Fang Lang, who had a clear understanding of this aircraft, no longer thought it was ugly when he looked at it again. On the contrary, the more I watch it, the more I like it.
He asked casually:
"Since it has passed the wind tunnel test, why hasn't it been manufactured? Is it because time is running out?"
Unexpectedly, after hearing Fang Lang's question, Kurt Tank smiled sheepishly, and then slowly said:
"It's not entirely because of time issues, it's mainly because we still have an unresolved problem, so we don't dare to start manufacturing prototypes directly."
When Fang Lang heard this, he frowned and said worriedly:
"Oh! What problem do you mean?"
Some things obviously cannot be concealed, so Kurt Tank could only sigh and said slightly distressed:
“Although swept wings allow the aircraft to have better high-speed controllability, it also brings about two problems. One is that it will cause the wing tip to stall, and the other is that the low-speed stability is not good.
If we cannot solve these two problems well, the reliability of the aircraft cannot be guaranteed at all, and it is impossible to obtain orders for such aircraft. "
These words made Fang Lang fall into deep thought. He had never participated in aircraft design and did not understand the design principles of these aircraft. But he has an advantage that no one else has, that is, he can clearly understand that since the MiG-15 can be mass-produced on a large scale, the same problem must be solved.
As long as I compare the differences between the MiG-15 and the TA-183 in front of me, I will definitely be able to solve this problem.
"Can you tell me what you mean by wingtip stall?"
Kurt Tank did not expect that his boss would have such a thirst for knowledge. Seeing that the other party seemed to be frowning and thinking, he very carefully stepped forward and pointed to the wingtips on the drawing and explained:
"The so-called wingtip stall is mainly caused by the jet flying too fast. When the wings cut the air, the airflow will separate at the wingtips. In this case, the wingtips will lose lift.
Once the wingtips lose lift, the aircraft's controllability will decrease. In the worst case, the aircraft may fall out of control, spin, or even crash. "
This answer made Fang Lang break into a cold sweat and thought to himself, What a guy! No wonder they dare not produce prototypes. No one would dare to fly such an aircraft once it is manufactured!
Following Kurt Tank's fingers, he looked at the wingtip position on the drawing, and various aircraft he had seen in later generations appeared in his mind involuntarily.
Is the wingtip position different from the one on the current drawing?
First of all, it can be determined that the position of the wingtips of fighter jets does not seem to be much different, but in my impression, the wingtips of civil aviation airliners seem to be a little different. The wingtips of the Boeing 737 he flew in in later generations did not seem to be straight, but It’s upturned!
Why is this?
Immediately afterwards, the MiG-15 and J-2 that later generations had seen in museums and pictures appeared in my mind again. There seemed to be two sharp protrusions on the wings of these two aircraft!
Could these two sharp protrusions be caused by the same reason as the Boeing 737's wingtips are upturned?
Fang Lang obviously couldn't answer this question, but he could ask this question to the expert in front of him?
"Since this wingtip stall is caused by airflow separation, can we try to add something to the wing to change the direction of the airflow?
For example, this..."
With that said, Fang Lang stretched out his hand and started drawing on the drawing.
The things he was gesturing at were exactly the wing blades on the MiG-15 wings that he remembered, and the upturned wing tips seen on the Boeing 737 passenger aircraft.
Kurt Tank, who originally thought that the boss was just asking him casually out of curiosity, was stunned when he heard Fang Lang's words. He didn't care much at first.
But soon his eyes began to become sharp. His eyes kept moving along with Fang Lang's fingers, and he began to make crazy calculations in his mind. In his ears, the boss's voice suddenly opened his mind.
Gradually, his eyes began to shine, and he secretly thought, Why didn't I think of such a simple question?
As Fang Lang spoke, he recalled the aircraft he had seen in later generations. What were the differences in the wings from the aircraft in front of him? First of all, upturned wingtips were rarely used on fighter jets.
The sharp bulges on the wings must have been designed to cut the air and disrupt the airflow, but why are they missing from later modern fighters?
Instead of cutting the air with such sharp protrusions, how do they disrupt the airflow?
Soon, Fang Lang remembered that the front and rear wings of the Boeing 737 were not smooth and integrated, but had a telescopic mechanism, especially when he was sitting by the window on a plane and saw the plane land.
The front of the aircraft's wings seemed to be pushed out, while the rear of the wings opened directly.
The same seems to be true for later fighter wings. Does this mean that this kind of wing structure later eliminated the raised structure on the wing?
Although he did not understand the principle, it did not prevent him from providing this idea to Kurt Tank for research.
Thinking of this, Fang Lang quickly continued:
"No, no, that's not good. Maybe we can add a movable part in front of the wing and push it out when needed, or let it move up and down to change the shape of the wing.
Will this change the airflow from being simply cut into upper and lower pieces?
