Chapter 11

The so-called air bearing is a type of bearing that uses air instead of the rolling elements to support the load and provide "lubrication." High-pressure air enters from one end of the bearing and then exits from the other. Under the impact of the high-pressure gas, the inner and outer walls of the bearing do not actually come into contact, maintaining a "suspended" state. The principle seems simple, and Americans achieved a breakthrough in the application of air bearings in the 1950s. However, for China, it was still a cutting-edge field in the 1980s. Air bearings, with their extremely long service life, high rotational speed, low heat generation, and high processing accuracy, can be said to comprehensively surpass ordinary bearings, establishing their position in high-end applications. However, the complexity of air bearings is the biggest issue hindering their widespread use in many fields. Unlike ordinary bearings, the entire air bearing system is not just the bearing itself but also includes auxiliary equipment such as compressors, expanders, and circulators for air supply and circulation, significantly increasing the application cost of air bearings.

Hu Wenhai's idea was not baseless. In fact, by the 21st century, air bearings had already seen many successful applications in aviation engines. By having the engine's compressor provide the air compression function, the complexity of air bearings in aviation engines was greatly simplified. Director Wang recalled and then shook his head, "But currently, only the 993 Factory in Shanghai can produce air bearings, and they don't have any products suitable for aviation engines."

"We can have the 501 Factory develop this product. There's no need for an auxiliary compressor; a compressed air tank can be used to supply the air. After all, a simulation aircraft only flies for a couple of hours, and a 2kg compressed air tank would be sufficient. Compared to replacing a set of mechanical bearings for each flight, the cost of replacing a compressed air tank is much lower."

Director Wang was surprised, "Can the 501 Factory meet the processing precision requirements?"

Hu Wenhai shrugged, "I'm not asking for a high-end product with over a million RPM. The air bearing for the simulation aircraft only needs to handle 100,000 RPM, which is at least one order of magnitude lower in processing precision than what the 993 Factory can achieve."

"Hmm, that's true..." Director Wang stroked his chin, nodding in agreement with Hu Wenhai's point. Seeing that Hu Wenhai could discuss such technical issues with Director Wang, Si Xingu couldn't help but reassess his opinion of him. While it's often said that a son benefits from his father's status, Si Xingu actually placed more value on Hu Wenhai, the young boy. Given that Hu Jiefang's 501 Factory could benefit, he was naturally pleased to see this.

"Old Wang, can your team actually do this engine improvement design? The micro-turbine project is still a novelty in China. If you can't do it, I can look for my comrades at Tianfu or Hongdu; they might be interested..."

This is the advantage of old revolutionaries like Si Xingu. The entire Chinese Air Force was almost entirely built on the foundation of the Northeast Aviation Brigade. Although decades have passed, the influence of the Northeast clique remains strong. Not to mention the extensive network of comrades, which would be hard to come by in the post-founding era.

"Hey, I didn't say we can't do it!" Director Wang was flustered, raising his voice, "I'm just discussing it with Little Hu. Why are you so anxious!"

Even though Director Wang is already a director, a project like a small turbojet engine could still yield several excellent papers. Not to mention the face of old friends and the 501 Factory's ability to coordinate resources within the system, even without these, Director Wang would be willing to spend his spare time on such a project.

"Alright, then we will optimize this engine with a target of 100,000 RPM and the use of air bearings. We will also increase the number of stages and the blade angle of the compressor. I estimate that we can increase the thrust-to-weight ratio to 12 to 13 to 1."

"12 to 13 to 1?" Hu Wenhai's eyes lit up, and he rubbed his hands together, "In that case, we can try many things with the aircraft's density."

An increase in engine thrust means more equipment can be carried on the aircraft. For Hu Wenhai, who is not content with just a simulation aircraft, this is excellent news.

Next, Director Wang, Hu Wenhai, and Si Xingu discussed various aspects of the collaboration. Fortunately, the bureaucratic style had not yet spread to this strategic-level research institute—indeed, the 601 Institute was so poor that scientists had to sell breakfast to make ends meet, and there were no resources for bureaucracy or proceduralism. For someone like Director Wang, who could independently secure projects, the organization would not only not obstruct but would also strongly support and praise such efforts. This is the principle of change and adaptation; civil servants with secure jobs naturally lack the motivation to find their own work.

