Jaw intake

As the name suggests, the layout of the newly proposed inlet is to adopt the layout of the intake duct in a manner similar to the belly intake, but the difference is that the air intake of the intake is moved forward from the belly to the rear position under the radome. In fact, the conservative design of the mandibular intake was also adopted in the early program demonstration, and the ventral intake was the product of the further development of the mandibular intake. (For specific reference to the chin intake, you can take a look at the American-made A7 attack aircraft A8 fighter, as well as the domestic J-7 New Century Overhaul Program J-7FS)

The use of the chin intake is quite early, if you want to calculate, some pistons in World War II are fighter jet air-cooled air intakes are the earliest prototype of the chin intake, and the real use of the chin intake on jet fighters is the U.S. Navy carrier-based aircraft fighter F8 Crusader that began to enter service in 1957.

Eighty years of jaw intake is no longer sought after, but now it is very suitable to use this chin intake on the new trainer aircraft.

Why do you want to say this, the air flow of the chin intake can enter the engine smoothly from beginning to end like the nose air intake, in the scheme of air intake on both sides, to ensure the training of J-7 pilots, it is necessary to ensure better supersonic performance, which must take into account the supersonic area rate, and the bee waist fuselage is a must.

This brings a trouble, the consideration of the bee waist fuselage, so that the air intake duct on both sides will immediately have a sharp retraction towards the body after absorbing the air flow. This is not conducive to the smooth flow of airflow, there will be a large bend, the airflow is very likely to produce small vortex, the air flow with vortex is absolutely not conducive to the normal operation of the engine. (If you are interested, you can find the map of the Jianjiao 9 Mountain Eagle and take a look, and look at the air intake of the Mountain Eagle from below)

Yang Hui knew the reasons why the later Jianjiao 9 adopted both sides of the air intake: first: in the modification of the Jian-7 in China, the two sides of the air intake were studied in depth; Second: there are small eddies in the incoming stream, and some special methods can be used to sort it out in actual use; The third point is that the turbojet 13 engine used by Shanying has a relatively good surge margin and a strong anti-distortion ability of the engine.

However, now in 83, the improved J-7 with both side air intakes and chin intakes has not been studied in depth, and naturally the first advantage in later generations does not exist; The design of the aircraft requires weight reduction as much as possible, and the later Jianjiao 9 adopted some special methods to pay the price of weight; One last point: for the engine, of course, the smoother the airflow, the better, who wants to inhale some disordered airflow, isn't this looking uncomfortable?

The total reason for the above analysis is that the lower jaw intake has a considerable advantage over the two side intakes.

However, in Yang Hui's view, although the chin intake is technically better than the two-sided air intake on the new machine, it doesn't look good and doesn't sound so fashionable, which may be a little difficult to accept for the Saudi tyrants who pursue fashion.

Regardless of performance, a good appearance is also a very important factor for a training aircraft that pursues a large number of exports. For these countries, this is actually the most popular among aircraft manufacturers.

After thinking about it, Yang Hui said his unreliable shortcomings: "I personally think that the chin intake is indeed a very good design, and it is indeed a good choice to apply it to our new model, but our new model should take into account Saudi Arabia, a country that pursues fashion, and people will provide half of the funds, and we must take it into account if they are not satisfied." And there are actually not many countries like Saudi Arabia, so in terms of appearance, the chin intake is the only shortcoming. ”

As soon as Yang Hui's point of view came out, the entire room was shattered with glasses

Even Chief Master Yu, who has always been more optimistic about Yang Hui, was so shocked by Yang Hui's words that he didn't know what to say: "Saudi Arabia still has this hobby?" Is the Air Force of such a country combat-ready? ”

Chief Yu's words are really to the point, the combat effectiveness of the Saudi army is really combat five, and the only five combat effectiveness is only due to the addition of the equipment boiled.

The director of the Shuangyang Factory, who proposed the lower jaw inlet plan, felt the most incredible about Yang Hui's statement, this Yang Hui should not be bragging, if such an army equipment procurement personnel are in the Republic, they will definitely be pulled out and shot, and if they are in the Jin Dynasty, they will be properly pulled to the anti-aircraft artillery execution.

Although the chin intake has technical advantages, this Yang Hui is one of the only few people who has contacted the Saudi side, and it will be difficult to do if Saudi Arabia is really so interesting.

The director of Shuangyang Factory didn't know how to get better, so he handed over this problem to Chief Engineer Yu. Take a look at the opinion of Chief Engineer Yu, who is engaged in aircraft design.

"Chief Engineer Yu is like this now, you think what to do, you are the chief designer of the base training aircraft, now you have to get an idea."

At this time, Chief Master Yu said in his heart that he was already biased towards this lower jaw inlet plan, but Yang Hui's opinion could not be ignored.

"That's it, let's listen to Yang Hui's opinion, which one is preferred, both projects have their own advantages, Yang Hui, you can talk about your thoughts again."

This question was thrown around and around, and finally it was thrown into my own hands, what is this? But now Yang Hui can't throw it into the hands of others, so he can only talk about his own way to deal with it.

"This question, I don't think the choice between the two options is in our hands, and we have to make both options. When it was time to report, we had two options, which showed that we were fully prepared, which was more conducive to our final win of the project. And the choice of the two plans will be left to the army, Saudi Arabia, and Pakistan at that time. ”

Chief Master Yu is a lot older, but after listening to Yang Hui's method, he couldn't help but applaud his legs, took a deep breath, and said slowly.

"This is a good way, we can't make a decision, then report both plans, say all the good and bad things, and then it will be up to us which plan to choose."

This method is also a feasible method now, and the director of Shuangyang Plant also agreed to do so. By saying the above two sentences, you agree to do so.

"This is the best, we first roughly determine the pneumatic modification plan. The specific data can only be seen after the project is finalized, and now we will discuss other aspects. ”

The new machine has changed a lot, all aspects are to be operated, not only to modify the pneumatic layout can be, the appearance has, but also to have the connotation, only all aspects have met the design requirements, then the new machine in the technology is considered a success.

There will be more modifications in other aspects, and at this time, Yang Hui needs to be specific about the requirements of the sand tyrants.

"Saudi Arabia wants to be in line with the West, the cockpit can not be full of dashboards like our current military aircraft, and the cockpit layout is required to be closer to the west design, reduce the flight pressure of pilots, pay attention to ergonomics, and be strict in the environmental control system.

I have long expected that the maximum of 300 million US dollars is not so easy to get, and now these are the shortcomings of domestic technology, if this is not handled well, this project may be dangerous. Chief Engineer Yu has not underestimated the difficulty of this project, and now the cockpit and environmental control are big problems.

"This environmental control system gritted its teeth in China, worked research and development, and the funds invested in it may still be able to meet the standard, but the use of the display screen required on this cockpit"

After a pause, he thought about it and continued, "Even if it is an early CRT display in the West, it is still difficult to do it in the current situation in China. ”

This is the problem caused by the current situation of the domestic electronics industry, and even CRT displays are high-end goods at this time. You don't see the hottest thing in the 80s is to be able to buy a color TV from abroad after going abroad, think about it at this time, CRT monitors have been used in the civilian field on a large scale abroad, but there is no achievement in this aspect of the republic.