F-35A versus Saab Gripen NG

[charlielima223]

Indeed, similar to the F-35 Y-duct

I don't quite follow that train of thought. The Gripen engine is buried deep inside the airframe, as you say. It is also centered in the airframe (seen from the front) whereas the intakes are positioned on the outside of the airframe. To me it seems that there must be some curves involved to allow the air enter the engine which is positioned in the "centre".

It could have a Y shaped inlet but it wouldn't be as extreme as the inlet design of the F-35.


Looking at the width of the fuselage and drawing a line to the engine itself... the engine face (I'm assuming on my part) would probably be more visible then other examples noted. Then there is the aspect of shaping and angles aforementioned, the Gripen doesn't appear to adhere much to LO reduction methods that could be visibly accounted for.

Remember South Korea's KAI KFX? If they build it and it looks very much like the models they displayed, at least we can say that that aircraft has LO features.

[optimist]

I too would give a plus, for the intake to be a potential LO feature. Subject to what the radar return is. The external shape isn't LO. I haven't seen pics looking down it, it may be a low return there. Is it enough to out weight the other features on the plane, that are not LO? I don't think so.

This Z has been mentioned again. I can see the protrusion on the miniature 'what if' I can't see it on the production craft. I have looked at the latest one.

[hornetfinn]

I think we are talking about pretty modest differences between different advanced Western 4th gen fighters. Gripen E very likely has lower RCS than Gripen C due to AESA and some modifications here and there. I think it would be interesting to compare say Dassault Rafale, EF Typhoon, Super Hornet and even F-16 with full Have Glass makeover.

I'd bet that SH has the lowest RCS overall due to fixed and canted AESA and some pretty significant LO treatments and solutions. USA also has done huge amount of work with stealth technology and likely has more possibilities (technologies and products) to lower signatures of fighter aircraft.

If I had to guess, then likely Dassault Rafale has second lowest RCS, but has fixed but not canted AESA which is not optimal from RCS PoV. Otherwise it has pretty good features, although single tail increases RCS considerably from sides like in all single-tailed fighters.

Difficult to say about Gripen E and EF Typhoon. Currently Typhoon probably has the largest RCS simply due to large mechanical dish. It does have some good things like recessed MRAAMs though.

Anyway we are very likely talking about pretty small differences and minor advantages or disadvantages.

Of course F-35 is totally different and has RCS that is probably three orders of magnitude lower than in any of Eurocanards or Super Hornet.

[swiss]

I think we are talking about pretty modest differences between different advanced Western 4th gen fighters. Gripen E very likely has lower RCS than Gripen C due to AESA and some modifications here and there. I think it would be interesting to compare say Dassault Rafale, EF Typhoon, Super Hornet and even F-16 with full Have Glass makeover.

I'd bet that SH has the lowest RCS overall due to fixed and canted AESA and some pretty significant LO treatments and solutions. USA also has done huge amount of work with stealth technology and likely has more possibilities (technologies and products) to lower signatures of fighter aircraft.

If I had to guess, then likely Dassault Rafale has second lowest RCS, but has fixed but not canted AESA which is not optimal from RCS PoV. Otherwise it has pretty good features, although single tail increases RCS considerably from sides like in all single-tailed fighters.

Difficult to say about Gripen E and EF Typhoon. Currently Typhoon probably has the largest RCS simply due to large mechanical dish. It does have some good things like recessed MRAAMs though.

Anyway we are very likely talking about pretty small differences and minor advantages or disadvantages.

Of course F-35 is totally different and has RCS that is probably three orders of magnitude lower than in any of Eurocanards or Super Hornet.

I fully agree with your opinion Hornetfinn. I assume SH, Rafale are in the 0.1-0.5 m2 range. Gripen-E 0.5-1m2 and EF roughly 1m2. And it seems EF with AESA will have the same frontal RCS. Because the dish of the Captor-e is not fixed.

[ricnunes]

Ricnunes, I used wiki as well as a LMT video to illustrate to you what is regarded as the most common description of planform alignment and which the Gripen canard/wing adheres to which you denied.

No, I didn't outright denied the planform alignment concept that you posted.
Like you could read on my last post, I admitted that the planform alignment concept which you mentioned is probably the or among the most well known concepts regarding Stealth/LO/VLO shaping.

There's even that well know B-2 diagram image over the web, showing the concept that you described.

Regardless thanks for your illustrations which does show what you claim on the frontal aspect with that particular common definition, not just the slants but the angling away.

