Iron Sonata of World War II

The third is to establish a new army based on the stormtroopers and merge the original Wehrmacht into the stormtroopers. In fact, it is to remove the control of the Junkers officer corps over the army.

If Rohm was just an ordinary Nazi party member, the Junker landlord class and monopoly bourgeoisie in Germany would probably laugh it off. After all, the composition of the Nazi Party is very complicated, and it is not surprising that there are a group of party members with left-wing political views.What really makes the Junkers and the bourgeoisie restless is that Roma has a stormtrooper with more than 300 million people in his hands, and this number is still expanding rapidly.Although in the eyes of the National Defense Forces, the stormtroopers are nothing more than a group of street gangsters, but this number is scary enough. Junkers and capitalists have to worry that if this continues, if one day Roma has full wings, it will really What should I do if I go crazy and plan to practice his political ideas?

It is not just the Junker landlords and the bourgeoisie who are worried about Roma. A group of veterans in the Nazi Party, including Hess, Himmler, Goebbels, Goering and others, also regard Roma as a serious problem.On the one hand, this is because Roma's strength in the party has taken away a large part of their power, and on the other hand, because in Roma's eyes, they also belong to the "betrayed revolutionaries" in the party and are the "second revolutionists" in the future. " Objects that must be cleared.

Very sadly, even by this time, Roma himself didn't know he was sitting on the crater.After Hitler rejected his political appeal, Rohm began to contact the left-wing forces outside the party, preparing to force Hitler to accept his political views at the upcoming Nazi Party Congress.

Roma even proudly declared: "Adolf can no longer trample on my claims as before. I am no longer what I used to be! Don't forget that I have 300 million stormtroopers, and all key positions are occupied by my people. Adolf also knows that I have many friends in the Wehrmacht. If Adolf is reasonable, we will solve the problem calmly. If he is not, I plan to use force, not for myself, but for our revolution!"

Beginning in January 1934, the monopoly bourgeoisie in Germany could not sit still first, and industrial giants such as Farben Chemicals, Siemens, and Krupp began to exert pressure on Hitler one after another.Hitler had to repeatedly assure his patrons that the Nazi Party would never engage in a second revolution, nor would it engage in total nationalization.

Hitler had just appeased the monopoly bourgeoisie. In April 1934, the Juncker officer group began to put pressure on Hitler again. Hitler had to agree to remove Rohm within two months.However, in June, there was still no sign of Rohm being dismissed, and the Junkers officer group finally couldn't bear it anymore.

On June 1934, 6, under the strong request of conservative forces, Hitler went to visit the sick German President Paul von Hindenburg, the head of the Ministry of Finance Fritz von Blomberg and the commander of the Wehrmacht Hans von Seeckt was also present, and Blomberg told Hitler that if he did not act soon against Roehm, President Hindenburg would declare a state of emergency and impose martial law.

This is almost directly telling Hitler that if you let Rohm mess around again, even if you Hitler is the idol of the whole people, the Junker Group and the big bourgeoisie are the main directors of this entertainment company, they still have the ability to hide you or force you to quit circle!Did Hitler have a choice at this time? On June 6, under the escort of the armored convoy of the Wehrmacht, Hitler personally led a team of secret police and rushed into the nursing home where Rohm and others stayed. Rohm was arrested.Just two days later, the SA, a paramilitary organization of four million people, was dismantled from the top.

Chapter 169 The Aftermath of the Incident

In the "Night of the Long Knives", in addition to a group of high-level members of the stormtroopers, including Rohm, who were purged, there was also a veteran of the Nazi party who was also assassinated by the SS. His name was Griegel. Strasser.Similar to Rohm's political stance, Strasser's views also had a strong socialist overtone, requiring the nationalization of all means of production of monopoly organizations.Dissatisfied with the compromise between the Nazi Party and the Junker class and the bourgeoisie, Strasser angrily quit the Nazi Party in 1932 and continued his political activities. Unexpectedly, he also suffered misfortune this time.

For Hitler's performance in "Night of the Long Knives", both the business and military circles expressed their approval, and Hindenburg even sent Hitler a congratulatory message.Blomberg, head of the Ministry of Housing and Housing, also highly praised Hitler, saying that he "shattered the putschists with military decisiveness and extraordinary courage." Beyond disputes, gratitude will be expressed for the loyalty and dedication of our military."

It can be said that through this bloody political incident, the Nazi Party cleaned up the left-wing forces with socialist tendencies inside.It is tantamount to handing over his own vote to the domestic ruling class by cutting off his own arm.As far as Hitler himself was concerned, the "Night of the Long Knives" did help him clean up many political opponents inside and outside the party, but this incident also made Mustache see his powerlessness in the face of joint pressure from the ruling class.Especially at the moment when Hindenburg issued the threat of martial law across the country if he did not do anything, Hitler felt a deep fear, a fear that he might be crushed into dust at any time.

