Iron Sonata of World War II

Although the "Wurzburg" radar in this plane still has a lot of room for improvement in Helena's eyes, but in the 30s when this radar technology was just entering the practical stage, this performance in the mid-40s on the previous plane was unimportant. Not counting as falling behind the radar, but against the backdrop of the group of stupid, black and thick colleagues from other countries, it can quite reveal a bit of handsome, rich and handsome temperament.At least even if it is presented to people who have no research on radar in later generations, the other party will most likely be able to easily recognize that it is a radar, and it will not be regarded as an iron shelf of unknown purpose by laymen like other radars of the same era.

However, after the prototype of the "Wurzburg" radar was developed, the high-spirited Telefunken company had not had time to be proud, and Helena's little leather whip began to urge them to work again.Just like they developed the fixed-deployed "Grand Würzburg" radar based on the circuit design of the "Wurzburg" D-type radar in the previous plane, Helena also asked the Telefunken company on this plane to On the basis of this radar, products with larger volume and superior performance have been developed for deployment in important places. After all, the first batch of air defense towers under construction have already reserved a place for this radar.

In Helena's plan for the construction of the future German air defense system, the ground radar network will be a crucial link. Helena plans to build it into a multi-level detection with high and low matching, dynamic and static combination, and long-range early warning and air defense guidance functions. system.In this system, the large-scale meter wave radar with long detection range but low precision is mainly used for long-range early warning, while the L-band decimeter wave radar with short detection distance but good accuracy can be used for anti-aircraft artillery and fighter guidance.

And this kind of L-band radar responsible for air defense guidance is divided into two types.They are the fixed-deployed large guidance radar and the mobile-deployed small guidance radar.

Among them, the fixedly deployed large-scale guidance radar has a larger detection distance and better detection accuracy, so it can form the grid of the ground air defense radar network together with the large-scale meter-wave early warning radar. Countless such grids are intertwined to form the entire The skeleton of homeland air defense.This kind of radar not only needs to be responsible for guiding large-caliber anti-aircraft firepower in important areas (mainly 130mm double-mounted heavy anti-aircraft guns on this plane), but also needs to organize fighter jets to intercept enemy fleets around the clock.

The mobile-deployed small guidance radar, that is, the "Wurzburg" radar just developed by Telefunken, is mainly used in combination with air defense firepower that also has mobile deployment capabilities (in this plane, it is mainly a 90mm towed radar) Anti-aircraft artillery), this kind of radar is not only a supplement and enhancement to the fixedly deployed large-scale guidance radar, but also can stand up when the large-scale guidance and guidance radar in the grid is damaged or the guidance capability is in an oversaturated state , to replace or share part of the functions of the former.

The flexible combination of the two guidance radars will also bring a hidden benefit, that is, for the enemy bomber groups that need to pass through these air defense grids, there are huge variables in the air defense guidance capabilities in each grid. The existence of such variables will make it difficult for the opponent to understand the depth of the air defense strength in the grid, and it will be difficult to formulate tit-for-tat tactics if they cannot know the enemy.That is to say, for the enemy's bomber fleet, it is uncertain how many guidance radars are in each air defense grid and how strong the interception force can be organized.Just like if you don't open Schrödinger's box (the original plane is Helena's), you will never know whether the cat is dead or alive.

In World War II on the previous plane, although Germany also adopted a grid-based air defense management model, the detection range and accuracy of the "Wurzburg" radar they could use for mobile deployment were relatively limited, and even guided anti-aircraft artillery It is difficult to complete the work independently, which greatly weakens the flexibility of the air defense system.As a result, after the Allies gradually figured out the strength of each air defense grid, they could not only better plan the bombing path, but also often broke down the large aircraft group into multiple Smaller aircraft fleet, so that the guidance capability of the radar in the grid is in an oversaturated state, because the "Grand Wurzburg" radar can only guide and intercept one target at a time, so this measure has reduced the casualties of the Allied pilots Not a lot.

Helena was very satisfied with the large-scale guidance radar proposal submitted by Telefunken. As a large-scale fixed-deployment radar that cooperates with the mobile-deployed "Wurzburg" radar, the size, weight, and power consumption of the radar are relatively small. Both restrictions can be significantly relaxed compared to the mobile deployed version.Therefore, when formulating the design draft of this radar, the designers of Telefunken also obviously let themselves go.Due to its huge size, this radar is called the "Great Würzburg" radar like the previous plane.

The "Great Würzburg" radar in this plane has a huge circular parabolic antenna with a diameter of up to 9 meters, and the entire rotating part of the radar including the transmitting and receiving equipment weighs more than 20 tons. This volume and weight are even higher than those in the previous plane. The "Greater Würzburg" radar is even bigger. Fortunately, the occasions where this kind of radar needs to be deployed have solid and thick concrete bases. almost 130 tons).As for the need for road or rail transportation, the radar can be dismantled into several large parts first, and then hoisted up at the destination.

