Chengdu next gen combat aircraft (?J-36) thread

latenlazy

Brigadier
Bro calculates that J-36 has favorable wing loading of 60 lb even if has a weight of 60 tonnes based on wing area calculation.

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As you might recall traditionally the tradeoff for delta designs was that while they had higher wing loading for the same span they had worse lift coefficients, especially for higher aspect deltas. This is why flying wing for the longest time adopted low aspect deltas mostly. But using vortex generators solved some of this issue. My thinking is that on the J-36 they’re probably going even harder on the vortex lift.
 

bsdnf

Junior Member
Registered Member
Exactly, I don't think using fuel as coolant is a great idea. Probably better to use specialized coolant.
One of the design features of the J-36 is the simplification and unification of energy forms. The engine shaft power is only converted into electricity and fuel hydraulic energy, air refrigeration cycle and special hydraulic oil will be eliminated. Part of the hydraulic power components is replaced by electricial components, and try to make single fuel pump responsible for the fuel hydraulic energy of as many components as possible. So that energy can be distributed on demand. For example, in the bvr phase, power can be concentrated on radar, ew and other systems, and the actuators only need a small amount of power to drive. In the evasion phase, power supply to the radar can be reduced, and most of the power can be converted into hydraulic power for the electro-hydraulic actuator to drive the rudder to deflect quickly

Using cars as an analogy, installing a refrigerator in a fuel vehicle requires a dedicated generator and electrical equipment to control it, so the cost is high, take some space, use some of the engine power even it is not working, and stop working as the engine stops running. In NEV, since everything in the cabin is transmitted in electricity and controlled by single electrical system, the refrigerator only needs to take power from the battery.

Special coolants will only waste space and energy, which is unacceptable.
 
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reservior dogs

Junior Member
Registered Member
My guess is that multi-stage heat pumps would be useful, assuming adequate weight and efficiency.

In terms of industrial or commercial scale heat pump technology, China has an advantage
Yes, that is the most promising path. However, finding the right coolant to operate in such elevated temperatures and building a system around this is new. Weight, efficiency and power consumption are all very important if you want to mount it inside an airplane. Come to think of it, the pilot cabin would also need to be cooled if the plane stays supersonic for prolong period of time, something that the fifth gen planes don't have to worry too much about.
 

siegecrossbow

General
Staff member
Super Moderator
As you might recall traditionally the tradeoff for delta designs was that while they had higher wing loading for the same span they had worse lift coefficients, especially for higher aspect deltas. This is why flying wing for the longest time adopted low aspect deltas mostly. But using vortex generators solved some of this issue. My thinking is that on the J-36 they’re probably going even harder on the vortex lift.

If they are going with no maneuverability period they could’ve made do with just two engines. Would eliminate third intake which complicates design. I think that although it is no knife fighter it will hold its own in high speed maneuverability.
 

bsdnf

Junior Member
Registered Member
As you might recall traditionally the tradeoff for delta designs was that while they had higher wing loading for the same span they had worse lift coefficients, especially for higher aspect deltas. This is why flying wing for the longest time adopted low aspect deltas mostly. But using vortex generators solved some of this issue. My thinking is that on the J-36 they’re probably going even harder on the vortex lift.
CAC has accumulated a lot of experience on vortex on the J-20 or even before
 

dingyibvs

Senior Member
One of the design features of the J-36 is the simplification and unification of energy forms. The engine shaft power is only converted into electricity and fuel hydraulic energy, air refrigeration cycle and special hydraulic oil will be eliminated. Part of the hydraulic power components is replaced by electricial components, and try to make single fuel pump responsible for the fuel hydraulic energy of as many components as possible. So that energy can be distributed on demand. For example, in the bvr phase, power can be concentrated on radar, ew and other systems, and the actuators only need a small amount of power to drive. In the evasion phase, power supply to the radar can be reduced, and most of the power can be converted into hydraulic power for the electro-hydraulic actuator to drive the rudder to deflect quickly

Using cars as an analogy, installing a refrigerator in a fuel vehicle requires a dedicated generator and electrical equipment to control it, so the cost is high, take some space and stop once the engine stops running. In NEV, since everything in the cabin is transmitted in electricity and controlled by single electrical system, the refrigerator only needs to take power from the battery.

Special coolants will only waste space and energy, which is unacceptable.

"Waste" suggests that it would not contribute enough value for the cost. As such it depends on what the value is and what the cost is. So my question to you is, how valuable do you think having a specialized coolant is in terms of allowing for higher power consumption throughout the J-36's flight? How much weight and space cost do you theorize there would be with such a system?
 

iewgnem

Junior Member
Registered Member
In most other areas, I believe the U.S. lead, if any, are small since both sides have the system. I gave the lead to the U.S. as we have been operating the system longer. In the realm of VCE, I gave the lead to the U.S. since the Chinese had just caught up to F-119 which was eighties tech and the U.S. have been at this for decades now. When it comes to research, we are not that incompetent. Do you have any basis for your claim that the Chinese have better VCE?
Evidently US talking about NGAD for 10 years didn't translate into US working on 6th gen for longer did it? Same for everything else.
ASPI has a technology tracker and China dominates aero-propulsion research, and people don't publish research on what already exist.
Then there's the matter of China operating top 3 of the world's fastest supercomputers with combined compute greater than all US supercomputers combined...
The time when US had a small lead was back when US thought it had a commanding lead, by the time US think it has a small lead it's already over.
 
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