But for Helena, Hitler's fear is not a bad thing.Helena knew that Hitler would not be willing to be the puppet of Junkers and the big bourgeoisie forever, even though Hitler was still looking like a low-browed and pleasing little wife in front of Hindenburg just now.So in the future, Mustache will definitely try to introduce other forces to increase his political chips, and this is precisely an opportunity for Helena, an opportunity to sell his own goods.

Helena chose to achieve her goals by selling private goods to Mustache, not because she had any special affection for Mustache, but because apart from Mustache, Helena's political affairs in Germany There is really no one on the stage who is both capable and willing to change the status quo.

Of course, Hitler didn't have any political integrity. However, it was precisely because he had no political integrity that Helena only needed to analyze the pros and cons when communicating with Moustache, instead of empty talk. This made all her political ideals All can be realized through the realization of interests.Compared with the flexible mustaches, those left-wing forces who are serious about seeking change in the German political arena are not suitable targets for support.Looking back at the history of "rebellion" by left-wing forces in the German political arena over the past few decades, Helena can only shake her head and sigh.

In 1918, the Social Democrats launched the November Revolution. As a result, the uprising was not yet successful, and the Social Democratic Party was split. The opportunist forces in the party and the conservative forces in the country united to strangle the left-wing forces in the party.In the end, the November Revolution did not achieve the goal of the revolution except to drive away the Hohenzollern royal family. The Social Democratic Party also carried a huge political burden because of the too harsh armistice agreement.

In 1923, the Central Committee of the German Communist Party first recklessly prepared to unite with the Social Democratic Party to launch a national workers’ uprising. After the Social Democratic Party withdrew, the Central Committee of the German Communist Party began to hesitate and retreat, and urgently canceled the uprising plan.Unfortunately, the party organization in Hamburg still launched the uprising on time because it failed to receive the notification of the cancellation of the uprising in time.The results can be imagined, the uprising was suppressed by the military and police within three days, thousands of people were arrested and sentenced, and the vitality of the German Communist Party was also severely damaged.

The Social Democratic Party and the German Communist Party are so useless, and the left-wing forces in the Nazi Party that stick to the socialist stance are not much better. Whether it is Strasser or Rohm, they are politically naive and ridiculous.

In fact, when Ernst Röhm demanded the nationalization of all monopoly organizations and the abolition of the Wehrmacht and its replacement by the SA, it was tantamount to an open war with the Junkers and the monopoly bourgeoisie.When Rohm said "If Adolf is reasonable, we will solve the problem calmly, if he doesn't, I plan to use force", it is tantamount to telling Hitler publicly that he is going to fight with Adolf at the upcoming party congress. Hitler had a showdown over the line of the Nazi Party.

If it is already a very serious mistake to reveal the strategic intention to the opponent, then Rohm's wonderful operation behind is simply stupid and inspirational.Just before the new Nazi party congress was held, in order to show that he had no intention of rebelling against Hitler, on June 1934, 6, Rohm announced that the SA was on a national holiday, which meant that he was separated from the only force he could rely on.

And just before putting the stormtroopers on vacation, Rohm also put down a cruel sentence: "If the enemies of the stormtroopers hope that the stormtroopers will not call up members to return to the team after the holiday, then let them think so for the time being. But when necessary At that time, I will answer them in the necessary way, and the SA will control the fate of Germany now and in the future!"

Roma's approach is equivalent to someone holding a gun in his hand, standing in front of a group of enemies, and saying loudly: "Do you see the gun in my hand? I want to use it to kill you I will put down the gun later, but when I pick up the gun again, it will be the time of your death!" Then the person really put down the gun while talking...

All in all, over the past decade or so, the Social Democratic Party, the German Communist Party, and the left wing of the Nazi Party have successively tried to use force to transform Germany's social structure, but they all failed without exception, and there was no suspense in the process of failure.

This is mainly because Germany is one of the strongest links in the imperialist chain. Lenin once called the German imperialist model "Junker bourgeois imperialism", that is, the Junker landlord class and the monopoly capitalist class are economically closely linked. The monopoly capitalist economic model formed by combination and political alliance.

It has to be said that the joint strength of the Junker landlord class and the monopoly bourgeoisie is much stronger than all the revolutionary forces, so that even when the front line of World War I was unfavorable, they could still easily suppress the wave of the November Revolution.This is why the socialist revolution was successful in Russia but failed miserably in Germany.

The strength of the opponent is so powerful, but the left-wing forces in Germany themselves are a bunch of war scum. The Social Democratic Party, the German Communist Party, and the left wing of the Nazi Party all emphasize "socialism". It is extremely developed, and the "socialism" advertised by all left-wing political forces in Germany contains a large number of urban petty bourgeois elements. If you do not do this, you will not be able to gain a foothold in Germany, so even the relatively radical KPD is not immune.

