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

[ougoah]

There is no way the plane flies Mach 3.

At 30,000m which btw is an insane operating ceiling, who knows. With three engines as well. Can an aerospace engineer weigh in on the limits to Mach 3 at 30K? That length to width ratio rule of thumb isn't a law. Even the Mig-25 pushed beyond mach 3 without the SR-71's length to width ratio. I'd say the top speed will be more a function of what engines the aircraft will be using. Seems like VCE engine is intended and all three are intended to be VCEs so not that 2 turbofans plus 1 ramjet or combined cycle theory. This could potentially make mach 3 with more optimal adaption to low - high altitude and low - high speed. It won't be like sticking three WS-10 or WS-15 into it like the prototypes and LRIP versions will probably be using.

While we don't know what the intended engines are for this "fighter". It's certainly taking a new approach to air combat. Taking sensors to next level with unprecedented available power and volume for sensors previously available on fighters. Combining that with speed which no AEWC, AWACS, EW, Signals and C4ISR platform has. Combining that with payload no stealth fighter has. Combining that with all aspect stealth that has only been available to subsonic recon UAVs and stealth bombers so far. This will be featuring later generation stealth materials and shaping.

The B-2, B-21, H-2 don't fly anywhere near as fast.

The F-22, J-20, F/J-35s don't carry anywhere near its payload, its power production or the volume of space available for next generation sensors and accompanying hardware.

The E-3, KJ-xyz platforms don't have anywhere near its stealth, speed and operating ceiling.

This thing is attempting to combine fighter, interceptor, strike aircraft and heavy electronics plus sensor platforms all into one flexible package that's shaped like a UFO.

Even without mach 3 top speed, it needs at least a mach 2 top speed to keep up with PLAAF 4.5 and 5th gens.

 

[qwerty3173]

At 30,000m which btw is an insane operating ceiling, who knows. With three engines as well. Can an aerospace engineer weigh in on the limits to Mach 3 at 30K? That length to width ratio rule of thumb isn't a law. Even the Mig-25 pushed beyond mach 3 without the SR-71's length to width ratio. I'd say the top speed will be more a function of what engines the aircraft will be using. Seems like VCE engine is intended and all three are intended to be VCEs so not that 2 turbofans plus 1 ramjet or combined cycle theory. This could potentially make mach 3 with more optimal adaption to low - high altitude and low - high speed. It won't be like sticking three WS-10 or WS-15 into it like the prototypes and LRIP versions will probably be using.

While we don't know what the intended engines are for this "fighter". It's certainly taking a new approach to air combat. Taking sensors to next level with unprecedented available power and volume for sensors previously available on fighters. Combining that with speed which no AEWC, AWACS, EW, Signals and C4ISR platform has. Combining that with payload no stealth fighter has. Combining that with all aspect stealth that has only been available to subsonic recon UAVs and stealth bombers so far. This will be featuring later generation stealth materials and shaping.

The B-2, B-21, H-2 don't fly anywhere near as fast.

The F-22, J-20, F/J-35s don't carry anywhere near its payload, its power production or the volume of space available for next generation sensors and accompanying hardware.

The E-3, KJ-xyz platforms don't have anywhere near its stealth, speed and operating ceiling.

This thing is attempting to combine fighter, interceptor, strike aircraft and heavy electronics plus sensor platforms all into one flexible package that's shaped like a UFO.

Even without mach 3 top speed, it needs at least a mach 2 top speed to keep up with PLAAF 4.5 and 5th gens.

Without ramjet-like abilities turbofans do not work at mach 3. SR71 uses an engine that can operate in ramjet mode and Mig25 uses a ramming semi-turbojet engine. You can expect a top speed of mach 2.8 if there is active cooling, or mach 2.5 without active cooling to avoid the heat barrier. On the other hand mach 2 supercruise should be pretty easy even without vce.