The "Greater Würzburg" radar on this plane still works in the L-band, using the same 1330 MHz transmission frequency and 22.5 cm wavelength as the "Wurzburg" radar, but the peak power will reach the level of 100 kilowatts.According to the estimates of the designers of Telefunken, the maximum detection range of this type of radar can exceed 100 kilometers, and the maximum tracking distance can reach more than 80 kilometers, which greatly exceeds the product of the same name in the previous plane.

However, what is even more commendable is that due to the shortening of the wavelength and the increase of the antenna gain, the angle measurement accuracy of the "Great Würzburg" radar on this plane is expected to reach the level of 0.04 degrees, which is 130 kilometers where the 12mm heavy antiaircraft gun normally fires. In terms of distance, the measurement error of this "Great Wurzburg" radar can be no more than 10 meters. It is undoubtedly fully qualified as a fire control radar for guiding anti-aircraft guns on anti-aircraft towers, and it is also suitable for all-weather guidance for fighter jets. It is very competent to be able to make it big.

Since the "Grand Würzburg" radar requires a much larger antenna and a much more powerful transmitter, the technical difficulty is much higher than that of the mobile-deployed "Wurzburg" radar, and Telefunken It is necessary to continue to improve the design of the "Wurzburg" radar at the same time. Helena estimates that these projects at hand are enough for the designers of Telefunken to toss for several years, and Siemens and Gemma are also full of radar development. project, so Helena also temporarily gave up the burden on designers in the field of radar development.

However, this does not mean that Helena will rest on her laurels in the radar field. She has already turned her attention back to the research of front-end technology. Her next breakthrough targets are quartz resonators and multi-cavity klystrons. With these She can further develop the main vibration amplified transmitter to obtain phase-coherent high-frequency stability signals, so that she can start to develop a more advanced pulse Doppler radar.Although it is too far away to say these things now, it is always right to choose the right direction of effort first.

Chapter 253 Band Selection

In addition to the "Wurzburg" series of radars responsible for commanding anti-aircraft artillery and guiding fighters, Germany also has several radar development projects including meter wave long-range early warning radars at different stages of development. Although Helena does not have enough time and energy to develop Helena asked about the development progress of each model in detail, but Helena, who was worried about the rascal designers in charge of radar design, still based on the engineering experience of later generations, prepared in advance for German designers in places where it was easier to step on thunder. Vaccination.

For example, Helena once specifically told radar designers: When selecting the radar working band, especially the high-frequency radar working band, considering that electromagnetic waves of certain frequencies will induce atmospheric molecular resonance, attention must be paid to the study of the earth's atmosphere. The absorption rate of the various molecules in the main component of the electromagnetic wave of this frequency, and try to avoid the peak interval of the molecular absorption rate of these components, so as to reduce the attenuation effect of the atmosphere on the radar wave, thereby effectively increasing the detection distance.

However, the vaccination that Helena discovered seems to be a bit too early, because the attenuation effect of the atmosphere mainly affects the high-frequency radar waves with a frequency above 10 GHz, that is to say, it can only work in the X-band or higher. It is only the radar of the frequency that needs to worry about this problem, and these bands are still rarely involved in German radar researchers.Therefore, although the designers all smiled kindly at Helena's reminder, most of them didn't take it seriously in their hearts. In fact, they didn't quite believe that they would set foot in this frequency band when designing radar in the future.

However, since Helena can seriously bring up this matter, it is naturally impossible for her to be aimless.Although several radars developed in Germany now work in the P-band, L-band and S-band, that is, the range of meter waves and decimeter waves.But Helena knew that with the expansion of the radar's role in the future, especially the development of airborne radar and fire control radar, the contradiction between improving the detection accuracy and reducing the size of the radar would become more and more intense.In order to coordinate this contradiction, it will be the general trend to increase the operating frequency of the radar, so the emergence of centimeter-wave or even millimeter-wave radar is also a historical necessity.

In fact, in the history of the last plane, when Germany developed the 20 GHz UHF radar, it "carelessly" selected the radar wavelength at the K-band of about 1.5 cm. Unfortunately, the radar wave of this wavelength is different from the The absorption peak of water vapor is too close, so it is very easy to be attenuated by water vapor in the atmosphere. As a result, the radar products developed by the Germans will have a serious drop in detection range whenever they encounter rainy weather.In order to prevent the German designers of this plane from making such low-level mistakes in the future, Helena had to fill in the pits before they fell.

After learning the experience and lessons of the Germans, when countries develop high-frequency radars after World War II, they usually pay attention to avoiding the frequency bands around 22 GHz (water vapor absorption peak) and 60 GHz (oxygen absorption peak) in the selection of bands. .This is why radars operating in the Ku-band, which is slightly lower than the K-band, or the Ka-band, which is slightly higher than the K-band, are more common, while radars operating in the K-band, which are easily absorbed by water vapor, are relatively rare.