Although the urban petty bourgeoisie was dissatisfied with the Junker landlords and the monopoly bourgeoisie who possessed a large amount of social resources, since they did not really have nothing, it was impossible to take a firm stand.This is also the class root of the general lack of combat effectiveness of left-wing parties in Germany.

Helena looked at the Social Democratic Party, which she was fighting among herself, at the German Communist Party, which was aggressively advancing and retreating, and at Strasser and Rohm, who were so naive in politics.The final conclusion is: all the left-wing forces in German politics, no matter which party they come from, there is almost no one who can beat them.Instead of counting on these people to rebel, it is better to transform the mustache, at least Hitler's political IQ is online most of the time.

As for the alliance between the Junker landlord class and the monopoly bourgeoisie, it will definitely change in the long run. This thing is the real "horcrux" of the German militaristic forces.But if you want to change it, you can't be like the five scumbags like Rom, who are rushing up with a dog-beating stick called the Stormtrooper.

What Helena has always believed in is: as long as the hoe is well swung, there is no corner that cannot be dug.Before the reform of land use rights, Helena had quietly dug away a small piece.Although the Junker landlord class gained some economic benefits in this reform, they also lost their common economic base.

Helena believes that when a class loses its common economic foundation, it is only a matter of time before its internal differentiation occurs. It is impossible to maintain the stable existence of a class for a long time only by relying on the word "Feng" in the surname, which marks the status of nobility. Yes, this is also an ulterior purpose of Helena's insistence on splitting up the land usufruct and control rights.

Of course, breaking the wall of Junker's imperialism cannot be accomplished overnight.Which piece should be dug next, now Helena has a rough idea.However, this timing is also very important. The small hoe in Helena's hand must wait until there is a double shortage of capital and labor in Germany before it can be wielded, which will be about one or two years later.

Chapter 1 Technology Migration

Since the end of 1933, after the first successful first flight of the world's first turbo-pumped rocket in Peenemünde, the launch vehicle technology has been approved by the German national project under Helena's suggestion, thus obtaining more development resources.

In Helena's plan, Germany's next-generation liquid rocket engine needs to cross two small goals: the first is to use kerosene fuel with higher specific impulse and good stability to replace ethanol fuel with lower specific impulse and volatile; It is to replace the relatively bulky and inefficient gas generator cycle with a more efficient gas generator cycle.

Not only can the performance of the liquid oxygen kerosene rocket engine take a big step, but as long as the liquid oxygen in the oxidizer is replaced with fuming nitric acid, it can be transformed into a very good entry-level liquid ballistic missile engine.In the last plane, the early model of the Soviet "Scud" missile used the kerosene nitrate engine with the gas generator cycle.

Of course, it will take some time to complete these technological leaps, but just as Helena said to Hitler earlier, the rocket research and development project is like the locomotive locomotive of a train, which has a strong pulling effect on many technological fields.Since the successful launch of the A-4 rocket that uses a turbo pump pressure cycle, Helena is ready to make full use of Germany's early achievements in this type of rocket, and open up a piece of technological virgin land that she has long coveted.

If Helena told military fans of later generations that the technological virgin land she was eyeing was jet engines, it is estimated that many military fans would be very surprised. After all, in the eyes of most people, rocket engines for spaceflight and jet engines for aviation The engine is very different, and it can even be said to be two completely unrelated things.

But in fact, in the early development process, the origin of liquid rocket engine and jet engine is quite deep.This is because in essence, the working principles of the pump-pressed liquid rocket engine and the jet engine are very similar only in terms of the impeller system. Both of them use high-temperature and high-pressure gas or gas to drive the turbine, and both use The turbine drives the fuel/oxidizer pump or compressor to pressurize the fluid.

This technical connection allows the two to learn from each other in many places, such as the seven-stage axial flow engine used in the J-2 hydrogen-oxygen engine used in the upper stage of the US "Saturn V" launch vehicle in the last plane. The liquid hydrogen pump, to a considerable extent, borrowed from the technical achievements of the United States on jet engines at that time.Moreover, Rocketdyne, which designed the J-2 engine, was finally acquired by Pratt & Whitney, a world-renowned aero engine manufacturer.

It must be added that although there are similarities in the impeller systems of liquid rocket engines and jet engines, there are many obvious differences between the two due to different work requirements.There are two notable differences:

One is the difference in working time. The working time of the impeller system of a liquid rocket engine is very short, generally only tens to hundreds of seconds, which is equivalent to a very explosive sprinter; while the working time of the impeller system of a jet engine is longer, Moreover, repeated use needs to be considered, and the maintenance interval should reach dozens of hours at worst, otherwise it will not be usable at all.

