Iron Sonata of World War II

The friendship across countries and races shown by the black American athlete Jesse Owens and the German athlete Lutz Lang in the long jump event just contributed highly infectious promotional materials to Germany in its own plane. After the game, the stands The picture of Hitler and Jesse Owens greeting each other in the game was recorded by the camera, and the photo of Owens and Lutz Lang appeared on the front pages of the major newspapers that day, and the two soon became famous. A well-known sports hero in Germany, even walking on the street, he will be stopped by enthusiastic sports fans at any time to ask for his autograph.Originally, Lutz Lang was still worried that he would be blamed by public opinion for consoling Owens on the spot and imparting game experience to him, causing him to lose the gold medal in front of tens of thousands of German spectators and heads of state. People are regarded as a symbol of great sportsmanship.

When the medal competition for the last event of the Berlin Olympics came to an end, Hitler followed Helena's suggestion to meet with all the medalists before the closing ceremony. The contestants shook hands cordially and posed for pictures.When it was the turn of Jesse Owens and Lutz Lang, the two athletes were obviously short of breath, but Hitler's actions and words were full of affinity, and soon Owens was completely conquered by the "approachable" Hitler and became a little Beard's new little fanboy.Not to mention Lutz Lang, who was originally a member of the Nazi Party and joined the SA.It may be hard to believe that Lutz Lang, an athlete who is famous for his sports friendship across races and national borders, and his solidarity and candid sportsmanship, was actually a Najib member and stormtrooper in the original historical plane , and he finally took part in the Nazi German and Allied operations in Italy and died there.

Germany won a total of 34 gold medals, 27 silver medals and 29 bronze medals in the Berlin Olympics on this plane.Compared with the original historical plane, there is one more gold medal and one silver medal, but one bronze medal is missing.This variable mainly comes from the women's high jump event. In the original historical plane, only Friede Cohen won a bronze medal in this event in Germany. ethnicity is excluded.However, Greta Bergman was not disqualified from the competition in this plane, and the two participating girls both adopted the new technology of arc run-up and back over the pole under Helena's suggestion. As a result, Germany won the event The harvest has changed from a bronze medal to a gold medal for Greta Bergman and a silver medal for Friede Cowan, which can be called a complete victory. It is a pity that the German men's high jump The team did not adopt Helena's suggestion based on prudent considerations, resulting in no medals, and the best scorer only stopped at No.4.

Germany leads all participating countries with 34 gold medals and a total of 90 medals, while the US team ranks second with 24 gold medals and a total of 59 medals.Goebbels, head of the Propaganda Department, excitedly declared that such good results were the result of the revival of Germany's national ambitions: "This Olympic Games is a great breakthrough, and now we have another reason to be proud of Germany, which is really great The number one sports power." Helena felt rather regretful that although her previous motherland sent a sports delegation of 59 people this time, they still hadn't won any medals. After all, sports achievements don't just rely on athletes Individual struggles also require the support of a strong comprehensive national strength. There is no doubt that China does not have the conditions to support professional sports.

It is worth mentioning that before the Chinese sports delegation came to Germany this time, they faced serious financial difficulties. Even the money for the train tickets had to be raised in Hong Kong and Nanyang. As an international friend, he helped the Chinese sports team buy a ferry ticket from Hong Kong to Hamburg. After this incident was widely reported in China, many Chinese people felt good about Helena and even Germany.So there was a scene of Shanghai Lena waving to the Chinese team in the stands at the opening ceremony, although the Chinese team didn't see her when they entered the arena because there were too many people in the auditorium.As for the failure of the Chinese team to win medals in this Olympic Games, although Helena still has a little regret, she also knows that the participating Chinese athletes have tried their best. No way.

The closing ceremony of the Berlin Olympic Games scheduled for the night of the 16th was also designed quite creatively. As the bell for the closing of the Olympic Games sounded from the bell tower next to the Reichsstadion, countless high-power searchlights around the stadium were lit up at the same time. Dazzling beams of light shot vertically into the star-studded sky.Then these vertical beams of light slowly converge towards the middle of the stadium, as if a water lily is gradually closing its petals.At the same time, Japan, the host of the next Olympic Games, performed a brief performance in the middle of the stadium, welcoming everyone to the Tokyo Olympic Games scheduled to be held in 1940. Although only Helena knew that the Olympic Games were destined to be unable to be held due to the expansion of the war, but All the audience present believe that peace can continue under the inspiration of the Olympic spirit.In this way, the 16-day Berlin Olympic Games came to an end slowly amid the cheers of countless spectators and the brilliant fireworks that were set off all over the sky.

3 Chapter Seventy International Repercussions

Although the Berlin Olympics in this plane carried out more systematic commercial value development based on Helena's suggestion, and it can even be said that many practices have provided a model worth learning for the commercialization of future Olympic Games, but when calculating the economic benefits after the game, it was found that the direct economic The income is still negative, that is to say, Germany even posted some money backwards in the income and expenditure accounts on the bright side.Helena was not very surprised by this result. After all, the first Olympic Games in the last plane that recorded a surplus in the direct account had to wait until the Los Angeles Olympics in 1984, and that was after mass media became highly popular around the world. something happened.

Although the comprehensive impact of hosting the Olympic Games on the host country's economy cannot be calculated by simple direct accounts, and there have been many disputes about the economic value of the Olympic Games for a long time in the later generations of scholars, there are two facts that are relatively clear: first, the impact of the Olympic Games on the host country The economic value of the Olympic Games depends to a large extent on the country's economic scale and industrial structure, because countries with sufficient economic scale and relatively complete industrial structure can fully absorb the benefits of the Olympic economy; secondly, at certain specific time points In fact, the Olympic Games can often generate political benefits that far exceed their economic value. For example, in the original historical plane, the Tokyo Olympics in 1964, the Munich Olympics in 1972, the Seoul Olympics in 1988, and the Beijing Olympics in 2008 are all regarded as It is a very symbolic event in the history of the economic take-off of the host country. The breadth and depth of this kind of influence are beyond the reach of other forms of political and economic activities.

It is said that before Helena traveled to Tokyo, Japan, Japan was preparing for the 32nd Summer Olympics, and she did not know whether Tokyo, the original historical plane, could relive the surprise of the 1964 Olympics for the world.But what she is sure of is that the Berlin Olympic Games in this plane are more successful than the original historical plane in terms of both economic and political benefits: internally, it sweeps away the long-term shadows that have been shrouded in every day due to the failure of the war and the economic crisis. The frustration in the hearts of German citizens has enhanced national self-confidence and national cohesion; externally, it has shown the world a new image of Germany with economic prosperity, scientific and technological progress, and cultural enlightenment in a concrete way. , clean and tidy streets, hospitable citizens, and even the Zeppelin airship hovering over the field to warm up the field and the aerobatic formations that added to the fun have left a deep impression on tens of thousands of foreign guests visiting Germany. These good impressions left by the Olympic Games to the world have strengthened Germany's international competitiveness in the ideological field to some extent.