 

[Tomboy]

There is also no way this thing will fly at 100,000 feet and no top speed isn't a function of what engines your plane is using; there are many aircraft that could go physically faster but is limited by the airframe's heat tolerance. 100,000 feet is literally higher 15,000 feet higher than what SR-71 could fly at sustainably and even then, SR-71 could barely sustain that altitude with its pseudo-turboramjet and low payload capacity. Even at 85,000 feet, SR-71's maximum cruising altitude it still heats up like crazy to over 300 degrees Celsius there's no way J-36 can survive that without irreversibly damaging its stealth coating. Flying at 100,000 feet is also ridiculous cause it requires your pilot to wear heavy pressure suits to survive not to mention ejecting at Mach 3 at 100,000 feet is basically a coin toss. Realistically J-36 might have a high operating ceiling compared to normal fighters perhaps at 60,000 feet plus, a top speed of around Mach 2 with a fast supercruise speed of M 1.6-1.8 and active skin cooling to minimise IR signature. Anyone claiming J-36 will be a M3 aircraft that could fly at 30km altitude is basically kidding themselves or fanboys with no engineering background.

 

[ougoah]

Without ramjet-like abilities turbofans do not work at mach 3. SR71 uses an engine that can operate in ramjet mode and Mig25 uses a ramming semi-turbojet engine. You can expect a top speed of mach 2.8 if there is active cooling, or mach 2.5 without active cooling to avoid the heat barrier. On the other hand mach 2 supercruise should be pretty easy even without vce.

I thought VCE could cover that mach 2.5 - 3 range.

I doubt the intended engines are going to be a pseudo turbine based combined cycle a la SR-71's J58. They hinted VCE pretty officially. If VCE doesn't cover that transition to turbojet territory, then mach 3 becomes doubtful. I'm not an expert on engines or aerodynamics though... are we so sure no VCE is able to achieve mach 3?

 

[qwerty3173]

I thought VCE could cover that mach 2.5 - 3 range.

I doubt the intended engines are going to be a pseudo turbine based combined cycle a la SR-71's J58. They hinted VCE pretty officially. If VCE doesn't cover that transition to turbojet territory, then mach 3 becomes doubtful. I'm not an expert on engines or aerodynamics though... are we so sure no VCE is able to achieve mach 3?

You got it wrong, even turbojets don't work at mach 3. The sole reason that mig25 don't have its engines melt is that it is designed as a fanned ramjet.

 

[ougoah]

There is also no way this thing will fly at 100,000 feet and no top speed isn't a function of what engines your plane is using; there are many aircraft that could go physically faster but is limited by the airframe's heat tolerance. 100,000 feet is literally higher 15,000 feet higher than what SR-71 could fly at sustainably and even then, SR-71 could barely sustain that altitude with its pseudo-turboramjet and low payload capacity. Even at 85,000 feet, SR-71's maximum cruising altitude it still heats up like crazy to over 300 degrees Celsius there's no way J-36 can survive that without irreversibly damaging its stealth coating. Flying at 100,000 feet is also ridiculous cause it requires your pilot to wear heavy pressure suits to survive not to mention ejecting at Mach 3 at 100,000 feet is basically a coin toss. Realistically J-36 might have a high operating ceiling compared to normal fighters perhaps at 60,000 feet plus, a top speed of around Mach 2 with a fast supercruise speed of M 1.6-1.8 and active skin cooling to minimise IR signature. Anyone claiming J-36 will be a M3 aircraft that could fly at 30km altitude is basically kidding themselves or fanboys with no engineering background.

Yes the claim of 30,000m ceiling is much more doubtful to me than mach 3.

Pilots would need pressurised flight suits. Materials for next generation stealth coatings could be far more resistant to creep and other temperature induced degradation. It's just far easier to achieve higher speeds with that thinner atmosphere if it's equipped with the right engines for this purpose. My thoughts were that VCE takes care of the transitions for both speed and altitude. Essentially a turbofan and turbojet achieved through varying compression ratio. Since turbojets can achieve mach 3.

 

[ougoah]

You got it wrong, even turbojets don't work at mach 3. The sole reason that mig25 don't have its engines melt is that it is designed as a fanned ramjet.