Here it is necessary to add an explanation about the frequency and wavelength of the radar.We know that the radio waves (including microwaves) emitted and received by radar are essentially the same as infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays. They all belong to electromagnetic waves and occupy a specific part of the electromagnetic spectrum. Position, but the frequency is getting higher and higher from front to back.Since the propagation speed of electromagnetic waves in vacuum is the constant speed of light, the frequency and wavelength of electromagnetic waves are inversely proportional, and the product of the two is the speed of light.The radio waves emitted by radar, as electromagnetic waves with a specific frequency range, naturally need to follow this rule.

Since the frequency interval of radio waves can extend from 10 kHz to 30 GHz, in order to more accurately describe the frequency characteristics of a certain radio wave, people continue to subdivide the interior of radio waves into different intervals according to frequency and wavelength , just like we describe visible light as red, orange, yellow, green, blue, blue and purple and other colors, and these artificially divided radio wave frequency intervals are what we call "bands".

The band usually used by radar actually only covers a small part of the entire radio wave frequency band, that is, the radio wave with a frequency ranging from several megahertz to tens of gigahertz and a wavelength ranging from tens of meters to several millimeters.The bands contained in this radio wave are arranged in order from low to high and wavelength from long to short, as follows: HF band, VHF band, P (UHF) band, L band, S band, C band, X band , Ku-band, K-band, Ka-band, U-band, V-band and W-band.For example, the "Wurzburg" radar developed by Telefunken on this plane with a frequency of 1330 MHz and a wavelength of 22.5 cm belongs to the L-band.

Although other conditions remain unchanged, the shorter the radar wavelength is, the higher the detection accuracy is, and since the effective aperture of the antenna is proportional to the square of the wavelength, a radar with a shorter wavelength can obtain a greater detection accuracy with the same aperture. Gain, or using an antenna with a smaller aperture while keeping the gain constant, facilitates the miniaturization of the radar.It seems that the designer should increase the operating frequency of the radar as much as possible, but many factors restrict the increase of the operating frequency of the radar.

The first is the loss of radar waves caused by atmospheric attenuation.In addition to a few attenuation rate peaks due to molecular resonance, generally speaking, the higher the operating frequency of the radar, the more significant the attenuation effect of the atmosphere on the radar wave, so when the power and antenna gain are the same, the higher the operating frequency The higher the radar, the more serious the loss of detection range caused by atmospheric attenuation.

Secondly, the higher the operating frequency of the radar, the more difficult it is to achieve sufficient transmission power. After all, how to make a high-power high-frequency oscillator is not a small technical problem. This is still in the initial stage of electronic technology. It was even more evident in World War II.A more obvious example is: Except for the three countries with relatively developed electronic industries, Britain, the United States and Germany, no other industrial country could develop a practical radar with a working frequency above GHz during the war.

Finally, radar with a lower working frequency has an irreplaceable role in some specific occasions, such as space detection and dealing with stealth targets.After all, the stealth shape and wave-absorbing coating of stealth aircraft are mainly designed for centimeter waves and millimeter waves. For radars working in the L-band or even the meter-wave band, the stealth effect will naturally be greatly discounted.

Based on the above reasons, even in the 21st century before Helena crossed, the frequency selection of military radar did not show the phenomenon that high frequency overwhelmed low frequency or low frequency overwhelmed high frequency. The pattern of balanced competition in the position.Generally speaking, low-frequency radars with high power and low atmospheric loss are mainly used for early warning, search and tracking, while high-frequency radars with small size and high precision are mainly used for fire control, imaging and guidance.

The author has something to say: The band division in this article is actually based on an old standard, and even though this old standard was not fully finalized in the 30s, it can only be written in this way for the convenience of expression.

Chapter 254 Guided Antennas

While the telefunken company on this plane was developing the "Wurzburg" series of guidance radars, Gema, founded by Dr. Early warning radar, and their first work is the two-coordinate long-range early warning radar called "Freya".This name actually overlaps with similar products from Gemma Company in the previous plane again, which made Helena sigh that the inertia of history is really strong.

The little butterfly Helena is gratified that although the name of this radar in this plane has not changed, its technical connotation is very different from the "Freya" radar in the previous plane. Even the antenna There is a visible difference in appearance.This is because unlike the big brother who used the "spring bed" antenna in history, the "Freya" radar on this plane uses a directional antenna array that has just been put into use in this era.

Don't be unfamiliar with the term "guided antenna", because in the homeland of Helena's previous life, the more common name of the guided antenna is "Yagi antenna" or the more popular "fishbone antenna".In areas where cable TV is not yet popular, this fishbone-like antenna and the parabolic antenna shaped like a frying pan are the most common types of broadcast TV antennas.

In the last historical plane, the directional antenna was invented by Yagi Hideji and Uda Taro of Tohoku University in 1925. This is also the origin of the name "Yagi antenna", but the more rigorous name should be "Yagi- Uda Antenna".However, the directional antenna of this plane will probably not be called "Yagi antenna" anymore, because Helena preemptively registered this patent as early as 1924 out of optimism about the radio and television market. This kind of immoral thing It's not the first time she's done it.

