Li Chengfeng took out a small watercolor pen and a small notebook and began to write and draw on them.

He was still muttering in his mouth: "The hot air balloon is lifted into the air by the hot air burned by the flame, and the lift-off force is generated! So I have to first calculate the weight of all of us plus the weight of the bamboo basket, and then calculate the absolute heat

How big should the balloon be?”

"If it is made too small, it will most likely not be able to fly, or it will fall halfway through the flight!"

"In addition, the gauze of the hot air balloon needs to be airtight and cannot leak! So later, you need to get some pine oil to apply on it. This may increase the weight of the hot air balloon! So

It needs to be doubled in size from its original area, so that it will be prepared!"

Li Chengfeng muttered vaguely, while Li Lizhi and Chang Sun Chong stood by and had no idea what he was talking about.

Several people looked confused. Changsun Chong opened his mouth and wanted to ask, but in the end he closed his mouth obediently.

Because he knew that this would only show that he had little knowledge and would be laughed at by Princess Changle and the Eighth Prince.

"Okay, Sister Changle, Xiao Wu, now you need to use needle and thread to sew a five-meter-long hot air balloon, and this hot air balloon needs a large area and a small diameter!"

"Ah? Is this so troublesome? What is a large area? What is a small diameter?"

Li Lizhi and Wu Xu looked confused.

I didn't expect that Li Chengfeng's flying plan would be so troublesome.

But then again, it’s not that easy to fly to the sky!

Immediately afterwards, Li Chengfeng drew the prototype of a hot air balloon in a small notebook.

He tore off the page of paper, handed it to Li Lizhi, and said, "Sister Changle, Xiao Wu, just follow the model above and start sewing!"

"Model? Let me take a look. It turns out that it is a big fan, and then it needs to be sewn to look like a ball?"

"By the way, do you know how to sew?"

Li Chengfeng asked with a frown.

Li Lizhi smiled and said: "Of course I will. Who do you look down on, brother Feng'er? As a princess of the Tang Dynasty, I am proficient in playing, chess, calligraphy and painting, and needlework is of course a no-brainer. This is what my mother never did*

*As I learned it, I said, this is a job that every lady must have!"

"Xiao Wu, can you do it?" Li Chengfeng turned to look at Wu Xu.

Wu Xu nodded slightly and said: "Yes, I once sewed winter cotton clothes for my mother. Eighth Prince, please don't underestimate me!"

"Haha, that's good! Okay, then you can start sewing according to the sample in this book!"

"Well, okay, Eighth Prince!"

Xiao Wu puffed out his cheeks and clenched his fists tightly, as if to cheer himself up.

Li Lizhi also took a deep breath, then picked up the needle and thread and started sewing the hot air balloon.

Li Chengfeng is not idle either. He is using bamboo strips to weave the huge bamboo basket for carrying people.

Changsun Chong was the only one standing aside, looking around, not knowing what to do.

Because he can't weave bamboo baskets or sew hot air balloons.

Changsun Chong came to Li Chenfeng's side and asked: "Eighth Prince, what's the matter? Do you need my help?"

"you?"

Li Chengfeng wiped the sweat from his forehead and said, "Oh, if something happens, go and find me a large jar of pine oil. Is that okay?"

"Pine oil? What do you want the pine oil for, Eighth Prince?"

"Don't ask, you don't understand even if I tell you. Anyway, just do what I say! Is it possible that we are busy here and you are just idle here? Hurry up and do something for me!"

"Okay, okay! I'll go find the pine oil right now!"

So, Changsun Chong ran out of the Prince's Mansion again.

It would be easy for Changsun Chong to use his status and connections within the palace to get some pine oil.

…

By the time Chang Sun Chong returned to the Zhen Wang Mansion with a large jar of pine oil in his arms, it was already getting very late.

Eunuch Wu went to the imperial dining room and asked his servants to bring eight dishes and one soup, which should be enough for Li Chengfeng and Li Lizhi to eat together.

After a busy day, Li Chengfeng wiped the sweat from his forehead and said, "I'm so tired, sister, Xiao Wu, it's time to eat! We'll stop here tonight, let's continue tomorrow!"

"Okay, Eighth Prince, we're coming over right now!"

Xiao Wu had been busy all day, and her face was still red until night.

Li Lizhi was also covered in sweat, and all her clothes were soaked through.

"I'm back, Eighth Prince. I've got a big jar of pine oil. Do you want to see if it's enough?"

Changsun Chong came to Li Chengfeng's side excitedly.

Li Chengfeng took the pine oil from Changsun Chong's hand and said: "Enough, enough, a full jar should be enough!"

"Okay, we can eat!"

"OK, all right!"

…

After dinner, Eunuch Wu suddenly came to Li Chengfeng's side, hemming and hawing, as if he wanted to say something, but he didn't dare to say it.

Li Chengfeng frowned, looked at Eunuch Wu, and said, "If you have anything to say, just tell me, don't hesitate!"

"This, is, the Eighth Prince!"

Eunuch Wu said: "The Eighth Prince, based on the response from this servant, he said that General Li Yuanba who is behind Fengcheng Mountain wants to see you and play with you!"

"What? He wants to see me? Play with me?"

Li Chengfeng frowned tightly.

Eunuch Wu continued: "Yes, the Eighth Prince, according to reports from servants, when he went to deliver food, your uncle was still having a temper! What should we do?"

"Oh, he, I'd better wait until I have time to see him again!"

Regarding Li Yuanba's matter, Li Chengfeng actually didn't really want to have anything to do with him.

But after all, Li Yuanba was his uncle, so Li Chengfeng thought that he might as well visit him when he had time in the future.

…

The next morning, Li Chengfeng called Li Lizhi, Wu Xu and Changsun Chong to continue their flying plan.

"Come on, come on, in three days, our flying plan will be successful!"

"Well, good. I feel like I want to fly to the sky to see what the outside world is like!"

Li Lizhi laughed happily.

So three days later, a huge hot air balloon stood up in the backyard of the Zhenwang Mansion.

Li Chengfeng lit the pine oil, and the hot air balloon began to expand due to the heat.

"Quickly, come up quickly. If you don't come up, the hot air balloon will fly away!"

Li Chengfeng said anxiously.

"Okay, okay, we're coming up right now!"

Li Lizhi and Wu Xu quickly stepped onto the hot air balloon.

Changsun Chong hesitated for a while because he was afraid that Li Chengfeng would trick him, but in the end, he gritted his teeth and jumped on the hot air balloon.
Chapter completed!