J-35A fighter (PLAAF) + FC-31

[Aval]

I would still point out the weaknesses in the rearward stealth profile given the two conspicuous nozzles, and probably higher heat signature due to lower bypass ratio and probably shallower IWB, when compared to the benchmark.

If the benchmark is the F-35, then its asymmetrically mitigated by its "bumpy" underside.

But aeronautical engineering isn't about slapping a bunch of different designs and subsystems together. The magnitude of the many small, not generally visible differences (like angles on edges, the quality of RAM etc.) have an unknown effect that can significantly alter the final result.

This is generally why I believe comparing the exact "stealthiness" of different designs isn't fruitful unless you have access to classified data.

 

[TMA1]

Stealthflanker did interesting work modelling the j20. Was one of the first steps in ameliorating the fudd lore that one would see repeated for the past decade or so. Similar issues of ignorance persist. For example data on a certain experimental j9 type was what finally made me realize the j10 is a wholly home brewed design and not based on the Israeli lavi, etc...

 

[Alfa_Particle]

I would still point out the weaknesses in the rearward stealth profile given the two conspicuous nozzles, and probably higher heat signature due to lower bypass ratio and probably shallower IWB, when compared to the benchmark.

Lol no. You might have a point for the J-35 but not the A with actual LOAN nozzles. Two smaller exhaust streams have a larger surface area compared to a giant singular one, and way easier to dissipate heat, so that's also a silly notion. BPR is only one small part of the equation, and even then the WS-19 seems to have a BPR of ~0.5 vs the F135's 0.57. That's absolutely negligible in terms of IR signature reduction compared to, for example, active film cooling that the nozzles provide.

IWB is simply a matter of different compromises and emphasis. A shallower IWB in exchange for a much wider one that can accommodate 6 PL-16s with no modifications unlike the Sidekick. Not like it's trying to haul 2k lbs bombs anyways.

 

[Gloire_bb]

(...) shallower IWB, when compared to the benchmark.

It isn't weakness per se, it's role.
F-35 the joint strike fighter (aka, light bomber) is the way it is due to combination of a hard length limit and 2x2000lb requirement. Which was accommodated at the expense of other metrics.
There's no hard prohibition against 2000lbs in J-35 arrangement either(see KF-21 blk.3), it's just, whether do you have it as a requirement, or you don't.

 

[Blitzo]

Rheal is perma-banned for flamebait on arrival sigh

 

[Deino]

@siegecrossbow @Deino @Blitzo Cleanup on aisle 2 please.

Thanks for the report and indeed it looks like one of the usual suspects, however - as You may know me - that’s why I like to try - at least initially - to give new members a) a second chance, provided they calm down, and b) simply for the love of debate, to ask a bit more about the basis for such "strong" statements!

So, to be specific: ... EDIT: Okay, Blitzo has already solved the problem...

Don't worry—if your next reply doesn't very quickly show that you're genuinely interested in the topic and the discussion, I'll take care of that for you!

Too many shallow minded folks here. I will delete my account.

Don't worry—if your next reply doesn't quickly show that you are genuinely interested in the topic and the honest exchange of ideas fased on FACTS, I’ll take care of that for you!

 

[douglaxd]

If the benchmark is the F-35, then its asymmetrically mitigated by its "bumpy" underside.

But aeronautical engineering isn't about slapping a bunch of different designs and subsystems together. The magnitude of the many small, not generally visible differences (like angles on edges, the quality of RAM etc.) have an unknown effect that can significantly alter the final result.

This is generally why I believe comparing the exact "stealthiness" of different designs isn't fruitful unless you have access to classified data.

I have no idea why this conception exists: that the "bumpy" underside of the F-35 was some unsolvable tradeoff as if it wasn't developed, modeled and refined with 2000s methods. The same thing as RF "Experts" eyeballing the J-20/J-35/SU-57's radar signature.

 

[Aval]

I have no idea why this conception exists: that the "bumpy" underside of the F-35 was some unsolvable tradeoff as if it wasn't developed, modeled and refined with 2000s methods. The same thing as RF "Experts" eyeballing the J-20/J-35/SU-57's radar signature.

In general, the public does not have access to clear data on stealth performance for any design characteristic, let alone a full platform.

As such, the best we can do is infer. For example, DSIs are said to be stealthier than Carets, and we see some support in this with most of the newer 5th-gen designs using DSI (F-22 vs F-35/J-20/J-35). In the same vein, we can tentatively infer that the F-35's "bumpy" underside is not as optimal to stealth as the cleaner surface on most other stealth designs (F-22/J-20/J-35).

But I agree that this is not far from, if actually is just, "eyeballing" a radar signature. If we must do comparisons between platforms, then its more practical to focus on aspects which are clearer. For example, the number of engines and how that relates to costs, reliability targets and power generation.

 

[douglaxd]

In general, the public does not have access to clear data on stealth performance for any design characteristic, let alone a full platform.

As such, the best we can do is infer. For example, DSIs are said to be stealthier than Carets, and we see some support in this with most of the newer 5th-gen designs using DSI (F-22 vs F-35/J-20/J-35). In the same vein, we can tentatively infer that the F-35's "bumpy" underside is not as optimal to stealth as the cleaner surface on most other stealth designs (F-22/J-20/J-35).

But I agree that this is not far from, if actually is just, "eyeballing" a radar signature. If we must do comparisons between platforms, then its more practical to focus on aspects which are clearer. For example, the number of engines and how that relates to costs, reliability targets and power generation.

So, doing very basic comparisons is what we should be doing (two versus one engine, DSI vs Caret intake, rectangular vs LOAN, etc.), but you are somehow able to get a rough idea of the impact on radar signature of a very complex OML of a very complex stealth aircraft designed with very thorough computation and modeling? I wish I had a superpower like that.

 

[valysre]

So, doing very basic comparisons is what we should be doing (two versus one engine, DSI vs Caret intake, rectangular vs LOAN, etc.), but you are somehow able to get a rough idea of the impact on radar signature of a very complex OML of a very complex stealth aircraft designed with very thorough computation and modeling? I wish I had a superpower like that.

I don't think Lockheed wanted to make the underside bumpy. It quite likely emerged in response to other things, perhaps for aerodynamic purposes or to accommodate internal structures. X-35 certainly did not have it, and neither did the earliest airframes following the X-35. I think it's not until AF-02 that the bumps begin to emerge.