Stealth in BMS
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You guys will pork completely Falcon.
You cant simply normalize the RCS of new acft based on the F-16. It does not work this way. The “RCS” in DB is a normalization factor in the radar range equation in Falcon. Did you check the excell table I put the link?
Moreover, the radar range equation DOES NOT scale linear with the radar cross section. -
@Mav-jp
Unless you have rewritten completely, this is not correct.
I dont think you have rewritten since the “RCS” are still similar to the old ones, i.e. I dont see the changes that would indicate that the code takes into account the real RCS in the calculation.The “RCS” in the Database is a multiplication factor for the nominal radar range:
Radar Detecion Range= Nominal Range (from DB) x “RCS” (from DB)If you plug the real RCS, it will simply not work, because the real RCS goes with ^1/4 in the max radar range formula.
EDIT: BY consequence, all max radar ranges in the DB are the nominal radar ranges where acft like the F-16C is detected…“RCS” is 1 (=normalized).
@drtbkj
Here is an example using the CMO DB as baseline (“true”) to calculate such “RCS” factor in BMS (all frontal values for E-M bands):
#1 Shows that BMS “RCS” factor matches the calculated ones using CMO, taking into account the corresponding power law.
#2 Shows that this matching gets even better if one takes into account an average RCS from CMO. Compare yellow marked cells for the case of F-15C -
@javelin10 said in Stealth in BMS:
I voted yes. I see BMS as remaining an F-16 simulator for the forseeable future, but if real life vipers may soon have to contend with stealthy adversaries, then we should have the choice to make theatres that represent this. No-one has to fly any particular theatre after all.
The way I see it is as a question of pure technical feasibility and how well-modelled ‘stealth’ will be.
Real life F-16 may soon have to deal with this threat, but real life F-16’s also still get updated with new toys (AESA radar etc.). So if you want to realistically model dealing with this new threat, then the BMS F-16 also needs to be updated. And most of the information on these new toys are still classified, so this will be difficult to do in a realistic way I’m afraid.
Interesting article on the F-16’s future:
https://www.thedrive.com/the-war-zone/air-force-holding-off-developing-new-f-16-replacement-for-now"608 F-16s from Blocks 40/42 and 50/52 — the service’s youngest F-16s — will receive a total of 22 modifications under the program. Planned updates include the addition of a Center Display Unit, a Programmable Data Generator, and “several other key hardware components to modernize the aircraft.” In addition, the F-16 will receive the AN/APG-83 Active Electronically Scanned Array radar (AESA), new electronic warfare capabilities, advanced mission computer, and a communications suite upgrade that includes an updated Link-16 datalink capability. The USAF says this new communication system will convert the fleet to “a high-speed data network.”
"Mark Rossi, Northrop Grumman’s director of SABR programs, told The War Zone that the addition of the SABR was the closest thing an F-16 could get to F-35 performance within the limitations of the jet. "
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@tiag said in Stealth in BMS:
@Mav-jp
Unless you have rewritten completely, this is not correct.
I dont think you have rewritten since the “RCS” are still similar to the old ones, i.e. I dont see the changes that would indicate that the code takes into account the real RCS in the calculation.The “RCS” in the Database is a multiplication factor for the nominal radar range:
Radar Detecion Range= Nominal Range (from DB) x “RCS” (from DB)If you plug the real RCS, it will simply not work, because the real RCS goes with ^1/4 in the max radar range formula.
EDIT: BY consequence, all max radar ranges in the DB are the nominal radar ranges where acft like the F-16C is detected…“RCS” is 1 (=normalized).
@drtbkj
Here is an example using the CMO DB as baseline (“true”) to calculate such “RCS” factor in BMS (all frontal values for E-M bands):
#1 Shows that BMS “RCS” factor matches the calculated ones using CMO, taking into account the corresponding power law.
#2 Shows that this matching gets even better if one takes into account an average RCS from CMO. Compare yellow marked cells for the case of F-15CYou misread me completely , I never said we need to plug real values
I said RCS real values need to be scaled on the f16 real value vs 1
If (4) power factor need to be taken into account need to be checked with current code
however I’m not sure the current DB values have been done with a power factor. This data is there since 2002/2004 , did you check if current DB more or less match Scaled RCS with (1/4) power factor ?
