F-35A versus Saab Grippen NG

The F-35 compared with other modern jets.
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madrat

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Unread post12 May 2019, 22:07

South Africa has a racism problem, purging the whites in the military that held a significant fraction of their intellectual base trained in upkeep. To double down they withdrew budgetary funding to drive out white participation. South Africa won their independence from the rule of law. Now they are one of those countries that is quite a garbage hole.
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loke

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Unread post12 May 2019, 22:20

kimjongnumbaun wrote: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.


Those issues are due to South Africa having internal problems, not due to Gripen... the other countries using Gripen do not have similar reliability issues.

I already told you about Hungary and how much they are doing with only 14 a/c, approx half of what SA got. How do you explain this ? Also Thailand, Sweden, Czechia seem to be doing quite well with their Gripen. Which leaves South Africa as the odd one out.

From Thailand:

Maintenance is performed at the base, with the aircraft kept inside a hangar overnight due to the humid environment. “We have had very high availability of the aircraft – some days they have 100% available,” says Mann. Referring to the delivery of QRA cover, he adds: “They haven’t missed a single day since going live in 2011.”
In a notable demonstration of its high fleet availability, Thailand had all 11 of its Gripens operationally available throughout the duration of the Royal Australian Air Force-led Pitch Black exercise, staged from late July through mid-August 2018. Bangkok sent ­almost 200 personnel and six jets to Australia for four weeks, while simultaneously ensuring the continuous provision of air-defence cover from Surat Thani.
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ricnunes

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Unread post12 May 2019, 22:42

marsavian wrote:Ricnunes, what you have described is not planform alignment while I did with the Gripen canard/wing pairing. This is a description of it on Wiki :-


So lets see,
two or three pages ago you "accused" me of using wikipedia but now you're the one using it. :wink:

Anyway, planform alignment goes well beyond the concept that is mentioned on that wikipedia link which you referred to.

But even thou and using you concept of planform alignment above which I admit is the most well known concept and if we extrapolate to the frontal aspect of the aircraft (Basically the most important aspect for RCS reduction) and continuing to use the F-22 as an example, we have:

Image

Using the images that I previously posted and applying the same concept, we have for the F-35:
Image

Now for the J-20 we have:
Image

And now for your "super" Gripen we have:
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So, which one exhibits BY FAR the worse planform alignment on the frontal aspect?? (which again is the one that matters the most)
No need to answer, this is a rhetoric question.

Finally, lets look at the Super Hornet:
Image

And even the planform alignment of the Super Hornet, is far, far superior to the one on the Gripen!

So and again, claiming that the Gripen has a lower RCS than the Super Hornet (or the J-20) is at best "far, far fetched" and ultimately a huge BS...
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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ricnunes

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Unread post12 May 2019, 22:51

loke wrote:
Unlike other 4.5th gen aircraft like the Super Hornet, Rafale and Typhoon the Gripen E doesn't seem to have any particular or noticeable RCS reduction measures (which can be well observed on the Super Hornet and Rafale for instance).
I remember (again if my memory isn't failing me) to have read somewhere that Saab even acknowledge this in the past (with all the rant that Stealth would't be needed, 6th gen - active stealth, bla bla bla).
What I'm also saying is that the Gripen E relative low RCS seems to come from the most part if not entirely from the aircraft's small size. This means that the Gripen E RCS (clean) should be above 1 square meter while for the example the Super Hornet and Rafale RCS while clean is below 1 square meter.


Anyway, if you now change your story I am fine with that ;)


Why would I change my story??
I stand by what I said and I won't change anything from what I said before, namely on the part which you put on bold.

I've said that the Super Hornet should be among the 4.5 gen fighter aircraft the one with the lowest RCS due to all the reasons which I previously mentioned, including those on my last post.
However I also admit that the Rafale also has a number of considerable RCS reduction measures, namely a considerable number of sawtooth surfaces (which are associated with all aircraft with LO and VLO features) like for example on the inlets/intakes - this could be seen on a few very good photos which were shared by swiss, if I'm not mistaken.
The Gripen E (like its -C predecessor) doesn't seem to have nothing like this at all!
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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marsavian

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Unread post13 May 2019, 00:18

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

Image
Last edited by marsavian on 13 May 2019, 03:11, edited 5 times in total.
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kimjongnumbaun

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Unread post13 May 2019, 00:53

loke wrote:
kimjongnumbaun wrote: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.


Those issues are due to South Africa having internal problems, not due to Gripen... the other countries using Gripen do not have similar reliability issues.
[/quote]

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!
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marsavian

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Unread post13 May 2019, 03:32

XanderCrews wrote: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.
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optimist

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Unread post13 May 2019, 05:27

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.
Aussie fanboy
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charlielima223

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Unread post13 May 2019, 06:24

marsavian wrote: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.


okay I'll beat this dead horse some more...

Ricnunes pointed out some very good observations about shaping and planform alignment. Shaping and angles is indeed a huge factor for greatly reducing RCS.



You also bring the intake designs and engine face... well lets take a look.

Rafale and Typhoon uses deep curves to obscure the face of the engine.
Image

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Now look at the Super Hornet's inlet design...
Image
The intake is slightly curved and as others have mentioned the inlet has RAM coating. Also note the shaping and angle design of the intake itself.

F-22 and F-35 take these design elements to the extreme and completely hide the engine face from any and all angles. The only way to see it is if you physical crawl into the aircraft.
Internally the F-22 uses a complex S shaped inlet design
Image
note how the Super Hornet is attempting to emulate the F-22's inlet but to a much lesser and simpler degree.

F-35 uses the same techniques as the F-22 but instead uses a Y shaped inlet design and uses the DSI design
Image
Image

Unfortunately I could not find any high resolution up close pictures of the Gripens inlet design. However some reasonable conclusions can be drawn from observation and publicly available information.

The Gripen has a relatively small engine and its is buried deep into the airframe. However when looking at pictures of its construction to cut away pictures, the Gripen appears (for the most part) to have a fairly straight line inlet design.
Image
Image
Image

Based purely on observation and comparison, to me the Gripen doesn't have much in the way of LO design characteristics .
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loke

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Unread post13 May 2019, 08:14

ricnunes wrote:
loke wrote:
Unlike other 4.5th gen aircraft like the Super Hornet, Rafale and Typhoon the Gripen E doesn't seem to have any particular or noticeable RCS reduction measures (which can be well observed on the Super Hornet and Rafale for instance).
I remember (again if my memory isn't failing me) to have read somewhere that Saab even acknowledge this in the past (with all the rant that Stealth would't be needed, 6th gen - active stealth, bla bla bla).
What I'm also saying is that the Gripen E relative low RCS seems to come from the most part if not entirely from the aircraft's small size. This means that the Gripen E RCS (clean) should be above 1 square meter while for the example the Super Hornet and Rafale RCS while clean is below 1 square meter.


Anyway, if you now change your story I am fine with that ;)


Why would I change my story??
I stand by what I said and I won't change anything from what I said before, namely on the part which you put on bold.

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 -- are you really an expert in this field? Or are you just guessing? I am not pretending to be an expert, thus I have no problems to say that I honestly do not know what the RCS of a clean Gripen E might be. I do not even know whether it is above or below 1 m2. It seems then that you are an expert in this field since you know the answer -- just by looking at internet photos.

Impressive.
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loke

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Unread post13 May 2019, 08:19

charlielima223 wrote:Unfortunately I could not find any high resolution up close pictures of the Gripens inlet design. However some reasonable conclusions can be drawn from observation and publicly available information.

The Gripen has a relatively small engine and its is buried deep into the airframe. However when looking at pictures of its construction to cut away pictures, the Gripen appears (for the most part) to have a fairly straight line inlet design.

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".
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mixelflick

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Unread post13 May 2019, 14:42

Seems like a silly argument.

If SAAB is claiming the Gripen is "stealthy" well, that's going to show up rather fast in any evaluation. Which means if it's not, it isn't going to win many contracts - which it hasn't.

Hmmm...
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loke

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Unread post13 May 2019, 15:45

mixelflick wrote:Seems like a silly argument.

If SAAB is claiming the Gripen is "stealthy" well, that's going to show up rather fast in any evaluation. Which means if it's not, it isn't going to win many contracts - which it hasn't.

Hmmm...


As we all know Gripen is not "stealthy" (if stealthy means VLO).

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.

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.

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

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. 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.

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.
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marsavian

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Unread post13 May 2019, 23:29

loke wrote:
charlielima223 wrote:Unfortunately I could not find any high resolution up close pictures of the Gripens inlet design. However some reasonable conclusions can be drawn from observation and publicly available information.

The Gripen has a relatively small engine and its is buried deep into the airframe. However when looking at pictures of its construction to cut away pictures, the Gripen appears (for the most part) to have a fairly straight line inlet design.

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".


Indeed, similar to the F-35 Y-duct

Image

Image
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kimjongnumbaun

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Unread post14 May 2019, 03:42

Let's just ignore those massive RCS returning intakes and canards.
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