Chapter 529 We can set a small goal, break through five times the speed of sound first!

   "How is my research? Vice President Tim!" After being excited for a while, Dennis turned his head to look at Tim who was stunned.

The latter was at a loss for words for a while, and Tim had no idea that Dennis's outrageous explosive propulsion theory was actually done, so he had to smile wryly and say that he was indeed wrong, and the research institute will send more people in the future to fully support his work. Research.

  Seeing that Tim finally gave in, Dennis immediately let out a bad breath.

   During the year of research on explosive propulsion devices, he has often been ridiculed by those ignorant people, especially after the research has hit a bottleneck, the Institute of Magic is not even willing to send more alchemists to assist him.

   Firstly, there is a lack of people everywhere in the kingdom, and secondly, many short-sighted great wizards think that his explosive propulsion plan is too crazy, there is no possibility of success at all, and it is just a waste of time and resources!

This is why Dennis had no choice but to find Lydia and others to help him. Although these halflings do not know magic, they are very strong and have good engineering talents. useful.

   "Unfortunately, it's a little late. It would be perfect if it can be completed before this year's academic seminar!" Dennis said regretfully.

   Otherwise, it is safe to get a Morning Star Medal for your own research!

"It's not too late. When you completely perfect the jet fighter, it will be just in time for next year's academic seminar." Lin En said with a smile, and then looked at the already red, faintly melting signs, but still The propeller that was glowing with flames reminded me.

   "Master Dennis, I don't know if you have thought about changing the internal structure of the propeller to further increase the speed of the air jet..."

  Now that Dennis has created the prototype of the jet propulsion device, Lynn naturally no longer hides it.

  A jet plane, how can a speed of 700 kilometers per hour be enough?

   Even three times or five times the speed of sound is just the beginning!

   You must know that what they are preparing to deal with this time is a cross-border war. The enemy cannot overestimate it. They must go all out and make as many preparations as possible.

  A supersonic fighter jet is no worse than a legend in terms of speed and convenience. If it can be equipped with a device that launches an indestructible flame or even a small fusion bomb, it should be able to pose a considerable threat to the legend.

   Still improving? All the wizards present looked at Lynn with weird eyes, and Tim was completely stunned. In his opinion, the speed of 700 kilometers per hour is already a terrifying speed, and one day is enough to travel in the empire. Come and go several times.

  Dennis was extremely excited. Of course he had considered increasing the speed by changing the shape of the air tank. In fact, he had already done a lot of experiments.

  For example, he made some improvements to the third gas chamber of the propeller, which can spray out the high-temperature and high-speed airflow brought by the hydrogen-oxygen mixed explosion to the greatest extent, greatly reducing the possibility of explosion.

  In order to let Lynn see it more clearly, Dennis stepped forward, stopped and disassembled the propeller, and explained the internal structural design in turn.

Although every structural improvement is the result of dozens or hundreds of experiments, Dennis has no intention of hiding it from the star of magic. He explained everything from the design concept to the problems that arise during practical application in detail. .

  After all, Lynn was very generous and directly took out all the drawings of the internal combustion engine, and let him do research by the way. Dennis didn't think that the other party would do something to **** the results of magic research.

  After listening to Dennis' narration, Lynn pondered for a moment, and then spoke quickly.

   "You designed the structure of the three gas chambers very well. The high-purity hydrogen and oxygen cannot be ignited alone to block the backflow of high-temperature gas produced by combustion, but this is not safe enough..."

"I suggest that you can add a step of compressing the gas in the first half of the third gas chamber, which can not only increase the power provided by the gas combustion and eruption again, but also create a pressure difference between the front and back, which becomes the second insurance... "

  Lin En combined the design concept of jet turbine engine, and explained to Dennis how to compress the produced gas multiple times and send it into the combustion chamber through a plurality of rotating and fixed blades forming a V-shaped structure.

   "But, in this way, isn't this thruster more dangerous?" Tim couldn't help but interrupted. He felt that the magic star was coming up with some bad ideas.