In recent years, with the protracted economic crisis in the world in this plane, the balance of power in the international ideological field is also undergoing profound changes. The most obvious trend is that the classical liberalism that has long dominated the political economy theory has been attacked. It is generally questioned, because classical liberalism and the Austrian School and the Chicago School derived from it are basically helpless in the face of such a severe economic crisis. The current economic depression will naturally pass when the market is completely cleared, and the new prosperity will come as expected.

Perhaps in the long run, with the continuation of the economic crisis, the damaged market can indeed be repaired automatically, but no one can tell how long this process of automatic market repair will last. At this time, if even the laziest government does not want to If you step down, you have to do something, at least pretend to be doing something in front of the public, after all, you can’t spread your hands and tell the unemployed workers: You just need to sleep in shacks and starve for a few more years, and the new Job opportunities will automatically drop from the sky.

Against such a background, Germany and the United States, the only two countries that have maintained rapid economic growth, have unsurprisingly attracted many Western intellectuals who have long been tired of the clichés of classical liberalism, and academic discussions related to this have also become unprecedentedly heated. , and even said that Su De has become the norm in the study of political economy in Western countries during this period.The economic system called "social market economy" in the German official expression was also regarded by many British and American scholars at the same time as the third way besides the free market economy and the Soviet-style planned economy. It even far exceeded Helena's expectations, because she felt that she was just taking out potentially useful policy proposals and desperately papering the dilapidated house of the German economy. Many people thought it was a mansion, which made Helena feel a little bit uneasy.

But then Helena had a second thought: Even the ultra-nationalist suture monster created by the Najib Party in the original historical plane can find a common language in the intellectual circles of Western countries, and it was created by the original plane itself. No matter how bad this thing is, it won't be worse than the one in the original historical plane. Why should I feel ashamed?It is not a bad thing if someone is willing to study the political and economic policies of Germany on this plane. This can enhance Germany’s international influence in ideology. After she goes back and further theorizes the political and economic suggestions she has provided to Hitler over the years, it can be regarded as the future. A plaque of German ideology was hoisted.Although many places may not be perfect, it is more scientific than the Aryan blood theory of the Najib Party in the original historical plane. After all, if we want to talk about the purity of Aryan blood, molecular anthropology in later generations has proved that The Gypsies who were massacred by Najib in history are the closest ethnicity to the ancient Aryans, and I don’t know how those Najib sticklers who regard the theory of Aryan blood as the standard will feel...

The author has something to say: Recently, the unit is engaged in anti-epidemic work, and the update may not be timely. Please forgive me, readers.

Chapter 371 The Rocket Base

Nearly three years have passed since Germany successfully launched the first turbo-pumped rocket on this plane in 1933. Peenemunde, a quiet fishing village on the island of Usedom at the mouth of the Penne River, has undergone a transformation. In fact, Helena designated this place as the location of Germany's future rocket research center. All year round, there are only dense forests, deep swamps and gentle beaches with more than a dozen villagers on the island. So Helena only The villagers here were given thousands of marks as compensation for each household, and they happily moved out of this desolate fishing village. The eagerness of the move obviously regarded Helena as a rich lady with a lot of money. , as if Helena's parents would chase after her if she was half a beat behind and demand a refund.

As a result, this fishing village named Peenemunde on the west side of the Baltic Sea, together with the Usedom Island where it is located, became the marriage of Helena and her husband, including Oberth, Goddard, Walter, von Carmen, etc. A paradise for the great gods to enjoy their tickets.Here, the masters started to play with the squeeze-cycle liquid rocket with an initial take-off weight of only tens to hundreds of kilograms, until three years ago with the FR-10 liquid rocket engine with a sea-level thrust of up to 1 tons and a turbo-pump pressure cycle, The A-7 rocket with a take-off weight of 4 tons was successfully sent into the sky.The rocket research and development team invested by Helena took less than ten years and relatively small research and development funds to make the technical performance of the rocket reach a level that was unimaginable before.

The great pioneer of spaceflight theory, the Russian scientist Konstantin Tsiolkovsky's seemingly unconstrained spaceflight ideas, with the launch of the first pump-type rocket in this plane, seems to have become no longer out of reach.Well, it's actually still very far away, but Helena can't pour cold water on the enthusiasm of the great gods at this time, can she?Although Helena started the pumping revolution in the field of liquid rockets on this plane by spending her own money and the great gods, their journey of playing tickets can only end here. After all, it is impossible for a project that burns money like aerospace Helena's private money has been supported for a long time.

But Helena succeeded in persuading Hitler to include the development of rockets as a national key scientific research project, and even Hitler himself became an enthusiast in the field of rockets under her leadership. Although he did not understand many technical details of rockets, he often Personally ask about the development progress of the rocket project.If it is said that Helena and the great gods played tickets before, which provided a pretty good starting line for the German rocket industry, then the comprehensive takeover of the national power will directly pull the progress of German rocket research and development onto the fast track of rapid development .

Thanks to the high-intensity research and development investment of tens of millions of marks per year since 1934, Peenemünde, a fishing village originally located in northeastern Germany, has rapidly emerged as a well-equipped rocket research center.Hundreds of large buildings with different purposes have sprung up on Usedom Island, not including residences and other outbuildings for temporary residence of scientific researchers and workers.Among these buildings are the sub-supersonic wind tunnel with the highest specifications in the world, a total of [-] engine test benches for different purposes, two large-scale liquid oxygen preparation plants, and three integrated fuel filling and maintenance functions There are numerous sophisticated test equipment and corresponding manufacturing workshops.In this way, the entire Peenemünde base can accommodate at most more than [-] scientific researchers and skilled workers to work and live there at the same time. Such a huge rocket research and development and manufacturing center can be said to be unique in today's world.

In order to ensure that the secrets of rocket research will not be leaked in the future, Usedom Island, where Peenemunde is located, has been designated as a military restricted area. Not only is the whole island surrounded by high security walls, but the entire island can only pass through Three newly constructed and heavily fortified bridges connect it to the mainland.The surrounding area is sparsely populated, the terrain is flat, and the transportation is convenient and easy to control. This is the main reason why Helena was willing to choose the location of the Rocket Research Center here. The relocation of Kumannsdorf in the western suburbs to Peenemünde should be based on the same considerations. Now she directly delineates Peenemünde as the location of the Rocket Research Center, which can be regarded as helping Germany's rocket development save the cost of moving. cost.

While the engineering team was in full swing to carry out infrastructure construction on Usedom Island, the German rocket research and development team was not idle. They started on the basis of the first pump-pressed rocket that had previously successfully flown for the first time. started a new journey.From the perspective of the scientific research team headed by Herman Oberth, Robert Goddard and Helmut Walter, their current research environment is not a small one, but a great one.They don't need to worry about the source of scientific research funding, and they don't need to argue with administrative bureaucrats who basically don't understand technology. Helena helps them solve all these common troublesome problems. The only thing they need to focus on is to work hard to overcome them. Immediate technical difficulties.

