Iron Sonata of World War II

Most technicians believe that the next-generation rocket should continue to follow the technical route of the first three generations of rockets, that is, to further enlarge the rocket body on the basis of the A-3 rocket to accommodate more propellant, so as to achieve a greater flight height and Flight distance, this is a relatively safe idea of ​​gradual improvement.However, Dr. Goddard, who has always been easy-going, appears to be extremely tough this time. He firmly believes that the development potential of the extrusion cycle adopted by the first three generations of rockets, including the A-3 rocket, is limited. The best circulation mode - pump pressure circulation.

Although Dr. Goddard's opinion on developing a pump-pressure rocket is very radical, it has received strong support from Helena. Helena, who is familiar with the development history of rockets in later generations, clearly knows that the squeeze-type cycle is simple and reliable, but it has some advantages. The performance defects that are difficult to overcome in the series will eventually be replaced by more advanced pump-pressure rockets.

However, Helena did not support Goddard unprincipled. Although she appreciated Dr. Goddard's general direction of research on pumping rockets, she did not approve of the specific technical solutions proposed by Dr. Goddard.Dr. Goddard's pumping scheme is to use a small gasoline engine (with nitrous oxide as the oxidant) to drive a piston pump to press the propellant into the combustion chamber.This solution is not only complex in structure, limited in power, and heavy in weight, but also works continuously and unreliably, so Helena naturally despises it.

In order to prevent the German rocket industry from being diverted by Dr. Goddard, Helena directly required that the new generation of rockets must adopt the technical route of gas turbine driven centrifugal pump.This is also the technical route adopted by almost all pump-type cycle rockets in the last plane since Germany launched the A-1942 rocket on October 10, 3.

In fact, after Dr. Goddard in the last plane realized the pitfalls of internal combustion engines with piston pumps, he began to turn his attention to gas turbine pumps (from this perspective, Goddard can also be regarded as a gas generator cycle. pioneer), but because the gas generator designed by Goddard used oxygen-enriched combustion, the technical level at that time was not enough to solve the oxidation problem caused by high-temperature oxygen-enriched gas (even if this problem was placed in Today, there are only a few countries that can handle it), so poor Dr. Goddard just jumped out of one pit and jumped into another bigger pit, and several experiments were not very successful...

Here we need to briefly explain the two major circulation modes of rocket engines: pneumatic circulation and pump pressure circulation.

We know that, unlike reciprocating internal combustion engines with intermittent combustion, the combustion process of liquid rocket engines is continuous, which means that when the rocket engine is working, its combustion chamber is always in a state of high temperature and high pressure.This means that if you want to send the propellant into the combustion chamber, you must apply a pressure to the propellant, and this pressure must be much higher than the pressure in the rocket engine combustion chamber!So a key question arises: how to pressurize the propellant?

One of the easiest ways to think of it is to make the pressure in the rocket propellant tank higher than the combustion chamber pressure, so that the propellant will automatically flow from the tank to the engine combustion chamber.

In the beginning, due to the low pressure of the rocket engine combustion chamber, the required propellant flow rate was also very small, and the researchers only had to simply rely on the internal pressure of the propellant tank itself (and possibly the gravity of the propellant itself) , the propellant can be sent into the combustion chamber of the engine.

This principle is actually the same as the common liquefied gas cylinders in our life. Since the internal pressure of the liquefied gas cylinder is as high as dozens of atmospheres, while the external pressure is very low, the liquefied gas cylinder can be released only by its own internal pressure. Most of the gas stored in it is transported into our liquefied gas stove.

The above circulation method that relies on the pressure of the propellant storage tank itself to press the propellant into the combustion chamber is the simplest pneumatic cycle. We can call this cycle a self-pressurized cycle. The disadvantages are obvious. Not only is the pressurization capacity very limited, but as the propellant in the propellant tank decreases, the pressure in the tank will decrease sharply. When the pressure in the propellant tank is equal to the pressure in the engine combustion chamber At this point, propellant can no longer be fed into the engine, and the engine stops working.

Due to the obvious shortcomings of the self-pressurized cycle, rocket researchers soon invented a more efficient pneumatic cycle, which is what we call the "squeeze cycle."

The biggest improvement of the "squeeze cycle" is that this cycle no longer relies solely on the internal pressure of the propellant storage tank itself to pressurize the propellant, but sets a nitrogen-filled cylinder outside the propellant storage tank. Or a high-pressure cylinder of inert gas, which is connected to the propellant storage tank through a valve.

