Chinese Engine Development

If the PLA can get the J-20 operational early with Al-31Fs, that's a big plus. Simply having 5th generation capability in the air, no matter how underpowered, is a dramatic game changer that would radically shift the regional balance of power. While the aircraft may not be sufficiently maneuverable in the air or have strong supercruise in its initial incarnations, it would still give you a stealth air superiority capability that would allow you to gain a radical BVR advantage over the 4th generation opponents that are common in the area.

The best part with early J-20s operating Al-31Fs is the ambiguity. Say, when J-20s operating 117S (it's possible) or WS-15s come up, the opponent can't tell at a glance whether you're operating with high-thrust engines or low-thrust engines. Since they're now likely to mis-estimate your capabilities, they're now liable to make mistakes that you can exploit, either overestimating your Al-31F craft or underestimating your WS-15s, leading to higher casualties.

I would call it a success if the Japanese get forced to the negotiating table because J-20s with air superiority functions show up in 2016 and they won't receive delivery of F-35s until 2018.

Inst said:

I would call it a success if the Japanese get forced to the negotiating table because J-20s with air superiority functions show up in 2016 and they won't receive delivery of F-35s until 2018.

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I refuse to believe you are actually being serious here.

Inst said:

The best part with early J-20s operating Al-31Fs is the ambiguity. Say, when J-20s operating 117S (it's possible) or WS-15s come up, the opponent can't tell at a glance whether you're operating with high-thrust engines or low-thrust engines. Since they're now likely to mis-estimate your capabilities, they're now liable to make mistakes that you can exploit, either overestimating your Al-31F craft or underestimating your WS-15s, leading to higher casualties.

I would call it a success if the Japanese get forced to the negotiating table because J-20s with air superiority functions show up in 2016 and they won't receive delivery of F-35s until 2018.

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Are you really serious about what you have mentioned? Really?

When the J-20 flies first with AL-31Fs and lets say it was underpowered... people wouldn't care a look, then when J-20 flies with 117 or WS-15 in later batch, it will take the opponent by surprise? If there are an impending battle between two countries, wouldn't both countries already more or less know the capability of each other? Especially when it came to singular weapons like an aircraft.

And you even come up with the Japanese being forced to the negotiating table because of one fifth generation fighter. I have not seen the Chinese being forced to negotiating table by the Japanese even in the 1980s when the Chinese are pretty weak all round back then. One single fifth generation fighter would force the Japanese to the negotiation table and if that didn't happen, according to your statement (unless I misread again) means it was not successful? Are you serious?

Don't know whether it is posted or not.

Axis-symmetric tandem combustion chambers design of SCRAMJET engine.

No, the point is not that your opponent won't expect J-20s with WS-15s or 117S engines, but that they won't be able to tell which aircraft is which. Imagine you have two aircraft, J-20 with AL-31 and J-20A with WS-15s. In performance respects, these two planes are quite dissimilar, but in visual respects these two planes are more or less identical, requiring a close look at the exhaust nozzle to figure out which is which.

If say, an AEW&C detects J-20 headed towards its escorting squadron with the flight characteristics of low-speed J-20, it can't tell whether these are actual low-speed J-20 or they're high-speed J-20A headed towards them. If you send a large force to counter the less effective J-20s, you've gone for a decoy and once your defenders have been deployed, high-speed J-20As would deploy to kill the AEW&C and its weakened escort force. If you send a small force to counter the more effective J-20As, you've likely sent inadequate forces, you've fallen for a trap, and your engaging force is likely to be wiped out.

Guess right and you win a prize, namely, that you live to fly another day. Guess wrong and you lose at least a few planes in an unfavorable trade-off and at worst you lose your AEW&C craft.

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Regarding screwing with the Japanese, the point is that having J-20s deployed while the Japanese don't have F-35s available further tilts the regional balance of power towards China. In the event of a conflict, the Japanese would be totally reliant on F-22s, more importantly, American F-22s, deployed from Kadena AFB to counter J-20s, even J-20s with T/W ratios comparable to F-35s. That weakens their negotiating position between 2016 and 2018, when they begin receiving delivery of F-35s.