But what makes everyone feel more helpful is that when Helena listens to their research progress, she often gives corresponding suggestions for the problems they find extremely difficult, and these suggestions are often proved to be quite effective after experiments.As for why Helena's random suggestions can often solve the problems that they have racked their brains, the technicians of the rocket research and development team can only attribute this phenomenon in private: Miss Seekert always has a genius for technology. intuition.

Chapter 372 Three Great Changes

Since the Peenemünde rocket research and development base tested the first A-1933 rocket with a pump-pressed engine in August 8, the research and development team with the full support of the government has begun to launch this type of rocket at a very high frequency However, even with Helena, a traveler who secretly controls the development of technology, the success rate of the initial rocket test launch is still as elusive as a lottery.Seven of the 4 test launches conducted by the rocket research and development team with the A-4 rocket in just three years have failed, but as the research team continues to summarize the experience and lessons of each launch failure and continue to The design flaws were corrected, and the launch success rate of this rocket has also been improved visible to the naked eye: in the last 34 launch tests, the improved A-7 rockets have all succeeded and passed the design. It is the first rocket product whose design has been finalized since the establishment of the German Rocket Research Center.

In Helena's eyes, the A-4 rocket with a take-off weight of only seven tons is certainly not the end goal of her grand plan. After all, the performance level of a rocket like the A-4 is at best equivalent to those that only A sounding rocket capable of flying in the atmosphere.So Helena began planning a new rocket called A-4 before the A-5 rocket under development had time to make its first flight.These years, the Peenemünde Rocket Research Center has actually continued to improve the design of the existing A-4 rocket, while developing the more powerful A-5 rocket.To develop a rocket more powerful than the A-4 rocket, the most important task is to develop a more powerful engine than the FR-4 liquid rocket engine used by the A-1 rocket. This is the A-5 The new engine developed by the rocket is called FR-4 in continuation of the A-2 rocket engine naming method, where FR is the acronym for German rocket engine.

Compared with the previous FR-2 rocket engine, the newly developed FR-1 rocket engine has changed mainly in that the maximum thrust of the FR-1 rocket engine has increased from 10 tons to 30 tons, and the combination of fuel and oxidant has changed from FR-1 to 1 tons. The liquid oxygen ethanol combination used in the -2 rocket engine is replaced by a liquid oxygen kerosene combination with better performance, and the cycle mode is changed from the hydrogen peroxide gas generator cycle used in the FR-30 rocket engine to the fuel-rich gas generator cycle. aspect.Among them, the increase of the thrust to three times the original is naturally the most intuitive among the changes. Greater engine thrust means that the rocket’s take-off weight can be made larger to carry more fuel and load, while the FR-2 in this plane The rocket engine will have a sea-level thrust of up to 27 tons, surpassing the 2-ton thrust of the doomsday revenge weapon V-[-] missile developed by Germany in the original historical plane. The more powerful rockets of the V-[-] missiles in the surface laid a solid power foundation.

Although the sea-level thrust of the FR-2 rocket engine is three times higher than that of the previous model, in Helena's eyes, the other two technological innovations of the FR-2 rocket engine compared with the previous model have a great impact on the future of the German rocket industry. The value of long-term development is even higher than the simple thrust increase.When developing the FR-4 rocket engine for the A-1 rocket, Helena chose the combination of hydrogen peroxide gas generator cycle and liquid oxygen ethanol propellant similar to the V-2 rocket in the original historical plane as the wedge To a large extent, it is an expedient measure adopted to lower the technical threshold of pump-pressed rocket engines as much as possible.But expedient measures are not long-term solutions after all. After relying on expedient measures to successfully cross the threshold of the pump rocket, Helena naturally does not want to continue to be bound by these expedient measures.

There are three main reasons why Helena chose the liquid oxygen ethanol combination of propellants:

First of all, ethanol is easier to obtain than other liquid fuels. It only needs 75% to 92% of the most common industrial ethanol to meet the requirements. Don’t think that the aerospace kerosene and ordinary kerosene used in liquid oxygen kerosene rockets are called kerosene. It's the same thing. In fact, the kerosene used in liquid rockets usually needs to be specially developed and given a special brand.Because aerospace kerosene must be neither easily decomposed nor polymerized or deposited at high temperatures, it is necessary to strictly control the content of harmful components such as olefins and aromatics, and the content of sulfides must be strictly controlled, otherwise The increase of combustion chamber pressure is easy to produce carbon deposits.

At that time, although Helena and the masters belonged to the absolute rich players in the ticket industry, it was unlikely that Farben would be required to develop and produce a kerosene brand suitable for space activities for their ticketing needs. In contrast, ethanol, which is easy to obtain and not demanding, is simply a fuel specially prepared for the gamers in the rocket field. It is still a very popular entry-level liquid rocket fuel for the gamers until the 21st century.

Secondly, ethanol solution has a higher specific heat capacity than other common fuels such as kerosene, so it can improve the cooling efficiency of the nozzle and combustion chamber.Taking the 1% ethanol used by the FR-92 rocket engine in this plane (75% ethanol used in Germany in the original historical plane) as an example, the specific heat capacity of the ethanol solution is about 2580 joules/kg·degree Celsius, Far more than 2100 joules/kg·degree Celsius of kerosene.Because the vast majority of rocket engines, including the FR-1 and FR-2 rocket engines on this plane, rely on the lower-temperature fuel to flow through the interlayer between the inner and outer walls of the combustion chamber and the nozzle to take away heat to prevent When the temperature of the combustion chamber and nozzle exceeds the material tolerance limit, this cooling method is called "regenerative cooling".Therefore, using ethanol solution with a higher specific heat capacity as fuel helps to simplify the cooling design of the rocket engine, and the cooling design of the nozzle and combustion chamber is usually a very difficult problem for novices in the field of rocket engines. Helena does not want to Just hit the road and hit a wall here.

Finally, the mixing ratio of liquid oxygen and ethanol as rocket propellants is closer to 1.0. In other words, the mass ratio of oxidizer and fuel consumed by the liquid oxygen ethanol engine is closer to that of fuel.For rocket engines using liquid oxygen ethanol propellants, the optimal mixing ratio is usually around 1.5, which means that the rocket engine needs to consume 3 kg of ethanol for every 2 kg of liquid oxygen consumed, while the optimal mixing ratios of other combinations are basically the same. More than 2.5, the optimal mixing ratio of liquid oxygen and liquid hydrogen combination may even reach 6.The similar mixing ratio of liquid oxygen and ethanol is beneficial to simplify the design of the rocket engine turbo pump. For example, the oxygen pump performance of the V-2 missile in the original historical plane is 75 kg per second.The performance of the ethanol pump is 50 kg per second.This relatively close performance requirement undoubtedly makes it difficult for the design of the oxygen pump and the fuel pump to constrain each other, and the hydrogen-oxygen engine known for its high specific impulse has brought great challenges to the design of the pump system of the engine because of its high mixing ratio. challenge.

