72: Chapter 72 Working through the night, overcoming all the technical difficulties of steam tractors!

While Zhao Fusu organized people to produce hexagonal boron nitride, the components of the steam rotary tiller were all manufactured under the division of labor within Elder Mo's Team.

Since the parts were made using the lost-wax method, their precision was quite high.

After lightly polishing the components, they proceeded with the installation.

Watching the steam rotary tiller, full of medieval character, being assembled, Zhao Fusu couldn't help but step forward to touch its silver-textured body.

The body of this steam rotary tiller was entirely forged from steel.

The open-hearth furnace in the Forging Workshop had a volume of sixty-four cubic meters.

The density of molten steel is approximately 7.8 tons per cubic meter.

A single batch of molten steel weighed five hundred tons.

The Forging Workshop did not lack steel these days.

Therefore, except for the piston which was made of cast iron, all other parts of the steam rotary tiller were forged from steel.

Elder Mo had people add water to the boiler of the steam rotary tiller and ignite the coal in the furnace.

The water in the boiler boiled, producing a large amount of steam.

Under the power of the steam, the piston was pushed, and the crankshaft and connecting rod moved accordingly, driving the flywheel to rotate.

The flywheel then transmitted mechanical energy to the drive shaft through gears.

Rotary tiller blades were arranged on the drive shaft.

Driven by the power, the rotary tiller blades rotated while the entire unit moved forward in a straight line.

Most of the floor in the Forging Workshop was made of earth.

However, after being compacted with wooden piles, the earthen floor was very hard.

Yet, the blades of the steam rotary tiller could easily turn over the soil!

"Good, good, very good!"

Elder Mo said joyfully, "With this steam rotary tiller, plowing the land will become simple for farmers."

"Yes."

After Zhao Fusu nodded, he asked, "Elder Mo, you didn't use cast iron for the molds because it's difficult to demold, right?"

"That's right."

Elder Mo nodded and said, "The molten liquid we pour into the mold assembly would bond with the metal mold, making it impossible to demold."

"I've already sent people to make a release agent."

"As long as the release agent is evenly applied inside the metal mold, the hot-forged metal can be easily removed from the mold."

Zhao Fusu said with a smile, "For mass-produced products, we will use metal molds in the future."

"Is that truly so!"

Elder Mo's eyes lit up upon hearing this.

If that were the case, then hot-melt parts could be molded quickly.

The production efficiency of steel swords could also be greatly improved.

A single batch of molten steel was five hundred tons, yet the daily production capacity of steel swords was only a few thousand; it was because too much time was wasted on making the molds for the swords.

"Yes."

Zhao Fusu nodded.

"Alright!"

Elder Mo continued his research on the steam thresher.

This was also relatively simple.

Leading his technical team, Elder Mo didn't take long to manufacture the steam thresher.

As for the steam tractor with one hundred and fifty horsepower and a maximum torque of 3690 Nm, the manufacturing difficulty was much higher.

The sky had already grown dark.

After Elder Mo hurriedly ate dinner, he began to study the steam tractor.

To speed up the research and development process, he had other Mohist craftsmen forge the four iron wheels and the Steam Engine head first.

Elder Mo focused his research on the steering and braking systems.

Without power assistance for the steering system, it would not be easy to turn a tractor weighing several tons just by hand.

To build the steam tractor as quickly as possible, Zhao Fusu and Elder Mo studied power assistance methods for the steering system together.

In the steam tractor design blueprints provided by the system, the steering assistance used hydraulics.

Hydraulic oil is generally refined petroleum, but vegetable oil can also be used.

Great Qin had vegetable oil.

The principle of hydraulics is the same as that of a jack: Force equals Pressure multiplied by the Surface Area.

Under the same pressure, the larger the surface area, the greater the force.

In a jack's hydraulic system, there are two pistons of different sizes. When a small force is applied to the small piston, it generates a certain pressure, which is transmitted to the large piston through the hydraulic oil.

With a constant pressure, the large piston has a large area, so it can generate a lifting force much greater than the force applied to the small piston.

Once the steering system used hydraulic assistance, the steering wheel would become much lighter.

In the braking system, a thick brake shoe made of steel was placed close to the wheel.

When braking, a brake screw would force the brake shoe to press tightly against the wheel.

Zhao Fusu also studied the safety valve with Elder Mo.

If the steam pressure inside the boiler became too high, the boiler would explode.

Zhao Fusu had seen photos of steam boilers after they exploded; the entire boiler was twisted like dough.

The operator would be blown directly into countless pieces of shredded meat.

Safety was something Zhao Fusu always paid attention to.

The safety valve of the Steam Engine operated on the lever principle, controlling the opening pressure through the position and weight of a counterweight.

One end of the lever was connected to the counterweight, and the other end to the valve core. When the force exerted by the steam pressure on the valve core exceeded the pressure applied by the counterweight through the lever, the valve core would be lifted, and steam would be discharged. By adjusting the distance of the counterweight from the lever's fulcrum, the opening pressure of the safety valve could be changed.

Considering that after the steam tractors were widely used, the safety valves might malfunction and the users might not know.

Zhao Fusu suggested to Elder Mo to add a pressure gauge.

The maximum working pressure of the Steam Engines they produced was typically 0.784 MPa.

Converted to pressure units, that is 7.84 kg per square centimeter!

Exceeding this pressure meant the boiler might explode.

How to make a pressure gauge was another difficult problem for Zhao Fusu.

The night grew very deep.

Neither Zhao Fusu nor Elder Mo could sleep as they researched how to make a pressure gauge.

The design blueprints for the steam tractor did explain how to make a pressure gauge, but understanding how to actually do it was not easy.

Zhao Fusu took a sip of strong tea to refresh himself.

The working principle of a steam pressure gauge is based on measuring pressure through the deformation of an elastic element under pressure. It measures the pressure in the steam system.

The core component of a steam pressure gauge is the Bourdon tube, which is a curved hollow tube, closed at one end and connected to the steam at the other.

When steam pressure enters the tube, the Bourdon tube undergoes elastic deformation, and the amount of deformation is proportional to the steam pressure.

This deformation is amplified through a transmission mechanism such as levers and gears, and finally, the pressure level is displayed by a pointer on a dial.

As long as the operator saw the working pressure of the steam boiler reach the red line of 0.784 MPa, if the safety valve did not automatically release pressure, they would have to release it manually.

Time passed quickly during their research; it was clearly just dark a moment ago, but when they looked up, the sky was already turning white.

They had researched for the entire night!

Both Zhao Fusu's and Elder Mo's eyes were bloodshot.

But their faces were full of excitement.

After a night of hard work by lamplight, they had overcome all the technical difficulties of the most difficult steam tractor.

Building the steam tractor was now only a matter of time.