The second is the difference of the pressurized object. The impeller system of the liquid rocket engine needs to be pressurized. Most of the objects are liquids that are not easily compressed. Therefore, the cavitation problem caused by the collapse of bubbles needs to be considered in the design; The object that the compressor needs to pressurize is the air that is relatively easy to be compressed. Here, the cavitation problem does not exist, but it is precisely because the air can be compressed that if it is not designed properly, it will cause surge.

It was precisely because she clearly saw the technical similarities between jet engines and turbopumps of rocket engines that, shortly after the successful launch of the A-4 rocket, in early 1934, Helena couldn't wait to put the development of jet engines on the agenda. schedule.In Helena's memory, Dr. Hans von O'Hain, the inventor of the jet engine in the last plane, entered the Heinkel Company in 1936 to carry out research on jet engines. The start of the engine was brought forward by more than two years.

Although a certain amount of technological spillover can be obtained from the turbo pump of the rocket engine, and although Helena can spend relatively abundant funds on research and development, there is still a very critical element that restricts the development of the German jet engine, that is, Helena temporarily Could not find a suitable leader to lead the development of this project.

In the last plane, the close friendship between the inventor of the jet engine, O'Hain, and his boss, Ernst Heinkel, the famous aircraft designer and founder of the Heinkel Company, has always been a good story. In March 1936, the 3-year-old O'Hain met the 26-year-old Heinkel with a letter of recommendation from his mentor, Professor Ball.Henkel already had a soft spot for high-speed aircraft, and after talking with O'Hain, he admired this energetic young man very much.So Henkel made a quick decision: "From today, you are hired. I will give you 48 marks, and you will produce a jet engine within 5 months!"

Because the development of jet engines was more difficult than expected, O'Haiin failed to meet Heinkel's six-month expectation to complete the development of a jet engine, and he spent a full 12 months. At the beginning of March 1937, the first jet engine using hydrogen as fuel finally ran successfully on the bench. This is also the first jet engine to successfully operate in human history.

It is worth mentioning that in the last plane, besides O'Hain, there is also a jet engine pioneer that must be mentioned. He is the British inventor Frank Whittle. In April 1937, only one month later than O'Hain, the jet engine developed by Whittle was put into bench operation for the first time.

Although the time of successful operation was one month later than Ohin, in fact, Whittle proposed the design of the jet engine in 1929 and applied for a patent in 1930, but neither the British Ministry of Aviation Still, the bosses of major British airlines thought Whittle was whimsical.It was not until 1935 that Whittle, with the help of alumni from the Royal Air Force Academy, got the first decent investment and spent two years designing Britain's first jet engine.

The problem Helena is facing now is that Olympian is busy working on his doctoral dissertation at the moment, and he will not be able to graduate until next year. Helena is embarrassed to let him put down his upcoming studies.And Whittle has already served in the Royal Air Force, and it is impossible for Germany to poach people in the Royal Air Force.Dr. Walter is the world's top impeller designer, but now he has not only the development project of hydrogen peroxide torpedo, but also the development project of rocket turbo pump. The dude added another burden.

Due to the lack of top-notch masters to lead the team, the current jet engine project can only be developed slowly. Fortunately, with Helena's regular checks, even if the development speed is slower and more bumpy, there will be no directional errors. .And even if you fail a few more times, the accumulated experience will be turned into wealth, and the progress will not be slower than that of the previous plane, so Helena is not particularly impatient.

Chapter 171 Axial and Runoff Flow

If the engine is the heart of the aircraft, then the heart of the turbojet engine is the core machine composed of three core components: the compressor, the combustion chamber, and the turbine.As one of the three major components of the core engine, the compressor is mainly responsible for inhaling and compressing the air and sending it into the combustion chamber, which has decisive significance for the performance of the jet engine.From a certain point of view, the development history of jet engines in the last plane for more than 80 years is a history of continuous increase in total pressure ratio and vortex front temperature.If you want to increase the total pressure ratio of the engine, you cannot do without the help of the compressor.

The working principle of the turbojet engine is generally as follows: the first step, driven by the turbine, the compressor sucks in and compresses the air and sends it to the combustion chamber behind; the second step, the fuel is burned in the high temperature environment of the combustion chamber , to generate high-temperature gas and flow to the turbine at the rear; in the third step, part of the energy of the high-temperature gas drives the turbine to do work to drive the compressor in front, and the other part is ejected backward through the engine exhaust pipe to generate thrust.

An additional point to be noted is that when the turbojet engine is working, the three steps mentioned above are actually carried out continuously, which is very different from the piston engine in which each stroke is carried out sequentially.Specific to the link of compressed air, the process of compressing air in a piston engine is only carried out in the compression stroke, while the compressor of a jet engine is pressurizing the air entering the engine every moment.