Also indeed average RCS values vs incidence must be taken into account and not only the lowest
I had the intention to code RCS vs incidence but I forgot and now it’s over .
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@Mav-jp Sorry, I understood well what you wrote but I thought that @drtbkj and @unkindled got it wrong, by reading their messages. My message was more to them.
“Did you check if current DB more or less match Scaled RCS with (1/4) power factor ?”
Yes, it matches. I wrote a quick script to extract the RCS from CMO DB, then calculated an average frontal/side RCS, then scaled to F-16C RCS, then used the power law, then compared to BMS.
This data is graphed below: X-Axis is “RCS” factor from the BMS 4.36 DB, Y-Axis is the calculated (as decribed in the previous line) from CMO DB.
Both data more or less match.
So, if someone wants to edit correctly the “RCS” factor in BMS, it needs to take into account the power law. Or you change the code and the whole RCS in the DB needs to be re-done.
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Go for realistic RCS values in BMS!!!
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@unkindled said in Stealth in BMS:
@drtbkj I may be missing something, but if we take the reported RCS of the F-18 mentioned in the two sources you have provided as truth, then the F-18 has a lower value. Not sure by how much relatively speaking.
If we assume that modern (as in now currently used) F-16C have an RCS of 1.2m^2, shouldn’t we divide the F-18’s RCS value by it to scale it to real world data (assuming a linear function in BMS). Therefore wouldn’t a higher value for the F-18 be “wrong”? E.g. In BMS F-16 RCS is 1, actual RCS is 1.2, F-18 RL is 1, so F-18 in BMS should have a value of 0.8333.
Please correct me if I’m wrong, haven’t managed to read the other source concerning RCS from the NPS.
Thanks again for the replies. Our original question was whether or not to make rcs changes in OFMKTO 1.5. As you can see, we didn’t do that. We simply were not ready, and the more I study (inc. Tiag’s link) the more there is to learn!
Unkindled, your method seems right. I have seen the 1.2 value for the Viper, others use 1. Finding accurate real life values, or at least a set of values we agree on, is a big part of the puzzle. The J-20 we’ve talked about in the other thread seems to have a rl value of 1-3, yet BMS has it at 0.4. But, that may be accurate frontally. One thing to note with the F-18 values is whether we’re talking about the 18C or the Super Hornet. The predominant value I see for the Legacy is “1-3”, so the 1.2… in BMS seems reasonable. It seems logical that the Viper would have lower frontal rcs then the F-18C. For the Rhino, on the other hand, I’ve seen values of 0.1. I agree with your .0833 for the Rhino .
Tiag, The bigger question we have is where does the Membership want us to go with this, and where CAN we go with this? Input like yours is invaluable. I saw your post over in our Discord, let’s continue that. In fact, anyone who wants to have a real time conversation ,join us on the help-resources channel on our Discord
In the meantime, I’d like the Group’s opinions on the following methodology. As Mav has already busted me for making assumptions I’ll try to keep them to a minimum.- I suggest we focus on frontal values, and agree on a real life list to use… BMS seems to have one value for rcs, independent of aspect. The RL Viper has a good rcs from the front, not as good from the side. So, if we can only adjust one, let’s do frontal. Another reason is that it would be most impactful on the frontal BVR engagement, that seem to be a predominant one in BMS.
- Investigate other sensors- Some have commented on the other aspects of Stealth. Unfortunately, IR Stealth seems to be in the hard code models, beyond our reach. But, in the Editor there are a couple of listings for IRST’s . Could they be useful? AESA seems beyond our reach. but the BMS Editor does have changeable detection ranges for the various radars. Could we simulate that aspect of AESA?
3)Overview- First, we determine what we can do. There is obviously a LOT os Science to this, but what can we do in BMS? From there, decide where we want to go with it.
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@tiag said in Stealth in BMS:
Sorry, I understood well what you wrote but I thought that @drtbkj and @unkindled got it wrong, by reading their messages. My message was more to them.
“Did you check if current DB more or less match Scaled RCS with (1/4) power factor ?”
Hi @tiag, thanks for the correction. I was mostly talking in hypotheticals and making assumptions not necessarily about what the actual BMS value should be for an aircraft, but what RL value to base the calculations for BMS.