Now many people may have doubts. Since the propellant combination of liquid oxygen ethanol has so many advantages, why did Helena abandon it when she newly developed the FR-2 rocket engine and choose liquid oxygen kerosene instead? What about the propellant combination?

Chapter 373 I Love the New and Dislike the Old

As mentioned earlier, the combination of liquid oxygen and ethanol as rocket propellants has the advantages of easy fuel availability, high regenerative cooling efficiency, and can simplify the design of turbo pumps to the greatest extent. However, looking at the liquid rockets and missiles of various countries in the original historical plane In the course of development, we can easily find that the rocket propellant partners of liquid oxygen and ethanol did not have a good time after the war. The SS-50 missile and the PGM-3 Redstone missile with ethanol as the propellant, but when the time entered the 11s, the propellant combination of liquid oxygen ethanol quickly fell out of favor.

Even the motherland of Helena's previous life did not retain more enthusiasm for the combination of liquid oxygen and ethanol propellants, except for the DF-1 missile imitated according to Sulian data at the initial stage and the DF-2 missile improved on this basis. In addition to using liquid oxygen ethanol propellant, Helena’s previous homeland also lost interest in continuing to develop rockets that use liquid oxygen ethanol as propellant. The DF-3/4/5 missiles developed subsequently all use highly toxic partial A combination of methylhydrazine fuel and concentrated nitric acid or dinitrogen tetroxide oxidizer as a rocket propellant. In fact, until Helena crossed, the classic combination of unsymmetrical dimethylhydrazine and dinitrogen tetroxide, dubbed the "poison rocket", was used in rockets. The field of propellants is still quite present.

The liquid oxygen ethanol combination gradually withdrew from the stage of rocket propellants after the 60s. Of course, it was not because rocket designers in various countries were blind to the benefits of liquid oxygen ethanol propellants, but because liquid oxygen ethanol propellants had a relatively high technical threshold. Low, so it is very suitable as an entry-level equipment for novice players to receive in Novice Village, but those who have played the game should know: Although the white version equipment provided by Novice Village has a low threshold for use, the upper limit of attributes is usually not very high. , so when the player's professional level increases, it is logical to replace the unusable Novice Village equipment.Liquid oxygen ethanol propellant is like the equipment provided by Xinshou Village to rocket players from all over the world. Although it can be equipped without many prerequisites, the inferior panel attributes can never make up for the flaws. Let me ask which one is ready to go out? The high-end players in Novice Village don't want to find a chance to replace the cheating white version equipment in their hands?

Compared with kerosene fuel, which is more commonly used in liquid rocket propellants in later generations, the performance disadvantages of ethanol fuel that have been eliminated are mainly reflected in poor safety and low specific impulse.Among them, the reason why ethanol is less safe than kerosene is easy to think. Ethanol has a much lower flash point than kerosene. High-concentration ethanol has a lower boiling point and is easier to volatilize than kerosene. Moreover, the vapor after volatilization is difficult because of its higher density. Diffusion, plus the explosion limit of the mixture of ethanol vapor and air is much wider than that of kerosene mixture.Therefore, if ethanol is used as rocket fuel, the safety hazards faced in storage and filling will be higher than that of kerosene.However, although the safety problem of ethanol fuel compared with kerosene is indeed a minus item, what really directly leads to the gradual retreat of the liquid oxygen ethanol propellant combination in later generations is its too mediocre specific impulse data.

The specific impulse mentioned here is a unit to measure the utilization efficiency of the propellant by the rocket engine, and it describes the momentum increase that the rocket engine can bring to the rocket by consuming a unit weight of propellant.Internationally, "second" is usually used as the unit to measure the specific impulse. The meaning of this unit can be roughly understood as the duration that each kilogram of propellant can produce each kilogram of thrust through the engine.Assuming that the specific impulse of a certain rocket engine can reach 300 seconds, it means that the momentum increase that the rocket engine can bring to the rocket per 1 kilogram of propellant consumed is equivalent to 1 kilogram of thrust lasting for 300 seconds .Obviously, the larger the value of the specific impulse, it means that the rocket engine can bring more momentum increment to the rocket when consuming a unit of propellant, in other words, the higher the efficiency of the engine’s use of propellant.

Considering that the forward momentum increment obtained by the rocket from the engine all comes from the high-speed gas ejected backward by the engine, according to the principle of conservation of momentum, it is not difficult to draw the conclusion that the forward momentum obtained by the rocket during flight is equal to the gas ejected from the engine. The backward momentum obtained when the rocket engine is working, and the specific impulse of the rocket engine is proportional to the speed of the gas ejected backwards when it works, so if you want to increase the efficiency of a rocket engine, it is the specific impulse. In fact, you need to increase the The speed at which the gas is injected when the engine is operating.The speed at which the rocket engine injects gas backwards mainly depends on four aspects: the pressure of the thrust chamber, the expansion ratio of the nozzle, the comprehensive working efficiency of each component, the type and ratio of the combination of fuel and oxidizer.

First look at the pressure of the thrust chamber: the influence of this factor on the contrast is easy to understand, just like the higher the pressure in the mouth when we blow with the mouth, the faster the airflow speed will be blown out. If other conditions remain unchanged, The higher the pressure in the thrust chamber, the more energy the gas injected through the nozzle can obtain to increase the injection speed, and the specific impulse of the engine will naturally be higher;

Next, look at the influence of the expansion ratio of the nozzle: the nozzle of the rocket engine is the place where the gas rushing out of the thrust chamber expands and accelerates to obtain kinetic energy. It seems that the larger and longer the nozzle, the more the gas can be fully accelerated here. , that is to say, when other conditions remain the same, the engine with a larger nozzle expansion ratio has a higher specific impulse.What needs to be emphasized here is that if it is in an ideal vacuum environment, it can indeed be considered this way, but if the rocket is flying in the atmosphere, the injection of the engine gas needs to overcome the atmospheric pressure first, and the larger the diameter of the engine nozzle The more energy that needs to be consumed to overcome the atmospheric pressure, the more energy consumed to overcome the atmospheric pressure will eventually offset the benefits brought by the enlarged nozzle.

Therefore, the increase in the expansion ratio of the rocket engine that mainly works in the atmosphere needs to be limited, and exceeding the limit will lead to a decrease in the specific impulse of the engine.As for the rocket engine that mainly works outside the atmosphere, in theory, the nozzle can be made nearly infinite to increase the specific impulse, but in actual operation, it is limited by the diameter of the rocket body and the weight of the engine, otherwise the nozzle of the engine must be too large It cannot be installed into the rocket body at all, or the engine nozzle is heavy enough to offset the benefits of the increase in specific impulse.

