Chapter 1135: Cloak of invisibility

"Nighthawk?"
For no reason, after hearing the name, Mahmoud and Chen Yijian had a slight chill on their bodies. This name will naturally make people associate it with words that represent negative emotions such as gloomy, bloodthirsty, and horror. .
"Yes, Nighthawk." Tan Zhenhua emphasized the name again: "The locals describe this as a mysterious aircraft. They have never been seen only at night, sometimes one or two, but they have never seen it before. There are more formations, and the flight is accompanied by huge noises similar to aircraft engines, but according to people who have witnessed this aircraft on a clear night, its outline shape is very strange, completely different from common types of aircraft, so Many locals firmly believe that it is not a human aircraft, but an alien spacecraft. There may be an alien base hidden nearby, and the "crash" incident was actually an alien spacecraft crashed. The U.S. government not only knew about this for a long time, but also obtained the wreckage of the crashed spacecraft. The strict security measures they took were to conceal the truth."
"UFO!" Mahmoud twitched, feeling that Tan Zhenhua's words today not only hide his head and show his tail, but he even started to talk utterly.
And Chen Yijian is obviously concerned about another aspect: "Zhenhua, you just said that the outline of this aircraft is very strange and completely different from all kinds of common aircraft. Can you briefly describe it? What kind of shape is it?"
"The results of my investigations were varied, but most of the so-called "witnesses" claimed that the aircraft was a polygon similar to a triangle. Out of fear of the unknown, they gave this strange and mysterious aircraft a Nickname-"Nighthawk"."
"A polygonal aircraft similar to a triangle?!"
Chen Yijian lowered his head and began to calculate, trying to outline the feasibility of manufacturing such a strangely shaped aircraft with the current level of technology known to mankind, its possible appearance and the key points that need attention, and try to derive the aircraft performance after adopting this aerodynamic shape. The pros and cons of, but after a short estimate, he reluctantly found that his imagination was not enough.
So he concluded: "Using American technology, it should be possible to make such a thing fly. However, no matter how I calculate it, there is no way to avoid the huge flight resistance and aerodynamic loss caused by this irregular shape. Of course people can use their powerful engines as a means of making up for it, but I still can’t imagine the meaning of doing so.

"First of all, I must solemnly declare that I do not believe that UFOs are alien ships." Tan Zhenhua said in a joking tone: "I am a fan of the "Fermi Paradox", so after understanding some basic information, I judge This should be a new kind of aircraft developed secretly by the Americans, and this unknown strange shape made me very interested. So, through other channels and means, I conducted some investigations and finally derived One conclusion."
"What is it?"
"The Americans secretly developed a fighter plane. This fighter plane has extremely excellent anti-radar interception capabilities, just like "stealth" in front of radar waves, so I gave this fighter a name, called "stealth fighter." ."
"Stealth fighter?" Mahamud and Chen Yijian couldn't help but change slightly after repeating the new term in a low voice.
"Can you be more specific?" Chen Yijian asked.
"Master Chen, the so-called "general aircraft design" has always been the result of performance compromises between the various subsystems. As for how to compromise, it depends on whether the mission needs can be met. I should be right?"
Chen Yijian nodded and said: "Yes, passenger planes need safety and economy, fighter planes need high maneuverability, bombers need large range and high load. According to the different missions of the aircraft, choosing different design directions and making trade-offs and compromises is for an overall designer. "The most basic requirements are not only for airplanes, but also for all walks of life."
"Okay, Chief Chen, you just calculated it. The use of irregular polygons as the shape of the aircraft will inevitably greatly increase the flight resistance of the fighter. Similarly, it will also greatly increase the power consumption of the fighter engine. Then, why do the Americans do this? Based on the simplest reasoning, it must be a compromise in exchange for a more important performance requirement. Then the question is, what kind of performance requirement is it worthy of the Americans to make such a big compromise for this aircraft? "
"Is it the radar stealth you said?"
"There is only this possibility." Tan Zhenhua replied: "The radar cross section (RCS) is a physical quantity that measures the strength of the aircraft radar echo, such as F16. Although I have not tested it, according to its volume and shape, It can be roughly estimated that its RCS value is between 3-6, and our "Flying Leopard" fighter is large in size, and I estimate it will exceed 10, possibly reaching about 12. If it is a large aircraft like a civil airliner, its RCS It must reach dozens or even hundreds. According to the basic principle of radar work, the relationship between the RCS value and the radar detection range is: the effective detection range of the radar is proportional to the fourth root of the RCS. For example, suppose the RCS of the F16 is 3. And the detection range of a certain type of radar for a 3 square meter RCS target is 200 kilometers, then the detection range for a 0.065 square meter RCS target is only 76.7 kilometers. Suppose I can design an aircraft with a very low RCS, such as lowering the RCS to At this level of 0.01, it is almost impossible for the active radar to spot me at medium and long distances, but I can sneak to the opponent's vicinity and calmly aim and lock. As a result, the opponent has almost no power to fight back."
Thinking of the terrible scene of being beaten but unable to fight back, the chill in Mahmoud and Chen Yijian's hearts reappeared. After a moment of silence, Mahmoud asked: "Erik, how can you be sure of the United States? Is that mysterious airplane designed for the purpose of lowering RCS?"
"Because it uses an irregular polygonal outer surface." Tan Zhenhua replied: "After reaching this hypothesis, I consulted a large number of materials and references and found that the Soviets proposed "radar" as early as 1975. The concept of
stealth fighter
has been studied and the results were published in one of its authoritative aviation magazines. This article proposes that the use of a polyhedral shape and a jagged body structure can guide radar waves to be refracted to both sides; The careful calculation of the shape can also make the reflected waves concentrate on a few narrow beams in the horizontal plane instead of omnidirectional scattering like conventional airplanes. Due to the narrow beams, the radar of the detecting party will not be able to obtain sufficient continuous echo signals. , So that it is impossible to determine whether the echo is an aircraft target or a transient noise."
"But that is the research result of the Soviet Russians?"
"I can retrieve this paper through public channels. Will Americans not be able to retrieve it?" Tan Zhenhua asked, after a pause, he added: "Moreover, we can get another conclusion based on the location of the crash: The Americans have not only completed the research and development of this fighter, but have even installed it. By the way, I personally think that the test flight of this fighter is probably at the famous UFO resort Grum Lake base. It was carried out in Area 51, and the large number of UFO deeds circulating there may also be related to this mysterious fighter."
The room fell into silence again. After a while, Mahmoud asked quietly: "Eric, is this the shield of the fighter you said?"
"Radar stealth is not just a shield of a fighter plane. Sometimes, it is also a cloak of invisibility, and the one who has obtained this equipment must be an extremely dangerous assassin."