As various sources from different moments in time mention different values for the same aircraft in general (e.g. not specifying which F-16 block that value corresponds to), or for the same revision of an aircraft (e.g. saying that the Block 40 has an RCS value of X, without specifying if that Block 40 has been through any “upgrading” programs that could differentiate its RCS value).
Hence the really naive assumption that BMS uses a linear function to make my point clearer with a more practical example.
Unfortunately I haven’t had the time to properly read through your linked excel file.
Also, as I am unaware, could you fill me in on what CMO is? Is it the war-sim game Command: Modern Operations?If so, how can we trust that the values its DB has are accurate? Again, I know it only by name so I don’t know how trustworthy/reputable/realistic it is. But I think it further proves what I’m trying to say and what Joe said in his latest reply.
With so many sources concerning what is the “real” RCS value of an aircraft, which do we choose and why?
I think we can even further complicate it by going on to say which RCS value do we choose depending on the era each theater tries to simulate. Would/should one choose the same value for Balkans, which “takes place” in late 90s and mid to late 00s, as they would for stock KTO or 80s ITO or even ODS in MidEast in their effort to strive for realism?
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There are a load of figures on the Internet that have mostly been pulled out of someones Ass I think nothing more.
cmano is just a game in the public domain so some info will be accurate and some will be way off…like RCS values.
The National Interest has never been a credible source…Jon Lake has made a career of providing naff information.
I have head on clean figures from better sources that are different and probably just as useless.
So yes different versions of F-16 and at least 5 generations of Have Glass from 1983 as is known.
At some point the pylons were improved and RCS will also change with weapons…then CFTs added.happy guessing
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FWIW, there is a related discussion regarding the future of DCS in the face of 5th gen vs older planes, in the Hoggit subreddit: https://reddit.com/r/hoggit/comments/x1q38w/where_is_dcs_modern_aircraft_going_to_go_in_the/
Maybe some arguments and insights from that thread are helpful for this thread here.
If you take a step back, the linked discussion is IMHO not really DCS-specific, but a proxy for a discussion about the future of any game modelled after the real world, where more-or-less recent developments in the real world are causing friction for game development and player experience. How to steer the game and its community in such a context? Keeping it very realisitic is nice, but at which point and for whom in the player base does the fun in the game stop? Focus only on a certain time area like cold war to keep different factions reasonably balanced (and thus, arguably, more enjoyable for a larger player base in a game where different factions are competing) vs. incorporating recent tech so the game retains its state-of-the-art flight sim feeling for players? Introduce features/properties like stealth when the majority of “things” in the game can’t deal with them? Adress the issue with mission design, e.g. creating scenarios with less A/A and more A/G? And so on.
I am new to the genre of Falcon BMS, DCS, et al., so I did not vote yet in this poll because I haven’t experienced much of the gameplay yet. Mostly listening to what people bring up as pro/con arguments here (stealth yes/no/how exactly).
PS: Personally, I started learning BMS a few days ago. I am knee-deep into tutorials, the manuals, etc. right now. So stealth or not, everything in BMS is new and shiny to me.
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@unkindled said in Stealth in BMS:
I think we can even further complicate it by going on to say which RCS value do we choose depending on the era each theater tries to simulate. Would/should one choose the same value for Balkans, which “takes place” in late 90s and mid to late 00s, as they would for stock KTO or 80s ITO or even ODS in MidEast in their effort to strive for realism?
First, Elegantly, welcome to BMS!
We can all agree that RCS values on the 'Net are all over the place.
Unkindled, your quote above addresses what I call the Big Picture Question. AFIAK, the RCS and possible other aspects changes listed in my last post are acdata and/or Editor changes, at least without hard code access. Those values are Theater, not campaign, specific. In other words, OFMKTO, for example, could not be made Stealthy or non -Stealthy in it’s entirety . But the campaigns within OFM can be adjusted. If you want an earlier era non-stealthy campaign, simply don’t include stealth jets. If you want a stealth campaign, exclude the Viper, Hornet, etc. The issue with that of course is if you want to explore the RL Viper/Hornet/other pilot issue of dealing with Stealth. You also have the issue of a lot of BMS pilots fly the F-16-50 and/or the F-18C in earlier era campaigns.