Needless to say, the comprehensive working efficiency of each component, the propellant must flow in the pipeline and the turbo pump, and the gas must flow in the thrust chamber and the nozzle, all of which will lose energy, and the combustion process in the thrust chamber cannot be guaranteed to be absolutely sufficient and Evenly, these will bring some energy loss and affect the final specific impulse of the engine, so the comprehensive working efficiency of each component and reducing various unnecessary energy losses are also ways to improve the specific impulse of the engine.

Finally, we have to talk about the type and ratio of the combination of fuel and oxidant, and this is precisely the biggest weakness of the combination of liquid oxygen ethanol as mentioned above. Compared with the very classic combination of liquid oxygen and kerosene in later generations, liquid oxygen The theoretical specific impulse of the ethanol combination has a disadvantage of 10 to 30 seconds (the specific value depends on the concentration of ethanol and the working conditions).Don't underestimate the specific impulse disadvantage of 10 to 30 seconds. You must know that the specific impulse of the V-2 missile engine in the original historical plane is only about 200 seconds, and it needs to consume more than nine tons of ethanol and liquid oxygen during the flight. That is to say, if the specific impulse of the engine can be increased by 20 seconds, nearly 900 kilograms of fuel can be saved, and these less consumed fuel can be converted into missile loads. Considering that the warhead of the V-2 missile weighs only 975 kilograms , if the specific impulse of the engine can be increased by 20 seconds, the weight of the warhead of the missile can be almost doubled without changing other technical indicators!

The temptation to double the rocket load is too great for designers from various countries. This alone is enough to make them give up the easy-to-use propellant combination of liquid oxygen ethanol. If you consider the safety advantages of kerosene over ethanol , Designers have even more reason to say goodbye to the liquid oxygen ethanol combination. Although this method of using the liquid oxygen ethanol combination to break through the bottleneck of the pump-pressure rocket technology and immediately turning against others is indeed a bit of a scumbag, but Helena doesn't care about such accusations. After all, in the process of scientific progress, it is normal to like the new and dislike the old. Since the newcomers of liquid oxygen kerosene laugh, they don't care about the old people of liquid oxygen ethanol crying.

What's more, after she clicks on the technology tree of liquid oxygen kerosene, she only needs to replace liquid oxygen with fuming nitric acid and it can be used directly for military purposes. If you don't believe me, look at the famous "Scud" missile in the original historical plane. The propellant used is the nitrokerosene combination. Although the specific impulse data of this combination is not very good, it is valuable because the fuel and oxidant are liquids at normal temperature and pressure, so after the missile is filled, it can be stored for a short time. There is no need to temporarily refuel at the launch site, and there is no need to launch immediately after refilling, so that the missile has a certain mobile launch capability, and can quickly enter the position when needed and then launch immediately, which greatly improves the suddenness of the attack. sex.

Chapter 374 No choice

Compared with the previously developed FR-2 rocket engine, the FR-1 rocket engine currently being developed in Germany, in addition to changing the propellant combination from liquid oxygen ethanol to liquid oxygen kerosene, which is safer and has a higher theoretical specific impulse, the most The revolutionary technological change is that the cycle mode of this rocket engine has been upgraded from the previous gas generator cycle to the gas generator cycle, and the cycle mode has been upgraded from the gas generator to the gas generator. It is an indispensable key step in the evolution of liquid rocket engines, so Helena is determined to conquer the gas generator cycle technology.

As mentioned earlier, the pressure of the thrust chamber and the comprehensive working efficiency of each component are important factors affecting the propulsion efficiency of the liquid rocket engine, that is, the specific impulse. In the original historical plane, from the 20s to nearly a century before Helena crossed, the most Amazing rocket engine designers have worked hard to achieve both goals, and the most important effort of these designers has been to improve the circulation of liquid rocket engines.As of Helena’s crossing, the circulation methods that appeared in the pump rocket can be divided into five categories, including the relatively common gas/gas generator cycle, fuel-rich/oxygen-rich/full-flow supplementary combustion cycle, closed/open expansion There are also pumping cycles that exist as a non-mainstream, and of course electric drive cycles that have gradually begun to emerge with the advancement of lithium battery technology in the new century.

If you only look at the circulation methods of these various liquid rocket engines listed above, you may think that Helena has many options when formulating the development route of German rocket engines on this plane, but Helena said that the problem in front of her seems to be There are many options, but most of these options are distractions that must be eliminated.After you eliminate all the interference options one by one, you will be surprised to find that if Germany wants to go further in the cycle mode of the engine, then this question is actually a damn multiple-choice question: and the gas generator cycle is that the only correct answer.

Next, let's analyze why other options should be excluded one by one:

First, let’s look at the well-known afterburning cycle in later generations, which is also called a staged combustion cycle.This cycle method has the highest limit performance among all cycle methods. Not only does it have the potential to increase the pressure stack of the thrust chamber to approach the theoretical limit of the propellant combination, but also its fuel or oxidant is almost fully utilized without waste. Therefore, the overall working efficiency of each component can be made very high without too much compromise. These advantages make the afterburning cycle almost become synonymous with high-performance liquid rocket engines in later generations.

Helena is very yearning for the rocket engine of the afterburning cycle, but the problem is that the technology tree of the afterburning cycle needs to be activated as the pre-technique of the gas generator cycle, because the afterburning cycle can be regarded as a The fuel-rich or oxygen-rich gas that is not fully utilized in the gas generator cycle is introduced into the main combustion chamber for secondary combustion, which is why this cycle is called the post-combustion cycle or the noun of the staged combustion cycle.But the problem is that Helena has not turned on the gas generator cycle at all. If the previous research on the gas generator cycle is to learn to crawl, then the research on the gas generator cycle is to learn to walk, and the final completion of the refueling cycle is to run and jump. .Now Germany has just learned to crawl in the field of pumped rocket engines. If they want to bypass the gas generator cycle and directly engage in the afterburning cycle, in Helena's eyes, it is like a baby learning to run and jump without learning to walk. It ended in tragedy, so the option of afterburning cycle must be excluded.

Then look at the expansion cycle. The expansion cycle is basically only suitable for rocket engines that use low-molecular-weight low-temperature fuels such as liquid hydrogen and methane, because the expansion cycle is generated by heating and gasification when the low-temperature fuel cools the nozzle. The expansion pressure is used to drive the turbine, and the fuels currently used by German rocket engines-ethanol and kerosene are room-temperature fuels that are difficult to gasify. Obviously, they are inherently incompatible with the expansion cycle, unless liquid oxygen is used as the injector. It can cool and expand the working fluid, but the molecular weight of liquid oxygen is too large, which leads to low work efficiency, and oxygen is easy to oxidize with metal after being heated. I believe that designers with a normal mind will not use expansion cycles on liquid oxygen kerosene engines. of the scheme, so the option of expansion cycle has to be excluded.

