this time...

It is a rotary engine. (Note: Yesterday, I got the thrust calculations mixed up and inadvertently wrote down the bypass ratio, causing some friends to think it was a turbofan...)

The rotary engine, also called the radial engine, actually belongs to a type of piston engine.

However, unlike inline piston engine blocks.

The rotary type is where the engine block rotates around the output shaft, while the block of an inline piston engine is fixed relative to the output shaft.

The engine template that Xu Yun designed this time is the CJ-6, which is a radial air-cooled 9-cylinder engine.

However, some aspects have been optimized so that all aspects are slightly higher than pulse jet engines, such as increased impeller curvature, etc.

Specific parameters are as follows:

Compression ratio: 6.1±0.1.

Main connecting rod strength ratio: 1.0032

Operational status: 2370 rpm

Piston stroke: 130mm

Advanced ignition angle: 29±2°

Maximum gas pressure value: 57.2 kg/cm².

Connecting rod length: 235mm

Crankshaft rotation radius: 63mm

Piston diameter: 105mm.

Crankshaft offset angle at maximum pressure: 13° (assuming the time from gas explosion to maximum value is 4/1000, stage 1 accounts for 12%, pressure rise accounts for 20%, the other dead point is 11°, I took the high value, by the way, this is a parameter from an engine I hand-built 9 years ago, tried in practical combat)

Of course.

Parameters are just parameters, they are just a small part of the whole design process of the machine.

There are also some data that Xu Yun cannot complete alone.

For example, cross-sectional thrust, reflection wave pressure of the vertical plate, etc.

This is why.

He sought the help of Old Jia and others through Xiaozhao.

Scientific research has never been a one-person affair.

.....

One night a week later.

On an open area in the Artifact Bureau.

At this moment, in the center of the open area, there stood a blast furnace similar to those used for smelting iron, about four meters high.

A pipeline was connected to the side of the furnace, on which was Old Su's self-invented self-priming pump.

Beside the blast furnace.

Xu Yun first looked at the sky to ensure there were no signs of rain, then turned to ask Siegfried:

"Master Qi, how's the equipment preparation going?"

Siegfried wiped the sweat from his forehead, steadied his breath, and replied:

"Mr. Wang, rest assured, I thoroughly checked it with the team yesterday, even tried to start it once, everything is perfectly normal."

Xu Yun glanced at the blast furnace again and said:

"That's good, Master Qi, this equipment is the core of our research this time, as significant as ears to a fat man, extremely crucial."

"Therefore, I entrust you to be extra diligent these days, ensure there are no mistakes."

Siegfried responded immediately with a puffed chest, full of energy:

"Rest assured, I'll be staying here and won't go anywhere until the task is done!"

Xu Yun finally nodded with relief.

In this construction process, there are two essential aspects with the same name:

One is "donkey."

The other is "aluminum."

That's right.

Aluminum.

Aluminum and aluminum alloy are the most widely used materials in aircraft manufacturing today.

As everyone knows.

By adding a small amount of Cu and Mg into ordinary aluminum, a type of MgCu2 microscopic grain called the Laves phase forms inside the aluminum.

These grains, dispersed through the aluminum, increase its hardness and reduce its ductility, creating what is known as "hard aluminum," an essential material for constructing aircraft hulls and engine casings.

Of course.

From a convenience standpoint, engines can actually make do with cast iron to some extent.

After all, cast iron engines are quite common in later years and also cheaper.

But considering the technical level of the Song Dynasty, the performance of the hull is already quite reduced, down to a very rudimentary level.

Hence, from a performance perspective, Xu Yun still planned to design with an aluminum-ceramic combination to enhance stability.

However, by doing so, a problem arises:

Aluminum is an extremely rare metal in ancient times, and it's hard to find pure aluminum in nature.

According to historical records.

It wasn't until 1827 that Germany's Weller produced metallic aluminum by coheating potassium and anhydrous aluminum chloride.

The modern method for producing aluminum primarily relies on electrolysis, specifically the cryolite-alumina molten salt electrolysis method.

In this process, molten cryolite acts as the solvent, and alumina as the solute.

Carbon bodies serve as the anode, and liquid aluminum as the cathode.

With the passage of strong direct current, metal aluminum can be extracted at temperatures between 950°C and 970°C.

However, this process requires a substantial amount of direct current and a series of auxiliary steps.

Considering the power output of the generator manually created by Xu Yun, it cannot achieve this.

Therefore, after considerable thought, he decided to use an alternative method to produce aluminum.

This technique is derived from copper and iron smelting, using copper, carbon, and bauxite.

Its primary chemical reaction equation is:

At high temperature, 3Cu+Al2O3=3CuO+2Al.

In a sealed environment, CuO+C = Cu+CO.

At this point, some students might find it strange.

No way.

Isn't this a reaction equation that contradicts modern chemistry theory?

Because the chemical properties of aluminum are far more active than copper, aluminum cannot lose oxygen atoms and give them to copper, so this equation is entirely wrong.

Actually.

This reaction has a prerequisite condition:

In a sealed high-temperature-resistant container without free-state oxygen, copper and Al2O3 are placed inside, and heated until the temperature rises to the boiling point of aluminum.

At this point, a minimal amount of Al2O3 can instantly lose oxygen and turn into aluminum vapor, promptly detaching from the surface of the molten copper-oxide mixture.

The copper in the molten state is then forced to accept oxygen and become copper oxide.

So, if the small channels on top of the sealed container are opened promptly, allowing aluminum vapor to flow to another oxygen-free sealed container, cooling it results in the pure state of aluminum.

Considering that aluminum's boiling point is 2467°C, far exceeding even the 1600°C of iron smelting blast furnaces, Xu Yun used ethanol to produce acetylene these days.

You see, the initial alcohol and hydrochloric acid finally found their use.

Returning to reality.

Once everything was ready.

Xu Yun looked at Siegfried and said:

"Master Qi, let's begin."

Siegfried nodded to him and personally walked to the furnace, lighting it at the low arch entrance.

The oxygen for burning acetylene still comes from the industrial production of heating potassium permanganate, just like in iron smelting.

Acetylene burning in oxygen can reach 3600°C; therefore, soon, aluminum vapor began to be produced in the equipment.

Guided by the self-priming pump invented by Old Su, the aluminum vapor rose into the channel, surrounded by ice blocks for cooling.

Don't ask where the ice blocks came from; remember the sour plum soup earlier?

About half an hour later.

As the reaction proceeded, an extremely rare substance of this era appeared in another container...

Metallic aluminum.

However, the current metallic aluminum amount is just a small mass, far from meeting Xu Yun's requirements.

Thus, after handing over the site to Siegfried,

Xu Yun excused himself, heading to another courtyard of the Artifact Bureau.

......

Note:

Remember what I said at the beginning? Every appearing item will be used in the end phase; this is why the protagonist had to go through so much trouble earlier. My goodness, holding it all in was tough...

There will be another chapter later on, a bit delayed.

If you find any errors ( broken links, non-standard content, etc.. ), Please let us know < report chapter > so we can fix it as soon as possible.