J-20 5th Gen Fighter Thread VI

[Blitzo]

I suspect that we haven’t seen mass production of J-20s because they were waiting for the domestic stopgag to be ready. The bad news is that the WS-15 might be an even longer wait.

I'm not sure about that,

1: we don't know what the production rate of J-20s have been thus far, so we don't know if "mass production" had begun. There's also the fact that J-20 production has only really been occurring in the last few years anyway so it would be normal if initial production rate is lower than eventual full production rate
2: we don't really know when we expect WS-15 to be ready, currently most projections go to 2025ish. Between now and then that is still 6 years of ramping up J-20 airframe production which could amount to quite a number of J-20s where the decision to use Al-31 or WS-10 needs to be made if a domestic WS-10 is ready.

 

[latenlazy]

I'm not sure about that,

1: we don't know what the production rate of J-20s have been thus far, so we don't know if "mass production" had begun. There's also the fact that J-20 production has only really been occurring in the last few years anyway so it would be normal if initial production rate is lower than eventual full production rate
2: we don't really know when we expect WS-15 to be ready, currently most projections go to 2025ish. Between now and then that is still 6 years of ramping up J-20 airframe production which could amount to quite a number of J-20s where the decision to use Al-31 or WS-10 needs to be made if a domestic WS-10 is ready.

Heck if the production rate is 24 a year even two or three years worth of engines would make the testing worthwhile.

 

[Brumby]

The last time WS-10 had serious issues was around 2009. Since then around two to three hundred combat aircraft have entered service with Taihangs without major problems. WS-10 equipped J-11Bs not only emerged victorious from several Golden Helmets exercises but also were involved in high profile interceptions of foreign aircraft in the South and East China Seas. If they didn't trust the WS-10, they wouldn't have allowed the J-10B TVC to perform at Zhuhai last November.

I am unable to reconcile the conversations that are going on. It seems that the WS-10 is a better engine for the J-20 than the Russian one and the WS-10 has been around for at least 10 years. What is stopping the adoption of it from day 1 for the J-20 or even now? .

 

[latenlazy]

I am unable to reconcile the conversations that are going on. It seems that the WS-10 is a better engine for the J-20 than the Russian one and the WS-10 has been around for at least 10 years. What is stopping the adoption of it from day 1 for the J-20 or even now? .

Production rates are a chokepoint.

 

[Blitzo]

Production rates are a chokepoint.

Well yes, but also maybe no.

We don't know whether the Al-31s used on J-20s were more capable than the WS-10s available to China at the time. (I.e. specific variants of Al-31 and/or WS-10 available at the time)

We also don't know if the WS-10s J-20 has been testing with were more capable than the WS-10s used on the likes of J-11B, J-16 etc.

A lot of unknowns that could potentially have greatly shifted the choice to initially go for Al-31s for J-20s.

 

[Equation]

Production rates are a chokepoint.

I surmise that there may be some breakthrough with the WS-10 line, even if it's that they have developed a new variant with greater thrust at the expense of lower lifespan. I supposed they will always give the best engine to J-20, so if the WS-10 variants used on the J-11B were superior to the AL-31 variants used on the J-20 and there weren't enough of them, they would fit the J-11Bs with the Al-31s and J-20 engines with the WS-10s. This is not up to Shenyang; this is a national decision to make the best 5th gen fighter possible. So it looks to me that the Russian AL-31 variant (FM2?) with 145kN were the best engine for the J-20 at the time but this new WS-10 is now better. That's what would make the most sense.

 

[Brumby]

which could amount to quite a number of J-20s where the decision to use Al-31 or WS-10 needs to be made if a domestic WS-10 is ready.

Initially I thought it was maybe a typo on your part referring to "WS-10" instead of "WS-15". Seige was saying earlier that WS-10 had been around a long time and that there are plenty of Flankers flying with it but in your statement it seems that the WS-10 may not be ready. It is why I am having trouble reconciling the different statements. .

Well yes, but also maybe no.

We don't know whether the Al-31s used on J-20s were more capable than the WS-10s available to China at the time. (I.e. specific variants of Al-31 and/or WS-10 available at the time)

We also don't know if the WS-10s J-20 has been testing with were more capable than the WS-10s used on the likes of J-11B, J-16 etc.

A lot of unknowns that could potentially have greatly shifted the choice to initially go for Al-31s for J-20s.

Regardless of history and the reasons for the decisions, is there now a shift to the WS-10 engine for the J-20?

 

[siegecrossbow]

I am unable to reconcile the conversations that are going on. It seems that the WS-10 is a better engine for the J-20 than the Russian one and the WS-10 has been around for at least 10 years. What is stopping the adoption of it from day 1 for the J-20 or even now? .

There are multiple iterations of WS-10. Early versions had slightly lower thrust than even AL-31FNs and took longer to spool up but later mature variants like the WS-10B are capable of much higher thrust and have improved significantly in terms of reliability. I don't think that the version ready on J-11B, for instance, is good enough even as a stop-gag for the J-20, but that's just my conjecture.

Regardless of history and the reasons for the decisions, is there now a shift to the WS-10 engine for the J-20?

Based on wall climber accounts, yes. I presume that they've seen production birds (ones in yellow-primer but has two-digit temporary serials instead of 4 digit serials for test demonstrators) sporting the WS-10 engines. We won't know for sure until we confirm them with official images since there has been a crackdown on wall-climbing for some time.

 

[vesicles]

I am unable to reconcile the conversations that are going on. It seems that the WS-10 is a better engine for the J-20 than the Russian one and the WS-10 has been around for at least 10 years. What is stopping the adoption of it from day 1 for the J-20 or even now? .

The WS-10 wasn’t considered a mature engine until the last few years although it has been around for a long while. The J-20 must’ve been designed and its design finalized long before the WS-10 was deemed a success by the PLAAF.

The PLA was faced with the options of either changing the engines of the J-20 then, or continuing with their original design. And they decided to stick with their original decision. With extremely mature engines (AL-31’s), they had one less thing to worry about when working on a clean design like the J-20.

Now they have worked out all the kinks on the J-20 and the WS-10 has also become a mature engine, they now move forward with putting their domestic engines on the J-20.

In my own opinion, this very methodical and pragmatic way of doing things has allowed them to focus their resources on one achievable and small goal after another. Although it may look slow and boring at first, this is in fact how they can move up so fast: small steps and fast pace. This is in stark contrast of how the Indians do things, I.e. keep moving the goal posts and always unnecessarily complicating their already complex projects.

 

[Brumby]

I would agree with the preliminary assessment that if indeed the J-20 has transitioned to a WS-10 type engine then it is probably a variant with sufficient thrust improvement to warrant a change.