When the extrusion cycle engine is working, it is only necessary to open the valve between the high-pressure gas cylinder and the propellant storage tank, and the high-pressure gas in the high-pressure gas cylinder will flow into the propellant storage tank to increase the pressure in the storage tank, so The propellant in the storage tank is pushed into the engine combustion chamber under the pressure of the high-pressure gas.

Since the squeezing cycle has an independent external pressurization source, the pressure in the propellant storage tank can be kept relatively stable, and the decay rate of the boosting effect is not as severe as that of the self-pressurized cycle.Coupled with its simple structure and high reliability (compared to pump-pressed rockets), squeeze cycle rockets have become the first choice for many research teams who have just started rocket design.The German A-1, A-2 and A-3 rockets on this plane all use this simple and reliable supercharging method.

So why did Dr. Goddard and Helena abandon this simple and reliable supercharging method that was proven on the previous A-1, A-2 and A-3 rockets?It turns out that the pneumatic cycle relies on the propellant storage tank itself or the external high-pressure gas as a pressure source to pressurize the propellant. , although the squeeze cycle is much more advanced than the self-pressure cycle, it still inevitably hits the "ceiling" of the pneumatic cycle.

When the squeeze cycle rocket engine is working, the pressure in the propellant storage tank must be higher than the engine combustion chamber, and the pressure in the high-pressure gas cylinder must be higher than the propellant storage tank, so that a pressure gradient can be formed to ensure that the propellant is normally pressed into the combustion chamber.As the size of the rocket increases and the pressure in the combustion chamber increases, this creates two serious problems:

The first problem is that the dead weight is too large. The propellant storage tank and high-pressure gas cylinder of the extrusion rocket must be made very strong, which greatly increases the structural weight of the rocket. The increase in the amount of filling, in order to ensure that the storage tank is always pressurized, a lot of high-pressure nitrogen or inert gas that cannot participate in combustion must be carried, which further increases the dead weight of the rocket.

The second problem is that the supercharging effect is limited. We know that in order to improve the working efficiency of the rocket engine (that is, the impulse that can be generated by a unit of propellant, referred to as "specific impulse"), in addition to improving the working efficiency of the various components of the rocket (including suitable In addition to the nozzle), the easiest way is to increase the combustion pressure of the propellant.And this is exactly the weakness of the squeeze cycle, because if you increase the combustion pressure of the propellant in the combustion chamber, you have to design a stronger propellant storage tank and a higher pressure and larger high-pressure cylinder to match the combustion pressure. Indoor stress fight.After reaching a certain critical value, you will find embarrassingly that the performance gain of the rocket brought by the increase in the specific impulse of the engine cannot offset the adverse effects of the increase in dead weight.

It is precisely because of the above two inherent defects that the performance ceiling of the pneumatic cycle rocket is not very high. Both Dr. Goddard and Helena believe that we should not spend too much energy on the squeeze cycle rocket (in fact Helena thinks that the extrusion cycle can still be saved on the upper stage of the rocket and the attitude control engine in the future.).After the technical accumulation of the A-1, A-2 and A-3 rockets, Helena believes that it is time to start a turbo pump pressure revolution in the field of rockets!

Chapter 118 Overcoming all obstacles

Since the pneumatic cycle is neither conducive to reducing the dry weight of the rocket nor to improving the efficiency of the rocket engine, people have begun to explore more advanced cycle methods, so a new pump pressure cycle has appeared.The so-called pump pressure cycle is a cycle method in which the propellant in the propellant storage tank is pumped out by a pump, pressurized and then sent to the combustion chamber for combustion.

It is not difficult to see that in this circulation mode, the pump is mainly used to pressurize the propellant, which brings three advantages to the pump rocket: the first advantage is that the propellant storage tank does not need to withstand The pressure is too high, so it can be made lighter and thinner, which greatly reduces the dry weight of the rocket; the second advantage is that the boosting capacity of the pump is much higher than that of the high-pressure cylinder (after all, the first-stage pump is not enough, and the can add a few more stages), so the pressure of the combustion chamber of the pump rocket can be designed to be higher than that of the air pressure rocket; the third advantage is that it can always be stably pressurized, and there is no pressure rocket. The problem of pressure degradation.

Under the generality of using a pump to pressurize the propellant, the pump pressure cycle can be divided into a gas/gas generator cycle, an expansion cycle and a supplementary combustion cycle.Since both the expansion cycle and the afterburning are too technically difficult for the technical level of the 20s, and the expansion cycle is only applicable to gaseous fuels, Helena did not consider the two cycle methods.

