Reborn in 2011, I am the chief designer of aerospace.

Song Xingye thought of a kind of "homemade fuel" that he had played with in high school.

At that time, he ground the potassium fertilizer into a fine powder, mixed it into heated and melted white sugar, and then cooled and solidified it into medicine columns.

Using this rudimentary fuel, his first small rocket soared more than a thousand meters into the air.

So Song Xingye put Cao Que in charge of collecting data and took Jiang Mian to test this fuel combination.

However, since it is located in the Nanyuan assembly plant, the raw materials naturally need to be upgraded.

The sugar was replaced with sorbitol, which has a lower melting point, and the potassium fertilizer, which serves as an oxidant, was upgraded to potassium nitrate.

The two set up a small pot and carefully coated the potassium nitrate powder with the heated and melted sorbitol.

After the amber-colored viscous slurry was poured into the modified steel pipe and cooled and solidified, a respectable solid fuel propellant column was born.

They found a small test bench, fixed the steel pipe on it, and tested it.

"3, 2, 1—Ignition!"

As the electric current broke down the fuse, the solid propellant inside the steel pipe burst into flames.

Crimson flames erupted, accompanied by billowing blue smoke, instantly filling the air with a unique, sweet, caramel-tinged aroma of gunpowder.

The instruments connected to the test bench quickly collected data, and Song Xingye asked Jiang Mian to perform the calculations.

Jiang Mian retrieved the ignition test form.

This record shows the jet velocity of the exhaust gas as it leaves the steel pipe, as well as the changes in propellant mass before and after the experiment.

Based on this data, ginger can obtain a lot of useful information, such as calculating the thrust and combustion rate of this formula based on the exhaust speed.

The two most crucial pieces of information are specific displacement and thrust-to-weight ratio.

The former is similar to a car's fuel consumption, which is the duration for which one kilogram of fuel produces one kilogram of thrust.

The latter is similar to the explosive power of a car, which is the ratio of engine thrust to its own weight.

Jiang Mian held a notebook, substituted the data from the experimental statistics into four intricate equations, and almost in the blink of an eye, effortlessly calculated the answer Song Xingye wanted.

"A 120-second burst, but a thrust-to-weight ratio of only 5:1." Jiang Mian shook her head. "Too weak. Our rockets will probably break down almost as soon as they leave the ground..."

Cao Que, standing nearby, exclaimed in astonishment, "Girl, tell me quickly, where did you hide the calculator? Is it in your pocket?"

Song Xingye smiled faintly, "Old Cao, don't make a fuss. This is a mini-Chen Jingrun; this kind of arithmetic is child's play for her!"

"Holy crap?"

Cao Que immediately looked at Jiang Mian with newfound respect, scrutinizing her like a panda, making the girl blush. She clicked her tongue in amazement and said, "You're quite the hidden talent! I knew everyone who gets into the Starry Sky Summer Camp is a shrewd operator, right?"

"Alright, stop joking. Since the sorbitol and potassium nitrate formula isn't working, let's try something even more potent—ammonium nitrate..."

Song Xingye offered his suggestion from the side.

"Ammonium nitrate?" Cao Que's eyelids twitched. "That stuff is used to make explosives. Can our little rockets withstand that kind of firepower?"

"Let's give it a try and see how high the specific thrust and thrust-to-weight ratio can be."

Under Song Xingye's arrangement, the new test was immediately launched.

After obtaining the test data, Jiang Mian performed calculations in her notebook. She navigated the equations with the ease and fluency of someone putting on shoes.

However, the result was not optimistic. The thrust-to-weight ratio soared to 20:1, far exceeding the structural strength limit of the small rocket.

To use this formula, the shell thickness would need to be increased, which goes against the original intention of "lightweight and low cost".

The three had no choice but to abandon their previous approach and instead start thinking about other recipes.

This 10-kilogram "simulated rocket," cobbled together from cheap auto parts, is like a picky monster.

We must find the perfect feed that can both launch it into the sky and keep it burning for tens of seconds!

