"Is there time for the thirteenth of the month?"

On the way home, Tang Rui received a call from his classmate Zhou Tao.

They are father and son in the same bedroom, and the relationship has nothing to say.

"If you get married, you will have time, and if you don't get married, you will not have time."

Tang Rui then replied.

"Roll on...... Dad is an unmarried, how can he get married. ”

"Huh."

"I won't talk to you about this, next Saturday is the thirteenth, our alma mater's model aircraft club and China Southern Airlines' model aircraft club jointly organize an event.

The flight airspace is applied for by China Southern Airlines, our alma mater is out of the venue, there is no height limit, you can fly casually, we who have graduated can also participate, do you want to go? ”

And this kind of good thing?

He was worried that there was no place to test the performance of the drone.

Today's test flight was just a test of the optoelectronic system.

As for the drone's ultimate altitude, ultimate speed, minimum stall speed, climb rate and other performance, there is no way to test it at all.

"Go, where's the location?"

"Over there at the Immortal Forest Purple Gold Academy."

"I know, kneel down."

"Get out."

After hanging up the phone, Tang Rui still had some smiles on the corner of his mouth.

Don't look at the relationship between the two is very iron, but they don't usually communicate much.

After all, everyone has graduated.

To each his own thing.

He opened his own online store and engaged in self-media, which is quite easy and free.

Like Zhou Tao, people whose homes are not local, but who choose to stay in Jinling, are the most tired.

Not to mention how tiring it is to go to work, there is not much money left after paying the rent every month.

Not to mention the need to eat, drink, shop, and occasionally go out and relax.

It's good that the money you earn can be used, and you don't have to think about saving money or anything.

Everyone is usually busy with their own affairs, only when they are in a bad mood, have accumulated too much negative energy in their hearts, and need to talk and vent, they call someone and come out for a drink together.

Under normal circumstances, Tang Rui would play the role of pouring salt on the other party's wounds.

In his words.

This is called fighting poison with poison.

Although he will be drunk in the end, he is still very happy with a wave of poisonous tongues.

Back to the community.

I parked the car and struggled to get the model airplane upstairs.

The first thing Tang Rui did when he got home was not to pack up his things, but to take a bath.

It was raining.

Sweating again.

The whole body is slimy and very uncomfortable.

Ten minutes later.

Tang Rui, who had finished taking a shower, sat on a chair with a bath towel draped, crossed Erlang's legs, and drank ice cola in his hand.

Dry half a bottle in one go.

Belch!

Comfortable.

But when he saw the paper airplanes all over the ground, his mood suddenly became unbeautiful.

"What to do with these paper airplanes?"

Throw it away, waste.

If you don't throw it away, there's nowhere to put it.

Paper airplanes can't be sold, at most they can only be sold as waste paper.

Wait a minute......

It doesn't seem to be impossible to sell.

Tang Rui picked up a paper airplane at his feet and looked at the system panel on it.

[Item: Paper airplane]

[Experience: 0/20]

[Source point: 0]

Leveling up experience is very small, only 20 experience points are enough.

Try the upgrade first.

"Ha~"

He sighed at the nose of the paper airplane and threw it.

Paper airplanes fly smoothly in mid-air.

Flight trajectory is like drawing a straight line in the air.

Bite!

The paper airplane hits the mirror of the shoe cabinet and then falls to the ground.

Tang Rui got up, ran to the shoe cabinet, and picked up the paper airplane on the ground.

[Item: Paper airplane]

[Experience: 6/20]

[Source point: 0]

It increases by 6 experience points at once, and you can level up by flying three or four times.

There's not much to say.

Go on.

With a slight drop, the paper airplane flew out again.

This time it may be because of the previous impact of the nose of the aircraft, which caused the flight trajectory to be a little crooked, but it did not affect anything.

Pick up the paper airplane again.

This flight, 7 experience points have been added, which is good.

Xiuxiu......

After two more flights, the experience of the paper airplane overflowed by 5 points, reaching the upgrade standard.

Tang Rui directly clicked to upgrade.

Swish!

A glimmer of light flashed.

Paper airplane upgrade completed.

[Item: Stable Paper Airplane +1]

[Experience: 5/40]

[Source point: 0]

He picked up the paper airplane and looked at it carefully, it didn't seem to have changed, but it seemed to have changed a little.

