Fly? Li Hang is not worried about this problem at all. Just make a hot air balloon. Now the coal mine has been found. It's perfectly possible to make a hot air balloon yourself, although it doesn't have to be huge. But enough for a flight. But now it takes a lot of heavy objects to fix it.

Li Hang glanced at them, and then picked up the wooden block on the side.

"Your Highness, I remember that I taught you before. How to float on this water. ”

Ying Yun thought about it for a moment and then nodded. "It doesn't matter what material you make, it's what matters is the ability to drain the water out."

nodded, then picked up the prepared fan and fanned it in front of them. "Has Your Highness ever wondered why there is wind?"

This kind of problem is not to say win. Even philosophers don't necessarily have answers.

After all, the ancient Greeks also used wind as one of the four elements on which the world was built. Let the ancients understand the concept of air, I am afraid that it is more difficult than climbing to the sky.

After thinking about it for a long time, he didn't have an answer. This is a question that even Yingqi and the others are pondering.

People have long been accustomed to the presence of wind. Do you need to wonder why this thing exists?

But what is it to say these at this time?

Thinking about the buoyancy before, Ying Yun seemed to have a thread in his mind, connecting the two.

"You're saying it's the same as water?"

Very smart. Li Hang glanced at this kid.

Sensei said something else. Just being able to connect the two at this time is a manifestation of a very important imagination.

"Water is liquid, and we are surrounded by gas, but there are many ways to observe their existence. For example, we can look at the air being heated next to a stove. This is the change in density that occurs when it is heated to a certain temperature. You'll see ......"

"Twisted?" Emperor Win Wu asked tentatively.

Ying Yun suddenly realized. Thermal expansion, something that Li Hang has said many times, this phenomenon can be used in many things. Like those grinders and stuff like that. "Wait. If you say that heating expands. Then at this time, as long as it cannot be replenished, it is equivalent to discharging this gas. It's the equivalent of creating buoyancy! Ying Yun suddenly realized.

But Emperor Win Wu and the others on the side of these things were in a fog when they heard it. Because this is more like some professional words, I don't understand it.

Several people couldn't help but touch their heads. It's only been a few years, has this outside knowledge become so profound? That's not right!

Several people looked at each other.

Wait until Li Hang took out a drawing. It was only then that everyone suddenly realized.

Drawings of a hot air balloon. It's not very rigorous, but it's at least useful.

"Put a stove in this. The rest of the parts are made of impermeable hides. This will keep the air inside as airtight as possible. As long as the fire is ignited and heated, the air in here will be heated and expanded, and then it will fly with me. It's no problem to bring another person. ”

As for the question of work, these are not problems at all in Li Hang's view. He didn't need to think about it at all. He just had to think about whether he could fly or not.

And because of the fear of this technique of rising and falling. He also had to be pulled by a heavy load.

You still need to pull it with a rope underneath.

Because of this need, it is still a hassle to manufacture.

The hanging basket is made of wood. Not to mention that the coal furnace above is made of all steel. The huge hot air balloon also had to be made of good materials. But the most important thing is this stuff underneath. At this time, the leash underneath must be strong. Li Hang wasn't sure how buoyant this was. He didn't know how dense the air was. But it's generally enough to be safe.

I'm arranging the making of this hot air balloon on my side. On the other side, those people from the Buddha Gate and the Taoist Gate are preparing for the festival. After all, this is a big deal, and they don't dare to treat it casually, if it is changed to previous years. They may have done it a long time ago. But this year, the drought was predicted. If something really goes wrong with them, it's hard to say. Therefore, the imperial court is also very generous in the budget for this year's festival. Not to mention the good things, even the monks invited to the festival have a very generous honorarium. And that's not all. If you count the gold leaf brocade in the sacrificial process. After they run out, they are left to dispose of it, and this time the sacrifice is afraid that they can get thousands of taels of silver. What is this concept? One sacrifice can be eaten for a year.

Don't look at these monk temples, they don't seem to be touching gold and silver, but they won't be soft when it comes to making money.

That's why they're so wealthy.

As for Li Hang's flying matter. They all thought it was a joke. If people can really fly to the sky, then why don't you ascend to immortals. What's more, in their eyes, Li Hang may not be able to fly.

"Senior brother, do you think that Li Hang can fly?"

"Fly? You see, we have a few more who can fly. What's more, this Li Hang is a talent. Even if he could fly, what if he could. It's not possible to grow wings. How much more can he grow wings? The one with wings spread is called a youkai! A great monk said with an indifferent face.

"But I've heard that the Prince's Mansion is now starting to move. He said he was looking for some kind of cloth and leather. ”

"After all, it's just pretending to be a ghost."

This sentence speaks to the hearts of many people.

It's no secret what the Prince's Mansion is buying. Now many people are inquiring about Li Hang's actions here. The people in the Prince's Mansion did not deliberately hide it. Because it's really unnecessary. What if they could do it? This is basically impossible to control the direction. Everywhere you can go depends on the sky, and things that take a long time to prepare have no secret value. Because this thing is just too weak.

Li Hang didn't even ask them to keep it a secret. It is estimated that this kind of thing will be pulled out to play during the festival in the future to increase the festive atmosphere. Not to mention practical use. When you use it, it is a great achievement to be able to kill two people less.

The principle of this kind of thing, the prince, Yingqi they all listened to it. But they were also shocked when the real thing was made. The huge hot air balloon has not yet restarted, and if it does inflat, I am afraid that it will inflate to be bigger than a house. Such a huge thing just wants to fly?

Looking at the busy people below, this large group of people was stunned.

The hanging basket was made, and it contained several bags of rice, which weighed almost 200 catties. It is enough to ensure that the test is used, that is to say, as long as these rice are guaranteed to go to the sky, people can go to the sky, and it is the absolute kind.