Iron Cross

On June 27, the Ceylon Campaign entered its fourth day. After four days of fighting, nearly 50,000 British and Indian officers and soldiers were captured or killed. Only a small number of them were still fighting stubbornly in the depths of the island under the leadership of company and battalion officers, but it was destined to be eliminated only a matter of time.

The magnificent armored assault campaign launched by the German Marine Corps, which combined amphibious landings and air-to-ground integration, not only shocked the British and Indian officers and soldiers, but also stunned the naval generals watching the battle on various warships. They always thought that sweeping Southeast Asia was a rapid use of troops. Now they understand what a real assault is like with a comparison. The Germans not only used 6,000 to fight 50,000, but also had very few casualties. The total casualties were less than 700, and only more than 200 were killed.

Now not only the bombardment fleet, but also the mobile fleet has docked at the dock. Those captured Indian soldiers are used as ready-made coolies. Not only do they have to undertake the task of repairing the airport, but they must also help unload supplies. What made the Japanese feel very troubled was that although the Indians were obedient, their labor efficiency seemed to be not very high. After several thousand people worked for two days, they could not even repair the airport completely. Finally, Cole thought of a way to let the Japanese army use guns to force British officers to command the Indians to work.

British officers were not very afraid of the Germans, because the German army was generally reasonable, but they were very afraid of the Japanese: Lieutenant General Percival, the commander of the Singapore garrison, told Yamashita Tomoyuki a lot of conditions before surrendering, but the Japanese only asked "Yes-or-No?" Otherwise, they were ready to open fire, forcing the British army to surrender unconditionally in the end. All British officers who heard about this incident knew that they should never try to reason with the Japanese. As for the "Geneva Convention", it was completely nonsense. Japan was not a signatory at all. The only thing to be thankful for is that the Japanese Navy finally learned from the Royal Navy and spoke English very well, so there was no language barrier.

Cole's strategy was successful again. The labor efficiency of Indian prisoners of war under the supervision of British officers was greatly improved. Through these things, Japanese generals all understood that it was not easy to manage the Indian colony well, and there was still a long way to go.

Trincomalee Airport was repaired first, and the pilots of carrier-based aircraft began to transfer to land airports for combat, and batches of new aircraft were unloaded from transport ships. In the first two days, there were still sporadic British aircraft coming to harass, but after most of them were shot down, they never dared to come again.

The unloaded aircraft included many Fw-190A series. After cooperating with Bf-219, even aircraft carrier pilots can now learn the German Air Force's high-low combination of double-layer tactics. Several ace pilots such as Akamatsu Sadaaki and Murata Shigeharu were not willing to be lonely, and went to test the F6F fighters or C-47 transport aircraft unloaded from the Borg. As a result, they forgot to paint off the US military logo on the aircraft during the test flight, and were almost surrounded and beaten by their own fighters. Fortunately, there were RB fighters flying next to them, which saved them from "cannibalism".

"How is the Grumman fighter?" Genda Minoru asked Akamatsu Sadaaki who had just gotten off the plane with curiosity.

"It's a good plane, better than the American F4F before, with better speed and maneuverability. Although it looks a bit ugly, the body is stronger than our military aircraft, and the engine horsepower is also very strong, except that the firepower is a bit weak." Akamatsu Sadaaki thought seriously, "If we still use the original Zero fighter, whether it is 21, 32 or 52, it will be difficult to deal with it. Fortunately, the improved Zero fighter by the Germans is good. I personally think it is better than this batch of F6F."

Genda Minoru breathed a sigh of relief: "That's good! Before returning from Europe, I was ordered by my superior to inquire about the next generation The aircraft design was reported to the German side, and it was reported that some difficulties had been encountered, and the mass production time might be later than expected. "

"How late?"

"The German side said that there was no hope for mass production before September, and hoped to catch up with mass production in December."

The new aircraft mentioned by Genda refers to the Do-412. The main problem is the engine: in order to achieve high targets during the initial design, the DFK Design Bureau chose the BMW901C series, which was a copy of the improved R-2800. BMW said that it could be completed together with the aircraft, so Dornier proposed to start small-scale mass production in September. But the actual situation is far from so optimistic. In early May, BMW said that it could not guarantee that the 901 series would be mass-produced in September, and even small-scale trial production could not be achieved. At most, it could only provide laboratory products, and the overall delay would be at least 3 months.

It doesn't matter to Dornier whether there are laboratory products or not. After shooting down a large number of P-47\\A-26, Germany collected a lot of R-2800s that can be used normally. It is not a problem to select some engines in particularly good condition for new aircraft verification.