If you're talking about a single J-20 forcing the Japanese to the negotiating table, you're making a straw-man argument and I said nothing of the sort. I am saying that having a significant advantage in the balance of power can be used as a tool of coercion and force your opponent to do things they don't want to do.

For instance, in the 1970s, the Chinese agreed to waive off their right to reparations from the Japanese over the Second Sino-Japanese War. That was probably prudent, since reparations would have unnecessarily antagonized the Japanese in an age where China needed all the FDI it could get from any possible source, and because China at that point was a relatively weak power, being weak economically, diplomatically, and politically.

But if say, China had its current military and economic force, or if China has the political and economic force we'd expect in the 2020s, would China have made the same decision to waive off its right to reparations? Sure, if the power ratios were appropriate to 2020, any economic reparations from Japan would not really be critical to Chinese development, but it would have significant political symbolism and essentially take away the right of the Japanese ultra-nationalist right to deny their atrocities during their Imperial period.

Inst said:

No, the point is not that your opponent won't expect J-20s with WS-15s or 117S engines, but that they won't be able to tell which aircraft is which. Imagine you have two aircraft, J-20 with AL-31 and J-20A with WS-15s. In performance respects, these two planes are quite dissimilar, but in visual respects these two planes are more or less identical, requiring a close look at the exhaust nozzle to figure out which is which.

If say, an AEW&C detects J-20 headed towards its escorting squadron with the flight characteristics of low-speed J-20, it can't tell whether these are actual low-speed J-20 or they're high-speed J-20A headed towards them. If you send a large force to counter the less effective J-20s, you've gone for a decoy and once your defenders have been deployed, high-speed J-20As would deploy to kill the AEW&C and its weakened escort force. If you send a small force to counter the more effective J-20As, you've likely sent inadequate forces, you've fallen for a trap, and your engaging force is likely to be wiped out.

Guess right and you win a prize, namely, that you live to fly another day. Guess wrong and you lose at least a few planes in an unfavorable trade-off and at worst you lose your AEW&C craft.

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Regarding screwing with the Japanese, the point is that having J-20s deployed while the Japanese don't have F-35s available further tilts the regional balance of power towards China. In the event of a conflict, the Japanese would be totally reliant on F-22s, more importantly, American F-22s, deployed from Kadena AFB to counter J-20s, even J-20s with T/W ratios comparable to F-35s. That weakens their negotiating position between 2016 and 2018, when they begin receiving delivery of F-35s.

If you're talking about a single J-20 forcing the Japanese to the negotiating table, you're making a straw-man argument and I said nothing of the sort. I am saying that having a significant advantage in the balance of power can be used as a tool of coercion and force your opponent to do things they don't want to do.

For instance, in the 1970s, the Chinese agreed to waive off their right to reparations from the Japanese over the Second Sino-Japanese War. That was probably prudent, since reparations would have unnecessarily antagonized the Japanese in an age where China needed all the FDI it could get from any possible source, and because China at that point was a relatively weak power, being weak economically, diplomatically, and politically.

But if say, China had its current military and economic force, or if China has the political and economic force we'd expect in the 2020s, would China have made the same decision to waive off its right to reparations? Sure, if the power ratios were appropriate to 2020, any economic reparations from Japan would not really be critical to Chinese development, but it would have significant political symbolism and essentially take away the right of the Japanese ultra-nationalist right to deny their atrocities during their Imperial period.

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There should be noticeable differences to the aft portion of the aircraft given the different engines as well as clear differences in performance, so I think they'd be able to tell. Furthermore, it's likely that once the WS-15 is introduced, J-20s with AL-31s will probably be refitted with them.

Your geopolitical scenario is unrealistic. If the J-20's earlier deployment really did hit home that China was militarizing faster, the more natural response for a country like Japan wouldn't be to fold diplomatically but to invest more in their own military to try to reverse the power balance.