Earlier in this thread I wrote about the F-35 v. J-20 testing that had an impact on me. It changed the dynamic of the engagement. So, once again it becomes a question of where do we go from here? I should probably mention again that our goal with OFMKTO is not to make it a Stealth or Non-Stealth Sim . All we’re discussing is to make RCS as accurate as possible within the boundaries of what we can do within the BMS structure -
@unkindled said in Stealth in BMS:
Also, as I am unaware, could you fill me in on what CMO is? Is it the war-sim game Command: Modern Operations?
CMO like @Migbuster already said, is a public domain simulation with its caveats. . There are 2 large DB, one for before 1980, and one after that time. Different to other bs sources, there is quite large group trying to control what goes inside the DB. They try to not be biased (very important) but assumptions needs to be done, of course. Contrary to BMS, the DB is protected to avoid wild edits etc: Users cannot edit it but we can request changes/additions. You can take a look on the public DB request tracker on how it works and what kind of information is required:
https://github.com/PygmalionOfCyprus/cmo-db-requests/issues-> To be really clear, I am not advocating that CMO is the absolute truth. I just used it to compare and to show the “RCS” in BMS needs the power law that I explained above.
What one could do though is to compare where BMS DB differs from CMO and check why is that difference. Take a look on the table below. It is the data I graphed in my post above. I also flagged the “RCS” (2nd=BMS and last collumns=CMO) which differs by more than 20% (red numbers), 20 to 10% (yellow cells), <10% (green cells) as an example. You guys could research in your group @drtbkj @unkindled if it makes sense and potentially supply the BMS dev group new “correcter” values. THAT would be in my humble opinion a great work for the community and fidelity of BMS.
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J-20 & FC-31 Radar signatures correction
https://github.com/PygmalionOfCyprus/cmo-db-requests/issues/1712Worth reading the comments.
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@tiag said in Stealth in BMS:
@Mav-jp Sorry, I understood well what you wrote but I thought that @drtbkj and @unkindled got it wrong, by reading their messages. My message was more to them.
“Did you check if current DB more or less match Scaled RCS with (1/4) power factor ?”
Yes, it matches. I wrote a quick script to extract the RCS from CMO DB, then calculated an average frontal/side RCS, then scaled to F-16C RCS, then used the power law, then compared to BMS.
This data is graphed below: X-Axis is “RCS” factor from the BMS 4.36 DB, Y-Axis is the calculated (as decribed in the previous line) from CMO DB.
Both data more or less match.
So, if someone wants to edit correctly the “RCS” factor in BMS, it needs to take into account the power law. Or you change the code and the whole RCS in the DB needs to be re-done.
In first step the eq. in the RP5 manual should be checked. Base on Mav-jp’s comment it is still valid.
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@drtbkj said in Stealth in BMS:
@unkindled said in Stealth in BMS:
@drtbkj I may be missing something, but if we take the reported RCS of the F-18 mentioned in the two sources you have provided as truth, then the F-18 has a lower value. Not sure by how much relatively speaking.
If we assume that modern (as in now currently used) F-16C have an RCS of 1.2m^2, shouldn’t we divide the F-18’s RCS value by it to scale it to real world data (assuming a linear function in BMS). Therefore wouldn’t a higher value for the F-18 be “wrong”? E.g. In BMS F-16 RCS is 1, actual RCS is 1.2, F-18 RL is 1, so F-18 in BMS should have a value of 0.8333.
Please correct me if I’m wrong, haven’t managed to read the other source concerning RCS from the NPS.
Thanks again for the replies. Our original question was whether or not to make rcs changes in OFMKTO 1.5. As you can see, we didn’t do that. We simply were not ready, and the more I study (inc. Tiag’s link) the more there is to learn!
Unkindled, your method seems right. I have seen the 1.2 value for the Viper, others use 1. Finding accurate real life values, or at least a set of values we agree on, is a big part of the puzzle. The J-20 we’ve talked about in the other thread seems to have a rl value of 1-3, yet BMS has it at 0.4. But, that may be accurate frontally. One thing to note with the F-18 values is whether we’re talking about the 18C or the Super Hornet. The predominant value I see for the Legacy is “1-3”, so the 1.2… in BMS seems reasonable. It seems logical that the Viper would have lower frontal rcs then the F-18C. For the Rhino, on the other hand, I’ve seen values of 0.1. I agree with your .0833 for the Rhino .
