Chapter 207: Flying Against the Wind (12th Update) However, this is not important in today's situation, because at present, Xue Rengui's main task is only one, that is, to watch the two ports of Singha Buluo and Fuchun for the Tang Dynasty, and wait for the follow-up army of the Tang Dynasty to come from the sea to accept Linyi.
To be honest, this proposal is very much in line with the bereavement of the house, but he just thought about it, and after thinking about it, he quickly shook his head and said: "No, I still have to show you the way, otherwise do you know where His Highness is?"
As for the situation here, it's enough to have Junmai and Duhe watch, I'll go back with you, I'm really not in the mood to enjoy happiness now. ” This is also one of the reasons why Fang Yiai came here, the place where Li Zhen is hiding now is too secretive, if there is no acquaintance to lead the way, ordinary people will not find it even if they walk by.
"It's okay, then I'll go and buy a handover task with Du Hejun."
Xue Rengui didn't say anything, in fact, when it came to their relationship, there was no need to say anything.
And Xue Rengui guessed well, although Linyi is a small country, but because of the long coastline, and the belief in Buddhism, the decoration is very luxurious, and the living expenses of the nobles are even more poor and luxurious, and the palace is naturally indispensable to the most exquisite silk from the Tang Dynasty.
Now that Lin Yi has surrendered, the entire Sangha Buluo has become the bag of Datang, not to mention asking for a little silk, even if he wants someone's life, Fan Xueyi will pick that person's head and give it to Datang as soon as possible - there is no need for the Young Army to take action in person.
With silk as an airbag, the rest of the things were easy to do, and with the efforts of the Four Thousand Divine Machine Battalion, in just half a day, a full six hundred hot air balloons with rudders and movable sails were placed in front of Xue Rengui.
"Not bad, very good."
I personally drove a hot air balloon to try it in the sky, and Xue Rengui was satisfied.
The craftsmanship of the Shenji Battalion is still very good, and as he imagined, after adding sails and rudders on both sides, today's hot air balloons have been able to fly in headwinds - although the journey is much farther (flying against the wind takes a zigzag route), but the speed is faster than flying downwind, and overall it is not much slower.
This actually makes use of the 'white noulli effect', which is often mentioned in aerodynamics, which is also known as suction.
In the case of sailboats, for example, it is generally believed that sailboats are pushed by the wind, and sailing downwind allows the boat to achieve the fastest speed.
Is that really the case?
Actually, no, the sailboat does not achieve the best speed when it is completely downwind, but can only achieve high speed when it is against the wind.
In fact, there are two forms of force that air exerts on the sail: one is dynamic pressure, that is, when the air flows, it can exert an impact force on the object blocking the way.
It is easy to understand that when a sailboat is sailing downwind, it is propelled by the dynamic force of the air.
The other is static pressure: when the air flow velocity on both sides of the sail is different, a pressure difference occurs.
Why?
This is where the 'Bernoulli effect' comes in.
This principle reveals that where the velocity of the gas is greater, the lower the static pressure; The lower the flow velocity, the greater the static pressure (e.g., fold a small paper bridge with paper, blow air into the bridge hole, and bend the bridge deck downwards instead of drumming).
In this way, the side with a small gas velocity creates a lateral pressure on the side with a large velocity, and this force is called static pressure.
When a sailboat sails against the wind, it is under this static pressure that pushes forward.
Why are sailboats able to sail "against the wind"?
The reason why the sail is able to generate static pressure is because the sail has an arc like a wing.
The same is true for the wings of airplanes, because the wings and sails are of different shapes, when the air flow through the wing or sail, the air flow speed on the protruding side of the wing and sail is faster, and the air flow speed on the other side is slow.
The pressure at the slower flow rate is stronger than the pressure at the fast flow, and it is this pressure difference that causes the wing to generate upward lift and also gives the sailboat forward momentum.
The pushing efficiency is highest when the bow is kept at an angle of 30-40 degrees to the direction of the sea breeze.
In August 2000, the French-designed sailing yacht "Hydroptere" reached a speed of 35 knots (just under 70 km/h) with a wind speed of only 15 knots.
Isn't that counter-intuitive?
But that's the objective fact.
And Xue Rengui's hot air balloon uses this principle, of course, he will not understand what is called the 'Bai Nooli effect', nor do he know what suction is, let alone understand how great his theory is.
It was only when he was at sea that he saw the sailors adjusting the direction of the ship and the angle of the sail in the headwind, so that the sailboat could get more speed, and he came up with the idea that he could sail with the help of the wind, and since the ship could do it, there was no reason why hot air balloons could not do this.
Six hundred hot air balloons, of which 500 were filled with people, and one hundred were filled with various medicinal herbs - because he didn't know what kind of dysentery Li Zhen was infected with, Xue Rengui directly swept all the medicine shops in the entire Sangha Bura, and caught a lot of all the medicines inside, which required more than 100 hot air balloons to load.
After the handover was completed, Xue Rengui entered the hot air balloon in an orderly manner with the selected five thousand elites, and under the burning of the flames, the airbags made of silk slowly bulged, and finally drove the hanging basket below to rise slowly.
After reaching a certain height, the soldiers on the ground swung their knives and cut the rope, and the hot air balloon completely broke away from the constraints of the ground and began to fly higher and freer into the sky.
More than 600 hot air balloons ascended to the sky together, the scene was quite spectacular, at least the people on the ground were enthusiastic to see it, and even some unsuspecting Linyi people had begun to kneel down and kowtow to worship.
"Wow, that's fast, faster than when I came."
Standing on the hot air balloon, feeling the oncoming wind, Fang Yiai suddenly came to the spirit inexplicably, standing in the hanging basket and shouting, completely without the wilting of the previous one, living like a plague chicken.
He was happy, and in the other hot air balloon next to him, Xue Rengui (as for why the two are not in the same hanging basket, I believe everyone understands that the truth is the same as that eggs can't be put in one basket) has already vomited - this is completely different from the imaginary appearance of riding the wind and riding the wind in the air?
Why is the hot air balloon shaking so violently, it is completely different from the feeling of going to the sky before.
He didn't know that before he went to the sky, there was a rope tied below, which was extremely stable, and naturally there would be no bumps, but now he was rootless and invincible floating in the sky, and the speed was so fast, it was strange if it didn't bumpy.
It's just that it's pitiful that Xue Rengui is a generation of men who can fight tigers and go to the sea to capture dragons when they go up the mountain, so they can only hold on to the edge of the hanging basket and vomit out their bile, and even the antiemetic medicine prescribed by Chen Tianlu is useless.