Moreover, the trailing edge of the wing can also allow him to move, what do you think? "
Kurt Tank, who had already opened his mind to the wing knife plan proposed by Fang Lang, looked at Fang Lang with a startled look after hearing this new plan.
This principle sounds very simple, but why didn’t I think of it before?
If these plans had been thought of, the TA-183 would have been launched long ago!
Thinking of this, Kurt Tank wanted to slap himself twice.
After Fang Lang finished explaining his thoughts, he found Kurt Tank staring at the drawings in a daze, and asked with some uncertainty:
"Professor Tan Ke, do you think what I said can solve the problem you mentioned? Which of the two options is better!"
Kurt Tank, who was in deep self-doubt, slowly recovered after hearing this, and squeezed out a smile with a hint of bitterness:
"Boss, why didn't I meet you earlier? Such a simple question has troubled us for so long."
After saying that, he shook his head helplessly, and then his expression slowly became serious. He crossed his arms across his chest, propped his chin on his right hand and looked at the drawings in front of him, his mind running rapidly.
He said firmly:
“Comparing these two solutions, the second one that pushes the front wing to telescope and move up and down is definitely better than the first one.
Because the first solution can solve the problem of wingtip stall, but the second solution can also have a very positive impact on the stability at low speeds.
If I had to choose, I would definitely choose the second option.
However, the process difficulty of the second plan is definitely more difficult than that of the first plan, and the calculation amount of the entire project will be very huge. "
Kurt Tank's words made Fang Lang feel elated for a moment. Unexpectedly, this old boy looked cold and cold, but his flattery was so smooth, which made people feel comfortable all over!
In response to what the other party said about the difficulty of the process and the large amount of calculations, Fang Lang waved his hands indifferently and said:
“There’s nothing to be afraid of because the process is difficult, we’re not short of money.
What are you afraid of when engineering calculations are large? Have you forgotten, we have a brand new electronic computer?
Since you are sure that the second plan can solve your problems, follow the second plan. "
After hearing Fang Lang's words, Kurt Tank looked surprised and quickly said to Ant Bollman next to him:
"Mr. General Manager, you heard me, the boss has agreed to our project, hurry up and fund it.
I need to organize manpower now to re-establish our jet fighter project. "
Looking at Kurt Tank with an excited look on his face, Fang Lang started to chew on his words, and he came back to his senses. Damn it! This old boy is waiting for me here! Whoever said that men in science and engineering are honest, stand up for me. Damn it, I came over to look at the drawings. As I looked at them, the jet project team was established.
Fortunately, he was also planning to start his own jet fighter research. Since he already has Kurt Tank's TA-183 as the basis, I believe the progress of the entire project should be faster than imagined!
After looking more at the TA-183 on the drawing, Fang Lang couldn't help but say one more thing:
"Professor Tan Ke, I agree with the jet fighter project. I have no problem with following your original TA-183 design idea. I especially like the shape of the swept wing.
However, I think it is necessary to make some adjustments to this short fuselage designed for maneuverability. After all, the current cross-sectional area of the TA-183 fuselage is too large, which will increase the probability of the aircraft being shot in combat.
Moreover, if our current turbojet engines need to be purchased from other countries, the power performance may not be particularly ideal. In this case, we need to work more on the streamlined shape of the aircraft.
Try to design a body with a lower drag coefficient.
Do you get me? "
After hearing this, Kurt Tank thought for a while, then raised his head and looked at Fang Lang seriously and said:
"Boss, I understand, you think he is ugly."
Hearing this, Fang Lang was so angry that he almost vomited blood. Only when he saw the smile on the corner of the other party's mouth did Fang Lang realize that the other party was joking with him. It seemed that this big German man was not as old-fashioned as rumored, which made Fang Lang relaxed a lot.
So he said directly without being polite:
"To be honest, it is indeed a bit ugly. I personally think that as a subsonic fighter capable of reaching Mach 0.8, there is no need to treat it as a propeller aircraft.
At such a high speed, the way of dogfighting is bound to change. If your TA-183 uses a stubby fuselage in exchange for control flexibility, it must sacrifice speed. I personally think that this deal Not a good deal. "
Kurt Tank was an excellent aircraft designer with a very smart mind. As soon as Fang Lang said it, he already understood what the other person meant.
He asked with a slight hesitation:
"You mean we should take advantage of the speed of the turbojet and give up the maneuverability of the aircraft?"
In fact, this involves a change in tactical thinking. Now that the two have talked about it today, Fang Lang feels that it is necessary to explain the future trends he knows to the two aviation experts.
"Actually, this is not a matter of choosing one or the other, but a matter of finding a balance between the two. A slender streamlined fuselage allows the aircraft to fly faster, while a thick and short fuselage allows the aircraft to have excellent maneuverability. .
What we have to do is to achieve the best balance between the two, and have sufficient mobility while maintaining our own speed advantage. "
