"You make so much sense, I'm speechless!"

Clea really can't fault Rain Spirit's statement, after all, there are really not many places where TNT is needed right now.

What! (╯"□′)╯(┻━┻Obviously there is no TNT, so I have been using a substitute! I was almost fooled by this guy Yuling!

"Well~ don't be so irritable, anyway, when the new round of expansion plan is completed, you will be able to have free capacity to build this." Yu Ling said helplessly, this is also the cost of TNT that suddenly came to mind...... It is one of the lowest explosives and the most widely used!

"Okay...... It's a defeat for you, and it will take seven months to complete all those plans. ”

"It's a time of war, there's no way."

Looking at the ammunition applications of the various units in his hand, Yu Ling felt a headache.

Not to mention the new TNT factory, it's a bit reluctant to even replenish ammunition now...... Seventy percent of the machine's production capacity is used to expand the ammunition plant, but it will take at least three months to fully meet the ammunition consumption.

"When will we be like the German artillery in World War I, smashing three million shells into it in five hours!"

"There is also the production of grenades and gun grenades, don't just focus on artillery shells, when soldiers fight, they don't rely on artillery shells."

"And guns, to be honest, I want to get a shotgun, it seems that the threshold for development is very low."

"Hmm...... The Air Research Institute has arrived. ”

"Boss, the balloon you want can already fly."

Yu Ling looked at her in surprise, the production of hydrogen balloons is not such a simple matter, it can fly so quickly?

Looking along the place where she came from, there was indeed a balloon more than thirty meters long floating dozens of meters above the ground in the distance, and it was indeed successful.

This balloon is quite dangerous, after all, it is the hydrogen used...... But the preparation of helium is too troublesome, not to mention whether to find natural gas containing 7% helium. Even the process of separating helium, she didn't have ...... This outdated and dangerous gas can only be used temporarily.

"That's good, but can it be folded and put in a box?"

The material of the balloon doesn't look as soft as I've seen before.

"Yes, though, the box might be a little bigger."

As she spoke, Liu Yuxin pushed up a "slightly large" box......

Rain Ling's eyes straightened...... A box eight meters long, three meters wide, and two meters high...... You actually say it's just a little big?!

"To change the material, the tethered balloon must be portable, otherwise, it will not have much tactical value, and it is best to pack it in a one-meter square box."

"But that's the only fabric we can do without leaking."

Liu Yuxin said helplessly, in order to make a balloon, they have already thought of a lot of ways, yesterday until now I tried all the fabrics to find a kind of air that will not leak, and now she also asks to change the material, she can only say that the concubine can't do it.

Yu Ling looked at Claya, although he had the impression that the balloons were made of synthetic materials such as nylon, but since the tethered balloons came out before 1918, the matching cloth must also be counted before 1918.

"Well, there's a suitable cloth here, Oxford cloth, in the 1918 category, and so on, and all the information is here."

"Sister Liu, I have the right materials, but I just want you to familiarize yourself with the production process of the new fabric."

…………

"I don't have to continue today, I'm already tired."

"It's war time now, I can rest assured that those things will be out sooner, ahem-"

With a tired face, Yu Ling suddenly coughed, and Clea quickly monitored her physiological values, but fortunately there was no major problem.

"This gunpowder is really a bit choking, whew~, the experiment of the two-base propellant is an order of magnitude more complicated than the single-base one."

Due to the lack of accelerants, Yuling's bullets will always emit more choking gunpowder smoke after firing, and this is even more true of the dual-base bullets made with nitrocell cotton and nitroglycerin, and it is normal to be choked.

"In the end, what should be the ratio factor?" After the experiment failed again, Yu Ling said unwillingly.

The rate of combustion that should theoretically be there has been calculated...... However, no matter how you experiment, you just don't live up to that standard.

It's either high or low, as if there is no such thing as a middle, which is really weird.

As for finding information for reference...... Until 1918, there was no concept of a bistatic propellant, and it is really difficult to start developing this now.

"And what should be the coefficients of dibutyl phthalate and potassium nitrate? What should be the diameter of the globular medicine? If only I could get the information on the US military in the 70s. ”

This time, Yuling has to solve not only the problem of launching, but also the problem of combustion.

The accelerant used now is still too inferior, although it is much better than this era of industrial backwardness, but this will lead to many weapons that cannot be further researched.

Yu Ling remembered a piece of information that he had roughly read, and there were more than 10 kinds of propellant ingredients in the US military, which also made the ballistics of American-made bullets and artillery shells stable, not easy to be affected by the environment, and did not damage the equipment...... In other countries, due to the lower cost, the process is not so complicated, at least on the one hand, it is flawed.

Luckily, Yu Ling happened to have the recipe in it at that time.

The additives in this recipe are all the most suitable for propellants, which have been experimented for decades, but ...... It's quite embarrassing to just know the raw materials, but not the ratio coefficient...... Even if there is no information about the US military, there is a US military bullet from the 70s.

"It's so hard to study this now, it's still too ambitious." Yu Ling couldn't help but sigh.

"It's very ambitious, generally speaking, the dual-base propellant is used on artillery, and if it is a bullet, it is better to use a single-base propellant, why do you want to study this now?" Rain Spirit's words were echoed by Claya.

She doesn't understand what is the use of Yu Ling so persistently studying the double base, even if it is a large-caliber artillery, the result of a single base propellant, is only a short range, she doesn't think there is any difference between eighteen kilometers and thirty kilometers, more than eight kilometers, basically depends on feeling, and the large-scale use of double bases was during World War II, and it is still early.

Yu Ling paused, indeed, why...... Feel? Gut feeling? It's too subjective.

"This is just to bring our gap a little closer to future generations, and I will study it again, if there is no way to get it out before May 10, it will not be too late to produce single-base shells." With a casual reason, Yu Ling started the combustion rate test experiment again, and it was obvious that Kleya's words did not have much effect.

"Ugh."

The time on the wall clock had already pointed to ten o'clock, and Claya sighed, after sleeping like this, her skin would soon expire.