You're welcome.

Do you happen to have a source for your one point of origin stealth claim for wings/tails/fins because I am genuinely interested.

No, I don't have a source explicitly saying that.

However I remember to have read something on that regard years ago but sorry I can't remember where and as such I don't have a source where I read something along this lines.

Anyway, this in the end is more a conclusion of mine based on the following facts:
1- Direct observation. All LO and VLO aircraft seem to have these features so I would say there's at least a strong possibility that these are paramount for a LO/VLO shape.
2- Together with the above, platform alignment together with surfaces coming from a single point of origin allows the creation of those "Z shapes" which allows for some RCS reduction (this can be read on the article posted by Energa, if I'm not mistaken in this same thread).
3- The concept of symmetry and how important it is for LO/VLO shaping. Well if you look carefully the platform alignment draws heavily on the concept of symmetry itself.
This means that if you have an aircraft from which all its surfaces have one point of origin than this aircraft will most likely have a much better symmetry - and therefore more likely to have LO/VLO features - compared to an aircraft which don't have such feature.
Here's an article showing how symmetry is very important to LO/VLO shaping:
https://www.sciencedirect.com/science/a ... 611730050X


The bottom line is that while initially there might be a logic to the "you cannon eyeball RCS" (which loke seems so eager to repeat so often) the truth is that in order to have a good perception of how good are the LO/VLO properties of an aircraft - specially in comparative terms - this requires a great deal of observation (i.e. "eyeballing") together will an also great deal of research on the subject (which again "eyeballing" is also part of).
This is because - and I believe you'll agree with me - we simply won't have anyone from LM or any other company which builds LO/VLO aircraft coming here explaining us how these aircraft shaping is made or should be made.

We may have access to some LO/VLO concepts like the general planform concept which you previously mentioned but we definitely won't have access to the whole picture. So if we look at the most features that actual stealth aircraft actually have we can observe that the Gripen (even the -E) don't have most of these same features.

One further point, the inlets were redesigned for the Gripen E to better align as well as retaining the advantage of the C in not showing its engine face at all so it does not have to resort to blockers or RAM there.

Well, I'm not saying that there aren't improvements from the -E compared to the -C in terms of RCS reduction.
But they certainly seem minimal just like a slightly more parallel inlet which still pale in comparison with all the other aircraft's inlets that we observed (included the Super Hornet) and such I strongly believe that any RCS reduction that the -E may have over the -C will still be minimal/small.

As to whether in its entirety the frontal RCS of the Super Hornet is superior, it's still not clear at least in my mind although all aspect round there is no doubt really. Bizarrely enough those SH slanted pylons although bad from a drag pov might actually work from a stealth pov .

Well, I'm more than convinced that the SH frontal RCS is lower (better) than the Gripen -E, this due to all that was discussed above.
Regarding the SH's RCS reductions, these were made/centered on basically the frontal aspect alone.
That I know of, there wasn't any considerable if any measures to reduce the SH RCS on any other aspect besides the front such as the sides. What I mean with this is that any RCS reduction measures that both SH and Gripen E have are centered on the frontal aspect and this is the aspect that we have to take into account when comparing both aircraft in terms of RCS.

Well, regarding the SH slanted pylons I haven't thought of that before to be honest with you.
I remember to have read that this was in great part due to reducing vibrations on the weapons mounted on those pylons or something along those lines.
But it's also possible that you could be right about the slanted pylons on the SH and how they could somehow reduce the RCS penalty but again this is something that I don't know of.

[ricnunes]

I find it strange that a person that seems to not be an expert can conclude that the Gripen E RCS should be above 1 square meter.

Yet, at the same time you don't find strange that a company (Saab) that basically lied with all its teeth regarding its Gripen E stats (weight, range, etc...) claims a RCS value of 0.1 square meters for the same aircraft (Gripen E) an aircraft of which doesn't have the vast majority of the features that all other LO/VLO aircraft have...

No, I'm not an expert on these subjects but at least I'm not a liar - Can you say the same about Saab?

For me its clear that the 0.1 square meter RCS for the Gripen E claim has the exact same credibility as the initial weight and range stats for the same Gripen E - which is total BS!

Anyway, if your counter-argumentation resumes to pointing out that I'm not an expert, well I guess that all I can say is:
- I rest my case!

[ricnunes]

I think we are talking about pretty modest differences between different advanced Western 4th gen fighters. Gripen E very likely has lower RCS than Gripen C due to AESA and some modifications here and there. I think it would be interesting to compare say Dassault Rafale, EF Typhoon, Super Hornet and even F-16 with full Have Glass makeover.

