Time is not forgiving, Jiang Liu'er seems to be a little nervous, the hand holding the drill stalk is also a little trembling, and the wrinkles on his forehead are even oozing fine beads of sweat.

It was almost dark.

Although she was anxious, Jiang Liu'er knew that drilling wood to make fire was a very technical thing, and it was necessary to have a lasting and uniform speed, not an excessively high rotation speed.

In terms of material mechanics, although the relationship between torque and bending moment and speed is not large, it is not easy to judge the force of the drill rod when the power and speed increase at the same time.

However, experience tells Jiang Liuer that the faster the rotation speed when rubbing the drill fire rod, the greater the tangential force required, which can easily cause the drill fire rod to break.

Jiang Liuer studied mechanical design, manufacturing and automation in college, although he was not proficient in learning, but these basic truths are still known.

Even Bei Ye's wilderness survival has said that the rubbing rate of drilling wood for fire should not be too fast, otherwise it is easy to cause the breaking of the drill stalk, and the gains outweigh the losses.

The next thing to do is to rub your hands together.

Fortunately, the surface of the remaining drill stalk after scraping off the bark of the drill stalk is quite smooth, and Jiang Liuer is relatively comfortable when he rubs it with both hands, and will not cause blisters on his hands because the surface is too rough.

Take a deep breath, first slowly rotate the drill stalk to make it seamless with the small hole in the floor, and then what you need to do is to try to keep the balance of the speed and the durability of the tangential force under the condition of ensuring that the drill stalk will not be broken.

Holding his breath, his brows were furrowed, his face was indescribably dignified, and the drill stalks held by his hands kept rotating at high speed under the action of his palms, rubbing against the small holes in the bottom plate, making a harsh and rough sound.

Jiang Liu'er knelt on her knees, nervous and didn't even dare to raise her head, for fear that the first operation in her life to drill wood for fire would fail.

"Hiss...... Hiss ......"

With the violent sound produced by the violent friction between the wood and the wood, the sky lived up to the painstaking people, and after drilling for nearly three minutes, Jiang Liu'er, who was already a little out of breath, suddenly found that at the part where the drill stalk and the bottom plate were violently rubbed, a very fine curling green smoke had emerged in the blink of an eye, and it disappeared in mid-air in an instant.

However, this thread-like movement as thin as a hair was still keenly captured by the attentive Jiang Liu'er.

That's great!

Jiang Liu'er's heart suddenly jumped fiercely, and her joy was beyond words.

Out of the smoke, it means that at least there is no major direction wrong in his approach, and as long as he continues to persevere, he will have a great chance of succeeding in making fire.

The first step of hard work has come to fruition, and there is also the motivation to continue to struggle, Jiang Liuer's heart is instantly full of fighting spirit and courage as if he has been beaten with chicken blood, and unconsciously, the speed of rubbing the drill stalk with both hands can't help but speed up a little.

It was completely dark, and I couldn't help but feel a little impatient.

However, at this time, there were unforeseen circumstances in the sky, and when Jiang Liu'er was engrossed in rubbing the drill stalks, suddenly a very harsh "click" sound came, and Jiang Liu'er's movements and highly tense body froze in place in an instant!

The drill stalk that he relies on to make a fire...... It's broken!!

I'm Nima!

Jiang Liu's anger just wanted to scold his mother, his efforts had been close to success indefinitely, since the first wisp of green smoke came out, there were already endless wisps of smoke coming out of the small holes, and he was panting and close to exhaustion, and he also poured a lot of expectations into it, but he didn't expect it...... The reality is so cruel.

"Alas!!"

With a burst of sighs, Jiang Liu'er sat on the ground weakly, and the beads of sweat flowed down her cheeks wantonly, seeping into the corners of her mouth, which was endless bitterness.

The drill stalk next to it has long been completely broken into two, and the black cave has no other wooden sticks that can be used as drill stalks, and even the half of the hardwood left after he broke it before is completely gone!

Creation makes people!