Chapter 294 Regrets
Fortunately, she now has the assistance of the absolute deduction space of the Enlightenment Stele, which is clearer and more intuitive than just trying to build a model in her mind before. She can physically perceive the advantages and disadvantages of the optimization direction and speed up the optimization process.
Within the limited time, we should compress the time as much as possible so that we won’t be the one who lags behind.
STOVL fighter jets are actually the inevitability and direction for the sustainable development of future aviation technology.
Most flying microbes in nature actually take off and land vertically or in short descents, from flies, mosquitoes and insects to most birds, and microbes have never been seen flying on Earth.
In order to facilitate take-off and landing, a special road runway was built, but it is actually a technical flaw and a second-rate option.
Most large birds can use river gliding to aid flight.
But in real life, since the large-scale use of active service, the world immediately realized that it had occupied too much load in the sudden battle on the ground and the comprehensive ups and downs at sea.
One can learn from others' experience. Wu Tong pondered over the confidential information she had read before, and flashed through her mind. From the perspective of equipment history, the propulsion system of the STOVL fighter has three engine models.
That is, the Harrier "Pegasus engine" from Britain, the R-79+RD-41 engine of the Yak-141 of the big brother next door, and the F135 engine of the United States.
These three engine models also correspond to three different technical solutions.
The Pegasus engine has a thrust reversing scheme using a rotating exhaust nozzle. When the aircraft takes off and lands vertically, the nozzle emits jet downward.
The biggest feature of this engine is "lift and thrust in one", that is, the cruise thrust and vertical lift are all undertaken by one engine. It has a simple and compact structure, a small dead weight of the propulsion system, good short-distance takeoff and landing performance, and even has the ability to take off vertically.
However, the disadvantages are also obvious. Since the rear nozzle ejects hot combustion gas, it causes a serious problem of exhaust re-inhalation. Because the hovering altitude is low during vertical take-off and landing, the oxygen-poor and high-temperature jet bounces off the ground and is easily inhaled by the engine again, reducing engine efficiency and even causing surge.
Vertical takeoff consumes a lot of fuel. It is said that one vertical takeoff of the Harrier uses up one-third to one-quarter of its internal fuel, and its combat radius is only about 100 kilometers.
In addition, the Pegasus engine has a large cross-section, which leads to large supersonic drag, so the Harrier has always been a subsonic fighter; in addition, the control system is very complex due to the adjustable nozzle area and afterburner, which is also a technical problem.
At present, this technology has lost its practical significance and can only serve as a reference in the history of engines.
The R-79+RD-41 engine of the Yak-141 was developed ten years later than the Pegasus, but, correspondingly, it was a step further than the Pegasus engine.
The most significant feature of the Yak-141 is the "separation of lift and thrust". The cruise and lift engines each perform their respective functions, ensuring the efficiency and effectiveness of the cruise engine, making the Yak the world's first supersonic STOVL fighter. During the test flight, the Yak-141 even reached a maximum level flight speed of Mach 1.4-1.7.
However, the shortcomings are still inevitable. The high-temperature airflow problem of cruise and lift engines is very prominent. When the aircraft is hovering, the high-temperature airflow is ejected from the engine nozzle and spreads outward after reaching the ground.
The low pressure area formed under the fuselage produced the suckdown effect, which would "suck" the aircraft firmly. This was also the reason why the Yak-36 crashed on its first test flight and failed to take off. Later, due to the disintegration of the big brother next door and a series of major national changes, the optimization of the Yak-141 could not continue, and it was a pity that it failed.
Finally, there is the F135 engine used by the F-35.
It is developed on the basis of F119 and adopts the three core parts of F119: high-pressure compressor, combustion chamber and high-pressure turbine. Fan, low-pressure compressor and low-pressure turbine are redesigned F135 engine.
The model used for the short-and-vertical F-35B is F135-PW-600, or F135 engine for short.
There is a rumor in the circle that during the selection process of the F-35B vertical launch propulsion technology, part of the design of the Yak-141 was plagiarized.
This is not funny in scientific research, not to mention that it is more of a reference! You can say it is taking advantage of the situation or something else that is even worse. However, they should not underestimate the other side of the sea.
Being able to develop one's own technology by learning from others is also a breakthrough.
The fact that they are now able to continuously produce scientific research results is actually because they are standing on the shoulders of their predecessors and extending on the basis of the foundation laid by their predecessors' struggles. They are not like floating duckweed without roots.
Across the sea, a major breakthrough was indeed made based on the Yak-141.
The advantages and disadvantages of the F135 engine are also very obvious. Its advantage is that it continues the Yak-14, with lift and thrust separated, and extends to using thrust instead of lift.
The airflow of the engine's lift fan comes from a low-temperature compressor, and the jet is room-temperature air. Therefore, even if it bounces on the ground and is sucked back into the engine, it will not cause surge. This largely solves the problem of engine inlet distortion caused by the re-inhalation of high-temperature airflow in the Yak series.
At the same time, it also avoids the complex dynamic conditions and reliability problems of multiple engines on one Yak series aircraft.
Just to achieve the above advantages, the structure of engine + drive shaft clutch + fan results in too much space and complex structure. The oversized structure naturally also brings about excessive weight. The excessive volume and heavy engine weight form a vicious cycle, leading to the core problems of too small payload and insufficient deterrence.
The wake temperature is high. Even though the suckdown effect of the Yak series has been greatly solved, with the addition of a low-temperature compressor and the conversion of the jet into normal-temperature air, the temperature of the tail flame is still as high as over 900 degrees, which still imposes an excessive burning load on the aircraft carrier deck.
Although it will not cause the steel structure of the deck to melt and collapse, it will still cause deformation and damage, and it will be enough to break the heat-resistant concrete of land airports into snow flakes or completely melt the asphalt.
Moreover, in the low-speed mode of vertical take-off and landing, the auxiliary air intake door of the lift fan is easily damaged due to the high wind pressure. This is a shortcoming of the fan.
However, even with so many shortcomings, the F-35B still successfully completed its test flight.
Confidential information shows that in the past two or three years, the F-35 has continuously announced successful test flights and successful research and development, and has announced that they will be deployed and put into service one by one within the next two years, bringing tremendous pressure to the entire world.
However, if Wu Tong remembered correctly,
In that future memory, the F-35B crashed more than once, and eventually, the entire F-35 was grounded ten years later.
Wu Tong did not laugh at the other party's arrogance, but she wanted to use it to warn herself. In the next engine optimization, she must avoid the detours that the international community has taken and the defects that have been discovered.
Being blindly proud and arrogant and laughing at others will make you a joke sooner or later. Wu Tong will not allow himself to make such a low-level mistake!
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