Helena doesn't have to worry that Guixiang Antenna will be called "Helena Antenna" in the motherland of later generations, because if her name is written in Chinese, the number of words and strokes will be more numerous than "Zhixiang".According to the experience she accumulated in her previous life, if a certain way of naming things can be generally accepted by everyone, it is either the most convenient way to speak or write, or the most vivid and easy to understand.

The typical structure of the directional antenna is composed of a group of horizontal dipole antennas fixed on the longitudinal support rod.If the fishbone is used to compare the shape of the antenna, the support rod is like the spine of the fish, and the vibrator antenna is like the ribs of the fish.There is only one active vibrator connected to the feed source in the vibrator (the frequency bandwidth of the antenna is often narrow, so the active vibrator usually uses a folded vibrator to improve the bandwidth); the others are passive vibrators that are not directly connected to the feed source Vibrator.

One of these passive oscillators is located on the back side of the active oscillator, and its length is slightly longer than that of the active oscillator. It can reflect the energy from the active oscillator as the excitation element, so it is called a reflective oscillator.The other oscillators are located in front of the active oscillator and are slightly shorter than the active oscillator. They can guide energy to a specific direction, so they are called directing oscillators.The greater the number of these directional dipoles, the higher the gain of the directional antenna.

Because the directional antenna has good directivity, it can achieve high gain with a relatively simple structure, which makes the directional antenna widely used in the field of long-range warning radar.In fact, until the 21st century before Helena crossed over, the directional antenna, which seemed to have a simple and even crude structure, was still not old. The method has been changed to a phased array system, which shows the strong vitality of this antenna.

The antenna system of the "Freya" radar on this plane uses an antenna array composed of 16 directional antennas, and these directional antennas are arranged in double rows of eight up and down.And each directional antenna is composed of reflective oscillator, folded active oscillator and seven directional oscillators.Although this antenna system is more than 20 meters wide when fully unfolded, the volume of such a huge antenna is quite compact when folded, so that it can be integrated into a large shelter with radar transmitters, receivers, and power systems. Gain certain mobility deployment capabilities.

The "Freya" radar on this plane works in the VHF band with a frequency of 125 MHz and a wavelength of 2.4 meters, which is exactly the same as the product of the same name on the previous plane.However, the peak transmission power of the "Freya" radar on this plane has reached 30 kilowatts, which is significantly higher than the 20 kilowatt level of the "Freya" radar on the previous plane.

The increase in antenna gain and the increase in transmission power make it possible for Gemma's "Freya" radar to detect large air targets such as bomber groups at a distance of 200 kilometers.However, since "Freya" is a two-coordinate meter wave radar, it can only roughly detect the azimuth and distance of the target, and the two-coordinate radar cannot measure the target's height parameters.

Therefore, Helena asked Gema Company to continue to develop a large-scale three-dimensional long-range early warning radar for fixed deployment. This time, the benchmark that Helena aimed at and decided to surpass was the black technology developed by Germany in the late World War II in the last plane: "Wassellman " and "Mammoth" phased array long-range early warning radar.Among the doomsday technologies of Nazi Germany in the last plane, the two phased array long-range early warning radars, "Wassellman" and "Mammoth", are the few that Helena sees that are both attractive and attractive. It is a pity that those senior traversers of Helena have never looked at it directly.

In fact, the large antenna arrays of the two radars on the previous plane are composed of 188 and 192 electronically controlled dipole dipoles respectively, and the radar beams can be controlled to perform three-dimensional scanning by controlling the phase changes of these dipoles, so that the two This kind of radar can describe the three-dimensional movement trajectory of the target 300 kilometers away.Under the background that most long-range early warning radars are unable to measure the height of the target, this is indeed a huge breakthrough beyond the times.

However, even for the level of electronic technology in Germany on this plane, this breakthrough may not be achieved in a short period of time.According to Gemma, it will not be possible until around 1940 at the earliest.

Chapter 255 Junkers Company

If you want to ask who is the greatest aircraft designer after the Wright Brothers invented the aircraft, Helena will not hesitate to say Hugo Junkers, and must definitely add "none of them" at the end These big characters.Because Mr. Hugo Junkers is the designer and manufacturer of the world's first aircraft with a cantilevered wing, the first aircraft with an all-metal structure, and the first aircraft with a low-wing design.Helena can even say without exaggeration: Mr. Hugo Junkers laid the general paradigm of modern aircraft structure design. Without Hugo Junkers, there would be no modern aircraft.

What is even more inspirational and legendary is that Hugo Junkers, who was born in 1859, did not officially change careers until he was 50 years old, and led his Junkers company in Dessau to get involved in aircraft design. Before that, the main product of Junkers was Car engine and heating equipment.But only six years later, in 1915, Dr. Junkers sent the world's first all-metal aircraft, the J-1 aircraft nicknamed "Tin Donkey", into the blue sky.However, this does not mean that Junkers belongs to the kind of late-blooming genius, because before that, he was already an engineer who had made great achievements in many fields, such as the wall-mounted gas water heater commonly used in our families in later generations. Invented by the versatile designer in 1896.

