I make a popular science video and all the emperors learn from it!

[Continue the science glider.] 】

【Rationale:】

[An airplane must overcome gravity with lift and air resistance with thrust in order to fly. 】

[Lift is mainly generated by the ring, subsonic aircraft airfoil (wing cross-section) is mostly approximately symmetrical up and down to reduce drag, while the airfoil of gliders usually adopts a similar Clark Y airfoil (typical upper convex lower flat), which can make the lift generated by the unpowered glider greater, the lift-to-drag ratio increases, and the air stay time becomes ~ longer. 】

[The glider does not have the power of the engine, it can be lifted into the air by four ways:]

[(1) Catapult - set the glider on the bungee cord and pull it back, and release the rope after the pilot gives a signal and ejects it out. 】

[(2) Car towing - after the glider is tethered to the car and dragged to an appropriate height, the driver releases the rope. 】

[(3) Winch towing - similar to car towing, except that a winch fixed on the ground and driven by a motor is used to pull the glider. 】

[(4) Aircraft towing - after another powered aircraft is towed to a certain height, the glider detachs and soars freely. 】

[After the glider lifts off, unless it encounters an updraft, the air resistance will gradually slow down the speed of the aircraft, the lift will become smaller and smaller, the gravity will be greater than the lift, the aircraft will fly lower and lower, and finally land on the ground. 】

[In order for a glider to fly far and long, it must have a high lift-to-drag ratio, which is why the wings of the glider are so slender. 】

[How to break the record of air time and flight altitude is the biggest challenge in the design and manufacture of gliders. 】

Gliding is a sport that requires altitude skills and flight knowledge, and uses natural energy to travel through the sky. 】

【Basic Structure:】

[Gliders have elongated wings (i.e., larger wing aspect ratios) that are significantly different from airplanes, and the fuselage is elongated and streamlined. 】

[The wing aspect ratio of the advanced glider can reach more than 30, and the design tends to be in the pilot's lying cabin in order to reduce the fuselage cross-sectional area. 】

[The surface of the fuselage is smooth, and even waxed, so as to improve the lift-to-drag ratio of the glider and reduce the gliding angle in gliding flight. 】

[People often use gliding ratio (the ratio of the distance traveled in gliding to the sinking height) to measure the quality of gliding performance. 】

[From the balance relationship of gliding flight, it can be seen that the gliding ratio is equal to the lift-to-drag ratio. 】

[The lift-to-drag ratio of modern advanced gliders has exceeded 50 at the maximum. Some gliders also have airbrakes on their wings that can be manipulated to open to increase drag if necessary, or to adjust the glide angle when landing to land in order to land accurately at a designated location. 】

[The powered glider is equipped with a small auxiliary engine, which can take off on its own without external traction, and when it reaches a predetermined altitude, the engine is turned off for basic gliding flight. 】

[Powered glider, which can improve the efficiency and safety of training flights. 】

[Modern gliders are made of materials with high strength and light weight. 】

[The main structural materials are: wood, laminate, fabric, aluminum alloy and glass fiber reinforced plastic, etc. 】

[After the 70s, high-end gliders made of carbon fiber composite materials appeared. 】

[The wings of modern hang gliders are mostly paragliders, which are triangular or rectangular in plan, and are covered with impermeable synthetic fiber cloth on a tapered skeleton. 】

【.......】

[Let's take a look at a video of a foreigner playing with a glider.] 】

The video begins.

A foreigner holding a simple glider on a hillside.

That's right, just hold it.

His upper body is inside the glider, and the lower two legs run on the ground.

"This is the lightest glider in the world, called Archaeopteryx."] "】

"It weighs only 60 kilograms, which is about the weight of an adult. "】

"It's easy to drive it, too. "】

["You just need to find a place on higher ground, carry it and run down to fly."] "】

"The maximum flight speed can reach 130 km/h. "】

["The person I see now is doing flight training. "】

["It can be observed that there is a strap between his legs, and this strap has two functions. "】

["One is to prevent people from falling off the glider, and the other is that when the glider takes off, the personnel can sit on the strap and use it as a seat. "】

["This dual-purpose design is still very ingenious. "】

["But if you have the opportunity to play this, it is recommended to prepare a pair of pants with a lower crotch and wear-resistant, because this glider requires basic training up to 20~40 times. "】