So how does the compressor of a jet engine ensure continuous compression of air?In a piston engine, compressing air is very simple, just close the valve on the cylinder, and then let the piston move from bottom to top driven by the flywheel.As the cylinder is sealed and the volume is reduced, the air in the cylinder is naturally compressed.However, this simple method of compressing air not only cannot work continuously, but also requires a closed environment, so it is naturally impossible to use it on a jet engine.

In order to continuously compress air in a non-airtight environment, the compressor of a jet engine is structurally divided into two parts: a rotor and a stator.When air flows over the high-speed rotating rotor wheel, the blades on the rotor do work on the air.In this process, the air gains energy, which is not only reflected in the increase of air pressure, but more importantly, the air gains a higher speed from the rotor.And as the high-speed air exits the rotor and enters the carefully designed stator, it slows down.According to the principle of energy conservation, the kinetic energy carried by the high-speed air will not disappear out of thin air, and this part of the reduced kinetic energy will be converted into the internal energy and pressure potential energy of the air.

To put it simply, the air flowing into the engine is accelerated and supercharged in the rotor, and decelerated and supercharged in the stator. In this process, the mechanical energy of the compressor rotor is converted into the internal energy and pressure potential energy of the air.The specific performance is: the temperature of the air flowing through the compressor rises, the volume shrinks, and the pressure increases.According to the structure of the rotor and stator of the jet engine compressor, we can roughly divide it into axial flow type, radial flow type (also known as centrifugal type) and oblique flow type between the two.

In the last plane, compared with the axial flow and centrifugal compressors that were born earlier, the oblique flow compressor was invented in 1942, and because the blades of the oblique flow compressor require complex three-dimensional twists, in Processing was difficult in the era without CNC machine tools, so the oblique flow compressor did not become popular until the 80s.It is precisely because there are some insurmountable technical obstacles in the oblique flow compressor at this stage, so although the oblique flow compressor has become more and more common in small-thrust jet engines in later generations, Helena still does not regard it as a development At most, only some preliminary technical exploration work will be carried out. At present, the research and development focus of compressors must be on the two types of axial flow and radial flow (centrifugal).

The rotor impeller of a radial (centrifugal) compressor is a disk covered with radial blades.As air flows into the high-speed rotating impeller, the impeller does work on the air and forces it out through the radial channels between the blades.In this process, the work done by the impeller to the air increases the temperature and pressure of the air on the one hand, and also gives the air a certain speed on the other hand.After the air flows out of the impeller at high speed, it enters the diffuser (stator) surrounding the impeller, where the kinetic energy of the air is converted into pressure potential energy and internal energy, which is specifically manifested as the speed slows down, while the pressure and temperature further rise.

Axial flow compressors and centrifugal compressors are very different in structure, but they are similar in terms of basic principles.Each stage of the axial flow compressor is composed of a high-speed rotating rotor blade and a fixed stator blade.The front rotor blades act like an electric fan to drive air, pressurizing and accelerating it into the rear stator blades.The orientation of the stator blades is exactly opposite to that of the rotor blades, so the speed of the air will be slowed down when it flows through the stator blades, and its temperature and pressure will naturally rise under the constraints of Joule's energy conservation principle.

It is not difficult to see that when the air entering the axial direction flows out of the radial (centrifugal) compressor, its flow direction changes from the axial direction to the radial or centrifugal direction; while when it flows out of the axial flow compressor, the flow direction remains the same. Keep axial.This difference is not only the biggest difference between centrifugal and axial flow compressors, but also the origin of their respective names.It is precisely because of this difference that the axial flow and centrifugal compressors have their own distinct advantages and disadvantages.

Let's talk about the centrifugal compressor first. Since the flow passages between the rotor blades of the centrifugal compressor are very long, the air passing through these flow passages can continuously obtain energy, so the boost ratio that a single-stage centrifugal compressor can provide (stage pressure ratio) is higher.Even if the stage pressure ratio of early centrifugal compressors can reach more than 3, in the 21st century of the last plane, centrifugal compressors with stage pressure ratios exceeding 10 are not uncommon.

The high stage pressure ratio brings many advantages to the centrifugal compressor. Since the one-stage centrifugal compressor can achieve the pressurization effect of the multi-stage axial flow compressor, the centrifugal compressor requires fewer stages.This makes the centrifugal compressor shorter in axial size, simpler in structure and more reliable in operation under the same conditions.