Right okay. Thought turbojets can reach mach 3. Wasn't aware of the intricacies of the Tumansky engines. Just knew they were basically ruined with every mach 3 flight. I assumed this was more due to the available tech back in the 1970s.

I guess this is why there were the speculation on ramjet or some combined cycle being third, central engine. Since reputable sources have since claimed that all three engines are intended to be VCEs, we can rule out mach 3.

 

[Tomboy]

Yes the claim of 30,000m ceiling is much more doubtful to me than mach 3.

Pilots would need pressurised flight suits. Materials for next generation stealth coatings could be far more resistant to creep and other temperature induced degradation. It's just far easier to achieve higher speeds with that thinner atmosphere if it's equipped with the right engines for this purpose. My thoughts were that VCE takes care of the transitions for both speed and altitude. Essentially a turbofan and turbojet achieved through varying compression ratio. Since turbojets can achieve mach 3.

Theoretically speaking I did remember seeing a paper on VCE and TBCC put together but from the looks of it, it's purely research at this point. Maybe 7th gen jets could use this technology if high speed and/or near space performance is required and they made major breakthrough in IR stealth technology. But right now it's too early for to think about it IMO, we barely have 6th gen working

 

[ougoah]

On a side note then, the idea of a super fast, near hypersonic, air to air "fighter" has merit. It would basically form a perfect trifecta of air supremacy on the shooting side.

You have the J-36 central piece - EW, AWACS, C4IRS, Signals, magazine depth, all aspect stealth, keeps up with 4.5 and 5th gen fighters in speed. Still flies high, fast and far. NOT a dogfighter.

J-50 - bit more of a traditional "fighter", improving on the 5th gen with greater all aspect stealth and generally upgrading software, systems, computing and integration... and engines. Newer and more modern everything, designed from the ground up to accept the tech of the 2020s instead of the 1990s in Raptor's case and 2000s in F-35, J-20's case. Can dogfight and do the near pointless hollywood bit turning around mountain ranges to strike some $5K truck but why be an idiot?

Then a near space, > mach 3 platform for dropping those hypersonic glide, > 1,000km air to air missiles being tested at the moment. Would never even get close to WVR.

Tied all together with CCAs and various UAVs.

The J-36 doesn't look like the air launching platform for the thousand km HGV AAMs. It won't be some subsonic giant H-6 or H-20 doing this either.

Edit to add that the thousand km ranged AAMs are just concept expansion of existing HGV tech. By no means are they proven to be feasible AAMs. Even without this long ranged weapon, a circa mach 4, near space aircraft firing PL-17 replacements does the job for next generation's hard kill, aerial A2AD. This generation's equivalent is represented by the J-16 J-20 combo with PL-16 and PL-17. It needs to be supported by striking regional military bases and the naval A2AD is a critical part of the kill chain. Next generation's should be more independent and serve as a redundancy. Soft kill side is probably more effective and secretive I would imagine. We almost never hear about PLA's cyber and EW programs.

 

[qwerty3173]

On a side note then, the idea of a super fast, near hypersonic, air to air "fighter" has merit. It would basically form a perfect trifecta of air supremacy on the shooting side.

You have the J-36 central piece - EW, AWACS, C4IRS, Signals, magazine depth, all aspect stealth, keeps up with 4.5 and 5th gen fighters in speed. Still flies high, fast and far. NOT a dogfighter.

J-50 - bit more of a traditional "fighter", improving on the 5th gen with greater all aspect stealth and generally upgrading software, systems, computing and integration. Newer and more modern everything, designed from the ground up to accept the tech of the 2020s instead of the 1990s in Raptor's case and 2000s in F-35, J-20's case. Can dogfight but why be an idiot?

Then a near space, > mach 3 platform for dropping those hypersonic glide, > 1,000km air to air missiles being tested at the moment. Would never even get close to WVR.

Tied all together with CCAs and various UAVs.

The J-36 doesn't look like the air launching platform for the thousand km HGV AAMs. It won't be some subsonic giant H-6 or H-20 doing this either.

Personally i'm skeptical about hgv aams. A ramjet-rocket staged aam should be able to reach 1000km range without all the fuss.