To be honest, Helena thinks that the wall-mounted gas water heater designed by Dr. Junkers is not outdated even 100 years later, so she bought it for her own home. It can be regarded as a small support for Dr. Junkers' business.

According to the timeline of the previous plane, Hugo Junkers will actually die in Bavaria on February 2 this year, which is his 3th birthday.But what puzzled Helena was that it was already August now, but the old Junkers seemed to be still in good health.Although it is impossible for Helena to run over and ask Grandpa Junkers, why is he still alive and well?But she vaguely felt that this variable might be related to her butterfly effect.

After all, in the history of the last plane, since the outbreak of the world economic crisis, various blows have come one after another to Hugo Junkers, who is already in his 70s.First, in 1931, Junkers faced heavy financial difficulties, so many investors asked Junkers to leave the company. However, because Junkers held a large number of technical patents of the company, the shareholders decided to buy out Junkers. patents, which were then injected into a new company, which in turn licensed them to Junkers.This is tantamount to excluding Dr. Junkers from the core decision-making level of the company.

Two years later, after the Nazi Party came to power in 1933, Germany's aviation industry ushered in explosive growth, but this may not be a boon for Junkers.Because Junkers' dream is to develop the civil air transport industry and develop economical and durable aircraft for this purpose.However, shortly after the Nazi Party came to power, it asked Junkers to cancel all long-range civilian aircraft models, which had a violent conflict with Junkers' ideas.The result of this conflict was that the patents in Junkers' hands were forcibly transferred, the shares were forcibly expropriated, and Junkers himself was kicked out of the company in the autumn of 1933.

For more than a year after that, Hugo Junkers, who was full of grief and indignation, was under surveillance and lived in seclusion in his Bavarian home until his death in 1935.However, this may not be a bad thing for the upright Dr. Junkers. This venerable old man who opposed the war of aggression all his life did not see with his own eyes that the aircraft he designed and the company he founded were reduced to Nazi Germany's colonization of the world. An accomplice to wild ambition, that may be a greater pain to him.

Hugo Junkers in this plane is much luckier than the previous plane. First of all, in the selection of aero-engines in 1930, the products of Junkers and Maybach were favored by Helena. , so it can obtain part of the financial support provided by the "Peace Fund". Therefore, although the performance of Junkers has been hit hard in the economic crisis, the overall financial situation is still healthy, and Junkers has not been collectively supported by investors. repel.

Secondly, the long-range civilian aircraft project favored by Dr. Junkers has not been cancelled, but has been retained under Helena's proposal. As soon as he took office, he tried his best to advocate the immediate priority development of four-engine long-range bombers with a combat radius that can reach the Ural Mountains, which is the so-called "Ural bomber".However, although Helena did not object to the development of four-engine heavy bombers, out of prudent considerations, she still suggested that the Air Force postpone this plan until 1937.

Because the German aviation industry has just begun to recover, and the engineering experience in designing large aircraft is still relatively lacking. Instead of starting to design a bomber that will lag behind in a few years, it is better for major aviation industry companies to first develop long-range civilian aircraft. Accumulate technical experience, and then design a model with relatively complete performance after accumulating a certain technical reserve.After all, in Helena's memory, the performance of the bidding models of the "Ural bombers" could hardly meet the needs of wars after 1940.Although Helena's suggestion did not make Walter Weaver directly give up the bidding for the "Ural Bomber", it also made the Air Force give up the rough decision to ask Junkers to terminate long-range civilian aircraft.

Helena thinks that it may be due to the above factors, coupled with the actions of the mustache government in this plane, that the overall perception of Dr. Junkers is much better than that of the previous plane, so Dr. Junkers is not like the previous plane. As before, he adopted a tough attitude of refusing to cooperate with the Nazi Party, and his own career and ideals were also on a thriving track.Especially the three-engine JU-1932 transport plane he designed in 52 is selling well all over the world. Every time he talks about this plane he is very proud of with Helena, Dr. Junkers is handsome (please allow Helena to use this word to describe Describe the 76-year-old man) can't hide the smile on his face.

Until last month when Helena visited Dr. Junkers, the old man was still writing and drawing vigorously in front of his beloved drawing tablet.Helena can even vaguely recognize it from the outline on the drawing, which is a four-engine long-range airliner similar to the Ju-89 developed by Junkers on the basis of the Ju-90 bomber of the previous plane. It may become a strong competitor to the Fw-200 airliner that Focke Wolf is designing, if the war does not break out so soon.

But no matter how old and strong, Dr. Hugo Junkers is old after all, and the future of Junkers must be handed over to young designers.And Hermann Baumann is obviously a leader among the younger generation of designers in the company, and one of Dr. Junkers' most promising juniors.And just last month, a new work designed by the young Bowman designer just completed its first test flight, which was also one of the important purposes of Helena's trip to Junkers.

Chapter 256 Dive Bombing

The new aircraft designed by Hermann Baumann, which Junkers has just test-flyed, is mainly aimed at competing for the bidding project for the new dive bomber issued by the Luftwaffe. This dive bomber, numbered Ju87, will soon compete with the The first flight, the He118 dive bomber designed by Heinkel, launched a fierce competition.It is particularly worth mentioning that the Ju87 dive bomber developed by Herman Baumann in the last plane later won a nickname that is more familiar to later generations. This is the German abbreviation of the word "dive bomber" "Stu Card".