Then look at the non-mainstream technical route of pumping cycle. On the surface, the structure and principle are very simple: a stream of gas is drawn directly from the injector of the main combustion chamber to drive the turbo pump, and there is no need to set up a separate gas generator at all. Or a gas generator.However, since this circulation method is a non-mainstream design in later generations, it is naturally because of insurmountable shortcomings.Although the extraction cycle chooses to draw gas from the position near the injector where the temperature is relatively low in the main combustion chamber, the temperature of the gas is still relatively high compared with other circulation methods, which undoubtedly brings a huge challenge to the heat-resistant design of the gas turbine. , and the pumping cycle is difficult to adjust, and the specific impulse has no advantage over other circulation methods. Of course, Helena has no interest in challenging this non-mainstream design, so the pumping cycle option still has to be ruled out.

As for Helena's first electric drive cycle before crossing?This circulation method has the ability to adjust the thrust in a wide range, which is difficult to match in other circulation methods. The question is, can Helena come up with a high power density motor now?Can you come up with lithium batteries with high power density like later generations?Helena estimated that even if Dr. Porsche was to design the rocket, he would not even look at the electric drive cycle!So the option of an electric drive cycle can be ruled out without thinking.

After such elimination one by one, does Helena have any other choices?Either continue to use the hydrogen peroxide gas generator cycle of the FR-1 rocket engine, or start to develop an advanced version of the gas generator cycle, but Helena is unwilling to see the rocket engine newly developed by Germany on this plane. The circulation method of the rocket is still standing still, so the circulation method of the new rocket is determined in this way.

The previous FR-1 rocket engine was the originator of the pumped rocket engine on the plane, and the direct driving force of its turbo pump came from the decomposition of hydrogen peroxide solution.When the high-concentration hydrogen peroxide solution flows through the multi-layer silver catalytic net in the gas generator, it will be catalyzed by these silver nets to decompose sharply and generate a high temperature of hundreds of degrees Celsius at the same time.Such a high temperature will directly vaporize the water produced by the decomposition of hydrogen peroxide and the hydrogen peroxide solution that has not yet reacted. These water vapor and hydrogen peroxide vapor are mixed with oxygen, another decomposition product of hydrogen peroxide. High-temperature gas mixtures have relatively high energy.

The turbine of the FR-1 rocket engine relies on this high-temperature mixed gas to drive the gas turbine, and then drives the oxygen pump and the ethanol pump coaxially arranged on both sides of the turbine to continuously pump liquid oxygen and ethanol into the combustion chamber of the rocket engine Combustion works.The gas mixture driving the FR-1 rocket engine turbopump obviously has not undergone any combustion process, so this cycle can only be called a gas generator cycle and not a gas generator cycle.So what are the disadvantages of this gas generator cycle compared to the gas generator cycle, so that Helena is determined to abandon it in the development of the FR-2 rocket engine and choose to use the real gas generator cycle instead?

Chapter 375 Gas Turbine

We mentioned earlier that the rocket engine using the gas generator cycle usually relies on the energy generated by the catalytic decomposition of hydrogen peroxide solution to drive the turbo pump. The biggest advantage of this ancient pump pressure cycle method is that it is relatively simple to control. When the efficiency of the device remains basically unchanged, only a set of throttle valve with a simple structure is needed to control the flow rate of the hydrogen peroxide solution that participates in the catalytic decomposition reaction, and the generation rate of the high-temperature working gas that drives the turbo pump can be controlled. Then control the speed of the turbo pump and the thrust of the engine.However, the disadvantages of this most primitive pumping cycle are also obvious:

First of all, if a certain type of rocket uses a gas generator cycle engine, it is necessary to additionally set up storage, pressurization and delivery systems for the hydrogen peroxide solution as a gas generating agent, so as to ensure a continuous flow of hydrogen peroxide solution. Sent to the gas generator to participate in catalytic decomposition.However, this additional system is relatively considerable in terms of volume and weight. While squeezing the precious space inside the rocket body, it increases the structural weight of the rocket body, resulting in more propellant energy having to be used to propel the rocket itself. Structural weight rather than transport payload.

The second is the rocket engine that uses a gas generator cycle, and the power density and efficiency of its turbo pump are usually unsatisfactory.It should be known that when the hydrogen peroxide solution is violently decomposed and exothermic, the mixed gas used to drive the turbine is rich in oxygen and hydrogen peroxide vapor that has not had time to react, and these two oxidizing gases follow As the ambient temperature increases, its chemical properties will become more and more active, and it can even corrode the poor turbine to be riddled with holes in a short period of time.Therefore, when rocket designers develop an engine that uses a gas generator cycle, they usually need to deliberately control the concentration of hydrogen peroxide solution, so that the temperature of the mixed gas generated by the reaction will not be high enough to allow the turbine to be oxidized in advance. The price to do is to sacrifice the power density of the turbo pump.

The gas generating agent used in the FR-1 rocket engine is hydrogen peroxide with a concentration of 80%, and the temperature of the gas generated by the reaction is only over 500 degrees Celsius.In fact, as long as the concentration of hydrogen peroxide solution is increased to about 90%, the temperature of the reaction gas can be increased to more than 700 degrees Celsius.Although a higher temperature of the working fluid can help improve the efficiency of the turbopump and increase the power density, if designers really want to do this on the FR-1 rocket engine, the turbine is likely to be unable to withstand the harsh oxidizing environment. In actual operation, we can only choose a relatively low working gas temperature. The purpose is actually to protect the turbine from premature strikes under the erosion of oxygen and hydrogen peroxide vapor, even if the working efficiency of the turbo pump is sacrificed for this purpose. And power density is spared.

Although the FR-1 rocket engine in this plane, under the suggestion of Helena, uses multi-layer silver mesh to catalyze the decomposition of hydrogen peroxide instead of simply and rudely injecting high manganese into the hydrogen peroxide storage tank as in the original historical plane. Sodium acid solution catalyst has greatly improved the working stability of the FR-1 rocket engine on this plane, but these technical improvement measures of Helena cannot eliminate the inherent defects of the gas generator cycle. Needs major surgery on circulation.

The gas generator cycle is a new type of cycle that emerged after the gas generator cycle in the original historical plane. The biggest feature of this cycle is that a small amount of propellant is introduced into a special gas generator for combustion to generate gas, and then the gas is used to The part of the gas generated by the generator drives the turbine pump to do work, and finally simply discharges the exhaust gas that completes the task of driving the turbine.

It needs to be additionally explained that for an engine that uses a gas generator cycle, the ratio of oxidant to fuel in the gas generator is very different from that in the main combustion chamber, because if the fuel and oxidant are burned according to the optimal mixing ratio, it will As a result, the temperature of the gas reaches a terrifying 3000 degrees Celsius or more. No material can work stably at such a high temperature without cooling, so the fuel in the gas generator is usually in excess of the oxidant, so that the The temperature of the generated gas is reduced to a level that the turbine material can withstand.

