Issues with the JAS 39 Gripen flight model

So do you think that it is reasonable that the Gripen has double the specific excess power of any plane in the game?

They aren’t moved continuously during flight as far as i understand the paper:

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as in they have the deflection ability but where tested statically to generally compare to other changes for future tests to be made with dynamic canards.
at least as far as i understand it.

the section you provided screenshots of is the design section and not a physical build. they continue to talk about computer tested models with actuated canards but as far as i can tell the later tests were done statically at specific deflections of the canards.

(and please start using the spoiler function. its getting hard to scroll and find stuff in the thread to point back to).

Edit:
they also state in the conclusions:

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Lift is still positive. The only way it would be negative is either the center of lift being behind the center of mass or the momentum created by engine thrust times sin(AoA) being high enough to do enough to prevent the aircraft from spinning.

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The article you posted is talking about supersonic performance. We are talking about subsonic performance.

What makes you think the Specific Excess Power figures we experience in game are even remotely accurate?

If you read the article it talks about all performance, it just specifically mentions a large reduction in supersonic trim drag in that conclusion I screencapped.

I’ve never once said that the Specific Excess Power of the Gripen in game is accurate.

Is the FM of the Gripen in game wrong? Yes. That has always been the case, as @MiG_23M points out it is modelled as statically stable. It should be modelled as having relaxed static stability, and until that happens it is never going to be “accurate”. With regards to the SEP, it is probably due to simplifications in the physics engine of War Thunder. They try to recreate set parameters in game as best they can, but as an imperfect simulation not everything will match up until they do improve it.

Is the canard delta planform inherently superior for RSS fighter aircraft when the primary consideration is manoeuvrability? With our current understanding of aerodynamics, yes.

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Then the article says basically the same thing that every other article says about canards, LEX, and strakes.

This seems to be the counter-argument you are trying to to form without explicitly stating it.

I am also trying to keep the thread on topic instead of hung up on idiosyncratic interpretations of a whole bunch of studies that more or less conclude the same thing.

There is a reason that conventional tail designs with LEX continue to be viable and why planes like F-16 and F-15 are still winning contracts and there is a reason that the only buyer for Gripen E has been Brazil.

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Responding to this because you added it as I was replying.

  1. Claiming that close coupled canard or long coupled canard is an inherently superior configuration for BFM is a huge stretch. Is it a good configuration? Yes. Are there other good configurations? Also yes.

  2. Having a good wing planform or good low speed maneuverability doesn’t make up for lack of thrust. There is a reason the Rafael and Eurofighters also have similar thrust to weight ratio compared to their American counterparts.

  3. High off-boresight missiles has changed the envelope of what can be considered good BFM performance. Newer planes are going to focus more on winning the fight at slower speeds because they need to min-radius the range at which they can be targeted by HOBS missiles.

So now you’re a mind reader too?

Doesn’t seem like much of a stretch when the most manoeuvrable aircraft in the world use it.

What does that have to do with my claim? I was talking about the planform, not the Gripen specifically.

That’s the exact opposite of what we are seeing with sixth generation fighter design.The future of air combat is not low-speed floating-leaf manoeuvres firing HOBS missiles. Unless you disagree with every single military developing a sixth gen fighter.

It was a nice discussion whilst it lasted, but you’ve proven multiple times you can’t keep things civil or without bringing in pilot/procurement anecdotes which have nothing to do with the hard facts of how the Gripen performs. I’m out.

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It not like the US military complex is massive or something

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He’s straw-manning again. Kind of comical considering you provided a straw-manning wiki article right after the quote he straw manned.

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Also if FeetPics want to get into it the Eurofighter is miles above anything in the game right now

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If you go literally 10 seconds before the time stamp you indicated he says “at transonic and supersonic speeds” before saying what he says, which is something I had said before.

As long as the centre of pressure (which is the point were we can apply the sum of all the forces of all the tiny (infinitesimal) part of a wing can be applied to calculate momentums) is in front of the centre of gravity if you are doing a force on the same side as that centre of pressure it needs to be in the opposite direction to keep a plane from spinning, while it needs to be in the same direction when it is applied on the other side.
Idk if it is not clear because my English sucks, if you think I can make it more clear by doing a small diagram and setting up the second cardinal equation tell me

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Both of you are most likely to never find a definite answer on what configuration is the best, it all depends on what you want to achieve and how developed a determined solution is.
A certain wing may work better or worse with or without slats and with or without canards, and small differences on the profile shape can create improvements without altering configuration.

In a general sense the gripen is a more modern design than the F-16 or the MiG-29, and I would expect it to have a better Cd/Cl polar than those planes, but the current values are really extremely high, and especially the polar curve itself behaves in a very unrealistic way

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This is what got the last thread closed. Let’s stop this type of discourse entirely, it isn’t useful to the discussion.

Can we instead focus on how the aircraft currently performs in relation to the canard types in the studies? It’s irrelevant how canard vs LERX work, Saab themselves stated their original conventional tailed design had better energy maneuverability performance over the delta canard but couldn’t meet some of their other criteria. The size and weight necessary to accomplish their requirements could best be done with a delta canard type.

To claim the delta canard is superior is irrelevant, what we need to look at is why the Gripen has such high excess power now and from there we can either justify it or demonstrate a discrepancy.

No. This is why I asked the question.
There has not been a single Gripen flight model change that I haven’t seen you oppose in the past.

The F-22 does not use it.
The Su-35 also does not use it.

This thread is specifically about the Gripen and thrust loading is an important performance metric when it comes to energy maneuverability.

I was speaking strictly in the context of BFM.

Procurement actually does have a good deal with how the Gripen performs.

Pretty much every time it’s put up against the other Euro-canard fighters or against F-35 or even late model F-16…it loses out because it is just overall a less capable aircraft.

It’s a small plane and with that comes some of the problems of being a small plane. Even Gripen E is facing some of the same problems that F-16 is where they are having to increase the engine power of the plane and the size of the wing to maintain performance and increase capabilities. But in doing, SAAB has made it cost too much for it to be an appealing alternative to the F-35

If the thing was half the wonderwaffe that Gripen fans claim it to be…it would have experienced more commerical success.

The closest thing we have to an EM diagram for the Gripen is going to be the calculated EM diagram for the Lavi.

Gripen in-game SEP values are effectively double what the Lavi would have under the same conditions.

it almost like if that same thing was on the EFT it wouldn’t improve performance that much

The Mirage 2000 doesn’t use it.
Neither does the F-16.
Neither does the F-18.

whole video is also very good, and it confirms what I stated before, that in order to be doing positive lift canards would have to be on a stable aircraft, and while positive lift is good the canards rotating that way would compromise the flow on the main wing.
Instead in an unstable configuration the canards do not have to provide positive lift (he then doesn’t explain further, but what they actually do is rotate in the opposite direction on what they would do if aircraft was stable, and by doing so they improve the airflow on the main wing and create a little negative lift that helps keeping the aircraft under control)

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which are all older designs and perform worse

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