The next few days were a long and tedious period of trial and error.

To date, there are at least dozens, or even hundreds, of feasible fuel formulations, making this work extremely time-consuming and labor-intensive.

Jiang Mian's slender fingers developed thin calluses from the intense calculations and recording.

Song Xingye would sometimes discuss things with her, searching for answers together among the dense numbers and tables.

If someone discovers a silly, incorrect equation, the other person will mercilessly laugh at the other's calculation flaws.

However, the three of them also gained a lot in the process. Song Xingye used an acetylene gun for the first time to weld a nickel steel nozzle onto their little rocket. He also learned how to bend an aluminum alloy sheet with a hammer, pliers, and an anvil to make his own tail fin.

During the testing of the fuel formula, the overall structure of the small rocket was also continuously improved.

Compared to the rudimentary first-generation rocket from a few days ago, it is now fully functional. Song Xingye even applied a layer of graphite protective coating to the combustion chamber, which was modified from a sewage valve.

Graphite has a melting point as high as 3,500 degrees Celsius, which can effectively prevent high-temperature deformation during combustion. It is inexpensive and highly effective.

Of course, there were also many unexpected events that even Song Xingye couldn't handle.

For example, when the "Wild Donkey No. 1" was testing some solid fuels, it would shake violently, or the seal of the exhaust valve would be blown open, the exhaust pipe would crack several times, or the nickel steel nozzle would simply melt off.

However, Song Xingye quickly came up with various countermeasures.

For example, replacing the original automotive aluminum manifold with a manifold made of aerospace-grade chromium-nickel-iron alloy can help it withstand extreme temperatures.

There are also some problems he can't solve, such as the flash memory driver for remote-controlled rocket ignition often malfunctioning. That's when Cao Que will jump out and show off.

In short, everything is moving in a positive direction.

……

That morning, just as dawn was breaking.

With dark circles under their eyes, the three hurriedly placed a gleaming steel pipe onto the test bench.

After conducting a water injection test on the steel pipe, they confirmed that there were no cracks or leaks inside caused by the previous ignition, then stirred the fuel and injected it into the pipe.

After the propellant column was formed, ignition began.

Song Xingye led the two men to hide behind a sandbag bunker, their three pairs of eyes fixed on the steel pipe, holding their breath.

"ignition!"

boom--

In an instant, a raging fire dragon roared out of the nozzle with astonishing force.

This time, everyone finally saw hope.

Judging from the ignition effect, the formula used in this experiment was quite rapid.

Jiang Mian believes this is the best result achieved so far.

The steel pipe was fixed to the test stand, and the internal propellant burned for more than a minute, making a loud noise that quickly attracted a group of students to watch.

Xu Zhe came over, patted his arm, and asked, "What are you guys doing? Why are you making such a commotion?"

Cao Que chuckled and stepped in front of him, "Old Xu, it's not very polite of you to come and spy on military intelligence in broad daylight. You should at least wait until the middle of the night."

Jiang Mian, who was standing to the side, smiled and squinted her eyes.

Song Xingye calmly crossed his arms and said, "In short, it's a propellant formula you'd never expect. You'll find out in a couple of days."

Xu Zhe didn't ask any further questions and left with a belly full of doubts.

Once the onlookers dispersed, the three could no longer contain themselves and excitedly clapped and cheered, their faces showing expressions of relief.

After much trial and error, they finally found a formula that could propel their "cheap Toyota" into the air.

A type of fuel that Xu Zhe could never have guessed, no matter how hard he tried.

asphalt!

That's right, it's the asphalt used for paving roads.

Using this dark, cheap raw material to send rockets into space sounds like a fantasy, but Song Xingye did it.

Everything has returned to the way it was at the beginning.

Based on the combination of sorbitol and potassium nitrate, Song Xingye boldly replaced sorbitol with pitch and potassium nitrate with potassium perchlorate, thus obtaining a series of relatively ideal specific impact and thrust-to-weight ratio data.

The test results just now prove that the formula proposed by Song Xingye is quite perfect!