Lu Bu said to Pang Tong and others that the flying kite was like a kite, but in fact, he knew very well that the so-called flying kite was actually the three-winged glider that many sports enthusiasts loved later.

After drawing a drawing overnight, Lu Bu rushed early in the morning and got together with a group of craftsmen, pondering how to make the gliding mechanism.

Unlike a balloon, a glider does not require additional kinetic energy, and only needs to use the resistance of the wind to achieve the purpose of flying into the sky.

When the aircraft takes off, there will be three different types of drag in mid-air.

The first is frictional resistance.

The frictional resistance is mostly determined by the appearance of the aircraft, the rougher the surface and the wider the head, the greater the frictional resistance.

Excessive frictional resistance, which will cause the aircraft to slow down sharply or lose its balance during flight, is the most important resistance to overcome.

The other two types of drag play a key role in the flight of the aircraft.

One of these is called differential pressure drag, which is created when the aircraft is in mid-air.

The air is split by the aircraft, creating different pressure differences in the head and tail.

The tail pressure difference will be infinitely close to zero.

Proper pressure difference plays an extremely important role in maintaining the balance of the aircraft.

Differential pressure resistance is a type of parallel resistance, while another type of resistance that determines the altitude of the aircraft is named induced resistance.

Before Lu Bu came to this era, he also studied mechanics.

Although what I learned was only scratching the surface, at least I knew more than the people of this era.

The glider doesn't seem to have much technological content, but Lu Bu knows very well that the simpler the thing, the more elaborate it needs to be made.

Using the gifts of nature to send people into the sky will test not only the ability of craftsmen to make flying machines, but also the skills of future glider soldiers.

The carpenter took the best firewood and polished it into solid round sticks.

Two carpenters are using ropes to try to tie sticks into a triangular skeleton.

Lu Bu stood beside them and watched.

When the two of them tied out a skeleton, Lu Bu said: "Such a skeleton will definitely not fly into the air, once the wind resistance is too large, it will definitely blow the flying kite away." ”

The two craftsmen looked up at him in fear.

They didn't dare to ask more, but they also knew that what Lu Bu said was right.

"There's a good way to fix the skeleton." Lu Bu said: "It is better to use nails, but we don't have nails, so we can only use your skills to make grooves and tenons in wooden sticks." ”

The carpenter, of course, knew how to open the groove and tenon, so he chose to use ropes instead of slotting on sticks, considering that it is more difficult to make slots, and it is difficult to make the bayonet exactly the same when slotting in a triangular skeleton.

Seeing the confusion on the faces of the two carpenters, Lu Bu asked, "Do you think that the notches and tenons of the sticks are difficult to join?" ”

"That's what Wen Hou said." One of the carpenters replied, "It is indeed difficult to close the sticks when they are notched. ”

"Then find a way to cut the chute." Lu Bu said: "The tenon and the groove are oblique, and the notch and the tenon should be wide and long enough, and there are several more grooves in the joint, so that the force in mid-air will be distributed to different grooves." Evenly stressed, it is difficult to break, and it is more secure. ”

The two carpenters glanced at each other, and both looked stunned in each other's eyes.

They really didn't think about what Lu Bu said.

After his click, the two craftsmen suddenly became stunned.

The two of them bowed down and said to Lu Bu: "Wen Hou rest assured, we will definitely carve the groove and tenon to the seams." ”

Walking away from the two carpenters who were making the skeletons, Lu Bu came to the tanners who were cutting the hides.

A few cobblers were busy putting the hides into the barrels where the saltpeter was stored.

The hides were put in, and a white mist of steaming came out.

As soon as he got close to the barrel, Lu Bu smelled a strong stench.

When the craftsmen saw him coming, they rose up and saluted.

"Why does it smell so big?" Lu Bu asked.

"Hui Wenhou." One of the craftsmen replied: "When the hides are made with nitrate, they do have a strong smell, and when the nitrate is finished, the smell is gone." ”

"What kind of skin do you use?" Lu Bu came to the barrel and looked at the rolls of animal skins inside.

"It's sheepskin." The craftsman replied: "The toughness of the sheepskin is good, but it is a little thinner. ”

"Why don't you use cowhide?" Lu Bu said: "Isn't the toughness of cowhide better? ”

"The Han Dynasty does not allow the use of cowhide." The craftsman lowered his head and whispered back.

He was also muttering in his heart, Lu Bu, as a Wen Hou, didn't even know that ploughing cattle were not allowed to be slaughtered at will.

"Is it because ploughing cattle are precious?" Lu Bu asked again.

"Yes!" The craftsman returned.

"The Hu people in the north also raise cattle, but their cattle are not used to cultivate the fields, but only to slaughter for skin and meat." Lu Bu said: "I will have people buy cowhides in large quantities from the north first. In the future, to make flying kites, it is better to use cowhide. ”

The flying kite he told the craftsmen was actually the most primitive triangular glider.

Just talking about gliders, craftsmen may not be easy to understand.

It is easier for them to accept that it is a flying kite.

Since they are things that are going to fly into the sky, of course, the better and stronger the toughness of the cortex, and the less unnecessary non-combat attrition will occur among the soldiers who use them.

Looking at the cobbler making sheepskin, Pang Tong walked over: "Wen Hou has been watching the production of flying kites?" ”

"Actually, you can call it a glider in the future." Lu Bu smiled at Pang Tongyi: "Shi Yuan came just in time, I happen to have something to discuss with you." ”

"What does Wen Hou think?" Pang Tong asked.

"Animal skins are used for gliders and balloons, and the armor worn by the soldiers is also used." Lu Bu said: "The use of cowhide in armor has always been allowed by the imperial court. However, the wings and balloons of the glider were only sufficiently sheepskin to use. The sheepskin is thinner and can easily burst when it goes to heaven. I wondered, do I need to breed more cattle? ”

"Cattle breeding?" Pang Tong said in surprise: "In today's troubled times, although the population is small, there is not enough food to eat. Who can still breed that many cattle? ”

"Cattle and sheep eat grass, and they don't consume much." Lu Bu said: "You can give out young cattle to the people and let them breed. When the oxen are old enough to be slaughtered, they send people to the people's homes to buy them. From now on, cattle and sheep, as special livestock, are not allowed to be sold privately, nor are they allowed to be slaughtered privately, but can only be sold to the government for unified slaughter. ”

He then added: "We can't fully control the local governments, and it is inevitable that some officials will benefit from it." If the officials are too fat, the people will suffer. You'll have to make local laws to bind them. Kill what should be killed, withdraw what should be withdrawn, we must ensure that the officialdom is clear, so that we can go further. ”

"Wen Hou has a long-term vision, I'll do it!" Pang Tong responded.