Su-57 stealth or ECM issue

[vrfgipjp]

I finally have the AI Su-57 firing its R-77 but I am a bit puzzled. I think its ECM could be very strong but the F-16CM cannot get a lock within 20nm, not to mention, still cannot get a lock when the Su-57 fires missiles, which I suppose the Felon has to open its bay door.

[vrfgipjp]

@molnibalage Noted with thanks.

[molnibalage]

@vrfgipjp said in Su-57 stealth or ECM issue:

I finally have the AI Su-57 firing its R-77 but I am a bit puzzled. I think its ECM could be very strong but the F-16CM cannot get a lock within 20nm, not to mention, still cannot get a lock when the Su-57 fires missiles, which I suppose the Felon has to open its bay door.

1. As I know the BMS cannot model the RCS change…
2. …and even it if did it would not matter. You are flying with mechanical scanning radar equipped F-16. The door is open for only ~ 2 sec. The total time of a single 4 bar scan is more than 2 sec.
3. Even if you had AESA radar equipped F-16 what would you expect after a 2 second “blip” on your radar screen?

[vrfgipjp]

@molnibalage Noted with thanks.

[drtbkj]

Hi, @vrfgipjp . We (OFM) previously done some testing with RCS , so there is some info I can share. As @molnibalage wrote. BMS does not model RCS changes with things like ay door opening. And I don’t believe that external racks are modeled either. So, in my personal flying in the F-35 I use the “honor system” and don’t load external racks unless it’s a Beast Mode Mission .
My personal testing was about a year ago, so someone please correct me if something has changed, however, this is how we did it…

1. BMS only has one RCS value. It is in the Editor/vehicle-aircraft tab. So, it does not reflect that in RL RCS changes with aspect. What we have used and entered are frontal aspect values .
2. The value you see in the Editor is not the RCS in m2 . It is in fact a ratio to the F-16, which is why the Viper’s are set to 1. The SU-57, for example , is set to 0.25 in the 2.60 OFM db. One reference we have used is https://www.globalsecurity.org/military/world/stealth-aircraft-rcs.htm . From this source, let’s use the F-35 as an example. The F-16C has a FA of 1.2, and the Panther has 0.005 So, the ratio for RCS would be 1/1.2=x/0.005=0.004.
3. However, that is not the value in the db. (it’s 0.056990). There are 2 reasons we use that value . The first is that we tried to derive an average value to cover all aspects. The second reason is the Member input at the time indicated they didn’t want us to go Full Stealth. My personal install is a different story .This part of the testing was mainly done by Yours Truly, and I would truly value any input on a better way to do it.
4. There is another factor you may see. At close range ( I think about 5 miles) a Stealth jet becomes detectable. Perhaps a player bubble factor??

[MCDeedle]

@drtbkj said in Su-57 stealth or ECM issue:

The second reason is the Member input at the time indicated they didn’t want us to go Full Stealth.

Sometimes the client is wrong, and it’s our responsibility to tell them they’re wrong

[Trigger]

I don’t mean to hi jack the threads original intent but RCS in BMS, how exactly is stealth modeled in 3D? Does it make something like an F-16 with an RCS of 1.2 mean a SA-2 for example will shoot at the F-16 with no jammer at 14nm where an F-117 with an RCS OF 0.4 no jammer it will shoot at 3nm? Or is it modeled in another way?

[molnibalage]

@Trigger said in Su-57 stealth or ECM issue:

I don’t mean to hi jack the threads original intent but RCS in BMS, how exactly is stealth modeled in 3D? Does it make something like an F-16 with an RCS of 1.2 mean a SA-2 for example will shoot at the F-16 with no jammer at 14nm where an F-117 with an RCS OF 0.4 no jammer it will shoot at 3nm? Or is it modeled in another way?

If the RP5 doc is still valid…

• Radars have range defined in feet in the DB.
• The targets have RCS, as was mentioned the reference is the F-16 with 1.
• If there is no jamming aspect is 0 degree if the range of the radar is higher than the distance with all the modifiers the radar can track the target.
• In RP5 era and since that - if nobody changed - the code defines a little aspect for the RCS. RP5 doc is still in the doc package as I can recall. I remember something 0.75 as lowest possible RCS at certain aspect.
• Jammer reduces the range of a radar BUT to me a not fully understandable way.
• Long, long time ago in 4.32 era every aircraft had “ECM strength” value. All had the same 0 value. It means that the range of the radar was reduced with a ECM factor. This factor is the property value of a given radar. BUT if you increased the ECM strength it reduced even more the range of the radar compared its ECM factor. When I set 20-30 values (as I can recall) the tracking range (burn through) was under 10 nm against a B-52 by an SA-2.
• Jamming strength has also aspect dependency and azimuth and elevation limitations.

Compared to RL the radar modeling and ECM is VERY, VERY abstract. It is essentially about Y/N switch regarding range and burn through with factors and angle limitations. Essentially every jamming is only something like a noise jamming = range denial. But if radar works correctly you can measure the direction of the jamming. Angle detection and other kind of jamming forms are not modeled in BMS. Because it would be insanely difficult even if we forget such thing as polarization…

And finally the SOJ (as I know) is invisible in the game. It simply blocks the radar but you can’t detect it. If the RP5’s model is still valid the game simply lowers the range value of the radars based on the distance between a SOJ plane and the radars.

In fact even your jammer is totally abstracted because the radio band coverage of even the best jammer pod in not full. In RL the rear / forward antenna of a jammer can act only in a certain radio band. For example, the AL-119 front antenna transmitted in the 2-4 GHz band while the rear antenna 6-10GHz.

While the fire control radar of the Dvina transmitted at 3GHz, the Volkhov at 6GHz and the radar of the 2K11 KRUG the Pat Hand at 10GHz. In the game your jammer works against EVERY radar while in RL reality is different…

This is the reason why the ALQ-119 became such thing from a single “pole”. The additional “layers” are the consequence of the added features.

[molnibalage]

Note on the margin. The stealth modeled with this RCS modifier. But if the range equation in BMS applies with an abstracted way what I remeber, just multiplying the range of the radar with this RCS, it means the -30 dBsm / 0.001 m2 RCS and its effect it does not mean that RCS a a stealth plane should be 0.001

If you wish to reduce the 4 m2 RCS (~ F-16) detection range from 250 km to 33 km (~1/8th of the original) then you have to decrease the RCS ~4000 times smaller to the original. But in the language of the BMS the RCS should be only about 0.125.

[molnibalage]

I remembered well.
RCS value in the DB

F-117
0.056

F-22
0.21 (way too high compared to public figures)

B-2
0.6 (waaaaaaaaaaaaaaaaaaaaay to high)

[Scorpion82]

@molnibalage

concur with much of what you said. Not sure about the bandwidth though, atm we have bands modelled in BMS, since 4.37. You can define the bands in use for a particular radar in its .dat file.

You’ll also find the abstract signatures modelling data for different aspect angles in the sigdata files.

Concerning ECM strength it can nowadays be directly set in the A/C .dat/txtpb files, so it’s still there, but no longer in the VCD database record.

I mean to remember that jumping contacts could at least be observed in the past, if range info where insufficient, maybe my memory fools me, but yes today it’s a bit more like you know the location of a jamming contact, but can’t track it.

Jane’s F/A-18 had a halfway decent similation of some ECM techniques, incl. angle tracking.

[molnibalage]

@Scorpion82 said in Su-57 stealth or ECM issue:

@molnibalage

Jane’s F/A-18 had a halfway decent similation of some ECM techniques, incl. angle tracking.

I’m planning to fly with this because of the Flight sim evolution series what I’m writing.