This is actually not the first time that Herman Baumann has presided over the design of this type of aircraft, because as early as 1929 Bowman had designed the K-47 with Carlo Proz, another designer of Junkers. Attack aircraft, but because Germany still needed to pay attention to avoiding the restrictions of the Treaty of Versailles, the production of this aircraft was placed in the subsidiary of Junkers in Sweden, and the production was still in the name of civilian aircraft .The famous Ju87 "Stuka" dive bomber in the last plane was developed on the basis of this attack aircraft.

This K-47 attack aircraft is said to have some fate with the motherland of Helena's previous life. The Air Force of the Republic of China purchased a total of 12 aircraft of this type before the outbreak of the Anti-Japanese War.The most striking of these planes is the plane painted with the words "Tianchu", which is the famous patriotic industrialist, founder of Tianchu MSG Factory, and Mr. Wu Yunchu, nicknamed "The King of MSG", through the German Zen It was purchased by Chen Yangxing and donated to the country.During the War to Resist US Aggression and Aid Korea after the founding of New China, this Mr. Wu Yunchu once again donated money to purchase MiG-15 fighter jets, making an indelible contribution to supporting the North Korean front.

As the predecessor of the "Stuka" dive bomber, when Bowman designed the K-20 attack aircraft in the late 47s, he had already made the dive bombing capability one of the design goals of this aircraft.Here we must first introduce the attack method of dive bombing, although the models of dive bombers that are familiar to military fans of later generations mostly appeared after the 20s.However, the origin of dive bombing as an effective means of air attack is actually very early, and can even be traced back to before World War I, although the concept of dive bombers may not have existed at that time.

The first documented case of dive bombing in the history of warfare occurred during the Mexican Civil War in the 20s, when an American pilot named Leonard Bunny was employed by the Mexican government army. The "Moissante" aircraft with the bombs swooped down on the enemy positions and dropped the bombs, and then successfully pulled up before the aircraft was about to touch the ground and crash.

After the outbreak of the First World War, although the aircraft had not yet become the protagonist of the battlefield at this time, the dive bombing tactics had already shown considerable potential.British Air Force Lieutenant William Henry Brown even sank a German barge in March 1918 using the dive bombing method with bombs weighing only 3 pounds.However, when the British wanted to promote Brown's tactics, they suffered heavy losses, because the structure of the aircraft at that time was very fragile, and the control system was also very simple, and the tragedy of aircraft crash and death would occur if the pilot operated a little carelessly.

Since the key problem of dive bombing has been difficult to break through, after the end of the World War, the two old colonial empires, Britain and France, lost interest in researching dive bombing technology. Different reasons have kept the exploration of this technology going.

The persistence of the United States, Germany, Japan and other countries in exploring new technologies is undoubtedly valuable. As time entered the mid-30s to the early 40s, such as the SBD Dreadnought in the United States, the Ju87 Stuka in Germany, and the Nine Professional dive bombers with relatively complete performance such as the Type [-] Ship Explosion have been put into service one after another, and have shown their prowess in subsequent wars, leaving countless permanent memories for the history of military equipment in the world.

The attack mode of dive bombing is relative to horizontal bombing.In the traditional horizontal bombing mode, the bomber needs to maintain a level flight at a certain altitude, and ensure that its own flight path is aligned with the target sky, and then drop the bomb when it is about to reach the target sky. During this process, the vertical height of the aircraft changes. not big.When the bomb falls, it will be given a corresponding horizontal speed by the plane's level flight speed to complete the remaining distance, but the vertical falling speed of the bomb is completely given by its own gravity.

The dive bombing mode is that the bomber carries a bomb and dives from a high altitude at a very steep angle. While accelerating, it aims the nose at the target, then drops the bomb on the target at a lower altitude and pulls the plane up again. The acrobatic attack will be accompanied by a sharp change in the altitude of the aircraft.Since the bomber's dive angle is very large when the bomb is dropped during dive bombing, when the bomb leaves the bomber, it will not be given too much horizontal speed, but it will be given a huge vertical speed.

During World War II on the last plane, the dive angle of a typical dive bomber could reach 60 degrees, and some of the numbers that were more extreme in dive performance, such as the German Ju87 "Stuka" bomber, had a dive angle of even 80 degrees. If it reaches more than [-] degrees, if you look at it from the perspective of the ground, the "Stuka" at this time is almost like rushing down from a high altitude vertically.This sudden palm technique brings two important advantages to dive bombing:

The first is that dive bombing has extremely high bombing accuracy.Due to the low altitude of the ammunition dropped by the dive bomber, the initial speed of the ammunition when it leaves the carrier aircraft is very fast, so the flight time of the bomb after leaving the aircraft is much shorter than that of the horizontal bomber, which causes the bomb to be disturbed by natural factors such as wind force during the dive bomber Much smaller than horizontal bombing.In addition, before the dive bomber drops the bomb, the pilot can continue to make small corrections to the dive bomber's glide trajectory, and after the horizontal bomber aims the route over the target, the only thing that can be corrected is the timing of the bomb drop. Combining these factors, it is Resulting in dive bombing with far greater precision than horizontal bombing.

