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

He still said in fragments: "The hot air balloon is the power of the air that is generated by the hot gas that burns in the flame!" So I'm going to calculate how much we all weigh plus the weight of the basket, and then how big the absolute hot air balloon needs to be. ”

"If it's too small, there's a good chance that it won't be able to fly, or it will fall halfway through!"

"In addition, the gauze of the hot air balloon needs to be airtight and not leak! So later, you will need to get some pine oil to apply on it, which may increase the weight of the hot air balloon again! So it needs to double in size in its original area, so that it can be prepared! ”

Li Chengfeng said in pieces, and Li Lizhen and Changsun Chong on the side couldn't understand what he was saying at all.

Several people looked confused, and the eldest grandson opened his mouth to ask, but finally closed his mouth obediently.

Because he knew that this would only make him appear to have little knowledge, so he would be ridiculed by Princess Changle and the Eighth Prince.

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

"Huh? Is this so troublesome? What is Large Area? What is a small caliber? ”

Li Lizhen and Wu Xu looked confused.

Unexpectedly, Li Chengfeng's flying plan was so troublesome.

But it's also true that it's not so easy to fly to the sky!

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

He tore off the page, handed it to Li Liqing, and said, "Sister Changle, Xiao Wu, you just follow this model above and start sewing!" ”

"Models? I see, it turns out that it is a big fan, and then it needs to be sewn together to form a round ball. ”

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

Li Chengfeng asked with a frown.

Li Li smiled and said, "Of course it will, who do you look down on Brother Feng'er?" As the princess of the Tang Dynasty, I am proficient in piano, chess, calligraphy and painting, and needlework, which is naturally not a problem, but my mother learned from me, saying, this is a job that everyone must have! ”

"Xiao Wu, will you?" Li Chengfeng turned his head to look at Wu Xu.

Wu Xu nodded slightly, and said, "Yes, I also sewed winter cotton clothes for my mother, Eighth Prince, 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 small fists tightly, as if to cheer himself up again.

Li Lizhi also took a deep breath, then picked up the needle and thread and began to sew the hot air balloon.

Li Chengfeng was not idle, he was using bamboo strips to weave that huge manned bamboo basket.

Only the eldest grandson Chong was alone, standing aside and looking around, not knowing what to do.

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

The eldest grandson Chong came to Li Chenfeng's side and asked, "This, Eighth Prince, is there anything you need the help of the minister?" ”

"You?"

Li Chengfeng wiped the sweat from his forehead and said, "Oh, something, you go and find me a big jar of pine oil, no problem, right?" ”

"Pine oil? Eight Princes, what do you want pine oil for? ”

"Don't ask, you don't understand what I said, anyway, you just do what I say! Could it be that we are busy here, and you are idle here? Hurry up and do things for me! ”

"This, good, good! Xiao Chen, let's go find pine oil! ”

So, the eldest grandson rushed out of the Zhenwang Mansion again.

Changsun Chong used his identity and connections in the palace to get a little pine oil, but it was not a problem.

……

When the eldest Sun Chong returned to the Zhenwang Mansion with a large jar of pine oil, it was already very late at this moment.

Gonggong Wu went to the imperial dining room and asked his subordinates 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 on his forehead and said, "I'm so tired, sister, Xiao Wu, eat!" We'll stop here tonight and continue tomorrow! ”

"Okay Eighth Prince, let's come here!"

Xiao Wu has also been busy for a day, and until the night, her face is still red.

Li Lizhi was also sweating, and the clothes on her whole body were soaked.

"I'm back, Eighth Prince, I got a big jar of pine oil, can you see enough!"

The eldest grandson Chong came to Li Chengfeng's side with great interest.

Li Chengfeng took the pine oil in Changsun Chong's hand and said, "Enough is enough, a big jar full of should be enough!" ”

"Alright, let's eat!"

"Well, okay!"

……

After dinner, Gonggong Wu suddenly came to Li Chengfeng's side, hesitant, as if he had something to say, but he didn't dare to say it.

Li Chengfeng frowned, looked at Gonggong Wu, and said, "Just say anything about it, don't be in a hurry!" ”

"This, yes, Eighth Prince!"

Wu Gong said fairly: "Eighth prince, according to the response of his subordinates, he said that Li Yuanba, the general behind the flattering mountain, wants to see you and play with you!" ”

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

Li Chengfeng's brows furrowed tightly.

Gonggong Wu continued: "Yes, Eighth Prince, according to the report of the next person, when he went to deliver food, where was your uncle still angry!" How can this be? ”

"Alas, he, let's wait for the moment when I have time in the future, and then go and see him!"

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

But after all, Li Yuanba is his uncle, so Li Chengfeng thinks that he should visit him if he has time in the future.

……

In the early morning of the next day, Li Chengfeng called Li Lizhen, Wu Xu and Changsun Chong again to continue their flying plan.

"Chong Chong Chong, in three days, our flying plan will be successful!"

"Well, good. It's as if I've flown into 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 ignited the pine oil, and the hot air balloon received the heat and began to inflate.

"Quick, come up, if you don't come up, the hot air balloon will fly away!"

Li Chengfeng said anxiously.

"Okay, let's come up!"

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

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

Gonggong Wu was on the side, stomped his feet anxiously, and said, "Eighth Prince, what are you going to make trouble again?" Could it be that you really want to fly into the sky? ”