If the advantage of the centrifugal compressor mainly comes from the high pressure ratio, then its main disadvantage is that the compressed air can only be exported radially. This output method undoubtedly puts a heavy burden on the centrifugal compressor. the shackles.This shackle is mainly reflected in two aspects:

For one thing, in an engine using a centrifugal compressor, the air makes at least two sharp bends.The axially input air must first turn into a radial flow in the impeller, and then turn back to the axial flow in the air collector after flowing out of the diffuser, so that the energy loss will naturally not be too small.Therefore, centrifugal compressors can generally only connect two stages in series at most. If more stages are connected in series, the energy loss will reach an unbearable level. If the compressor consumes too much energy, the efficiency of the engine will not increase but decrease.

On the other hand, since the impeller of the centrifugal compressor imparts energy to the air through centrifugal action.This results in that the performance of the centrifugal compressor depends largely on the diameter of its rotor impeller, but the increase in the diameter of the impeller will lead to an increase in the windward area of ​​the engine, which is the same as the pursuit of a smaller windward area by jet fighters. contradictory.On a low-flow engine, this problem may not be particularly prominent, but as the engine flow increases, this problem will become quite serious.

To sum up, the single-stage pressure ratio of the centrifugal compressor has advantages, so it has the advantages of simplicity and reliability in occasions where the requirements for flow rate and total pressure ratio are not high.However, in the case where larger flow rate and higher total pressure ratio are required, the development potential of the centrifugal compressor will be limited due to the constraints that too many booster stages cannot be connected in series and the diameter of the impeller cannot be expanded infinitely.

On the other hand, the advantages and disadvantages of the axial flow compressor are just opposite to those of the centrifugal compressor.Although the single-stage axial flow compressor can only provide a lower stage pressure ratio, which is below 1.5 in most cases, but because in the axial flow compressor, the air flows in axially and flows out axially, there is no centrifugal As the compressor turns sharply, the energy loss is small.This advantage allows the axial flow compressor to stack the total pressure ratio in series almost at will.If a few levels are not enough, go to a dozen levels, or if it is not enough, go to dozens of levels.In the 21st century in the last plane, it is not uncommon for military engines using multi-stage axial flow compressors to have a total pressure ratio exceeding 20 or even 30, while commercial engines pursuing high fuel efficiency have even surpassed the 50 mark. .

In addition, since the process of compressing air by the axial flow compressor is carried out in the axial direction rather than in the radial direction, the diameter of the engine using the axial flow compressor only needs to ensure that the air can pass through smoothly, which gives The smaller windward area and windward resistance of the axial flow engine, although the price is the increase of the axial length of the engine, but for fighter jet engines, the radial dimension is always more sensitive than the axial dimension.

In the last plane, both Ohain in Germany and Whittle in England used simple and reliable centrifugal compressors at the beginning, but in the subsequent development, the scientists of the two countries had differences.

The Germans soon turned their energy to the axial flow engine with greater potential. The result was the Jumo004 and Bmw003 engines. It was picked up by the French and became the prototype of the famous "Ata" series engine. The "Ata" series has been continuously improved since then, and the ultimate development model obtained is the M262 series turbofan engine used on the Mirage 2000 fighter jet (this is the real modification that even my mother doesn't know, but the single-rotor structure has always been Be retained, of course, this also greatly limits the development potential of Mirage 53).

The British further tapped the potential of the centrifugal engine. First, they installed the "Derwent" engine using a centrifugal compressor on their own Meteor fighter jets, and then developed the "Nin" series of engines on this basis.It is worth mentioning that the "Nin" engine was later sold by the British to the Soviet Union. After the Soviet Union improved it, imitated and improved it, it got the VK-1 series engine, which is the power of the MiG 15 and MiG 17 series fighters. .Later, China introduced and imitated the VK-1F engine and the MiG-17 together. This is the turbojet-5 engine that military fans are familiar with.

So how will Helena choose whether the compressor should be centrifugal or axial?

Chapter 172 Three Step Layup

According to the experience of the last plane, in the long run, the multi-stage axial flow compressor will definitely overwhelm the centrifugal compressor, thus becoming the mainstream option for jet fighter power.This is because with the continuous improvement of fighter jets' power requirements, greater air flow, higher total compression ratio, less energy loss, and smaller windward area have become the goals pursued by the new generation of engines, and these are exactly the The shortcomings of the centrifugal compressor.

According to the general experience of later generations, when the flow rate of the core machine of the jet engine exceeds the order of 5 kg/s, if the centrifugal compressor is still used, the loss outweighs the gain gradually.So we can see that almost all engines with medium or higher thrust on later generations of fighter jets use axial flow compressors.However, even in the era when the axial flow type was popular, the centrifugal compressor did not disappear completely, but showed extremely tenacious vitality.In small-thrust turbojet, turbofan, and low-to-medium-power turboprop and turboshaft engines, centrifugal compressors are favored by later generations of engine designers for their unique advantages of high single-stage compression ratio, simple structure, and low cost. Welcome, became one of the mainstream forms of compressors for these types of engines.