After careful weighing, Helena finally chose the unpretentious gas generator cycle. This is also the cycle method used by the German V-2 ballistic missile in the previous plane. It is the most primitive and simple type of pump cycle. cycle mode.Its basic principle is to use the decomposition reaction of hydrogen peroxide to generate high-temperature steam, so as to drive the turbo pump to operate, and then continuously pump out the liquid oxygen and ethanol in the storage tank, and then pump them into the combustion chamber.

In order to overcome the difficulties of the pump-pressure rocket engine as soon as possible, at the warm invitation of Helena, Dr. Hermann Oberth and Dr. Helmut Walter also enthusiastically joined in the research and development of the pump-pressure rocket .

These two doctors are also great god-level figures.In the previous plane, Dr. Oberth was one of the three pioneers of aerospace with the same reputation as Goddard and Tsiolkovsky, and he was also an important participant in the development of the V-2 missile.His book "The Road to Astronautics" published in 1929 has a biblical lofty status in the field of aerospace engineering in later generations.

Dr. Walter is the inventor of the famous "Walter Steam Turbine". Before this buddy has been immersed in the research of two-component torpedoes driven by hydrogen peroxide and kerosene.When Helena invited Dr. Walter, after years of hard work, his research and development team had just touched some doors in the key technology of hydrogen peroxide torpedoes.However, before the poor Dr. Walter had time to live a relaxed life for a few days, he was pulled by Helen.Although the torpedoes swimming in the water and the rockets flying in the sky sound like nothing to hit, but the turbo pumps of the German rockets in the previous plane were indeed improved from Walter's turbines!

Although the world's top research talents are concentrated, although the world's most abundant financial guarantee is available, although the development of the gas generator cycle is the least difficult among pump rockets, although Helena is concerned about the setbacks that may be encountered in the development I have been fully mentally prepared for the ups and downs.But the facts have proved that it is not free to light up the advanced technology in advance, and the difficulty of developing the pump rocket far exceeds Helena's expectations.The development of the pump-type rocket code-named A-4 has not been very smooth from the beginning. The first obstacle is the propellant pressurization system of the rocket.

Like the V-2 missile in the previous plane, the propellant pressurization system of the A-4 rocket in this plane uses a relatively simple coaxial pump, with a gas turbine in the middle, and an oxygen pump and an ethanol pump respectively. on both sides of the turbine.The power source of the turbo pump is a device called a gas generator. The shape of the device is like a jar. There are multi-layer silver catalytic mesh and stainless steel filter mesh inside the jar. When the hydrogen peroxide solution with a concentration of up to 80% passes through these When the catalytic net is used, hydrogen peroxide is catalyzed and decomposed to produce high-temperature vapor mixed with oxygen at a temperature close to 500 degrees Celsius.When the turbo pump is working, the turbine is driven by the high-temperature steam generated by the decomposition of hydrogen peroxide, which drives the oxygen pump and ethanol pump on both sides to pressurize the propellant.

Compared with the V-2 missile in the previous plane, the pump system structure of the A-4 rocket in this plane is very similar, but the design of the gas generator is more reasonable than the V-2 missile in the previous plane. The gas generator of the V-2 missile above relies on spraying sodium permanganate solution into a high-concentration hydrogen peroxide solution to catalyze the decomposition of hydrogen peroxide (does this catalytic reaction sound familiar to you? I learned it in middle school ), the catalytic reaction process is not as stable as the silver catalytic net of the A-4 rocket on the original plane.

The gas generator with silver catalytic net designed by Helena for the A-4 rocket is indeed a proven design on the American "Redstone" rocket in the last plane, and it has performed very stably in various experiments. However, the biggest technical problem lies in the coaxial turbo pump.

As the pioneering work of turbopump rockets in Germany and even the world, the R&D team was actually very conservative when determining the technical parameters of the turbopump of the A-4 rocket: the turbine power was no more than 300 horsepower, and the speed was no more than 4000 rpm. The temperature is less than 450 degrees Celsius, and the working time is only tens of seconds.However, no one thought that it was these tens of seconds of working time that tortured Dr. Walter, who was in charge of the turbine design, to death.

"Congratulations! Dr. Walter, I think you can buy lottery tickets again." After another gas generator-turbo pump joint test failed, and after carefully inspecting the turbo pump that was damaged in the test, Helena took a picture He patted the dejected Dr. Walter on the shoulder and said, no matter how he heard it, there was an unconcealable schadenfreude in his tone.

"Congratulations? Buy a lottery ticket?" After hearing what Helena said, Dr. Walter was a little confused for a while.

"I think you may have encountered the resonance induced by the cavitation of the oxygen pump. You can't get this special prize every time." When Helena spoke, she still had a heartless smile on her face: "You can add a guide wheel to the oxygen pump to see if it can alleviate cavitation. The rest is to design a few more configurations and try slowly. Since you have encountered this big hole, lie down and enjoy filling it Have fun! I like you very much, Dr. Walter."