Inst said:

No, the point is not that your opponent won't expect J-20s with WS-15s or 117S engines, but that they won't be able to tell which aircraft is which. Imagine you have two aircraft, J-20 with AL-31 and J-20A with WS-15s. In performance respects, these two planes are quite dissimilar, but in visual respects these two planes are more or less identical, requiring a close look at the exhaust nozzle to figure out which is which.

If say, an AEW&C detects J-20 headed towards its escorting squadron with the flight characteristics of low-speed J-20, it can't tell whether these are actual low-speed J-20 or they're high-speed J-20A headed towards them. If you send a large force to counter the less effective J-20s, you've gone for a decoy and once your defenders have been deployed, high-speed J-20As would deploy to kill the AEW&C and its weakened escort force. If you send a small force to counter the more effective J-20As, you've likely sent inadequate forces, you've fallen for a trap, and your engaging force is likely to be wiped out.

Guess right and you win a prize, namely, that you live to fly another day. Guess wrong and you lose at least a few planes in an unfavorable trade-off and at worst you lose your AEW&C craft.

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Wouldn't it be easier to just send unmanned decoy planes the same size as the J-20, rather than the J-20 and J-20A and let the enemy guess which is which? You didn't see the US doing that, putting less powerful engines in their F-22 and send two different version of the F-22 around right?

No matter if the J-20 armed with AL-31 or a J-20 armed with WS-15/ 117S, it is still very very expensive and plainly not feasible to just throw the 'lower' version around.

Inst said:

Regarding screwing with the Japanese, the point is that having J-20s deployed while the Japanese don't have F-35s available further tilts the regional balance of power towards China. In the event of a conflict, the Japanese would be totally reliant on F-22s, more importantly, American F-22s, deployed from Kadena AFB to counter J-20s, even J-20s with T/W ratios comparable to F-35s. That weakens their negotiating position between 2016 and 2018, when they begin receiving delivery of F-35s.

If you're talking about a single J-20 forcing the Japanese to the negotiating table, you're making a straw-man argument and I said nothing of the sort. I am saying that having a significant advantage in the balance of power can be used as a tool of coercion and force your opponent to do things they don't want to do.

For instance, in the 1970s, the Chinese agreed to waive off their right to reparations from the Japanese over the Second Sino-Japanese War. That was probably prudent, since reparations would have unnecessarily antagonized the Japanese in an age where China needed all the FDI it could get from any possible source, and because China at that point was a relatively weak power, being weak economically, diplomatically, and politically.

But if say, China had its current military and economic force, or if China has the political and economic force we'd expect in the 2020s, would China have made the same decision to waive off its right to reparations? Sure, if the power ratios were appropriate to 2020, any economic reparations from Japan would not really be critical to Chinese development, but it would have significant political symbolism and essentially take away the right of the Japanese ultra-nationalist right to deny their atrocities during their Imperial period.

Click to expand...

No I am not making a strawman argument. I suggest you look back at your own words. You mentioned these words,

I would call it a success if the Japanese get forced to the negotiating table because J-20s with air superiority functions show up in 2016 and they won't receive delivery of F-35s until 2018

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So I am pointing out, to force the Japanese onto the negotiating table because of a singular weapon is not possible. It is quite laughable actually. And if this is the case, shouldn't the Chinese actually start forcing the Japanese to the table already? The Chinese had J-11/J-11B/J-16 (soon), an aircraft carrier with some J-15, J-10/ J-10A and soon J-10B... what does the Japanese has now? Old model F-15 and F-2 and F-4.

But does the Japanese yield now? Hardly. So even if the Chinese has the J-20 and the Japanese didn't have the F-35, it is still the same.

latenlazy: I think the issue is that you're talking about visual differences in the aft portion of the J-20s. You'd have to somehow manage to detect that at long range, and if the aircraft is flying headed towards you you're not going to see the aft portion.

