SAAF JAS-39C Technical Data and Discussion

Oh. Ye-ye-ye, that what i was mean.
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This 12 is large. I agree.
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But that 80 large too? C’mon.
Or it’s just rule “if in the fuselage, then large”?
P.S. Funny, but if you remove 2 outer pylon, then block of countermeasures was removed too. But not in the countermeasures counter.

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They should be considered large. The typical square NATO countermeasures that go in these types of launcher are either 1x1inches (~25x25 mm) for the small ones (such as No.118s) or 2x1inches (~50x25 mm) for the big ones (such as No.218s).

These are lower capacity magazines for ALE-45 dispensers (as seen on Japanese Phantoms) rather than the BOP-G magazines on Gripen which seem to be larger. But illustrate the difference in size between between the countermeasure formats

I assume the round ones on Gripen’s pylon are the 55mm format that was on BOZ, which are indeed bigger than the 2x1s. But the point is, the ones in BOP-G dispensers could be smaller and twice as many.

The fact gaijin often choose to count 25x50mm flares as “small” alongside Russian 26mm dia., NATO 36mm dia. and 25x25mm flares as an arbitrary nerf, to half their number of potential CMs is ridiculous.

Edit:- messed up link for the No.118 brochure.

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Understood. It seemed to me that the Gripen’s fuselage countermeasures were about the same as those on a conventional F-16. Now that you pointed this out to me, I see that I was wrong.

do you have a breakdown of the HMD symbology? like I’m guessing the 6 and 7k is altitude (in metres?)

Actually devs have decided that the in game performance of chaff is what they prefer. Personally I would argue that a 3dB, ie 2:1 RCS ratio between chaff and the defending aircraft should be necessary to break the lock, but I suppose the current in game implementation is fine. The are British sources complementing my reasoning.

Mostly if an Su-27 with head-on 10m^2 RCS notches, it’s RCS will ballon to ~1000m^2 to ~2000m^2 when facing side on. May be even ~5000m^2 when its belly is facing the radar. a single chaff with 150-200m^2 RCS should not be sufficient to transfer the lock or decoy the seeker. This is one reason BOL pods exists to be able to dump huge amounts of chaff.

Based on current review from a game play perspective ARH missiles are already too potent. If my suggestion is implemented then you either have to deplete huge amount of countermeasure while correctly notching, or have to defeat the missile by wasting all of its energy, which maybe too drastic of a change

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Mostly the lack of signal to noise ratio comparison when deciding if a seeker should be decoyed by chaff. In game RCS depends on direction but it’s not as drastic as real life. In game it’s a modest 1.1X increase if memory serves correct. But IRL it’s often ~10 ~20dB, which is a ~10X ~100X increase in relative RCS. As such larger aircraft’s such as Su-27, F-14, Tornados should have less protection from a single drop of chaff if the same chaff was deployed on a JAS39 for example.

However this would most likely make the seekers to strong.

How did you get 1000 out of 10m^2?

10m^2 is already the average RCS for the Su-27

Yet it has unintended consequences. Look at radars that use a LPRF waveform. A single chaff is able to transfer lock to it, rendering them useless with a single one.

10m² frontal may just be an example but they do increase to higher order of magnitude, 20-30dBsm, from the side aspect

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It does not increase 20-30 times
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Su-27
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Average -10dBsm

You first just quote a made up drawing, I don’t know why lol
Then you quote a computer simulation (which according to you is not useful due to reasons, example su57s plots)of a SU-27, without any frequency or scattering region mention, nor even element count. Yet you see it climb to 30dBsm on the sides.

Secondly, its not 20 or 30 times. But dBsm. 30x isn’t 30dB

Here you have a 21 in the optical region. 27-29 dBsm at 90° aspectdBsm
MIG21 RCS

T-33. 20-25 dBsm at sideaspect.
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computer sim of F-22 also spikes to 20dBsm side aspect.
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B57, 22dBsm at side aspect.
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BQM-34 drone RCS, also spikes to 20dBsm side aspect.
2024-06-21 (2)

They all tend to rise to an order of 20-30 dBsm at sides. Dunno why you fight it, it’s just a fact. Other aircraft dedicated specifically made to reduce RCS is another subject

These are meters

This is not even a unit for RCS.

And m^2 is certainly not it, dBsm was used.

Once again, square meters were used for the Su-27
If you use dBsm, the Su-27 will have 1000m ^2 in front, which is not possible

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Do you even know what decibels are? how they are calculated from linear units? HOW TO PASS THEM FROM dB TO LINEAR?
It says 10 dBsm front and 30dBsm sideaspect. I’ll let you figure that out yourself

just ask him what dBsm means and it will tell you everything you need to know

He knows. The lines on the left which correspond to a real aircraft and the right with reduced RCS. The line of the left are impossible to read tbh. And you have another set of graduation 1 and 2 which are an average ±30° or something like that, which I don’t understand.

Either way, it’s a computer simulation, which he generally discards like on others like the SU57. But either way. 10dBsm front and 30dBsm at the sides is reasonable.

Where does it say m^2? That is scale logarithmic using decibels, you should have better intuition reading these kind of charts, dBsm or log is the standard as RCS varies alot.

It is shown here to simplify perception. And not so that the reader sits with a calculator and translates

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