Dr. Walter: Suddenly, I really want to kill this heartless guy in front of me...

Chapter 119 Injector Disk

In the face of failure, Helena is certainly not as heartless as she appears on the surface. The development of the turbo pump has suffered repeated setbacks, and she is actually as uncomfortable as Dr. Walter.Among other things, behind those turbo pumps that failed during the test run, it was all the reduction of real money in the "Peace Fund" account.Although the money on the "Peace Fund" is not Helena's in name, the various scientific research projects that Helena wants to promote cannot do without the support of funds.This means that for every additional mark spent on the rocket project, Helena's investment in other projects will be reduced by one mark.

Although the huge research and development costs made Helena feel distressed, Helena knew that scientific research work was not allowed to be abandoned halfway, and giving up halfway would only cause greater waste of resources.In Helena's day and age, rocket turbopumps were new to everyone.Developers lack both strong theoretical guidance and sufficient practical experience in this regard, and they do not have the help of high-performance computers like later generations, so many designs must rely on continuous trial and error during the development process to be finalized.

From this perspective, the previous process of continuous failure by Dr. Walter and others is actually a process of continuous trial and error.In the process of trial and error, the experience from later generations in Helena's brain has indeed inspired researchers a lot, thus greatly reducing the cost of trial and error, but it is absolutely impossible to skip the trial and error link.

It is precisely because she knows that trial and error is inevitable, so whenever the news of the failure of the experiment comes, Helena will bleed from her heart, and at the same time pretend to be relaxed and say some heartless jokes to the research team.The optimism shown by Helena really infected the entire design team, keeping the morale of the designers high.

After hitting the wall repeatedly for a period of time, Dr. Walter's team finally made a breakthrough.At Helena's suggestion, they perfected the rocket's liquid oxygen self-generating pressurization system, improved the shape of the oxygen pump and designed a guide wheel for the oxygen pump, finally eliminating the resonance induced by cavitation.The gas generator-turbo pump joint test of the rocket engine began to succeed one after another, which made everyone, including Helena, breathe a sigh of relief.

However, the researchers were not able to breathe a sigh of relief. When the rocket entered the test run of the whole machine, the "devil" made a comeback again. This time the problem was in the combustion chamber.During the test run, the engine of the A-4 rocket began to experience combustion instability from time to time. Several times, the propellant injection plate on the top of the combustion chamber was burned through. The most serious engine even failed on the test bench. An explosion occurred directly, but fortunately the test bench was not irreversibly damaged, which did not have much impact on the subsequent engine test plan.

While the experts in the design team were still arguing about the cause of the unstable combustion, Helena was the first to analyze the cause of the unstable combustion problem. This was not because Helena had a sharper vision than the great gods, but because Helena had seen pigs run in her previous life!

This situation has occurred in the development process of many rocket engines in the previous plane (including the German V-2 ballistic missile and the American "Saturn V" launch vehicle).As the thrust of the engine increases, the area of ​​the propellant injector at the top of the engine combustion chamber increases, and the number of injection units also increases.When the engine is working, complex disturbances will be formed between the injection streams of these injection units. If these nonlinear disturbances are not suppressed, there is a certain probability that they will cause combustion vibration, which will affect the normal operation of the engine and even damage the engine.

The way for the V-2 missiles in the last plane to deal with combustion instability is to cancel the original planar propellant injection disk design, and design the engine propellant injectors into an inverted cup-shaped structure. Known as the "Burner Cup".When the V-2 engine is running, liquid oxygen is sprayed into the burner cup from the top of the burner cup, and ethanol is sprayed from a small hole in the cup wall. The two are pre-ignited in the burner cup before entering the main burner cup. The combustion chamber carries out further combustion. There are a total of 2 such burner cups on the top of the engine combustion chamber of the V-18 rocket, which makes the engine combustion chamber of the V-2 rocket look like a monk in appearance.

Although the injector design used in the V-2 rocket engine of the last plane is ugly in appearance, since the injection and ignition process of the engine propellant are limited to a small area, it is difficult to Interference and coupling with other areas has indeed effectively solved the problem of combustion instability.

However, the design of the "injector cup" on the V-2 rocket engine in the last plane is not without problems. First of all, each injector cup needs to be connected to a separate liquid oxygen pipeline.The messy liquid oxygen pipeline not only increases the complexity of the engine, but also makes the engine less reliable.Secondly, the atomization of the propellant by the burner cup is not thorough. On the one hand, the incomplete atomization reduces the combustion efficiency of the engine, and on the other hand, the designer must use a larger combustion chamber to accommodate the combustion area, which will increase The weight of the engine reduces the engine thrust-to-weight ratio.