Regarding performance, a WS-15 equipped aircraft could try to mask its engine performance as that of an Al-31. As far as upgrading all J-20s to WS-15 engines, that would take time and would take older aircraft out of operation. As time progresses, of course all operating J-20s would either be built with WS-15 or retrofitted to WS-15, but there would be quite some time where decoy tactics would be either necessary or effective.

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About Japan, if you assume the Japanese will militarize, the Japanese will simply beg the United States and Lockmart to expedite delivery of their F-35s, likely to 2017 instead of 2018. If Lockmart does so, it'll put strains in the rest of F-35 delivery, if Lockmart doesn't do so, it'll put strains in US-Japan relations. Either way, mission accomplished.

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Rhino, my point of view with regards to decoy tactics using WS-15s in combination with Al-31s is that it's more of a side or fringe benefit. The main benefit of sending up Al-31-equipped J-20s is that you get the aircraft airborne early. Even if you have a very poor thrust-to-weight ratio, something like .75, that's still roughly comparable to that on the F-35C with full load, and you still have a fifth generation airframe that is drastically more effective than its fourth generation peers.

I don't actually disagree that dollar for dollar a J-20 equipped with a WS-15 is more effective than a J-20 equipped with an Al-31, but if you rush the J-20s into production with Al-31, it will take a significant amount of time, especially considering that China is likely to encounter difficulties with mass producing WS-15 engines at least early on, to switch the fleet over to WS-15s. And that's when decoy tactics offer the greatest advantages.

Besides that, Al-31-equipped J-20s are liable to encourage opponents to underestimate the J-20's capabilities, lining them up for a rude surprise when the WS-15s are properly equipped.

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So I am pointing out, to force the Japanese onto the negotiating table because of a singular weapon is not possible. It is quite laughable actually. And if this is the case, shouldn't the Chinese actually start forcing the Japanese to the table already? The Chinese had J-11/J-11B/J-16 (soon), an aircraft carrier with some J-15, J-10/ J-10A and soon J-10B... what does the Japanese has now? Old model F-15 and F-2 and F-4.

But does the Japanese yield now? Hardly. So even if the Chinese has the J-20 and the Japanese didn't have the F-35, it is still the same.

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Well, remember August 9th and the atomic bombing of Nagasaki, that's a case where a single weapon achieved drastic effects.

As far as JASDF vs PLAAF disparities, the PLA has never been qualitatively superior to the Japanese, and quantitatively, the PLA cannot focus all its forces to the ECS region as it needs to maintain assets against the InAF to the southwest. The first Su-27 sold to the Chinese were equipped with downgraded BVR missiles, and it took until 2002 before the PL-12 hit operation status, around the same time the first AAM-4s reached operational status. If you compare the J-11s to the F-15Js, they have a rough parity, since in the Chinese case the J-11s were running pulse doppler radars until recently, and are only rumored, but not confirmed, to operate AESA.

The Chinese having fifth generation capability before the Japanese do would be a significant psychological shock to the Japanese state.

Inst said:

latenlazy: I think the issue is that you're talking about visual differences in the aft portion of the J-20s. You'd have to somehow manage to detect that at long range, and if the aircraft is flying headed towards you you're not going to see the aft portion.

Regarding performance, a WS-15 equipped aircraft could try to mask its engine performance as that of an Al-31. As far as upgrading all J-20s to WS-15 engines, that would take time and would take older aircraft out of operation. As time progresses, of course all operating J-20s would either be built with WS-15 or retrofitted to WS-15, but there would be quite some time where decoy tactics would be either necessary or effective.

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Probably not a worthwhile trade off, since approaching your bogie at a lower speed and altitude impacts your kinematic performance and reduces your survivability. It matters little if you have great engines if you're coming into combat with less energy than your opponent.

Depending on how they implement the different engines, refitting may not take that much time. It's not even likely that they would need their full force on the ready while they refit the first block. Nor is it likely that they would prefer to send the less powerful variant to conduct an intercept. An adversary would probably just engage under the assumption that they are facing the better variant.