I'd bet that SH has the lowest RCS overall due to fixed and canted AESA and some pretty significant LO treatments and solutions. USA also has done huge amount of work with stealth technology and likely has more possibilities (technologies and products) to lower signatures of fighter aircraft.

If I had to guess, then likely Dassault Rafale has second lowest RCS, but has fixed but not canted AESA which is not optimal from RCS PoV. Otherwise it has pretty good features, although single tail increases RCS considerably from sides like in all single-tailed fighters.

Difficult to say about Gripen E and EF Typhoon. Currently Typhoon probably has the largest RCS simply due to large mechanical dish. It does have some good things like recessed MRAAMs though.

Anyway we are very likely talking about pretty small differences and minor advantages or disadvantages.

Of course F-35 is totally different and has RCS that is probably three orders of magnitude lower than in any of Eurocanards or Super Hornet.

I fully agree with your opinion Hornetfinn. I assume SH, Rafale are in the 0.1-0.5 m2 range. Gripen-E 0.5-1m2 and EF roughly 1m2. And it seems EF with AESA will have the same frontal RCS. Because the dish of the Captor-e is not fixed.

I also fully agree with Hornetfinn's assessment.

And I also tend to agree with your assessment swiss although I still think that the Super Hornet should have a better/lower RCS than the Rafale although I agree that the Rafale also has some interesting and relatively extensive built-in features to reduce RCS (which again the Gripen doesn't seem to have) and as such in alignment with what Hornetfinn said. Anyway, the RCS diference between the SH and the Rafale shouldn't be big (also in alignment with what Hornetfinn said).

Also due to what was previously mentioned I have my doubts that the Gripen E RCS is lower than 1 square meter.
For example I remember to have read on an aviation magazine (years ago) a value of 0.9 square meters as being the RCS for the Super Hornet, although I would say that this was probably the value for a Block I (one) Super Hornet (this also due to the fact that magazine article was already old).

[playloud]

IIRC, the claim was 0.1 m2 for the Gripen A, with improvements in both the C and E.

[marsavian]

Ricnunes, I think the SH's all round RCS reductions are better than you think seeing all the work done around the body and don't forget the slanted tails already being an advantage there. If as I suspect the slanted pylons help as well then the Growler is a good stealth base for an EW aircraft that must carry pods.

Back to Gripen, yes the inlets are head on but the insides curve inwards so there is no flat plate at the bottom and they look too narrow to see the engine face from any angle IMO. As to what was done further on Gripen E Saab said this which I quoted earlier "Effort will also be expended on reducing the aircraft's radar cross section (RCS) through modifications to the air-intakes and wing leading edge and the use of composite materials and new surface coatings. RCS reduction measures are not new to the Gripen programme." so it's a bit more than a paint job with more composite structures like the wings.

As for Saab's range estimates have they been officially debunked anywhere or is it just the Swiss report on the Gripen C ?

[loke]

I find it strange that a person that seems to not be an expert can conclude that the Gripen E RCS should be above 1 square meter.

Yet, at the same time you don't find strange that a company (Saab) that basically lied with all its teeth regarding its Gripen E stats (weight, range, etc...) claims a RCS value of 0.1 square meters for the same aircraft (Gripen E) an aircraft of which doesn't have the vast majority of the features that all other LO/VLO aircraft have...

Where did Saab claim an RCS value of 0.1 square meters? I have seen that some people on the internet make such claims, but I cannot recall having seen Saab make such a claim. Can you please provide the link to this claim from Saab.

[magitsu]

Is it guaranteed that non-fixed radar produces less frontal RCS? I remember reading something that suggested such a mechanism it requires would produce higher RCS (apart from having an extra mechanism in the plane that can fail).

[swiss]

I also fully agree with Hornetfinn's assessment.

And I also tend to agree with your assessment swiss although I still think that the Super Hornet should have a better/lower RCS than the Rafale although I agree that the Rafale also has some interesting and relatively extensive built-in features to reduce RCS (which again the Gripen doesn't seem to have) and as such in alignment with what Hornetfinn said. Anyway, the RCS diference between the SH and the Rafale shouldn't be big (also in alignment with what Hornetfinn said).

Yes, it seems very likely the SH has the lowest RCS of all 4.5. Fighters.