The engine of the A-4 rocket in this plane did not follow the practice of the V-2 missile in the previous plane. Under Helena’s suggestion, the design team adopted a method that is more widely used in later generations to suppress combustion instability: The flat injection disc increases the partition.This method is also the main weapon for many rocket engines in the last plane, including the main engine of the Saturn V, to deal with unstable combustion.The partition above the injector disk divides the plane injector disk into multiple regions. In terms of the mechanism of suppressing combustion instability, it is actually similar to the "burner cup" of the V-2 missile. Wonderful.

After verifying that the injection plate partition can effectively suppress combustion instability, the designers spent a lot of time further optimizing the design of the injection plate and the partition, and finally determined the injection plate partition The shape: two concentric partitions inside and outside plus four radial partitions between the two circles.These partitions divide the hundreds of injection units (each unit consisting of a liquid oxygen nozzle and two ethanol nozzles) on the plane injection disk of the A-4 rocket engine into five separate areas. It was shown that this measure was very successful in suppressing combustion instabilities.

After solving the problem of unstable combustion, this rocket engine finally did not have any bigger moths. Even Helena had been worried about the regenerative cooling system before, and she did not lose the chain.After years of hard work, this liquid oxygen ethanol rocket engine with a gas generator cycle was finally released. Helena named this engine FR-1, where FR is the German abbreviation for liquid rocket engine.

Although the thrust at sea level is only 10 tons, although the pressure in the thrust chamber is only 3 MPa, and although the specific impulse at sea level is only a little over 200 seconds, in the 30s, the FR-1 engine can still be regarded as an industry unparalleled in the industry. masterpiece.Its success means that the design team has taken the most critical step in the development of the A-4 rocket, and the practical pump-pressed liquid rocket seems to have appeared on the distant horizon.

Chapter 1 Twenty

After passing various tests, the first full-state A-4 rocket that can be used for launch missions finally stands firmly on the launch tower in Peenemünde.This is a big guy with a height of 12 meters and a weight of 7 tons.With a sharp nose cone, a slender arrow body, and four large-area stabilized fins, this rocket shape may have been commonplace in the eyes of later generations, but in the early 20s, it had an unspeakable technology. beauty.

Standing side by side under the high launch tower, looking up at the rocket like a giant bamboo shoot breaking out of the ground, Helena and the four leaders of the rocket research and development team: Goddard, Von Karman, Oberth and Walter His expression was in a trance for a moment.In the past few years, this beautiful "big baby" in front of us has really poured too much effort and sweat into the R&D team.

After taking a group photo in front of the launch tower, a few people walked into the bunker-like safety bunker and rocket control room that looked a little crude beside the launch site. In order to save unnecessary expenses, the current Peenemunde base can still see simple Mark of.Then, staff wearing anti-static suits began to fill the rocket with ethanol and liquid oxygen.The five people in the bunker control room didn't speak, but everyone's eyes were fixed on the rocket not far away, watching the staff in charge of propellant filling busy there.

"Don't be bored, guys, talk about it, what will we do if this launch fails?" Dr. Walter, who was the most eccentric among the five, probably couldn't bear the silence. Suddenly, out of his black-rimmed glasses, such a sentence popped out.

"Shut up!" Four voices sounded almost at the same time, and then eight eye knives flew towards Dr. Walter, scaring the unlit cigarette that Dr. Walter had been holding in his mouth since entering the bunker to the ground. .After Dr. Walter shrank his neck and turned into a quail, the tense and quiet state returned to the small bunker control room.

As if centuries had passed, the A-4 rocket on the launch tower finally completed propellant filling and pre-launch preparations, and the on-site staff and propellant filling vehicles began to evacuate in an orderly manner.After all the personnel and equipment at the scene are evacuated, there are only 15 minutes left before the scheduled launch time.

"5 minutes to prepare!" Dr. Goddard, who was in charge of commanding the launch of the Navy, shouted into the microphone with 5 minutes left before the scheduled launch time.At Helena's suggestion, Germany on this plane began to use countdown timers in rocket launches as early as 1925 when the A-1 rocket was launched.

In the last plane, the genius idea of ​​"Countdown" did not come from the scientific community, but from the German film director Fritz Lange.In 1927 on the last plane, when Fritz Lange directed the space sci-fi film "Moon Girl" invested by the German Ufa Film Company, he designed "...5, 4, 3, 2" for the shot of the rocket launch. , 1, launch!" This countdown launch program.Later, this fictitious plot in the movie aroused the strong interest of rocket experts, so the "countdown" was introduced into the real space launch program, and finally became the common timing method for launching missions in the international space community.