Although in order to reduce the temperature of the gas, in addition to the method of rich combustion, the technical route of oxygen-rich combustion can also be adopted in theory, but in actual operation, basically no one uses oxygen-rich gas to generate electricity on the engine of the gas generator cycle. After all, the technical difficulty of high-temperature oxygen-enriched turbines is an internationally recognized hell level, so high-temperature oxygen-enriched turbines basically only appear on high-performance engines that use oxygen-enriched supplementary combustion cycles or full-flow staged combustion cycles. The use of such high-end technology in the cycle is suspected of superfluous.

Compared with the gas generator cycle, the performance advantage of the gas generator cycle is self-evident: because the gas generator directly uses the fuel and oxidizer of the rocket to generate gas, so there is no need to regenerate the fuel and oxidizer outside the gas generator cycle. A separate set of storage and pressurization equipment is prepared for the gas generator, so it can greatly reduce the volume and weight occupied, so the rocket engine using the gas generator cycle can easily achieve a considerable thrust-to-weight ratio, so that even later generations The advanced afterburning cycle has taken away the glory of the gas generator cycle, and this cycle can still tenaciously guard its place in the rocket engine family by virtue of its simple structure and high thrust-to-weight ratio.

In addition, the turbine pump efficiency of the gas generator cycle can usually be made higher than that of the gas generator, because the fuel that drives the gas generator cycle turbine is usually fuel-rich and oxygen-poor gas, so the turbine of the gas generator basically does not need Considering the problem of oxidation corrosion at high temperature, the only limiting factor is the high temperature tolerance of the turbine itself.Therefore, on the FR-2 rocket engine that uses the gas generator cycle on this plane, the German designers increased the temperature in front of the turbine from 2 degrees Celsius of the FR-500 rocket engine to 750 degrees Celsius. At the same time, it has obtained a longer turbine life, and the improvement of the performance of the turbo pump is also one of the foundations for the improvement of the performance of the FR-2 rocket engine on this plane.

虽然推动涡轮泵的工质和采用气体发生器循环的FR-1型火箭发动机不同，但是本位面FR-2型火箭发动机的涡轮泵结构却基本延续了FR-1型火箭发动机的同轴设计：燃气涡轮居中而煤油泵和液氧泵分别位于涡轮两侧。但涡轮泵功率和效率的大幅提高使得FR-2型火箭发动机在推力提高到FR-1型火箭发动机三倍的同时，推力室压力也从3.0兆帕提高到了5.7兆帕，理论比冲更高的液氧煤油推进剂组合配合更高的燃烧室压力，使得FR-2型火箭发动机的海平面设计比冲直接从FR-1型火箭发动机的220秒提高到了258秒，虽然这样的比冲和后世的同类发动机相比依然是渣渣，但放在30年代却属于惊世骇俗的存在。

However, the facts have proved that when you click on the technology tree, if you go too far in a certain technology, you will be punished ahead of time. When the FR-2 rocket engine entered the actual test run, the rocket design team of Helena and Peenemünde was immediately punished. The most serious punishment for advanced technology in history, so that Helena's most commonly used greeting when greeting rocket gods has almost become: Has the engine test bench XX been blown up by you recently?Don't worry, the No. XX test stand that you just bombed last time has been repaired, and you can continue bombing there...

Chapter 376 Trial and Error Accumulation

In fact, Helena was fully prepared for the setbacks encountered by the FR-2 rocket engine during the test run. You must know that the rocket engine is the device with the highest energy density ever made by mankind, which can continuously convert chemical energy into mechanical energy. Wanting to develop such a device is undoubtedly a challenging technological adventure.Helena understands that even if she has rocket engine design experience from later generations in her mind for reference, she still needs to go through an arduous trial and error process when actually developing a new rocket engine, because her motherland in her previous life was developing a high-pressure oxygen-enriched supplementary combustion cycle. I had a similar experience with the liquid oxygen kerosene engine.

The original historical plane Zhongxia began to explore the oxygen-enriched high-pressure supplementary combustion technology in the late 80s, but due to the weak accumulation in this field, the progress was relatively slow. However, the subsequent changes in the international political situation gave Huaxia a rocket engine development. An unexpected gift.As the foundation of Sulian, the red empire entrenched in the north, began to shake, many high-end equipment and technologies that were impossible to sell outside were also put on the shelves for sale.So Huaxia seized the opportunity to introduce two RD-120 high-pressure oxygen-enriched supplementary combustion cycle liquid oxygen kerosene engines and related technical materials. Through years of research and analysis on this 85-ton thrust high-altitude engine, Huaxia finally Gained a more systematic understanding of this type of rocket engine.

With the rocket engine model of the same type as the technical reference system, the process of China's self-developed oxygen-enriched supplementary combustion liquid oxygen kerosene engine with greater thrust began to accelerate.In the meantime, with the sudden collapse and disintegration of the Crisis United Empire, Huaxia also took the opportunity to buy more related technologies from the economically depressed Russia and Ukraine.However, even with the help of such a dreamy foreign aid combination, the development of Huaxia's own high-pressure oxygen-enriched supplementary combustion engine is still very difficult. The bench test stage has just started and experienced two gas start-up explosions and two gas system burnouts.

In fact, from Helena's point of view, Zhongxia, the original historical plane, experienced only four major test accidents, and was able to master the high-end technology of oxygen-enriched supplementary combustion cycle, which is already a lot of money. The country of crabs has experienced many times more major test accidents than Huaxia in order to master the oxygen-enriched supplementary combustion cycle technology.From here, it is not difficult to see that having an external frame of reference can indeed greatly save the cost of trial and error, but no matter how good the external frame of reference is, it still belongs to someone else. Only by falling all over the head can you turn other people's experience into your own wealth.

The setbacks encountered by Germany in the development of rocket engines in this plane are also the same. Although Helena has experience from later generations for reference, these experiences of Helena are after all the experience in the original historical plane. The experience in the original historical plane becomes the wealth of the original plane, and it still needs to be practiced down-to-earth.

In short, the experience of future generations in Helena's mind is valuable, but it is by no means omnipotent. When developing the FR-1 rocket engine, Helena and the research team encountered combustion instability in the combustion chamber and cavitation in the oxygen pump. The resulting resonance problem was later resolved at Helena's suggestion by adding an injector disk partition and an oxygen pump guide wheel.But now they have encountered new problems in the process of developing the FR-2 rocket engine with more advanced performance.

After the post-event analysis of each test accident, Peenemünde’s rocket research team finally determined that there are two main culprits that caused the explosion of the FR-2 rocket engine during the test run: one is that the cooling of some areas of the combustion chamber is insufficient. The high-temperature and high-pressure gas burns through the outer wall of the combustion chamber, and the high-pressure gas in the combustion chamber instantly breaks through the shackles and explodes. The second is that the seal of the turbo pump is not tight enough to cause part of the liquid oxygen in the oxygen pump to flow to the gas turbine next door. The high-temperature fuel-rich gas, the happy lovers, met unexpectedly in the gas turbine, and its explosive power was enough to restore the entire turbo pump to the state of its parts.