With its extremely high bombing accuracy, dive bombers are very suitable for fixed-point elimination of high-value enemy targets, such as bridges, strong fortifications, material distribution centers, etc., so they can well complete the task of battlefield interception, that is, to block the enemy in a certain area. The enemy forces in this area are separated from the enemy forces in other combat areas, so that the enemy forces in this area are relatively isolated.

In addition, dive bombers can also rely on their high precision to attack moving targets, such as moving chariots on land and evading warships on the sea.In World War II on the last plane, some "Stuka" bomber pilots could even directly hit a moving tank with a bomb, and the attack accuracy is evident.However, if horizontal bombing wants to effectively strike such a moving target, the hit probability is almost the same as winning the lottery.During World War II when precision-guided attack methods were not yet popular, this capability of the dive bomber obviously had an irreplaceable value.

The second is that dive bombing has a relatively high probability of penetration.Although in the face of the enemy's intensive anti-aircraft firepower, the dive bombers swooped down like eagles, and they did need to face extremely high risks.However, compared with other air penetration methods in the same period, such as horizontal neutralization and torpedo bombing, the penetration probability of dive bombing is actually relatively high.

This is because compared with those horizontal bombers and torpedo bombers whose routes are basically stable, with the technical level of ground or ship-based anti-aircraft firepower at that time, it is indeed very difficult to intercept a dive bomber with a sharp change in altitude at a large elevation angle. Moreover, once a dive bomber enters a stable dive trajectory, it can continue to complete the attack process even if it is damaged in many cases. Usually, it needs to be completely destroyed to truly remove the threat.

Of course, dive bombing also has many limitations compared to horizontal bombing. For example, the carrier aircraft must have sufficient structural strength, otherwise the body will be difficult to resist the huge overload when diving and pulling up, which will increase the empty weight of the aircraft and affect the loading of fuel and weapons. For example, dive-bombing has higher requirements for pilots' physical fitness and flying skills, which will greatly increase the average training time and cost of each qualified pilot; another example is that although dive-bombing is very suitable for hitting point targets, it is not suitable for large-area targets. The coverage effect is not as good as the horizontal bombing of heavy bombers...

However, the reason to equip a dive bomber has never been its perfection, but its irreplaceability.As the only airborne high-precision strike method that can be used on a large scale in this era, for the German army that was overwhelming in the European continent in the early days of World War II on the last plane, the aerial interception of dive bombers can be said to be two major parallels with the concentrated use of armored forces. The tactical soul, and to a large extent made up for the performance disadvantage of the German ground heavy equipment in the early days of the war.

Although Helena knows that the brilliance of the dive bomber can last for more than ten years, she still has to take the research and development of this type of aircraft very seriously. Therefore, in the last plane, the Ju87 dive bomber of the Junkers Company and the Henkel The company's He118 dive bomber has been reappeared in this plane, but because of the direct or indirect influence of Helena, these two planes have undergone great changes from their appearance in the previous plane, and These changes are all in a good direction.This is a good thing in itself, but it also brings a side effect, that is, Helena's difficulty in choosing is about to attack again.

Chapter 257

Although Junkers' plan to bid for the air force's dive bomber project on the original plane can basically be regarded as a spiritual continuation of the model of the same name in the previous plane in a different time and space.However, Helena's direct or indirect influence on the German aviation industry over the years still left a deep imprint on Junkers' new bomber.

It not only perfectly retains the simple and practical design features of the "Stuka" dive bomber in the previous plane, but also makes full use of the achievements of Germany's technological progress in aerodynamics over the years, which is very in line with Helena's insistence on weapon design. The principle of "odd and positive coincidence".

Unlike the Maybach HL-109 engine used on the BF-360 fighter jet that flew for the first time this year, Junkers used the Jumo-87 with a larger displacement on the prototype of the Ju-213 dive bomber. Type engine, which is also the fist engine product developed by Junkers itself.By equipping its own aircraft with its own engines, Junkers, which likes to play vertical integration, can be regarded as rotten in its own pot.

In the aerodynamic tender five years ago, Junkers beat the strong Mercedes-Benz and won the bid jointly with Maybach.Next, Junkers carried out a large-scale redesign of their engine prototype numbered Jumo211 according to Helena's improvement requirements, and the workload was almost as great as designing a new engine.The final result of Junkers' years of hard work on the engine is the Jumo87 engine that has just flown with the prototype of the Ju-213 dive bomber.