Tiag, The bigger question we have is where does the Membership want us to go with this, and where CAN we go with this? Input like yours is invaluable. I saw your post over in our Discord, let’s continue that. In fact, anyone who wants to have a real time conversation ,join us on the help-resources channel on our Discord
In the meantime, I’d like the Group’s opinions on the following methodology. As Mav has already busted me for making assumptions I’ll try to keep them to a minimum.- I suggest we focus on frontal values, and agree on a real life list to use… BMS seems to have one value for rcs, independent of aspect. The RL Viper has a good rcs from the front, not as good from the side. So, if we can only adjust one, let’s do frontal. Another reason is that it would be most impactful on the frontal BVR engagement, that seem to be a predominant one in BMS.
- Investigate other sensors- Some have commented on the other aspects of Stealth. Unfortunately, IR Stealth seems to be in the hard code models, beyond our reach. But, in the Editor there are a couple of listings for IRST’s . Could they be useful? AESA seems beyond our reach. but the BMS Editor does have changeable detection ranges for the various radars. Could we simulate that aspect of AESA?
3)Overview- First, we determine what we can do. There is obviously a LOT os Science to this, but what can we do in BMS? From there, decide where we want to go with it.
In RP5 is defined the aspect dependency which is the same for all airplanes.
I do not know what the current code is in BMS4. Maybe in dat files are something about this to have a real char.Only problem NOBODY here knows what can be the real char. of a stealth fighter. Just forget the funny models on the Net by random enthusiasts. They are not correct not even the magnitude of the RCS.
This is B-2 modeling and measuring the scale model. If you check you can see there are larger spikes only because edge diffraction and perpendicularly to leading edge. While the quite “interesting” RCS chars. of the fighters are totally different. So I rather would not use them…
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@molnibalage You problably missed my posts explaining where this is coming from…AF, RP5 where at page 289 it says:
Detection Range = Radar Cross Section x Radar Range
at page 290 it is better explained what they have done. They have opted to not calculate the physically correct ^1/4 in the radar equations, but they modified the “RCS” in the DB to include that power law in order to have a simple multiplication when running the simulation.
The test is very simple in BMS itself. Put (wrongly) a scaled RCS of 0,001 in the DB, and the detection range in game will be so small, 1/1000th of the radar range, that a 40nm becomes 0,04nm. Which is phyisically not correct. One also needs indeed the power law as explained.
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@tiag said in Stealth in BMS:
@molnibalage You problably missed my posts explaining where this is coming from…AF, RP5 where at page 289 it says:
Detection Range = Radar Cross Section x Radar Range
at page 290 it is better explained what they have done. They have opted to not calculate the physically correct ^1/4 in the radar equations, but they modified the “RCS” in the DB to include that power law in order to have a simple multiplication when running the simulation.
The test is very simple in BMS itself. Put (wrongly) a scaled RCS of 0,001 in the DB, and the detection range in game will be so small, 1/1000th of the radar range, that a 40nm becomes 0,04nm. Which is phyisically not correct. One also needs indeed the power law as explained.
The RCS of an F-16 is ~ 4m. SNR-75 tracking range in wide beam mode 115 km.
So if we accept the ~ 0.001 m2 of the F-117, tracking range is 14 km.F-16’s RCS is 1 in BMS.
F-117’s RCS 0.1 in BMS.to have the 115 --> 15 km reduction.
But this also means that radar range should be 377 000 ft. DB uses feet for radar range.I guess most of radar does not have accurate range value.
I can gather some RL radar range to an reference RCS to set radar ranges well. -
Good morning, All. Tiag, I replied on our Discord. Also, some interesting stuff in the chart.
Molni, what you wrote about tracking range reminded me of something I had been told about this aspect of Sim development. How they adjusted the numbers so that targets could be tracked at 5 nm, for the sake of gameplay. It also reminded me of our recent MQ-25 tanker testing. We tried a value similar to the F-117 value and couldn’t lock it on radar. -
@Armagedon said in Stealth in BMS:
Can AESA radar detect stealth?
Any radar can detect stealth. It’s only a question of when…