He really can't say where there are changes.

The prefix on the system panel also appears the word stable.

After Tang Rui frowned, he threw out the paper airplane again.

He wanted to see the effect of the paper airplane upgrade.

Shout......

The paper airplane drew a standard horizontal line in the air and flew straight towards the window.

It doesn't seem like much has changed.

The previous paper airplanes also flew in this way.

Just when he was a little disappointed.

A sudden gust of wind blew in the window.

The paper airplane, which was flying towards the window, suddenly paused at this moment, and then slowly retreated backwards.

Grass!

Tang Rui was dumbfounded.

In his astonishment, the slowly reversing paper airplane stopped after rising ten centimeters in height, and hovered steadily in mid-air.

Just like that, more than ten seconds passed.

The wind blowing in from the window decreases.

The paper airplane hovering in the air flew forward again, and slowly descended as it flew.

But before the paper airplane landed, another wind blew in the window.

And then the wind.

The paper airplane slowly reverses again, gains altitude, and finally hovers in the air again.

See here.

The corners of Tang Rui's mouth twitched unconsciously.

Is this magic?

Yes.

It's aerodynamic magic.

At this moment, Tang Rui had already figured out why the paper airplane was regressing, rising and hovering.

Theoretically, if you want a paper airplane to achieve such an effect, you must first ensure one point.

That's the folded paper airplane, with a complete gravity balance on both sides of the central axis.

That is, the weight on the left and right sides of the central axis, absolutely balanced, exactly the same.

And this is consistent, not only the weight, but also the shape and tilt angle of the wings.

Secondly, it is the center of gravity of the paper airplane.

He stacked a canard paper airplane, and normally the center of gravity of a canard plane is between the canard wings and the wings.

But the problem is, he's a paper airplane.

The overall center of gravity is on the nose, which is very forward.

As we all know, the higher the center of gravity of the aircraft, the more stable it is and the easier it is to fly in a straight line.

In such a situation, the center of gravity at the front, the perfect balance, the exact same lift on both wings, the aerodynamic airframe, plus the ultra-light weight of the paper airplane itself.

All of this adds up to a perfect balance of lift, drag and gravity.

That's why paper airplanes are able to hover in the air.

Tang Rui picked up a paper airplane that he had stacked and had not yet undergone a system upgrade, and threw it towards the window.

Shout......

At first, the paper airplane can draw a straight line, but when it gets close to the window, it immediately starts to deviate in the face of the wind blowing in from the window, and finally hits the wall.

He was not surprised by this situation.

It would not be possible to achieve that ideal state without a paper airplane that has been optimized for the system panel.

It's handmade after all.

The perfect balance is not reached.

After a while.

The wind blowing in from the window stopped.

The paper airplane hovering in mid-air also glides slowly and lands.

Tang Rui walked over and picked up the paper airplane.

[Item: Stable Paper Airplane +1]

[Experience: 58/40 (Upgradeable)]

[Source point: 0]

Unexpectedly, this wind not only allowed him to discover the awesomeness of paper airplanes, but also filled up the experience of upgrading.

There is nothing to hesitate about.

Directly click Upgrade.

Swish!

With a glimmer of light.

The shape of the paper airplane has become more aerodynamic, and there are even two missing tails in the tail, and with the curvature of the upper wing, it has even become two horizontal tails.

[Item: Stable Paper Airplane +2]

[Experience: 18/?] (Non-upgradeable)】

[Source point: 0]

Tang Rui looked at the upgraded panel and found that the paper airplane could no longer be upgraded.

There's nothing wrong with thinking about it.

After all, it was just a paper airplane, and the first time it was upgraded and optimized for the overall structure, and the second time the body shape was adjusted.

Without reinforcement, there is no room for improvement in paper airplanes.

As for reinforced paper airplanes?

Impossible.

Source points are still precious, and he won't waste them on paper airplanes.

At the moment, such paper airplanes are amazing enough.

Tang Rui picked up a few paper airplanes from the ground that had not been upgraded and threw them towards the window.

He plans to build a few more upgraded paper airplanes, and then shoot a video of the paper airplanes hovering in the air.

This kind of hunting video, even if it is fake, has many people like to watch it.

Not to mention that he's real.

When the time comes, upload the video, and by the way, put the paper airplane on the shelf, there should be a lot of people who buy it.