Also due to what was previously mentioned I have my doubts that the Gripen E RCS is lower than 1 square meter.
For example I remember to have read on an aviation magazine (years ago) a value of 0.9 square meters as being the RCS for the Super Hornet, although I would say that this was probably the value for a Block I (one) Super Hornet (this also due to the fact that magazine article was already old).

Well as Horentfinn said in an older post, the Hornet C/D has a frontal RCS of several m2. The SH Bl1 has one order of magnitude lower RCS. Lets say 0.5m2. And Bl 2 is even lower thanks to the APG-79.

The YF-16 has an RCS of 1.2m2 with MSA Radar. So i would guess 1m2 or even a bit lower cold be possible for the Gripen-E thanks to the AESA and RAM.

But as Hornetfinn pointed out. We talk about small differences here.

[marsavian]

The thing is though Saab claimed a tenth RCS of F-16 for Gripen C so whatever version of F-16 you are looking at Gripen C alone has to be well under 1 sq m unless Saab is outright lying as many seem to think. Legacy Falcon has a lower RCS than legacy Hornet so on the face of it Saab are claiming the better job with their existing model.

[loke]

The thing is though Saab claimed a tenth RCS of F-16 for Gripen C so whatever version of F-16 you are looking at Gripen C alone has to be well under 1 sq m unless Saab is outright lying as many seem to think. Legacy Falcon has a lower RCS than legacy Hornet so on the face of it Saab are claiming the better job with their existing model.

AFAIK there were some F-16 versions having frontal RCS of around 5m2 -- so probably the implication of the Saab claim was 0.5m2, no less than that.

https://www.globalsecurity.org/military ... ft-rcs.htm

[XanderCrews]

I agree that the Saab marketing dept are going overboard many times, and in particular in the "early days" of selling Gripen NG as it was called at that time.

My main point was that eyeballing RCS is not really easy. Of course we all understand that Gripen E is not a VLO airframe it should not even be necessary to make that clear, since it should be clear to everybody. I am just pointing out that nobody (apart from Saab/FMV) knows what the RCS of Gripen E is. And also, that some efforts have been made to reduce the RCS.

Are we sure these efforts aren't more marketing?

Isn't it odd that the marketing team is not bringing it up as often, and in a matter of amazing coincidence everyone digging up anything official is from years and years ago?

These are coincidences, surely.

Anyway, the reason why Sweden did not bomb in Libya is not because of lack of capability but because the Swedish politicians would not allow it. If you read the stories printed at that time, it is very clear that this was the case.

Yes, i understand that.

The problem with canards is that they are constantly changing their pitch. It is impossible to predict the return from the frontal aspect, which should be the lowest RCS value.

And if you think the Gripen doesn't have reliability issues, look at South African. They can't even fly their Gripens due to maintenance problems.

But this airplane can be maintained in the worst conditions, by the most ignorant of people for barely any cost.

So what you’re saying is that an aircraft’s reliability is directly tied to the country’s ability to fund the maintenance program? Are you also saying that the Gripen isn’t free to fly and poorly trained conscripts can’t turn it around to fly in between their lunch break?

I am shocked to come to this revelation. Shocked, I tell you!

This is a revelation

Why is this airplane being sold as low RCS? Why are people convinced it has reduced RCS?
Why does this always come up? who implanted that seed?

Saab explicitly stated it first with Gripen C and then further with Gripen E, the quotes being in the last few pages. Why are some convinced ? Because it totally eliminates the major source of frontal RCS, an exposed engine fan as well as having composite wings and RAM. All very simple stuff but it gets the job done elegantly and efficiently.

No it doesn't. The engine face has always been hidden on Gripen (kudos) but the Canards are the dogs bullocks sticking out. And there is no lipstick one can put on them. Even if they are planformed to the delta wing, its been explained in here several times that theres no fixing them.

Gets the job done how? Its band-aids. Nicer band aides indeed, but band aids none the less. I'm also informed by "team gripen fanboy" that RAM is bad for maint. So now we are talking about materials improvements and thats about it. Its the same thing its always been (but bigger!) when I'm told that the Gripens size is a big part of its stealth? Hmmm

These are improvements that to me border on irrelevant.

But as shown, compared to all the LO airframes. There are basic design elements lacking, that support this view. It's a pixie dust claim.

Here here

In the past few years Saab marketing dept has reduced their emphasis on RCS reduction. Still being mentioned ocationally but not highglighted as a main feature. Clearly they have changed their messaging compared to 10 years ago.

I wonder why...

As you know Gripen did one competition in Switzerland -- we do have some info about that one because of the leaks, and because of official documents. As linked to in a previous page, RCS reduction was actually one of the technical requirements.

"Reduced" from what? and in the end it was picked based on cost. MOREOVER, and just to beat this dead horse one more time-- The Swiss Bought off on a Gripen CONCEPT. an ESTIMATE.

I'm not trying to beat a dead horse here, and I'm not trying to be difficult, but the bottom line is the Gripen E in the swiss competition was a PAPER PLANE. When Saab was shopping around the Gripen NG concept, it was (rationally so) catering the concept to whatever the customer wanted to emphasize. If the Swiss wanted that, they were going to present a Gripen NG concept that fit that.

Its not shenanigans, I'm not accusing them of lying, I'm not accusing them of chicanery. My point is that what Gripen E was going to be, was going to be based on which customer bought it. NG was a rather loose idea when it came to the details. If customer A wanted more LO, and Customer S bought it first then it was going to have more LO. If Customer B ought it, perhaps other things would be emphasized. When they presented it to the dutch, Range was emphasized.

In the document linked to above where they highlighted RCS reduction as a requirement they also emphasized that Gripen did meet all requirements.

LOL of course it did.

In addition, In the leaked pages the weakness and strenght of each fighter was highlighted. I cannot recall having seen "high RCS" being listed as a weakness of Gripen, which may seem strange if, as some seem to claim here, that RCS of Gripen is so high.

I'm not claiming its "high" I'm saying its not Low, as in not LO. So I'm saying its about the same as every other teen and eurocanard. I'd put the Rafale above it though.

How many Gripen Es flew in that swiss Competition?

We had F-18s, Rafales, Typhoons, all known commodities... I cannot recall seeing a Gripen E out there.

in particucular since that seems to have been one of the basic requirements... unless of course the RCS of Gripen is not much higher than what was required by the Swiss.

or the marketing dept wrote what they presented.

No doubt the RCS of Gripen E is not going to be very low, after all RCS reduction was not the primary design driver. Saab has demonstrated that they have tricks to reduce RCS of a canard configuration, as demonstrated by the "Z" trick. The "Z" technique seems not to have been implemented in Gripen E, but can we exclude the possibility that they do not have other tricks up their sleeve? I for sure cannot exclude that possibility; this does of course not imply that they have developed such techniques and implemented them on Gripen.

Unless somebody can point to data I think we are left with speculations regarding the RCS of Gripen E.

Heres a quick caveat, because I'm guilty of using these things interchangably. LO and RCS are not inherently the same thing. By put in an AESA radar, they reduce detection. LO is not just RCS but electronic emmisions, signals, heat, etc.

Its possible the RCS is the exact same but the LO is reduced because the engine is better shrouded to hide heat, the radar is harder to detect etc. etc. The Radar alone should improve its LO. if one could find a way to retrofit the E radar into a C, then the C's LO would be reduced.

I just remembered that, we may all resume our bickering over small detail that really don't change much as it is, and certainly matter even less when all the guns, gizmos, and gas are popped onto those wings.


I'll be completely 100 percent cynical here and say that the RCS could be absolutely worse, but things have gone too far for them to abandon the project or do a redesign.

I remember when the F-35 was going to cost like 30 million or whatever. Its now around 80 million yet we didn't abandon it. But surely its 30 million or we wouldn't be building it so it must be 30 million! Things didn't change? results havn't come up short? solution we thought might work, failed? etc etc.

I've been running the numbers and it turns out the Swedish are humans. They do indeed make mistakes and miscalcualtions and are just as capable of bluff and bluster and disaster as all the other meat Popsicles.


Lastly, Saab needs to reign in its marketers. I know the Gripen E took a long time to finally pop into the air, but for a long while there this was a PR firm with some airplanes instead of an airplane firm with some PR.

People are still confusing the two, which is bad especially as they both go by the same name. Saab the airplane company might need that name someday, so perhaps it should be handled with a little more care.

And no, I don't seperate the two. The narratives are joined, and anyone trying to say "but that was the marketing guys everyone!" give me a break. theyre one in the same and these lies weren't a guy bragging at a bar, this was official company stuff for YEARS. big meanies like myself might actually think they are one in the same when everyone says the exact same things.


The Gripen is like staring at a 1 dollar bill and convincing yourself its a 100 dollar bill. I mean if you squint just right, its got a "1" there... and the color is the same... And then you snap out of it, and realize not only is not 100 dollars, its not even 5 dollars.