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About Japan, if you assume the Japanese will militarize, the Japanese will simply beg the United States and Lockmart to expedite delivery of their F-35s, likely to 2017 instead of 2018. If Lockmart does so, it'll put strains in the rest of F-35 delivery, if Lockmart doesn't do so, it'll put strains in US-Japan relations. Either way, mission accomplished.

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I would not underestimate Japan's willingness to handle their security alone. And I think you misunderstood my point. You're suggesting that Japan would fold because they would have to wait a few years to match capabilities. I'm saying they would simply buy time while they begin to accelerate their own force building. Japan wouldn't be begging the US for anything if the US couldn't reasonably deliver. They would simply accelerate their own indigenous fighter program and let the dispute continue for a decade or two while they attempt to change the power balance. (This should sound familiar, because that's what you're asserting China did).

Inst said:

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Rhino, my point of view with regards to decoy tactics using WS-15s in combination with Al-31s is that it's more of a side or fringe benefit. The main benefit of sending up Al-31-equipped J-20s is that you get the aircraft airborne early. Even if you have a very poor thrust-to-weight ratio, something like .75, that's still roughly comparable to that on the F-35C with full load, and you still have a fifth generation airframe that is drastically more effective than its fourth generation peers.

I don't actually disagree that dollar for dollar a J-20 equipped with a WS-15 is more effective than a J-20 equipped with an Al-31, but if you rush the J-20s into production with Al-31, it will take a significant amount of time, especially considering that China is likely to encounter difficulties with mass producing WS-15 engines at least early on, to switch the fleet over to WS-15s. And that's when decoy tactics offer the greatest advantages.

Besides that, Al-31-equipped J-20s are liable to encourage opponents to underestimate the J-20's capabilities, lining them up for a rude surprise when the WS-15s are properly equipped.

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The thing is... when it came to using J-20 or J-11 or J-10, or whatever in close combat. It means the two countries are already at war. Do you seriously think that whoever is going to fight the Chinese doesn't actually know the basic of what is the capability of the Chinese's weaponry like the much announced systems such as the J-20 and what engines the J-20 is using? I seriously doubt that. There will not be any added advantages. The only thing about the J-20 being rushed into service was to give the Chinese's airforce an edge over their adversary or at least close the gap.

Inst said:

Well, remember August 9th and the atomic bombing of Nagasaki, that's a case where a single weapon achieved drastic effects.

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Then the Chinese should focus more on their weapon of mass destruction rather than a single fighter type. Nuclear and conventional system is different.

Inst said:

As far as JASDF vs PLAAF disparities, the PLA has never been qualitatively superior to the Japanese, and quantitatively, the PLA cannot focus all its forces to the ECS region as it needs to maintain assets against the InAF to the southwest. The first Su-27 sold to the Chinese were equipped with downgraded BVR missiles, and it took until 2002 before the PL-12 hit operation status, around the same time the first AAM-4s reached operational status. If you compare the J-11s to the F-15Js, they have a rough parity, since in the Chinese case the J-11s were running pulse doppler radars until recently, and are only rumored, but not confirmed, to operate AESA.

The Chinese having fifth generation capability before the Japanese do would be a significant psychological shock to the Japanese state.

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And the Japanese can focus all their aircraft against the Chinese? They still have to face North Korea, Russia and South Korea and Russia and South Korea both had argument with the Japanese on land issues. The amount of aircraft - both J-11 and J-10 around the area is roughly the same or more than the Japanese. Not to mentioned the Chinese had Japan's entire soil under coverage of their missiles. But I do not want to go there. All I am saying is... whether the Chinese had the J-20 or not, make no difference. It will close the gap or be slightly stronger than the Japanese, but that is about all. As to whether that would be enough to force the Japanese to the negotiating table... my point is... it will not.

It can be use as one of the factor, but not a deciding factor.