Considering that "Moon Girl" is the world's first sci-fi film with space travel as the main theme, and has a high status in the history of world film, Helena felt that it was necessary for her to make this film more classic and give Future space sci-fi movies set a good example.So when the filming of the film "Girl on the Moon" started in 1927, Helena took out a large sum of her own money to increase investment in the film, and also volunteered to be a scientific consultant for the film.

Director Fritz Lange was preparing for the filming of "Moon Girl" at that time, and even the child star who played the heroine had already been selected.At this time, when he heard that a "relationship household" who had no filming experience wanted to "bring capital into the team", he was so angry that he cursed the unhealthy trends in the film industry, and his people were not old...but when others told Fritz Director Lange wisely chose not to say anything after the other party's capital injection amount was at least 100 million marks.

Just when Lange was still ashamed that he was about to bow his head to money, he received a piece of news that almost dropped his jaw: "What did you say? The 'relationship account' brought money into the team not to grab the role? Just preparing to serve as the scientific advisor of "Moon Girl"? Are you mistaken?"

After getting an affirmative answer, Director Lang heaved a long sigh of relief. He finally didn't need to give up the principle of casting for money.Although he felt that it was unreliable to ask a related accountant to be a scientific consultant, he couldn't understand the way rich people play tickets now.However, as a director, he still has the right to decide whether to adopt the advice of the consultant

Helena knows nothing about these psychological activities of Director Lange. If she knew that Director Lange thought she was here to snatch the heroine of the movie at the beginning, she would have spread her hands helplessly and said to Director Lange: "Your brain hole is too big!".Regarding her talent in acting, Helena is quite self-aware. She doesn't want her poor acting skills to be left on the video tape forever, and then be ridiculed by the audience of later generations.

Except that when Helena met Fritz Lange for the first time, the poor sci-fi director almost had a heart attack on the spot after learning that Helena was the "relationship household" who brought money into the group, Helena It is still very pleasant to cooperate with the film crew of "Moon Girl".Helena not only used a large sum of money to build a large number of high-precision scale models for the crew, rented a pool for shooting weightless shots, but also designed a large number of vivid images of launch vehicles and spacecraft for the crew, each of which can withstand future generations. Scientific deliberation.This is of course nonsense. These images are all modeled on the Saturn V, the space shuttle, the International Space Station, etc. Can they not stand up to scientific scrutiny?

In order to improve the realism of the shooting, Helena even allowed the crew to enter the Peenemünde launch site, dress up an A-3 rocket to look like a Saturn V, and launch it with a real arrow.However, director Fritz Lange is indeed a talented person. He shot a small rocket of less than 1 ton with the momentum of a 3000-ton super-heavy moon landing rocket!It is worth mentioning that, in fact, Dr. Aubert was the scientific advisor of "Girl on the Moon" in the last plane, and in order to shoot this movie, Dr. Aubert also specially designed a rocket for the movie, but this plane Helena steals Oberth's job.

In June 1928, "Moon Girl" was officially released in Berlin, which immediately shocked the entire German film industry, and numerous praises flew over like snowflakes.Even the scientific community was drawn to the film, including Dr. Oberth, who is now in the bunker control room waiting for the rocket to launch.When Aubert learned that Helena was the scientific advisor of the film, he immediately readily accepted Helena's invitation to join the rocket project. It has to be said that Helena can abduct the great god Auberte, and the "Moon Girl" The movie is also a great credit!

"One minute to prepare!" Dr. Goddard's voice interrupted Helena's memory, and the atmosphere in the bunker control room became more tense.

"30 seconds!" The five people in the control room clenched their fists.

"20 seconds...ten, nine, eight, seven, six, five, four, three, two, one, launch!" Dr. Goddard pressed the launch button himself.

At this time, the accident happened suddenly. After a slight crack, orange-red flames suddenly emerged from the side of the projectile above the engine compartment.Then the engine that had just started went on strike, and the flame on the side of the projectile continued to burn for a while, and then went out by itself.

"Oh no! My God! What's going on?" Dr. Walter put his head in his hands.

"Is this a failure?" Dr. Goddard slumped on the chair in front of the console.

On the contrary, Helena seemed calmer. She pondered for a while, then slowly said: "I think it should be a problem with the liquid oxygen ethanol pipeline above the engine."