The DFK Design Bureau had no choice but to turn its attention to the backup engine - the Yu series, which imitated RB. However, this model also had many problems. The reliability was very poor during the test flight. Everything was normal in the short-term test flight, and it even performed better than the R-2800, but it would overheat and even cause combustion after a long time. The test pilot encountered this terrible problem during the verification process, but fortunately he successfully parachuted in the end.

At first, everyone thought it was a problem with the engine manufacturing, but the German quality was impeccable, and RB swore that it had provided a full set of drawings and did not hide anything. This problem was not solved until one day when the technicians went to BMW to observe the production on site and concluded that the problem with the Yu engine was not a manufacturing problem, but a design problem.

As an 18-cylinder engine, it is very compact. Not only is it lighter than the BMW801, it is even smaller in diameter - but the BMW801 only has 14 cylinders. In order to pursue a good aerodynamic shape, Japanese designers designed the engine cross-section to be very small based on the ideas of the Sakae series engines, and all aspects were designed to be very compact and precise.

This idea is good in theory, but there is a fatal problem in practical application - heat dissipation! The heat dissipation capacity of those tightly wound heat sinks decreases very quickly, and the performance is not obvious in the short term. However, it is easy to overheat when running continuously for a long time. Due to the low engine power of the Rong series, the related problems are not obvious, but for the 2000 horsepower level reputation, the problem is so serious that it cannot be used - RB has been on the evil path of one-sided pursuit of small engine cross-section for too long.

There is no way to solve the problem. The original design must be modified before it can be used. In such a tense state during wartime, it is equivalent to a direct death sentence for this model. There are only two choices before Dornier. First, delay the progress and wait for the BMW901 series to mature before launching. First, use R2800 for testing to allow other subsystems of the aircraft to mature as soon as possible; second, immediately retrofit the aircraft with mature and reliable BMW 801 engine, although the maximum horsepower of the 801E engine is only 2,000 hp, which is 300 hp smaller than the 901 series, its diameter is slightly smaller than the 901, so the performance on the machine will not be that much worse after considering the aerodynamic shape.

Dornier told his old friend Dr. Tank about his troubles, hoping to hear his thoughts. Tan Ke initially expressed sympathy for the Do-412, which was forced to install the 801 engine due to BMW's delayed purchase. After carefully looking at the drawings, he suddenly widened his eyes and shouted: "Isn't this the idea of ​​​​the Fw-190 carrier version? ? You not only solved the maneuverability problem at low speed, but also made it lightweight? ”

"Yes, the Do-412 is lighter than the Fw-190. As you know, the aircraft created by RB designers are very light. I have already strengthened the structure once."

With the help of Tan Ke and the design ideas of the Fw-190, the Do-412 equipped with the 801E engine quickly completed the design modification. The overall design was indeed slightly worse than the original preset indicator: the empty weight was 3016 kg - Dornier On the one hand, it strengthens the structure of the aircraft, and on the other hand, it reduces the weight. The ammunition capacity of the cannon, which was obviously too large in the original design, was reduced from 200 rounds per door to 120 rounds per door. The four cannons were reduced by 320 rounds, which is a reduction. Nearly 100kg in weight.

Under normal operating conditions of the engine (not taking drugs), the Do-412 has a maximum land speed of 675 km/h (ship-based version 656 km/h), a maximum range of 1,600 km, and can carry four 20mm MG213 aerial cannons (120 rounds of ammunition) , the maximum climb speed is 1280 meters/min, and the range after adding auxiliary fuel tanks is roughly more than 2400 kilometers. The performance will deteriorate at altitudes above 6000 meters, but this is not something that carrier-based aircraft should consider. The overall performance is better than that of Bf-219, but the advantage has shrunk a lot.

What made Dornier dumbfounded the most was that in mid-June, after he had finished changing the design to adapt to the 801 engine, BMW notified the DFK Design Bureau that the 801F model engine might be successful in December this year, with an estimated horsepower of 2,300 horsepower. Like the R2800, he originally deeply regretted the detour he had taken, but Tank reminded him: If they can get the 2,300-horsepower 801 engine in December, the Americans might be able to make the R2800 more than 2,600 horsepower. Reserved It is still necessary to continue to improve the design using the 901 engine, and all bets cannot be placed on a certain engine.

Seeing that the Do-412 project, which has been making rapid progress, has slowed down, the Gale Kai (codenamed Bf-339) project, cooperating with Messerschmitt and chaired by Jiro Horikoshi, is catching up. Although it also faces engine problems, according to the schedule, the Bf The design and finalization of the -339 will be completed in October at the earliest, and mass production will not be considered until the spring of 1944. The first verification machine has not even rolled off the assembly line, and the progress is more than half a year slower than the Do-412.

Hoffman originally had high expectations for the Do-412, but in the end he was forced to agree to allow the Do-412A, which was equipped with an 801E engine and had worse performance than the original design, to be put into production trials first.