Helena's long-term plan is naturally to apply the full axial flow compressor to the German fighter jet engine, but Helena is not going to abandon the centrifugal compressor and go straight to the full axial flow compressor. Start with a centrifugal compressor and work your way up to this goal step by step.There are three reasons for doing this:

The first reason is that developing a centrifugal compressor first can make full use of Germany's past technology accumulation. Previously, when Germany developed aero-engine superchargers, it used centrifugal impellers, and the fuel pump and liquid oxygen of the A-4 rocket The pump also uses a centrifugal impeller. Compared with the axial-flow compressor, which has almost no technology accumulation, developing the centrifugal compressor first can obtain more technology transfer from other fields, which is very beneficial to reduce engineering risks.As for the axial-flow compressor, you can get on the bus first and then pay the fare.

The second reason is that developing centrifugal compressors first can lower the threshold for Germany to enter Xinshou Village. Since the compression provided by each stage is relatively low, axial flow compressors must be connected in series in multiple stages to achieve the ideal total pressure ratio, so the axial flow The structure of the centrifugal compressor is much more complicated than that of the centrifugal compressor. This kind of complexity is undoubtedly very unfriendly to Germany who has just entered Xinshou Village.

In World War II on the previous plane, the Juom262 turbojet engine on the German Me004 fighter jet used eight stages of axial flow compressors to achieve a total compression ratio of 3.1, and the average stage pressure ratio was only about 1.15.If a centrifugal compressor is used, only one stage is needed to achieve the same compression effect, and each Jumo004 engine requires hundreds of compressor blades alone, and each piece must ensure good processing accuracy, which is difficult to manufacture One can imagine.

The third aspect is that starting from the centrifugal compressor can help Germany improve the pedigree of the jet engine.Even if Germany turns to axial-flow compressors on fighter jet engines in the future, it does not mean that the investment in centrifugal compressors has been in vain.Centrifugal compressors are found in turboprops, helicopters, and even cruise missile engines.Although it depends on the development of future history when these things can be produced in this plane and whether they can be used in the next war, there is always nothing wrong with retaining the technical route of centrifugal compressors for Germany. of.

In the plan for the development of German jet engines in the next ten years, Helena plans to adopt a three-step development strategy for the impeller system, and sets a relatively reasonable technical span for each of the three steps.In this way, it can be ensured that while the technology is rapidly iterating, it will neither stumble because of taking too big steps, nor stagnate because of taking too small steps.The specific development steps of the compressor planned by Helena are as follows:

The first step was to develop a single-rotor turbojet engine using a single-stage centrifugal compressor.The compressor is driven by a single-stage radial gas turbine, the simplest form of jet engine impeller.From a certain point of view, this combination directly borrows from the pump system structure on the previous liquid rocket engine, and is also in line with the structure of the exhaust gas turbocharger of the internal combustion engine, which can minimize the entry threshold of jet engines.In fact, Dr. O'Hain from the last plane used this simple impeller structure when developing the world's first jet engine.

As for technical challenges, there are naturally some. The operating temperature of the turbine of the jet engine is much higher than that of the gas turbine of the A-4 rocket and the exhaust gas turbine of the internal combustion engine.In March 1937 on the last plane, when O'Haiyin was conducting the first jet engine test run, due to underestimation of the gas temperature, the turbine blades made of stainless steel were almost burned through by the hot gas.At the beginning, O'Hain used hydrogen with a high combustion temperature as fuel, which aggravated the problem. Later, after switching to gasoline as fuel, the gas temperature decreased and the problem was alleviated.

Fortunately, Helena, the original plane, has done a lot of technological exploration in the field of superalloys in advance. Even without using additional cooling methods, the existing iron-based superalloys can work stably at a vortex front temperature of about 1000 Kelvin. The conditions were simply unimaginable for Ohain and Whittle in the last plane in 1937.

The second step is to develop a single-rotor turbojet engine using an axial flow/centrifugal combined compressor.In Helena's plan, this compressor is actually composed of several stages (preliminarily conceived as three stages) axial flow compressor followed by a centrifugal compressor.The axial and centrifugal stages of the compressor are designed coaxially, still driven by the first-stage gas turbine.However, the turbine form will be changed from a centripetal type to a more efficient axial flow type, so that the engine exhaust thrust loss will be relatively small.The purpose of using this combination is to give full play to the respective advantages of axial flow and centrifugal compressors.

On the one hand, since the front three-stage axial flow compressor can perform a round of preliminary compression on the air, the volume of the air has been greatly reduced when it enters the last stage of the centrifugal compressor.This allows the diameter of the last-stage centrifugal compressor to be made smaller, and the adverse effect on the diameter of the engine will therefore be reduced a lot.

