The density of the atmosphere in the ionosphere is very low, as can be seen by the presence of satellites operating in the ionosphere.

Thus, when flying in the ionosphere, the air resistance is negligible.

Under continuous acceleration, Fang Yuan's speed reached Mach 5, which is 5 times the speed of sound, and it was 6,120 kilometers per hour.

Eventually rushed into the stratosphere at Mach 5.

"Watch the temperature! Watch the temperature! Watch out for slowing down, 30 seconds, 30 seconds before hitting the ground! Yang Yuping shouted into the intercom, his voice was very anxious.

Since he was able to crystallize dark matter and fabricate materials with strong interaction forces, Fang Yuan has a deep understanding of the properties of materials with strong interaction forces.

It is precisely because I know the nature of materials with strong interaction forces that I decided to play so big.

Rushing into the atmosphere at 5 times the speed of sound, this speed is already comparable to that of the intercontinental missile Dongfeng Express.

If it is a missile, it rushes into the atmosphere at five times the speed of sound, and the heat generated by friction with the air will cause the temperature of the shell to reach one or two thousand degrees.

As a result, the outer layer of the missile will turn red, as if it were burning.

In the same way, meteors do not burn in outer space, but only begin to burn when they enter the atmosphere.

The meteors that can be seen by the human eye across the sky are all meteors that have entered the atmosphere.

Two thousand degrees of heat.

Under normal circumstances, it is difficult for humans to withstand such high temperatures.

However, when Fang Yuan was wearing the Black Dragon Battle Armor and rushed into the atmosphere at a speed of Mach 5, the expected combustion situation did not appear.

If it was a missile, the shell would have burned to a fiery red color long ago.

However, the Black Dragon Armor still maintained the color of the Black Crystal Shield Armor, without the slightest sign of burning.

Fang Yuan was actually very nervous, and he had been paying close attention to the temperature inside the battle armor, after rushing into the stratosphere and the temperature did not increase significantly, it was finally determined that the properties of the strong interaction force material were as strong as expected.

A strong interaction force material is a layer of material formed by atoms locked by a strong interaction force and closely arranged together.

This material is naturally found in the universe, and that is the neutron star, the densest star in the universe except for black holes.

The strength of highly interacting materials is so terrifying.

Because the atoms are closely aligned, the particles hardly vibrate, which makes the strongly interacting material a thermal insulator.

Because there is no particle vibration, theoretically, the temperature of a material with strong interaction force is absolute zero, and because it is a thermal insulator, it does not absorb heat itself, so there is no heat transfer when touched, so it does not feel cold.

It was precisely because he knew in advance the special properties of materials with strong interaction forces that Fang Yuan dared to rush into the stratosphere with 5 times the speed of sound.

After entering the stratosphere, it passes through the ozone layer and continues to rush down towards the troposphere, like a vertically falling missile, locking onto the target on the ground and rushing straight down.

Airplanes!

After 20 seconds, it crossed the stratosphere and rushed into the troposphere, only 15 kilometers above the surface.

"Slow down, slow down." Yang Yuping kept reminding, but it didn't have any effect.

At a speed of Mach 5 and an altitude of 15 kilometers, it can be crossed in less than 10 seconds, and then it will directly hit the ground.

At this time, Admiral Rhodes also spoke: "Slow down, this is an order." ”

Fang Yuan didn't want to try what it was like to hit his head and break the blood flow, so after entering the troposphere, he began to slow down.

After 10 seconds, it falls to the ground at subsonic speed.

Boom!

With a bang, his feet hit the ground, stepping out of two pits on the ground.

After three seconds of silence, there was a round of applause.

Bang Bang Bang ......

The first test of the Black Dragon Warframe has ended.

Fang Yuan returned to the battle suit laboratory, took off the black dragon battle armor, and handed it over to the laboratory for optimization and improvement.

"Do you have any comments on Warframes? We will try to optimize according to your wishes. The researchers in the suit lab asked while checking the condition of the suit.

"I think the appearance can be a little more domineering, and besides, has the name 'Black Dragon' been decided? It doesn't feel like it matches my handsome appearance. I think the little white dragon in the waves is actually okay. Fang Yuan rubbed his chin and said.

When Admiral Rhodes heard it on the side, he couldn't help but roll his eyes when he was old, and said: "This is considering that you are too young to look like a strong one, so using the code name 'Black Dragon' will appear more calm and cover up the shortcomings of your appearance." ”

"I'm a flaw? Don't they all say that appearance is combat effectiveness? Fang Yuan was speechless.

……

After testing the Black Dragon Battle Armor, Fang Yuan found that the strength of the suit design team of the Academy of Military Sciences was still very strong.

Originally, I thought that the black dragon armor that came out would be similar to the Longwei-level battle suit.

But after testing it, I found that the Black Dragon Battle Armor was much stronger than the Longwei-level Battle Suit.

Actually, if you think about it, you can see it.

The Longwei-level suit is a mass-produced suit, and the pursuit is to reduce the cost as much as possible on the premise of ensuring a certain combat effectiveness.

In other words, the Longwei-level suit has high requirements for cost performance.

The Black Dragon Armor is different, if there are no special circumstances, only one set will be built, so it is no problem to smash billions into it.

A lightning vortex propulsion engine cost three billion, and this was made on the premise of omitting the electron beam generator.

After the first Black Dragon Warframe test was over, after two days of optimization and adjustment, Fang Yuan received a notice to start the second test of the Black Dragon Warframe.

There are superpower engineers in charge of manufacturing the suit, and the speed of optimization and adjustment is really fast, and the process is almost manual.

The second test was carried out in the test site of the Academy of Military Sciences, although it was an open-air test site, but this time it was a ground test.

"The optimization process went smoothly, and the Black Dragon Warframe weighed 280 kilograms after loading the strong interaction materials, and with your weight, the total weight reached 350 kilograms. This weight is much heavier than the average suit, and today it is necessary to test the movement on the ground to see if it will hinder the movement. Professor Yang Yuping talked about the content of today's test.

"350 kilograms? In this case, wouldn't the kinetic energy of the Dragon Fist skyrocket by 5 times? Fang Yuan was very satisfied with this weight.

According to the kinetic energy formula Ek=(mv^2)/2, mass and kinetic energy are directly proportional, and the kinetic energy increases by a factor of increasing mass.

"The premise is that you are carrying such a heavy armor and your speed is not reduced." Yang Yuping corrected.

According to the kinetic energy formula, if the velocity decreases, the kinetic energy will naturally decrease.

The heavier the armor, the faster it will naturally be.

Therefore, whether the final kinetic energy increases or decreases depends on the test results.

The ground speed is not the same as the sky speed tested the other day.

The last time it was able to reach 5 times the speed of sound, it was outside the atmosphere when it started to accelerate, and outside the atmosphere, there is no air resistance, so it can accelerate to Mach 5.

Theoretically, flying in space, as long as the acceleration is maintained, it can continue to accelerate to the speed of light.

However, on the ground it is different, with the presence of air resistance, there will be a limit to the speed.

When fighting, there is no time to run into outer space to complete the acceleration process.

Therefore, the speed data on the ground is more important.