Considering the high technical complexity of the rocket engine, Helena was unable to provide the research team with a clear solution to the two problems. She could only list all the possible useful technical paths based on the experience of later generations, and then through permutations and combinations Form more than a dozen candidate solutions, and then use the most primitive but most effective search method of elimination: actually make each candidate solution and test it again, and finally find the solution with the best experimental effect for the next step Optimize and refine designs.

Although this method seems to have no technical content, the advantage is that the foundation is solid: it allows the scientific research team to know which design solutions are feasible, and at the same time know which design solutions are not feasible and why they are not feasible.Because only with an in-depth understanding of the advantages and disadvantages of each design scheme, German designers can truly be confident when designing more advanced rocket engine models in the future.In Helena's eyes, the cultivation of the ability of this scientific research team is more important than simply developing a rocket engine with advanced performance.

This is just like the principle that it is better to teach a man to fish than to teach a man to fish. If a specific model is compared to a fish, the exercise of the ability of the scientific research team is like the exploration of fishing skills. There is nothing heartbreaking about dropping the engine test bench a few times, not to mention that Helena’s experience from later generations has helped the design team save a lot of trial and error costs, and the rest of the test costs have to be paid to obtain fishing skills Naturally, Helena doesn’t care about money here. Anyway, it’s not her own money that was spent after the rocket was developed and approved by the state. I have to say that with the state’s scientific research funding, I feel like a group of science and technology masters are playing together. It couldn't be better.

In this way, for more than two years, Peenemünde's rocket engine test stand has been damaged by explosions many times, and has been repaired many times, and Helena's patience has finally been rewarded. Recently, she I was just relieved to learn that the 2-second full-thrust test of the FR-[-] rocket engine was successful.

Chapter 377

The 2-second test run of the new engine at full thrust was successful at the Peenemünde Research Center, marking two major technical problems that have plagued the development of FR-[-] rocket engines for a long time: the cooling of the thrust chamber and nozzle and the leakage of the turbo pump. get resolved.The combination of Helena's experience from later generations and the hard work of scientific researchers on this plane, coupled with years of high-intensity investment from the German state finance, finally succeeded in moving ahead of schedule. A more powerful rocket engine lays a solid foundation.

The cooling method of the thrust chamber and nozzle of the FR-2 rocket engine in this plane is finally determined to adopt the design scheme of regenerative cooling as the main supplement and shield cooling: use corrugated plate brazing between the combustion chamber and the inner and outer walls of the nozzle Cooling channels are processed by welding. The kerosene fuel with lower temperature flows through these cooling channels to take away part of the heat, and then enters the thrust chamber through the injector for combustion.But as we said earlier, the cooling efficiency of kerosene per unit flow is far inferior to that of ethanol at the same flow rate, so in order to prevent the combustion chamber from being burned by high-temperature and high-pressure gas, the research team added shield cooling to the FR-2 rocket engine according to Helena’s suggestion as an auxiliary cooling measure.

The specific method of shielded cooling is to set a circle of surplus kerosene nozzles along the inner wall of the combustion chamber on the outermost side of the engine injector disk. When the engine is running, this circle of nozzles directly sprays kerosene to the inner wall of the combustion chamber to form a layer The thin liquid film and steam film separate the high-temperature gas inside from the inner wall of the combustion chamber outside, thereby preventing the temperature of the gas from propagating to the inner wall of the thrust chamber and reducing the temperature of the inner wall of the thrust chamber.In the original historical plane, such a simple but exquisite design was first adopted by Sulian scientists on the RD-107 liquid oxygen kerosene rocket engine, and Helena in this plane just happened to use this design as an alternative and recommended it to German designers who had receding hairlines were plagued by thrust chamber and nozzle cooling problems.

Aiming at the problem of explosion caused by the leakage of the turbo pump due to the contact of liquid oxygen and fuel-rich gas, Germany adopted a labyrinth seal design that is very commonly used in rocket turbo pumps in later generations on the turbo pump of the FR-2 rocket engine. This labyrinth seal The design belongs to a kind of non-contact seal. A group of sealing gears are used to form multiple throttling gaps and expansion cavities between the seal cavity and the rotating shaft. The purpose of sealing is achieved by gradually weakening the flow rate and pressure of the sealed medium. .However, the effectiveness of the turbo pump seal design is not limited to the specific seal design, it largely needs to test the design team's grasp of the dynamic characteristics of the system, and also needs to test the material science foundation and machining accuracy of the manufacturing team. These all depend on the accumulation of time and funds, and Helena's experience from later generations can help very little. Therefore, the final solution to the turbo pump sealing problem can basically be said to be the collective efforts of the German scientific research team on this plane.

After solving the cooling problem of the thrust chamber and nozzle and the leakage problem of the turbo pump, the FR-2 rocket engine manufactured according to the new design finally did not have to be blown to pieces directly on the test bench like its predecessors , but continued to spray out bright yellow tail flames amidst deafening roars, until the scheduled [-]-second test run time ended before the cheers of the entire Peenemünde Research Base quieted down.If the engine performs well in the planned several hundred-second test runs, the research team at the Peenemünde base is also planning to arrange a four-hundred-second long-distance test run for this engine, with the purpose of further confirming the long-range performance of the engine. Operational stability under extreme conditions.

"Congratulations on the development progress of our new rocket engine. The prototype has just passed the full-thrust 2-second test run! It seems that the comrades in the Peenemünde Research Base are very motivated recently." Helena learned that FR- After the news of the successful test of the Type [-] rocket engine, he immediately shared the good news with Hitler. Now Hitler has become a rocket fan under the leadership of Helena. The specific principles of it, but I feel that this thing seems to be very powerful, but Hitler is indeed the first person in Germany to realize the potential military value of rockets besides Helena, so he is very interested in Peenemünde. The news of the success of the first rocket engine test was equally joyful, but it was Helena's last sentence that made Hitler most joyful.

"According to the current research and development progress, our rockets will soon become practical weapons of war. Has your Excellency ever considered that we can rely on rockets, a brand-new high-tech equipment, to be used in Germany's existing land, sea and air forces?" In addition to the traditional military system, start a new stove, and your Excellency the Fuhrer will personally establish a brand-new military with rockets as the main means of attack?" Although Hitler's relationship with the Wehrmacht or the Junkers in this plane is not as relaxed as in the original historical plane. Therefore, for the time being, Hitler has not shown his intention to formalize the organization controlled by the Najib Party in order to fight for control of the army as he did in the original historical plane, because that would not only make the country's armed forces overwhelm The dispersal of development resources will also destroy the trust relationship he has established through Helena and the Junker Group, but this does not mean that Hitler in his own plane does not want to obtain a regularized armed force that he can directly control all the time, so this picture drawn by Helena The flatbread immediately made Hitler's blood boil.

"Miss Helena means to establish a new military branch independent of land, sea and air, an independent Rocket Army?" Hitler asked again in disbelief, to reconfirm Helena's attitude.