Chapter 598: Do we have the power to fly big bricks one day?
As the test flight and transportation site of Shengfei Group, Beiling Airport is not large in size. After all, there is no daily take-off and landing pressure here.
Therefore, within a few minutes, aircraft No. 1401 had stopped at the end of the takeoff runway, and the wings were readjusted to a 20° sweep angle, which was more conducive to takeoff.
"The area has been cleared. Unit 1401 is ready to take off."
Fu Guoxiang put on an oxygen mask, maintained the brakes while slowly pushing the throttle valve, and watched as the replacement The pointer of the Chinese-style engine tachometer slowly turns to the right.
As a test pilot stationed at Field 112, this is his first time coming into contact with the turbofan 9A model.
In fact, there are currently only three aircraft in total in China - the JH-7A No. 01 and No. 02 prototypes, and this No. 1401 aircraft, which only uses the turbofan 9A.
However, the steady increase in speed still brings considerable confidence.
It even reminded him of the situation of the J-8C after a major flight test two years ago.
They are also two engines installed for the first time, and they also have such a stable speed.
After the engine reached takeoff thrust and stabilized for a few seconds, Fu Guoxiang released the brakes and the plane began to roar and accelerate on the runway.
Fu Guoxiang himself was a little surprised by the pushing feeling coming from behind him.
In his opinion, such an aircraft, which still has an empty weight of about 17.5 tons even after weight reduction, seems to be relatively clumsy.
Compared with the J-11 he had flown before, the F14's greater weight and drag made the acceleration capabilities of this model less optimistic, which was a slight hindrance. However, the excellent lift coefficient still made The plane only used about one-tenth of the runway, that is, a distance of about 350 meters, before reaching takeoff conditions.
After all, the F14 is a relatively mature design. After all, the "first flight" after modification is not exactly the same as the real first flight. The setting of flight subjects is much more open.
After pulling up the plane, Fu Guoxiang retracted the landing gear, then allowed the plane to accumulate some speed, and then made his customary high-angle climb.
Almost at the same time as the throttle valve was pushed to the end, the two engines sprayed light blue tail flames with Mach rings downward in mid-air, and the wings also flew in less than 7 seconds. Here, it is adjusted to a 68° sweep angle state with lower resistance and more suitable for acceleration.
Two new engines with abundant low-altitude and low-speed output have provided Fu Guoxiang with quite confident climbing capabilities. At least in his opinion, the current climb process is close to 70°, and there is almost no loss of speed.
Increasing the sweep angle will greatly reduce the lift coefficient provided by the wing, but...
Strength works wonders.
On the other side, this slightly wild action also caused a burst of exclamations in the command center of the tower.
A representative from the Persian Air Force, of course.
Since there has been no formal means of importing spare parts for more than 20 years, in order to save the life of the machine, they rarely engage in such "wild" driving.
And, on the other hand, if the TF30 engine in the past dared to carry out such large-scale and violent maneuvers at low altitude, 80% of it would have entered a surge state...
"The performance shown this time The climb rate is obviously higher than before..."
A colonel standing next to the leading Persian general stared at it for a while, and then estimated.
“Of course.”
He Ming already knew the performance of this aircraft, so his attention was not always focused on the aircraft outside. When he heard the Persians Immediately after the evaluation, he explained:
“We replaced the material of the skin part that does not involve the main load-bearing structure, reducing the empty weight by about 700kg. Moreover, the sea level thrust of the replaced turbofan 9A engine is also An increase of more than 17% compared to the past.”
“In this way, the thrust-to-weight ratio of the entire aircraft during takeoff can be increased by almost one-fifth, and the power performance is naturally completely different.”
When he said this sentence, He Ming even had a confused feeling -
The principle of powerful bricks flying could one day be spoken from his own mouth.
It’s amazing. "Besides."
He Ming's tone suddenly sounded like he was holding back a smile:
"I can assure you that the aircraft had been filled with a standard amount of fuel before the test flight, and there was absolutely no situation where the engine was turned on in advance to consume fuel, thereby reducing the take-off weight."
Hear this sentence , even the Persian general laughed directly:
"Well, we have been watching just now, you really didn't play any tricks in this regard..."
What the two said It happened when Persia purchased US military fighter jets.
The candidates at the time were Grumman's F14 and McDonnell Douglas' F15.
Originally, the flight performance of the latter should be much better, but Grumman specifically asked McDonnell Douglas to perform the performance first, while its F14 kept running its engine on the ground to consume fuel, thus making up for the thrust-to-weight ratio to a certain extent. disadvantages.
Although the authenticity is virtually impossible to test, this story has become one of the famous urban legends in the field of international arms sales.
After the brief joke, He Ming quickly returned to the topic:
“Getting back to the subject, in addition to the advantage of sea level thrust, we adopted the turbofan 9A engine in the design process. Blade separation flow active control technology can cope with extremely extreme air intake distortion.”
“Although we still need to wait for the specific flight envelope data to be released by our test pilots, from a qualitative perspective. , the improved F14 can allow pilots to perform violent maneuvers that were unimaginable in the past, such as...you have seen it anyway."
The F14A purchased by Persia is an earlier batch of technical versions. The sea-level afterburning thrust of the engine is only 8,530kgf. However, the turbofan 9A, which has been partially improved by the turbofan 10 technology, has this data above 10,000kgf.
“Looking at it this way, the improved F14IC model can probably be equivalent to the level of the US military’s F14D?”
Obviously, the Persian Air Force has always been very concerned about the improvement of the US military’s Tomcat. focus on.
“You can say that.”
He Ming nodded after hesitating for a moment:
"Although the sea level thrust of the turbofan 9A is smaller than that of the F110GE400 replaced by the F14D, the overall improvement ideas and the performance orientation of the improved model are similar."
Speaking of this, he suddenly remembered An interesting thing happened:
“Speaking of which, the total pressure ratio of the two engines, F110GE400 and Turbofan 9A, happens to be 30.7, which is 50% higher than the TF30 engine.”
"Of course, as a price, the high-speed performance and maximum flight speed of the F14 after the replacement, whether our F14IC or the US military's F14D, have actually been reduced."
"Oh?"
The Persian general, who had been holding a telescope, was also attracted by this topic about the engine:
“Did you consider benchmarking the F110 when designing?”
In fact, The reason why they decided to hand over the F14 to China for modification was partly because the size, weight and performance of the 1493 radar could perfectly replace the AWG9. The other half was that when they visited the Haofei Group, they discovered that the turbofan 9A engine Performance is quite good.
“That’s not true.”
He Ming shook his head:
"This is a complete coincidence. In fact, the turbofan 9A is a by-product created by one of our chief designers for technical verification. It is impossible to bother to benchmark other models in terms of total pressure ratio."< br>
This answer was originally just that he told the truth without any deep meaning, but the effect was surprisingly good.
"Wait, you mean, the by-product... already has such good performance?"
Now that Unit 1401 has flown far away, it is impossible to see it even with a telescope arrived, so the Persian general simply put it aside, turned around and asked with a shocked expression.
He Mingxin on the opposite side said that it was because you didn’t know what kind of ruthless work Mr. Chang was preparing to do on the turbofan 10, but the contents of the third-generation (actually 3.75-generation) turbofan engine were all confidential. I had to change to a more traditional answer:
"Although it is a by-product, the technologies used on it are the latest cutting-edge technologies from the 1990s and even into the next century."
"It can be said that although the turbofan 9A was born out of the British Spey, But now there is no direct relationship with Sibei..."
(End of this chapter)