Chapter 509 happens to be the direction that Mr. Chang is paying attention to (1 per day, please

Liu Hongbo had not done much research on helicopters before, so he did not respond immediately, but turned his attention back to the computer screen again.

The Z-9 is basically a 4-ton model, and its potential is relatively limited.

Of course, the Z-9 is currently the only type of helicopter that China can clearly build. The Z-8 introduced during the same period is even worse. Even the French themselves have completely given up on this model.

So there is no room for pickiness.

Moreover, the 4-6 ton class is indeed the largest class in the helicopter market. From this perspective, the Ice Flying Group's vision was indeed good.

Moreover, the planning of the four configurations is quite clear.

Needless to say, the civilian model is already available. The AS9 Dolphin, the prototype of the Z-365, already has a civilian model. It only needs to slightly improve the cabin comfort and reliability to make it comply with the current CAAC requirements for civil aircraft.

Of course, there is a problem here, that is, when the airworthiness mutual recognition agreement was concluded with the EU and the United States, the mutual recognition objects were only "aircraft", that is, fixed-wing aircraft, excluding helicopters.

But as long as it doesn't target the European and American markets, it won't be a big problem.

This mutual recognition of airworthiness itself is equivalent to Europe and the United States recognizing China's strength in manufacturing small and medium-sized aircraft. For those third world countries whose airworthiness regulations are not strict, they actually have little energy to pay attention to those laws. the difference.

The naval type is developed on the basis of the civilian type. The basic design plan and prototype have been completed. The main difference is that in order to meet the needs of submarine search, patrol and search and rescue, a radar dome is installed on the nose part.

This model is planned to be equipped with a turboshaft 500F engine whose power has been increased to 8kw, so as to at least meet the requirements of carrying a suspended sonar and two anti-submarine torpedoes at the same time, or a suspended sonar, a sonar buoy and an anti-submarine torpedo.

For specific models with different functions, other equipment such as ultra-short hanging beams and electric winches can also be specifically modified.

But this is not a structural difference.

Generally speaking, the difference from the civilian type is relatively limited.

As for the assault transport type, which is the model Liu Hongbo came to take charge of this time, the design drawings were obviously only half completed.

However, general ideas for improvement can already be seen.

The overall design remains unchanged. The nose part is also elongated, but it is not used to accommodate radar. Instead, a photoelectric detection and targeting device is added underneath to provide the aircraft with the ability to use precision-guided weapons.

Additional reinforcements were made under the fuselage to accommodate a set of curved beams for mounting weapons.

At the same time, this model will still retain the personnel transportation capabilities of the original Z-9, which can carry 4-6 fully armed soldiers and undertake transportation and combat tasks at the same time.

To this end, the take-off weight of the assault transport type will be increased to 5 tons, and the engine is also planned to be replaced with a 600kw-class improved turboshaft 8G

As for the final dedicated armed type, there is not even a schematic diagram at the moment, only some text descriptions.

Except for the ducted tail rotor, there is basically not much trace of the original model. Even the side-by-side cockpit has been changed to a tandem cockpit, and the landing gear has also been changed from the main wheel at the rear to the main wheel at the front. The last three points.

That is what Liu Hongbo mentioned before, changing from UH1 to AH1, or from Mi 8 to Mi 24.

For the Mi-24 and AH1, such changes are equivalent to redesigning everything except the engine and transmission system.

As for the Z-9, which is smaller and less powerful, a dedicated armed helicopter must have a take-off weight of about 6 tons, and even the power system must be changed...

Relatively speaking, it is not a project that can produce results in a short period of time, so it is normal for it to be prioritized later.

It is basically equivalent to "a fan work that perfectly understands the spirit of the original work."

"This plan of yours...is not a small move."

After thinking for a long time, Liu Hongbo finally commented.

Guo Jingshan waved his hand in embarrassment:

"Sigh... After all, we are known as the cradle of the Republic's helicopter industry. We have to come up with something, right?"

"Especially the navy's anti-submarine helicopters and the army's armed helicopters. These are the equipment that the two services are most eager to need. Now that the entire aviation industry is exploding, we at Ice Flying cannot just watch..."

Liu Hongbo went through the material he just read in his mind, and then said:

"The Z-9 is generally an aircraft with a relatively mature structure. You just said that you have improved the aircraft's defective transmission system in the past, so what we need to assist should be the structural reinforcement of the assault transport model, and also Is there...research on the rotor flow field and noise characteristics?"

"Yes."

Guo Jingshan nodded:

"The previous Z-9 mainly solved the problem of helicopter availability, and the performance requirements were not high. But now these four configurations cannot be careless, especially the hovering stability, as well as the vibration and noise during flight. For The survivability and performance of the aircraft have a fatal impact."

“We have previously conducted tests with the AS565 Panther anti-submarine helicopter imported directly from France by the Navy, and found that even in level 4 sea conditions, it cannot maintain a stable hover for more than two minutes, and the noise level in the cabin will affect the search and attack submarine operations. There are clear adverse effects.”

"The original French products are all like this, so the Z-9A that was copied before will definitely not meet the requirements, so our plan is to keep the transmission mechanism unchanged, but redesign the fuselage and rotor, but..."

Speaking of this, Guo Jingshan showed some embarrassment on his face:

"However, our technical strength in this area is really limited. Even in developed countries, helicopter acoustic research is a new field that has only started to be applied in the past two years, so... I wanted to find your help."

"Rotor calculations are really a problem."

Liu Hongbo turned his chair so that he faced Guo Jingshan:

"Due to the rotation of the blades, when the helicopter flies forward at high speed, shock waves may exist on the forward rotor blades. If the shock waves are strong, they will expand to areas outside the blade radius, which will have a strong impact on the flow field. .”

“In addition, when the angle of attack is large, interference from shock waves and boundary layers may occur; in hovering, low-speed forward flight, and near-earth flight states, the tip vortex that escapes from the blade cannot leave the rotor quickly, and the blade tip cannot leave the rotor quickly. The vortex will dominate, which is very different from a fixed-wing aircraft, even a propeller-powered fixed-wing aircraft."

Seeing Liu Hongbo analyzing the difficulties when he came up, Guo Jingshan thought he was asking for more time and immediately said with relief:

"We are relatively loose in setting the timetable. The assault transport type and naval type are both planned to fly before 2001. The dedicated armed type... there is no specific progress plan..."

Obviously, Bingfei is very aware of his own situation and has no ambitious plans.

However, perhaps because he has followed Chang Haonan for a long time, Liu Hongbo is somewhat dissatisfied with such a conservative plan:

"2001 was too slow, this is not okay..."

"what?"

Guo Jingshan was immediately stunned.

"Rotor calculation is a typical unsteady flow problem, which happens to be the research direction that our CEO Chang is focusing on recently."

Liu Hongbo continued:

"In addition, I already have some ideas about sound field calculations, but I am not sure about the feasibility. I will consult Mr. Chang tomorrow morning."

"Anyway, we will install the latest version of TORCH Multiphysics overnight today and start work as soon as possible!"