On the other hand, since the stage pressure ratio of the centrifugal compressor is much higher than that of the axial flow compressor, only one stage can achieve the compression effect of the multi-stage axial flow compressor, which avoids the use of the full axial flow compressor on the one hand. Too many stages lead to the problem that the axial length of the engine is too long, and on the other hand, it also greatly reduces the manufacturing cost.

It should be known that for a full axial flow compressor, the characteristics of the last few stages of impellers are: the length of the blades is getting shorter and shorter, the number of blades is increasing, the density of blades is increasing, and the requirements for blade manufacturing are getting higher and higher. , but due to the increasing difficulty of pressurization, the supercharging efficiency of each stage is actually getting lower and lower.But now only one centrifugal stage is needed to solve all the embarrassments. According to Helena's estimate, the combination of three axial flow and one centrifugal is enough to achieve the supercharging effect of a twelve-stage axial compressor.

The main difficulty in the development of this stage is the matching of the axial flow stage of the compressor and the centrifuge. Due to the coaxial design of the upper single rotor, the axial flow stage and the centrifugal stage can only run at the same speed.In this case, how to balance the work efficiency of both will become a difficult point in design.

The way to completely solve this problem, of course, is to adopt a dual-rotor design, use independent turbines to drive the axial flow stage and the centrifugal stage respectively, and let them run at different speeds can completely solve this problem, but the supporting structure of the dual-rotor engine It is more complicated, which somewhat violates Helena's original intention of simplifying manufacturing.

The third step is to develop a twin-rotor turbojet engine using a full axial flow compressor, and overcome the afterburner technology of jet engines by the way.This kind of compressor is also the mainstream form of fighter compressors in later generations. The P-21 engine used by the MiG 13 on the previous plane is actually a typical twin-rotor afterburning turbojet engine.

The twin-rotor engine divides the fan/compressor of the engine into a high-pressure part and a low-pressure part, which are driven by a set of gas turbines respectively.The front fan/low-pressure compressor rotates at a slower speed, and the rear high-pressure compressor rotates faster, which can further improve the boosting efficiency, reduce surge, and reduce fuel consumption.

As for the afterburner, it is a means to make full use of the residual oxygen in the gas. The gas in the main combustion chamber also contains a part of oxygen that does not participate in the combustion. When the gas flows through the turbine, it can enter the afterburner.In the afterburner, the engine injects a large amount of oil into this hot gas, which causes the gas to be ignited again and then ejected.Using this method, the thrust of the engine can be increased by 30%-80% in a short period of time (the afterburner ratio of the turbojet engine is smaller, and the afterburner ratio of the turbofan engine is larger).

Of course, this step is still a bit far for Helena, so that it is impossible for Helena to come up with a more detailed plan now, so she can only take one step at a time.But when the third step is taken, the basket of the speed of sound is close to Helena's fingertips.

Chapter 173 In charge of burning

Well, the above are currently just Helena's beautiful vision for the future.In fact, according to Helena's estimate, to develop a supersonic aircraft with practical value in this plane, even if you don't make directional mistakes, it will take at least ten years of hard work. Power also requires a series of breakthroughs in the field of aerodynamics.In the last plane, the first manned aircraft capable of supersonic flight was the X-1 demonstration aircraft designed by Bell Aircraft Company of the United States.Moreover, this aircraft does not use the jet engine commonly used in later generations, but an ethanol-fueled liquid rocket engine.During a flight in October 1947, the X-10 reached a speed of Mach 1.

All in all, the dual-rotor full-axial afterburning turbojet is a good thing, and the supersonic fighter is also a very tempting target, but Helena is deeply skeptical about whether this thing can catch up with the next world war.According to the normal research and development progress estimate, Helena believes that if the German plane can stabilize the second step of her vision, which is the single-rotor axial-flow centrifugal combined compressor, around 1940, it will be quite difficult.Moreover, as long as this step can be reached, it means that Germany can obtain a jet engine with better performance than the Jumo004 of the previous plane one to two years in advance, and the military value contained in it can be imagined.

In addition to the turbine and compressor, a very important part of the jet engine's core machine is the combustion chamber.The combustion chamber is the place where the air compressed by the compressor is mixed with fuel and burned to generate high-temperature gas, and it is also the energy source of the entire jet engine.If the engine is the heart of a fighter, and the core engine is the heart of a jet engine, then the combustion chamber is the heart of the core engine.To a large extent, the reliability of the combustion chamber and the effectiveness of combustion determine the reliability and economy of the engine, so the combustion chamber technology, like the impeller technology, is regarded as the top priority of research by Helena.

The combustion chambers of jet engines can be roughly divided into three types: split-pipe (single-pipe) combustors, ring-pipe (joint-pipe) combustors, and annular combustors.Let's briefly introduce these three combustion chambers: