Chapter 714

What's also incredible is Maxim standing on the edge of the grassland, landing unbelievably, carrying the wounded and then taking off in such a strange way. How far is the distance of the running just now?

400 meters or 500 meters?

But whether it's 400 meters or 500 meters, as a light transport aircraft with a maximum take-off weight of 32 tons, it can be regarded as a miracle of miracles, so that the yun-15plus has been flying away for a long time, and maxim feels that he is sleepwalking.

I can't help it. What I saw just now is beyond the scope of his attempt. I can only find the answer from the Scriptures.

The problem is that the Scriptures formed more than a thousand years ago can't describe today's affairs. So Maxim spent countless brain cells and didn't find any answer. Finally, he could only look at the cold sky and silently say a long suppressed sentence: "how did he do it?"

"Yun-15plus uses a technology called external flap blowing." Just as Maxim was mumbling to himself, a rude and crazy voice came from behind him. When Maxim looked back, he found that Zarif, the former Pakistani military officer in China, had arrived here by the plane just now.

However, at this time, Zarif had left his post as Pakistan's military attache in China and returned to China to become director of the Emergency Management Bureau of the Ministry of the interior of Pakistan.

Because they both belong to the interior department, Zarif and Maxim's old father are old acquaintances. Of course, they also know this young local tyrant who once worked in the Interior Department of Bahrain.

Maxim didn't expect Zarif to come by himself. He was slightly surprised. Seeing this, Zarif said, "you just focused too much on yun-15plus, and didn't notice that I was normal."

"Er..." Maxim was a little embarrassed, but he and Zarif were old acquaintances, so he continued the topic just now: "what kind of external blowing flap technology did you use for yun-15plus? What's that? "

"This..." Now it's Zarif's turn to be embarrassed. It was only when he first participated in the introduction of yun-15plus that Tengfei group knew about it. Later, he was transferred back to China and transferred to the Ministry of the interior to deal with domestic emergencies. Later, he didn't participate in the introduction of yun-15plus. Naturally, he didn't know what the so-called external blowing flap technology was.

But just now 13 have already pretended to go out, at this time if show timid, his Zarif's old face where to put?

So he licked his big stomach, and his dark old face laughed, showing an expression that I didn't understand. Then he said something that made Maxim misty again: "what can it be? Of course, it's very advanced technology... "

Then Zarif lowered his voice seriously: "it's said that only the Americans mastered this technology before, and even the Soviets couldn't understand it."

If this scene is known by Zhuang Jianye, who arrived in Peshawar with the take-off medical team, he will definitely pull Zarif's neck and introduce the product to local tyrants without hesitation?

Only the Americans have it. The Soviets don't have it. Do you want to pretend like this!

It's clear that only China's Tengfei group knows the most about external flapping technology, while others just know a little bit about it, OK? This is low-key, luxurious, simple and not simple!

Of course, if Zhuang Jianye really said that, there would be no one in the world who really dares to come out. The reason is very simple. There are quite a few countries and aviation manufacturing enterprises that study the external flap technology, such as McDonnell Douglas and Boeing in the United States; Antonov and ilyushen in the Soviet Union; Dassault and BAE in Europe, etc.

Many of them have completed engineering verification, such as McDonnell Douglas yc-15 and Boeing yc-14.

Some have entered mass production. Antonov's an-72 short takeoff and landing transport aircraft is the first mass production short takeoff and landing transport aircraft in the world.

However, only the yun-15plus of China Tengfei group can really apply this technology to the extreme and meet the requirements of modern aircraft, such as convenient maintenance, simple structure and mass production.

Unlike another mass-produced short takeoff and landing an-72 transport aircraft, the yun-15plus did not adopt the shoulder mounted engine layout favored by the US and Soviet aviation circles in the 1970s.

That is to say, the jet engine is placed on the upper part of the wing, and the "CONDA effect" is used to form a downward air guiding effect on the surface of the wing, so as to form an upward reverse lift.

The theoretical description of "Kangda effect" here is very boring, but the experiment is very simple. The simplest Kangda effect is to use a slice to place the curved surface above the flowing water, and the phenomenon that the flowing water changes its flow direction along the curved surface of the slice.

An-72 transport aircraft and Boeing's yc-14 engineering verification aircraft are both supporters of "CONDA effect" and have achieved undoubted success. Both aircraft can take off and land normally on the runway of 600 to 800 meters under full load.

Based on this, the Soviet Union even used an-72 transport aircraft as the carrier platform of Shipborne early warning aircraft, and developed an-71 shipborne early warning aircraft in the early 1980s. What it valued was the excellent short-range take-off and landing capability of an-72 transport aircraft.However, despite the success of the an-72 and yc-14, the so-called success and failure are not obvious. The shoulder mounted engine layout can make full use of the "Kangda effect" to make it have the ability of short takeoff and landing.

But this kind of layout also obviously limits the further development of this type of aircraft.

The reason is very simple. The adaptability of the fixed engine compartment is too poor. We can only use the engine with fixed size. If we want to replace the engine with better performance, it is impossible to replace the engine with a large bypass ratio with a larger thrust weight ratio, unless we push the pneumatic layout upside down and redo it.

In addition, the maintenance work of the engine is also greatly increased. With the wing suspended layout, the maintenance personnel can simply check the engine with a simple miter ladder.

But when the engine was carried to the shoulder, the maintenance personnel had to climb along the fuselage to the wing, and then they could open the engine hood for inspection, which virtually increased the workload of maintenance support.

Finally, and most importantly, this kind of aircraft has insufficient expansion capacity. At most, it can only carry two engines. It's not impossible to increase to four engines. The key is that the structural strength of the wing should reach a very changeable state. The key is that even if it does, it's not cost-effective, because the weight of the aircraft increases virtually, which reduces the performance of the aircraft.

This means that there is not much room for this kind of aircraft to rise. It is very difficult to increase the fuselage length and expand the mission flexibility as the conventional aircraft.

All of the above are the important reasons why the yc-14 of the United States was dejected and the an-71 carrier based early warning aircraft of the Soviet Union was finally replaced by the Jacques 44.

In contrast, the route of yun-15plus is much more flexible. Similar to McDonnell Douglas yc-15, this model is very strange to most people, but another model based on this model is widely known. That is the US C-17 "global overlord III" strategic and tactical transport aircraft, which rewrites the rules of military transport aircraft.

The yun-15plus uses the same short takeoff and landing technology as the C-17!