JA37 FM discussion

Ever since the nerf, it hasn’t been the same, but has certainly been more realistic. I noticed something while reading however, and it’s that the AJ/AJS with the RB8A engine had issues with compressor stalling hay high AoA. However, this issue was fixed on the JA models, in the form of the RM-8B, solving the AoA stall issue.

The peacetime limiters of the JA and AJ’s limit the G-pull to 7 G’s, while it would freely take any G’s in wartime. While the JA pilots could only pull 7g’s, they also had a “tattle box” which would record the max AoA and time at that AoA in flight, if they were to go over 23.5 for 2 seconds, they would be disciplined, and if they hit 25 ever, the same fate would lie.

However this got me to think, the Viggens are more than capable of these G-pulls, and while high AoA or instantaneous turns are fast and effective; they would cause you to turn into a flying air brake. Does anyone know the Max AoA in game? Can anyone provide any more info in this subject?

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I believe compressor stall was still there, but it kicked in at a higher AOA than before for the JA37. Anyways that stuff isn’t modelled in WT

Well, yes, it still does it, but I feel like it maneuvers worse in game than in it does in real life, but its speed drop at high AoA is pretty realistic.

I’m starting to think it’s the thing that other planes are too maneuverable.

I was watching a bunch of FM threads way back and pretty much came to the conclusion that it’s not worth my time, the standard for FM accuracy is way lower than people give WT credit for.

They’ll try to match basically 2 things, sustained turn rate graph and acceleration. Everything else is basically just a biproduct/on accident.
Gaijin simply allowing you to pull 15+G’s is more of a discrepancy than anything when it comes to realism and how dogfights should turn out

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unfortunately that is still classified but i dont think the acceleration is in which i believe it is underperforming but i have no idea how to prove it

It’s not classified for the Viggen, neither is accelleration. The manual is declassified with those figures IIRC. in-game flight model is probably tuned after it, problem is drag and unloading, devs struggle to model that stuff

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thats from volume 1 which is declassified

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this is its performance one from 1983, retrieved i think 2016 ish

Wasn’t SFI part 4 declassified thanks to that guy from DCS?

It’s definitely underperforming, but the engine eats fuel in afterburner, like 18kg a second, which makes it have a large mass curve. It also has a super high TWR, about 2.21 or 2.12 IIRC.

no clue, i pay no attention to dcs

Found this, don’t know what sources it uses or if they are reputable.

icl it sounds about right

at what altitude

That’s what he claims, SFI part 4, which includes the performance graphs. I don’t play/pay attention to DCS either but I recall some guy from there got it declassified. I’m not gonna share it further here just in case I’m wrong, don’t want to be breaking any laws lol

Surface IIRC

Don’t remember, but I have the Flight Manual for all of them.

sfi part 4 is declassified as it is stated on the front cover
but the dcs story i have no idea and it all translates very poorly

no, its at best like 0.6 max load (with FT and rockets + 2 RB74s and full ammo)
the rockets are heavier than the standard air to air load

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After burning, should have stated that, here is the full Del 4

Was standard combat load in a squadron though.

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thats one of the two i have open lmao
dont think it says anything much except acceleration and climb
the rest translates poorly and i have no idea

Here’s the full systems and flight manual

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thats the second one i have open already