However, the price of large-scale redesign is that the development progress of the Jumo-213 engine is far behind the short and fast Maybach company, so that Junkers did not complete all the finalization of this engine until April this year. It failed to catch up with the Ju-87 dive bomber prototype.If such a bad thing really happened, the Ju-87 bomber of Junkers may be forced to use the Jumo-820A engine with a maximum power of only 210 horsepower to complete its first flight. Fortunately, the Jumo213 engine finally caught up with the time node , with a happy ending.

The Jumo-213 engine developed by Junkers is a relatively high-end product in the high-low matching system formed with the Maybach HL-360 engine.This inverted V12-cylinder engine has a large displacement of 42 liters, which is 35% higher than the 20-liter displacement product of the same number in the previous plane, and compared with the 27-liter displacement of the same period in the UK. The Merlin series engines and the Griffin series engines with a displacement of 36.7 liters are also much larger, very close to the displacement of the DB603 series engines developed by Germany at the end of World War II on the last plane.

Although this method of increasing power by stacking exhaust volume seems too simple and crude, even clumsy and crude, but Helena knows that for the German Air Force, which is likely to have insufficient supply of high-grade fuel, in the future, it is necessary to rely on increasing engine air intake. It is bound to be more difficult to increase the output power by pressure than the opponent with relatively sufficient fuel supply, and the technical route to increase the engine speed cannot be used without limit, otherwise not only will it face cooling problems, but the strength of the crankshaft and piston will also face tests.

Therefore, relying on the increase in displacement to improve engine performance will become an option that no German engine designer can refuse. The German designers on the previous plane gradually understood this truth during the course of the war, so there is The DB603 engine that took the large-displacement route, but the liquid-cooled engine that Dr. Tan Ke liked most had not had time to mass-produce, and the war was over.Therefore, Helena chose to go directly to the displacement, even at the cost of weight.

It is worth mentioning that this Jumo-213 engine also uses a four-valve design that is still very trendy in this era, although four-valve is already a commonly used technology in family passenger cars in later generations.The so-called four-valve design is actually to decompose the two larger valves on each cylinder of the past engine into four relatively small valves, and then arrange the spark plug in the middle of the four valves.This design can not only reduce the inertial mass of the engine's air distribution structure, but also greatly improve the ventilation efficiency at high engine speeds, which is very beneficial for increasing engine speed and compression ratio.

容克公司的Jumo-213发动机凭借42升的较大排气量，在由液力变矩器驱动的一级机械增压器所提供的1.3ata的进气压力下，可以在每分钟2500转的转速下可以输出高达1650马力的功率。通过驱动机头的自动变矩四叶螺旋桨，该发动机可以给身材略显臃肿（相对于战斗机而言）的Ju-87俯冲轰炸机提供较为充沛的动力。

相比之下，上个位面中容克公司的那款Ju-87“斯图卡”轰炸机首飞时，却只有最大功率仅有680马力的Jumo-210D发动机可用。直到1936年容克公司研制出功率1200马力的Jumo-211A型发动机后，“斯图卡”轰炸机动力不足的问题才算得到初步缓解。

Thanks to the powerful Jumo213 engine support in this plane, Hermann Bowman had fewer scruples when designing the Ju-87 dive bomber, and he could use new technologies more boldly.Even from a layman's point of view, purely from the appearance of the aircraft, it can be seen that the Ju-87 of Junkers in this plane has more modern features than the one in the previous plane.

The Ju-87 dive bomber in this plane still adopts a tandem two-seater layout similar to the previous plane. The pilot sits in the front seat of the plane, and the electromechanical operator and rear-facing machine gunner sits in the back seat.The wing also adopts the classic inverted seagull design in the previous plane, that is, the inner section of the wing presents a certain dihedral angle, while the outer section presents a certain dihedral angle, which will form a knuckle in the middle of the wing. The main landing gear of the aircraft is installed just below this knuckle.The advantage of this design is that it can increase the ground clearance of the belly of the fighter without lengthening the landing gear, so that it is more convenient to mount large bombs or other loads under the belly of the fighter.

Since the dive bomber's body structure needs to withstand a huge overload during the dive-pull-up process, the Ju-87 in this plane has a very strong body structure like the previous plane. The main structure of the plane and the mask The skin is made of duralumin, and some parts that need to withstand greater stress are manufactured by stainless steel extrusion molding process.According to the results of the static test, its structural strength is sufficient to ensure that the aircraft can lift the nose at a very high dive speed of 600-700 kilometers without structural damage.

Although all of the above are successful designs tested in actual combat on the "Stuka" bomber in the previous plane, the Ju-87 dive bomber in this plane is not a reprinted version of the previous plane after all. There are more design highlights, some of which were produced under Helena's direct suggestion.

Chapter 258 Killing Two Birds With One Stone

The fixed landing gear wrapped by the rounded large streamlined fairing is undoubtedly the most eye-catching appearance feature of the "Stuka" dive bomber in the previous plane, and it is also one of the most controversial designs on this famous bomber Some people think that this kind of landing gear is a relic of the barbarian era, some people praise this kind of landing gear as a simple and practical model, and some people consider it purely from an aesthetic point of view, thinking that it is a serious problem for the landing gear. Destroyed the appearance of the "Stuka" bomber.