After discussing the collaboration, Hu Wenhai hesitated, scratched his head, and suddenly asked Director Wang, "Grandpa Wang, I have something I want to ask you. But it might be confidential, so you don't have to answer if it's inconvenient."

Director Wang was slightly taken aback, thinking that Hu Wenhai, being a child, might be curious about the progress of new fighter jet research in China—this could be discussed to some extent, but not in detail. Moreover, given Hu Wenhai's political background, he could not possibly be a spy or cause a leak.

Thinking this, he nodded slightly and smiled, "Alright, what do you want to ask?"

"Grandpa Wang, is there a group of Pakistanis at the 601 Institute?"

"How did you know!" Director Wang's eyes widened in surprise.

"What's so strange about that? Haven't there been rumors that Pakistan is going to introduce the J-7?" Hu Wenhai blinked his big eyes, looking puzzled, "Last year, Aviation World had an article analyzing that Pakistan might introduce the J-7 to upgrade their current J-6. In that case, it's not surprising that Pakistani pilots are being trained in China."

"Aviation World had such an article?" Director Wang was puzzled.

Hu Wenhai nodded vigorously, "The tenth issue had an article introducing a certain squadron's J-7. The article mentioned that Pakistan is interested in introducing this aircraft to counter India's third-generation fighters. The high-altitude, high-speed J-8 is clearly not suitable for Pakistan's needs, and only the low-altitude, highly maneuverable J-7 can meet this requirement. If Pakistan is really going to import the J-7, they will definitely send pilots for training and test flights."

Indeed, last year's Aviation World did have such an article, but Hu Wenhai certainly didn't deduce this fact from the article alone. Pakistan introduced China's J7-MP in 1985 to replace their J-6, which was no longer a secret decades later. In 1983, two Pakistani pilots were trained in China, and both sides agreed on the specific modifications to the J-7 to suit Pakistan's operational needs. By 1985, Pakistan had signed an order for the first 20 J7-MPs, which is not obscure knowledge for those with some knowledge of the Air Force.

For Hu Wenhai, who already knew the answer, it was easy to find a plausible excuse. For the CIA to deduce such information from a few words in a regular magazine might be impossible, but for Hu Wenhai, who already knew the answer and was just looking for a process, it was much easier.

However, Aviation World is just a popular magazine for aviation enthusiasts, and a professional like Director Wang, even if he had read it, wouldn't take it seriously. He recalled but had no clear memory of the tenth issue, so he gave up thinking about it.

To be honest, Hu Wenhai's question was just a guess, and Director Wang inadvertently confirmed it. Given that Hu Wenhai had no espionage potential or motive for a leak, this wasn't a significant issue.

"What do you want to know this for?" Even so, Director Wang still looked at Hu Wenhai with some caution.

"I was just thinking, if we develop the simulation aircraft, wouldn't it be a waste if we only use it ourselves?" Hu Wenhai pursed his lips and smiled innocently, "So I was wondering if the Pakistani side might also be interested."

"..." Director Wang thought about it and realized there was a possibility. After the Third Indo-Pakistani War in the 1970s, Pakistan was in a state of national mourning—after all, they were almost defeated and had to recognize the independence of Bangladesh. Under this stimulus, Pakistan was now determined to build a nation of soldiers. However, the Air Force is an expensive branch, and training pilots is not a short-term task. Therefore, it's not easy for the Air Force to achieve a nation of soldiers.

From this perspective, Pakistan might indeed have a need for simulation aircraft. In fact, it's not just Pakistan; for most Air Forces with limited budgets, simulation aircraft would be quite attractive. As Hu Wenhai predicted, the demand for simulation aircraft would last at least ten years before computer CG performance could meet the simulation requirements. After all, even if the simulation effect of the simulation aircraft is poor, it's still better than nothing. Moreover, the cost of manufacturing, using, and maintaining simulation aircraft is negligible for a well-funded Air Force. In summary, the training cost-effectiveness of simulation aircraft is very appealing.