The previous multiple explosions of the propeller were due to the high-temperature airflow generated by the hydrogen-oxygen combustion reaction being too strong, which directly blasted through the gas chamber. If the density of the gas is increased again, the thrust that erupts during combustion will be stronger, but the corresponding unexpected The likelihood is also higher.

"That's because the steel used to make it is too weak to withstand pressure and heat. If the key parts are replaced with stronger alloys or Mithril, this level of pressure is nothing." Lynn shook his head. After taking the blueprint on the table, he started to draw while continuing to speak.

"Also, Master Dennis, the heat dissipation of your propeller is also a big problem. I suggest that you design the combustion chamber as an embedded structure, open a few vents, and directly use the high-speed airflow around the fighter plane to cool down. "

"Wonderful, what a wonderful idea..." Dennis said excitedly. Originally, he planned to fill the combustion chamber with cryogenic liquid to achieve the cooling effect. However, Lynn's design is obviously more energy-efficient, because the wind comes directly from the fighter plane when it is flying. airflow.

  Lin En painted and painted, adding many ideas into it, so that the thruster that was modified after seven changes is simply like a sewing monster.

   But as long as it is useful and efficient!

  How convenient and how to come!

   "Why does this thruster structure look so strange?" Dennis glanced at Lynn's improved drawings and asked in confusion.

  It looks like two funnels, the front and the back, and the narrow parts are spliced ​​together.

"This is the most hydrodynamic structure that I have researched recently. It is estimated that doubling the flow rate of gas and liquid passing through the pipeline should not be a problem!" Lynn smiled and explained that this structure In fact, it is the famous Laval tube, also known as the transonic nozzle.

  Dennis frowned when he looked at the blueprint. He believed in increasing the speed by optimizing the propeller pipeline structure, but it would be too exaggerated to double the original speed just by changing one structure.

   You know, his explosive thruster can reach a speed of 700 kilometers per hour, and after the step of compressing the gas, its speed will only be faster!

   On this basis, it can continue to double, what kind of concept is that?

  Dennis is really hard to imagine, let alone see what is so special about the trumpet-shaped structure in front of him, which can play such a big role.

   "Is it okay, just try it out?" Lynn said with a smile, he was also curious about what the suture propeller in front of him could do.

  Dennis nodded, not talking nonsense, rolled up his sleeves, and Dang even began to improve the propeller.

  Lin En was not idle either, and personally took charge of making the third air tank that needed to be under pressure, and even called Tim who was idle on the side.

  The great wizard possesses atomic-level control ability, and can manipulate, analyze, and mimic almost all elements except special elements, which can only be described as efficiency in engineering.

   Even with the burning of the alchemy circle, the transformation of the new propeller was completed within two hours.

   Now it's time to experiment!

  A group of alchemists and Darren and other halflings immediately evacuated to a safe place. Perhaps because of their participation in the production, Tim didn't have such a big psychological obstacle this time.

  Dennis cautiously pressed his hand on the magic transmission device, and with the rapid influx of magic power, the propeller was activated again.

  A burst of loud explosion sounded in everyone's ears very quickly, and then the crimson tail flame shot out from the nozzle behind the thruster.

  The high platform used to fix the thrusters below was shaking constantly. If Lynn hadn't specially reinforced it, the thrusters might have flown out at this moment!

   "What a strong tail flame..." Dennis said in amazement, the high-temperature flames jetting out from the nozzle were actually gathered into a beam of jet fire two meters long, even longer than the propeller itself!

  Even with the naked eye, he can see that the thrust provided by this thing has improved several grades compared to before.

  Under the gaze of everyone, the scale on the thrust detection device is also rising...

  Six hundred, seven hundred, eight hundred, nine hundred... Then it got stuck here and didn't move.

   "Master Dennis, I'm afraid it has exceeded the limit we can detect!" An alchemist said in horror.

  This means that the maximum speed of the jet stream exceeds one thousand kilometers per hour!

