All Things Stealth

[KV7]

2 hours ago, Stuart Galbraith said:

Are they going with a suppressed engine nozzle, or is that how the final design is going to look?

Do you mean a duct like on F-22 ? It would be hard to do with 3d thrust vectoring and require a major air-frame change.

An interesting question is how much they want to use J-20 as the cutting edge test bed, I think at some point they will be doing most risky developments via another project. J-20A I think is going to go into quite serious volume production, this is seemingly indicated by the scaling back of production plans for older models.

[Stuart Galbraith]

8 minutes ago, KV7 said:

Do you mean a duct like on F-22 ? It would be hard to do with 3d thrust vectoring and require a major air-frame change.

An interesting question is how much they want to use J-20 as the cutting edge test bed, I think at some point they will be doing most risky developments via another project. J-20A I think is going to go into quite serious volume production, this is seemingly indicated by the scaling back of production plans for older models.

Well, both the F22 and the YF23 managed that. I find it surprising the Chinese didnt get access to that information.

Of course perhaps they just want a usable fighter now, and intend to do all the crazy shit later with a Mk2. Though I think it strange they think they are going to win a fight in the merge with thrust vectoring, when they have no IR suppression. Its just odd. This is something like 30 year old thinking here.

[KV7]

13 minutes ago, Stuart Galbraith said:

Well, both the F22 and the YF23 managed that. I find it surprising the Chinese didnt get access to that information.

Of course perhaps they just want a usable fighter now, and intend to do all the crazy shit later with a Mk2. Though I think it strange they think they are going to win a fight in the merge with thrust vectoring, when they have no IR suppression. Its just odd. This is something like 30 year old thinking here.

I do not think thrust vectoring is evidence of some strong desire for dogfighting ability, it is more a case of it being not very hard to do, and it also offering advantages in evasion of missiles that have lost much of their energy. I think it perhaps also can lower RCS a bit under maneuvre from the frontal aspect as you can use less control surface deflection.

[Stuart Galbraith]

I think if you are depending on thrust vectoring to get out the way of a missile, you put yourself in a place you probably shouldn't.

[KV7]

4 hours ago, Stuart Galbraith said:

I think if you are depending on thrust vectoring to get out the way of a missile, you put yourself in a place you probably shouldn't.

Sure, but the case for it depends on a cost benefit analysis, they probably reason that they get quite a bit of advantage for not much additional costs.

If you think that agility is just not such a big deal, then even still TV can make sense as you can get a given agility with less use of features that are costly in terms of RCS or top speed, such a huge wings with low loading etc.

[Stuart Galbraith]

I think if you have supercruise and stealth, then yes, I dont think supermanoeuvrablity  is necessary.

Its worth remembering, Typhoon was designed to be able to plug in thrust vectoring, but they never felt it was necessary. With supercruise, a stealthy leading edge, and with missiles like Meteor hung on it, its kind of hard to justify such investment for a short range fight that is going to happen once in a blue moon.

Im not saying dogfighting is obsolete. Im suggesting its becoming less and less likely. If you are going to guns, it probably means you ran out of missiles and its time to poke off home.

Edited September 10 by Stuart Galbraith

[KV7]

26 minutes ago, Stuart Galbraith said:

I think if you have supercruise and stealth, then yes, I dont think supermanoeuvrablity  is necessary.

Its worth remembering, Typhoon was designed to be able to plug in thrust vectoring, but they never felt it was necessary. With supercruise, a stealthy leading edge, and with missiles like Meteor hung on it, its kind of hard to justify such investment for a short range fight that is going to happen once in a blue moon.

Im not saying dogfighting is obsolete. Im suggesting its becoming less and less likely. If you are going to guns, it probably means you ran out of missiles and its time to poke off home.

I think this is plausible, but Typhoon was designed to be, and is, very agile, TVC likely didn't happen because of development etc. expenses.

The other consideration is that for China it is also a case of "unlocking the tech tree", if they develop an expertise in TVC it is another option for many future platforms and variants, it becomes e.g easier to add it to FC-31 etc. with some WS-19 variant, or some future unmanned platforms etc.

[Josh]

5 hours ago, Stuart Galbraith said:

I think if you are depending on thrust vectoring to get out the way of a missile, you put yourself in a place you probably shouldn't.

It’s pretty inevitable that some of ones fighters get shot at. I think the usefulness of thrust vectoring is debatable given the extra weight and complexity involved, but it will become increasingly difficult to avoid fire all together with modern detection systems and datalinks. If nothing else the IR signal produced by launching your missiles is a road flare to mark your position, and if two platforms witness it and can share data in real time, then they know your exact position for a brief moment and can focus sensor coverage/radar energy there. I think this why the USAF wants to offload the missile launch event to a CCA.

[Stuart Galbraith]

Well if your ir signature is going to flare from just firing missiles, imagine what kind of signature a non suppressed exhaust is going to give off.

Besides, it's academic, it's not a choice between super manoeuvreabilty and suppressed IR, you can do both. For whatever reason, they aren't.

[DB]

I think that cost scuppered completion of the thrust vectoring and increased thrust EJ200 variants.

It's now an old engine, so Tempest (FCAS/GCAP/whatever) will get a shiny new thing, although EJ200s are pencilled in for the prototype.

TVC gives more benefits than just high agility - it allows for thrust axis trimming which can be very useful for optimising cruise performance. For dogfighting agility, perhaps the need has been reduced by LOAL missiles with extreme agility and also improved LOBL performance due to better seeker geometries, too.

Still useful to be able to point the nose wherever you want for a guns engagement, I suppose, but if you're actually gunfighting, you're doing it wrong.

[Stuart Galbraith]

That is a fair point about supercruise I must concede.

 

[KV7]

11 hours ago, Stuart Galbraith said:

Well, both the F22 and the YF23 managed that. I find it surprising the Chinese didnt get access to that information.

Of course perhaps they just want a usable fighter now, and intend to do all the crazy shit later with a Mk2. Though I think it strange they think they are going to win a fight in the merge with thrust vectoring, when they have no IR suppression. Its just odd. This is something like 30 year old thinking here.

I missed something earlier, F-22 only has 2d thrust vectoring. In theory you could use an F-22 style nozzle with vertical vanes or similar to get 3d.

[KV7]

3 hours ago, Stuart Galbraith said:

Well if your ir signature is going to flare from just firing missiles, imagine what kind of signature a non suppressed exhaust is going to give off.

Besides, it's academic, it's not a choice between super manoeuvreabilty and suppressed IR, you can do both. For whatever reason, they aren't.

Can a cowling make much difference to the frontal aspect returns when the nozzles are already obscured by the fuselage ?

You might be right that it would be desirable.

[Stuart Galbraith]

8 hours ago, KV7 said:

I missed something earlier, F-22 only has 2d thrust vectoring. In theory you could use an F-22 style nozzle with vertical vanes or similar to get 3d.

Then I stand corrected, though tbh, its manoeuvrable enough to not need lateral deflection.

7 hours ago, KV7 said:

Can a cowling make much difference to the frontal aspect returns when the nozzles are already obscured by the fuselage ?

You might be right that it would be desirable.

Probably not, but if you are at all offset from the target, you are going to get a signature. That is if your IR sensors are that sensitive, and im not aware they are yet.

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