After sorting out her thoughts, Helena went on to say: "It is likely that the vibration and structural stress during ignition damaged the pipeline above the engine, causing liquid oxygen and ethanol to leak, and then a small-scale explosion occurred and caught fire, but the explosion It just happened to destroy the gas generator-turbo pump system, so that the entire engine stopped working, and there was no follow-up fuel replenishment, and the flame went out by itself." After a pause, Helena patted her chest with some fear and said, "Fortunately, the ethanol storage The tank and the liquid oxygen storage tank did not seem to have ruptured, otherwise, what happened just now was a full-blown explosion!"

"You stay here, I'll go out and have a look!" Dr. Aubert picked up the protective suit and was about to go out.However, Helena had already put on the anti-static suit before him, and ran out quickly. "Keep an eye on them, and don't let them get out of the bunker." Helena told the staff at the door of the control room, and Helena said to herself, "Negelin bless me!" and rushed towards the launch tower. .

Chapter 121 Backup Improvements

Just as Helena hurriedly rushed from the command post to the edge of the launch site, several fire trucks that had been waiting outside the launch site roared into the launch site.Helena hurriedly commanded the fire truck to approach the rocket still standing on the launch tower from the upwind direction, and sprayed and cooled the part of the rocket engine that had caught fire before.

Helena is now worried about two things: one is that the liquid oxygen storage tank near the fire point ruptures due to excessive internal pressure after being continuously heated; Mixed gas (ethanol vapor and oxygen are heavier than air, so it is not easy to dissipate under windless conditions, but also easy to gather in various low-lying places), once this dangerous mixed gas is ignited by static electricity, the consequences will be disastrous.

Since Helena was only wearing level-three protective clothing, although she went to the scene to command and dispose of the work, she did not enter the safety cordon that had been drawn before the launch. Crews on respirators entered the danger zone and struggled to salvage the accidental rocket.

Fortunately, what Helena was worried about before did not happen. After the staff drained all the propellant in the rocket storage tank, her heart that had been hanging was slightly relieved.Helena took off her protective mask, and let out a long mouthful of the turbid air that had been suppressed in her chest. She suddenly felt her legs go limp, and then she really wanted to sit down on the ground without getting up, but Helena finally Still resisting the urge to lie down and be a salted fish.

Instead, she effortlessly brushed back her blond hair, which was stuck to her cheeks with sweat, and simply pulled it back into what she thought was a cool look.This is because in Helena's eyes, the more peerless a person is, the less messy his hairstyle will be after going through danger!Then Helena walked among the staff involved in the rescue, shook hands with them one by one, and promised to give them red envelopes back to express her admiration and gratitude for their heroic behavior just now.

Although after a brief inspection, Helena was sure that the accidental rocket was completely scrapped, but the significance of her and the staff working hard to rescue the accidental rocket from danger was still of great significance.In addition to avoiding greater losses caused by the explosion of the rocket on the launch tower, the most important significance is that by analyzing the accident rocket, the scientific research team can determine the location of the failure faster, so as to formulate more targeted solutions. improvement measures.

Since the accident rocket was well protected, the design team quickly analyzed the cause of the fire.The analysis results showed that Helena's judgment at the first time was completely correct. It was precisely because of the structural stress during the rocket launch that the liquid oxygen and ethanol pipelines above the engine leaked, and then mixed above the engine, resulting in explode.The force of the explosion destroyed the engine's gas generator, causing the pump system to stop working and the engine to shut down.

"Come on, guys! At least now we have found the problem, which means we are one step closer to success!" In the accident summary meeting, Helena faced all the researchers of the A-4 rocket encouraged.In the end, Helena applied the famous saying in the aerospace field of later generations: "The cause you are engaged in is great not because it is easy, but because it is difficult!"

"You just said it so well, Miss Seekert! Your last sentence can definitely become the motto of all researchers at the Peenemünde base in the future!" After the meeting, Dr. von Karmen patted Helena on the shoulder explain.Dr. Goddard, Dr. Aubert, and Dr. Walter on the side also nodded. "Thank you uncles for your support!" Helena hastily bowed to thank the four great gods sincerely.

"Fortunately, this accident was not caused by fundamental design flaws, and the difficulty of solving it is not too great. We don't need to redo the entire design plan." Dr. Goddard brought the topic back to work Above: "We made a total of two A-4 rockets in the first batch. It was originally planned that one of them would be used for the first flight test, and the other would be used as a backup for supplementary tests. So now we have a backup arrow available, and we can Carry out structural improvement work directly on the basis of this backup arrow.” With the encouragement of Helena, on the second day after the cause of the accident was found out, the entire A-4 rocket research and development team worked with the highest efficiency. , and once again invested in the intense research and development work.