After more than ten seconds of gaining momentum and accelerating, the shape of the high-temperature airflow jetting out of the nozzle changed again, and the part of the flame near the nozzle was slightly sunken inward, and the flame flow in this area was much brighter than the rest. In the shape of a ring, shaking slightly...

  Lin En took the initiative to explain without waiting for everyone to ask. "This is the speed of sound ring, which represents that the jet speed of the airflow exceeds the speed of sound propagation!"

  The pressure of the supersonic airflow is very high, so when it is sprayed into the air from the nozzle, it will expand rapidly, but the pressure of the expanded airflow will be significantly lower than the atmospheric pressure, so it will be compressed again.

In this way, the supersonic airflow will reciprocate between expansion and compression. This process will form expansion waves and compression waves. The two meet and superimpose during the propagation process, forming rings on the propeller exhaust flame. Also known as the sonic ring or the Mach ring!

  Because the steam flow formed by the mixed combustion of hydrogen and oxygen increases the humidity of the nearby air, this colored sonic ring looks particularly obvious.

   "The appearance of a ring represents double the speed of sound!" Lynn looked at the surging tail flame, but the second sonic ring did not appear. "Unfortunately, I still haven't been able to reach twice the speed of sound, but I think it should be very close..."

According to his expectation, after the gas compression step, the high-temperature gas flow erupted during combustion can reach subsonic speed before entering the Laval tube, and after two accelerations before and after passing through the Laval tube, it should be able to reach about twice the speed of sound. It's a pity that it was a little bit worse in the end.

   "Speaker Lynn, you mean that the speed of the jet of high-temperature air is now exceeding 2,000 kilometers per hour?" Tim said incredulously.

  Although the speed of sound propagation will vary depending on air pressure and temperature, the average speed is about 340 meters per second, which is 1,200 kilometers per hour!

  And close to twice the speed of sound means more than 2,000 kilometers per hour...

  Tim clicked his tongue, what kind of monster are they trying to create?

  Even Dennis was a little unbelievable. Even though he had guessed that after their transformation, the power of the propeller would inevitably have a qualitative improvement, but he didn't expect it to be so fast.

   "Dean Lynn, can you fly so fast?" Lydia asked curiously.

   "Not yet..." Lynn shook his head, his flying speed was about 1.5 times the speed of sound.

   "Doesn't that mean that even legendary wizards can't catch up with me as long as I fly this fighter plane?" Lydia said expectantly.

   "It's not certain." Lynn laughed, because Lydia was too confident, so she poured cold water on her. "The speed of some magic is still very fast. For example, my electromagnetic rail gun can reach more than 20 times the speed of sound. If it is replaced with a laser beam, you may not even have the possibility of dodging."

  Lydia thought about the scene where she was flying a fighter plane and being pointed at by several laser beams, and suddenly shrank her neck.

  Lin En asked Dennis to stop the operation of the propeller, disassembled it again to find out which point affected the speed of the airflow to the limit, and continued to improve the internal structure.

   "Do you want to change?" The corner of Tim's mouth twitched involuntarily. Such a fast speed made him feel a little bit of fear, which was completely beyond his imagination.

  In the past, the speed of sound was a field that only legends could reach, which means breaking the sound barrier and breaking through the natural limitations.

   In his opinion, this speed is fast enough!

   "It's only close to twice the speed of sound, and it's far from reaching the limit of jet propulsion!" Lynn said with a smile.

  For jet fighters, three times the speed of sound is not much, five times the speed of sound is acceptable, and ten times the speed of sound is enough to say the last sentence...

"In addition, the shape of the fighter plane also needs to be continuously optimized. Supersonic speed and subsonic speed are two completely different concepts. A supersonic fighter jet will accelerate the flow of surrounding air, compress the gas, and form a shock wave surface on the windward side of the plane... "

  Lynn explained to Dennis the various obstacles that a fighter plane would encounter when flying at high speed, and drew the design drawings of a simple wind tunnel to simulate the airflow state during supersonic flight.

  (end of this chapter)