"Isn't the specific impulse related to the structural design? At present, the cost of superalloys in China is very high......"

Du Feng is in charge of logistics, and naturally he is heartbroken.

As long as the rocket flies for more than two minutes, Liu Yue is good and designed to let the rocket fly to the target, and the engine is still intact in the end.

You can't just launch rockets at the enemy's position during a war and then go and recover the engine, right?

Specific impulse is an important physical parameter to measure the combustion efficiency of rocket engine and jet engine, the higher the specific impulse, the higher the working efficiency of the engine, and the higher the speed and longer range can be obtained under the same mass of fuel propellant.

"Leader, this, is for the subsequent development of the argument, the structure is reliable, as the engine grows, the combustion chamber will withstand higher temperatures...... Moreover, according to theoretical calculations, the service life of the engine will be greatly reduced if the material with worse heat resistance is replaced...... "Liu Yue will not agree to replace it with a worse material."

"The production of superalloys is very difficult and costly......"

"There is no use of superalloys in this regard!" Liu Yue shook his head, "Leader, we are researching a new solid fuel propellant with high chemical energy and high combustion efficiency." That would result in higher temperatures, which would also reduce the service life......"

Several people from the 2109 factory who are engaged in fuel propellant research work have been specially invited to do fuel propellant research work, and Liu Yue has given Ren Dongsheng and others the HTPB solid propellant fuel formula commonly used in missiles and rocket artillery decades later.

As soon as this material comes out, the engine efficiency will naturally be higher.

"I haven't calculated how much the punch is yet, so let's continue experimenting. The first one has been scrapped...... "Jiang Zhihe feels that it is a little inappropriate to discuss this now.

The leaders all spoke, and naturally no one said anything more.

The experiment continues.

On the launch pad, a flat 273mm model of a rocket is loaded with solid fuel and a tail engine.

The same non-compliant experiments.

After all, the shape of the rocket has not been tested in the wind to verify whether the design is reliable.

Anyway, the first experiment has already been violated, and if it is violated, it will be much easier for others to accept it.

In fact, the most fundamental problem is that the base does not pay much attention to these small projects.

You must know that in the entire base, the main business is Dongfeng and the Long March.

The Dongfeng is a thing that sends express delivery to other continents, and the Long March is a thing that sends express delivery to space.

There are the top technology bases in China, who wants to play these small ones?

Otherwise, the base would not have left the development of small projects to its subordinate factories.

These missile and rocket artillery factories at the base were originally established just for backup.

The biggest function of the three-line unit is backup.

Otherwise, it would be impossible for Base 002 to have all the scientific research systems and production technologies related to the entire missile and rocket artillery......

The rocket model is fixed on the workbench, and two large bearings are used on the outside to fix the rocket model inside the bearing, and the outer ring of the bearing is directly installed on the test bench to test the rotation of the rocket.

"Ignition!"

With Liu Yue's order, the rocket model placed horizontally on the test bench, the tail engine "boom~" sounded, and a dense cloud of smoke was sprayed backwards.

In order to control the thrust, the propellant fuel enters the engine very slowly, so as to avoid excessive thrust and damage to the bearings.

At the same time, on top of the model, there are fixtures to counteract the power generated by the thrust......

Tests are carried out almost with the minimum power of the engine.

The flame at the tail is completely powerless, not to mention spewing out a long tongue of fire, and the color has faded or something.

In order to test the spin function of the engine, special treatment must be done so that the airflow into the inclined nozzle cannot be reduced.

After the engine was successfully ignited, a circle of nozzles scattered at the tail also spewed out small flames to the outside.

The crowd observing outside the explosion-proof glass found that the oblique nozzles did not start to spray air outwards at the same time, but gradually along the involute.

"A special design has been made, inside these inclined nozzles of the engine, the time of spraying air flow from different angles to the outward of the nozzle is different, so as to ensure that the spin is ensured, when all the nozzles are sprayed outward, the cyclone is completed, and the rocket will fly at high speed while maintaining the rotation ......"

Without Liu Yue's explanation, everyone had already seen the rocket model on the test bench begin to rotate.

On the outside of the model, there are color markings to make it easier to see the rotation.

"The spin speed is very slow, can this be controlled?"

"It's fixed, even if you increase the engine power, it won't increase much. If the rotation speed is too fast, there are easy problems in attitude control, and the attitude stability cannot be ensured, which will further affect the accuracy of the landing point......"

Liu Yue explained.

The experiment has been carried out so far, and it can be said that it has been very successful.

Indeed, the whole experiment went very smoothly, and the final results proved that Liu Yue's design was completely reliable.

"Leader, after calculation, the specific impulse of this tail flame spin engine is 2370 m/s, and the spin speed is 1.7 rpm......" At the summary meeting later, Tian Li, a technician at the experimental station, reported various data.

The data isn't too good.

But it's not bad.

"The color of the flames is like that, the tongue of fire is so long, it is only 2370 than Chong, shouldn't it......" Jiang Zhihe was a little surprised.

Originally, he thought that the specific impulse of such an engine exceeded 3000 m/s.

There is still a big gap between domestic rocket engine technology and international ones.

Liu Yue also knows that in the next few decades, the specific impulse of solid-fuel rocket engines is generally 250~300S, that is, the effective exhaust speed is 2500~3000 meters per second, liquid rocket engines can reach 250~500S, and electric rocket engines can reach 700~2500S, but the thrust is small, and it is not suitable for large rockets and missiles at all......

Even 30 years later, the country's most powerful killer DF-5 is still improving, just because of the high efficiency and low cost of liquid fuel propellant......

In Liu Yue's time, the electromagnetic rocket engine had been put into use, but because the technology was not mature enough and the cost was high, it was still the use of liquid fuel rockets to send spacecraft and materials to the Tiangong space station in outer space, and then fly from the space station to the moon base using the Shenzhou spacecraft......

"That's not bad, either. The only thing is that the engine life is too long...... "Du Feng still thinks that this cost can be reduced.

"Leader, the new fuel research is expected to make the specific impulse reach 2800~3000 m/s, and the service life of the rocket engine will be reduced to ......about seven minutes," Liu Yue quickly explained.

At present, the old solid fuel is used for testing, which has low chemical energy and poor fuel efficiency.

Just kidding, that's pretty low.

The cost of a rocket engine, according to current calculations, is more than 18,000, and if it is reduced, it will not be possible.

"Isn't that still researched?" Du Feng was very painful.

Young people don't belong to their families, and they don't know that firewood, rice, oil, and salt are expensive.

With such a huge base to feed and the troops poor, if you can save a little, maybe you can save a few more artillery shots.

"Leader, now that the engine has been successfully tested, the 273 mm rocket artillery project ......" Zheng Jianguo directly asked the leaders whether this project could be carried out.

Of course, he is more concerned about the 8 million funds for this project.

According to Liu Yue's current experimental method, he simply can't need so much money.

"Why not? What is the next step?" The leaders of the base did not say a word.

It's all come to this point.

"To verify the aerodynamic layout of the rocket, you need to ......experiment in a hypersonic wind tunnel," Liu Yue stared at Jiang Zhihe's demeanor when he said this.

Sure enough, Jiang Zhihe frowned, "3x sonic wind tunnel?"

"No, 5 times. Liu Yue shook his head, "We need to test the ultimate speed, the new fuel research is successful, the rocket engine has a higher specific impulse, and the speed will be ......faster."