During the communication between the research and development team, Helena also met Dr. Aubert's student and the famous rocket expert in later generations——Werner von Braun.Now Braun is actually still studying for a Ph.D. at the University of Berlin, but in order to exercise the practical ability of his beloved apprentice, Oberth still drew Braun into the A-4 rocket project team as his assistant.The joining of Braun made Helena feel relieved that there are successors in the Rockets business.

You know, in the last plane, Dr. Braun not only led the development project of the V-2 missile in Peenemünde, but also went to the United States after the war to preside over the design of the famous super-heavy moon landing rocket—" Saturn V".In fact, until the beginning of the 21st century before Helena crossed, the "Saturn V", a rocket designed in the 60s, still topped the list of rocket carrying capacity with a capacity of 118 tons in low-Earth orbit (in fact, the actual capacity of Saturn V The potential is even higher than this number)!

With the full cooperation of the entire design team, the improvement of the A-4 rocket backup arrow is progressing rapidly. Just over a month later, on September 9, the structurally strengthened A-25 rocket backup arrow was once again erected on the high ground. on a high launch tower.The efficiency of handling accidents is almost comparable to the development speed of the German rocket in 4 on the previous plane!Of course, this speed is also inseparable from Helena's suggestions based on the experience of later generations.

"Let's talk about it, this time, do we need to plug Helmut's crow's mouth with a rag?" Dr. von Karmen, who always likes to play humor, held a piece in his hand and looked at it for a long time. The washed rag, winking at Helmut Walter.The poor Dr. Walter backed away again and again: "Don't mess around, Theodore! It wasn't my fault that the rocket failed last time! Okay, okay, okay, I promise I won't say a word this time. ?"

Dr. von Kármán's amusing vignette about Dr. Walter dispelled everyone's tension at once.Helena even couldn't help laughing out loud, she thought while laughing: Who is raising all the great gods who have become second-hand?

"5 minutes to prepare!" Dr. Goddard's countdown call rang out in the rocket control room for the second time, so everyone put away their smiles and looked at the rocket in the launch site with serious expressions. .

Chapter 122 God's Arrow Soaring to the Sky

"One minute to prepare!" In the quiet rocket control room, Dr. Goddard shouted the latest countdown reading in front of the microphone.This time his volume was a little higher than before, as if he could vent all the tension accumulated in his heart with this loud shout.

Helena, who was startled by the yelling, turned her head and glared at Dr. Goddard, and then looked around at the other three great gods in the control room, only to find that the gazes of the several great gods were like Like a demon, he was glued to the rocket with striking black and white stripes in the launch site, and no one noticed his reaction at all.

"30 seconds!" Dr. Goddard's voice sounded again, and Helena also retracted her wandering gaze just now, and refocused her attention on the rocket launch site.

"20 seconds!" At this moment, an invisible bowstring seemed to be pulled taut in the frozen air.

"Ten, nine, eight, seven, six, five, four, three, two, one, launch!"

Dr. Goddard resolutely pressed the launch button, and saw a large cloud of milky white smoke rising from the bottom of the launch tower.Then amidst the more and more furious roar of the engine, a beam of bright flames suddenly gushed out from the bottom of the rocket, illuminating the surrounding smoke that had not yet dispersed.Immediately afterwards, under the support of this beam of flames, the huge body of the rocket finally slowly broke away from the base of the launch tower.

At the beginning, the rocket rose very slowly, as if a newly awakened dragon was breaking free from the chains that bound it.But all of this is only temporary, I saw that it rushed out of the still spreading smoke first!Then fly away from the towering tower!Its height is getting higher and higher, and its speed is getting faster and faster!

Finally, the rising rocket was like a sharp and unparalleled sword, with a bright tail flame, easily pierced the dark green shadow of the distant mountains, and flew towards the unobstructed sky without looking back , as if there is its eternal hometown outside the blue sky.

At the same time as the rocket flew into the distance, five people including Helena rushed out of the control room with a relatively narrow field of view, and ran to the edge of the launch site.Several people did not speak, but stood shoulder to shoulder, watching the rocket gradually go away, and finally turned into a small shining light spot and sank into the sky.

"Did we succeed?" It took a long time for the rocket to fly out of everyone's sight before Dr. Walter broke the silence first, with a bit of disbelief in his voice.

"I think so. In fact, I think that as long as the rocket can fly smoothly, it is more than half the success!" This is the voice of Dr. Aubert.

"Now there is only one question left, who do you think this thing will fall on if it falls headlong?" Dr. von Kármán said.

"I don't know either." Dr. Goddard, the chief designer of the rocket, spared words like gold.