["Once you've mastered the basics, you'll be able to take it to the skies."] "】

In the air, you can use a combination of rudder pedals and joysticks for direction control and altitude lifting. "】

"It's no different from any other glider. "】

"Thanks to its wide flaps, it can be easily controlled both in flight and when landing. "】

"There is no need to worry about security at all. "】

"It is equipped with a parachute inside. "】

["In the event of an accident, the pilot can activate it manually. "】

"It has two landing methods, one is the conventional wheel brake, and the other is the foot brake. "】

"The second type is more difficult. "】

["If you don't have skydiving experience, or if the wind is strong on the day, it is not recommended to use this method. "】

["Not to mention the high risk, it is also more expensive. "】

["At present, this glider has developed a 2.0 gameplay. "】

["In addition to sliding down from high ground as described above, you can also pull it up like a kite by pulling it up with a car on flat ground."] "】

["If you don't find it enjoyable, you can change the car to an airplane."] "】

["In addition, the manufacturer has also developed supporting power components. "】

["The rear of the glider can be fitted with an engine and propeller, and the glider itself will power the take-off. "】

["What's even more commendable is that its storage is also very convenient. "】

["After disassembling all the parts, a small van is enough to fit. "】

["And in terms of price, the lowest entry-level version is only 58,000 yuan. (If you read a violent novel, you can go to Feilu Novel Network!)

【......】

The video is finished.

But the ancients were not calm.

"It turned out to be a glider, and it didn't look like a chicken, but like a thinner bird with longer wings. "

"What is this thing made of, it's about the same weight as a person when it's so big?"

"I don't know, what new material it is, we definitely don't have it anyway. "

"I really want to have fun, I want to experience the feeling of flying..."

"It's okay, brother wants to open a little, and on the day you die, you will be able to experience the feeling of flying. "

"I'm Nima, you kid have a lot of humor, don't you!?"

“..."

Qin Dynasty.

Hu Hai was envious. []

He rode a wooden horse wheel, and he could use the foot brake.

People can fly gliders, and they can also play with foot brakes!

Glancing at the wooden horse wheels made of broken wood again, Hu Hai suddenly felt that this thing was not fragrant.

It's not fun at all.

And he looks very low-minded when he rides it!

No wonder the other princes were reluctant to take the initiative to try, it turned out that they found someone riding on it and looked stupid!

"Phew, don't play this, Fan Xiliang, you make a glider for this prince. "

Hu Hai threw down the wooden horse wheel and ran in front of Fan Xiliang.

Fan Xiliang, who was watching the video intently, was directly dumbfounded.

His tone was embarrassed: "Your Royal Highness, don't embarrass the ministers, the glider... We can't do it. "

"Hu Hai, don't mess around. Ying Zheng found out about the situation and walked straight over there.

"Fan Aiqing, can't this thing really be made?"

To be honest, he still had a bit of luck.

If he could make a glider, he wanted to see what it was like to fly.

Fan Xiliang smiled bitterly, "Back to Your Majesty, even if you use the lightest bamboo, considering the degree of sturdiness, it can't be as heavy as a person." "

"Besides, I don't know what a parachute is. "

"And how to control the glider..."

After Ying Zheng heard this, he waved his hand directly.

Forget it, the gap of thousands of years is not possible to make up for it in a short time.

Ming dynasty.

"Grandpa Huang, my grandson wants to play that. "

Zhu Xiongying looked up with a small face and pulled the hem of Lao Zhu's clothes crisply.

In the entire Ming Dynasty, it is estimated that he is the only one who dares to do this.

"It's Xiong Ying, Grandpa Huang knows. Zhu Yuanzhang smiled and picked him up.

Then he carefully explained: "The glider is not fun, let's not play it, you see how high it flies, if it falls, it will not break everyone." "

"Besides, you're so small, you can't see the way even if you get in. "

When Zhu Xiongying heard this, he was very unhappy.

With a stiff face, he asked, "Grandpa Huang, can't you build a glider?"

Zhu Yuanzhang was directly embarrassed.

After a long while, he replied, "You kid, go play by yourself." "

As he spoke, he let the man down from his arms.

Zhu Xiongying was unforgiving, and ran to Zhu Biao to complain, "Daddy, the emperor's grandfather can't build a glider, you make one for the child, the child wants to fly into the sky." "

Zhu Biao helplessly held his forehead.

Son, who gave you confidence.

What the emperor can't make today, let me make it for a prince?