The CBU 97/105 Effectiveness (lack there of)
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@SyntaxErol I agree, that it’s not a smart enough munition to target the engine compartment while the skeet is wobbling/spinning around. I am saying that the engine compartment when hit should be penetrated by a skeet (like through the maintenance hatches) and result in the worst kind of M kill. I would also say that if the engine is warm, the heat signature of the tank is going to skew towards the engine compartment anyway too, making slightly higher odds of hitting that area.
So overall, commenting to @white_fang it is still probably possible that if a CBU-97/105 is dropped on a company of T-90s, there will be at least a few hard M Kills and but I still think there is a possible K kill through the top of the turret unless there is more data out there.
Since I’ve been lurking in this thread since you have started it here are my thoughts:
Yes, many of the CBUs in BMS since at least 4.35 seem to have too low of coverage except the now fixed JSOW which did have too large of coverage (I would also say that DCS’s CBU-97/105 seems a little strong for those coming over as comparison). I have not tested a JSOW in 4.37.@airtex2019 said in The CBU 97/105 Effectiveness (lack there of):
@jayb said in The CBU 97/105 Effectiveness (lack there of):
@Seifer Any insight from the code on this?
@jayb said in The CBU 97/105 Effectiveness (lack there of):
That old post brought up some interesting points. Is burst altitude stated in Sea Level or AGL ? Seems to be some mixed information in that thread and that is pretty crucial for the dispersion
There’s a pretty tight limit on the MFD input (I think 2000 ft or something like that?) so I sincerely hope it’s AGL.
As always I have no idea what’s more realistic, MSL or AGL. I can think of arguments either way.
I would quote the BMS training manual in regards to MSL vs AGL burst altitude question posed here: “As with any other CBUs in BMS the burst altitude should actually be called burst height, as it is a distance from the ground and not an altitude.” I would say that there seems to be a very narrow band of setting here than can produce more than 1-2 hits and often it seems to be to not exactly above ground height because the number seems to change. But that is also anecdotal. @seifer’s suggestion of 1800 I think tends to be about the height I have found the most effectiveness.
I would also agree that it seems all too often the main source of the kill is the actual CBU canister striking the target when viewed through the TGP. Not sure if that is really what is happening, but when I can see the bomblets go off in the TGP, they do not often seem to result in a kill.
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I get decent results with CBU-97 with BA 2,000 but prefer Mk-20, you can carry more. The CBUs in game are not too bad IMO.
In recent wars a lot of the submunitions failed to detonate and weapon specs get inflated for marketing. I’ve seen some footage of CBUs being tested and they spread and can miss targets in the kill zone. IRL they don’t usually get huge kill counts per sortie my 2c. -
Guys… your dealing just speculation. Nothing more.
Yes top armor is the worst, Javelin… and also, even probably older then you - Swedish “Bill” (1988 - I remember) uses this approach, Bill was the first to use the technique, before Javelin was even born.But… both of those missiles uses faaaar more powerful warheads then any BLU… skeet /sub. - furthermore… hard kill T90 with sub/skeet, give me a break - possible damage/destroy to remotely op. machine gun on top.
Yes you do like things that go boom , but unfortunately, AGM154 , CBU-87, even CBU-97, CBU-100 are just for lightly armored and older gen armor. - they are designed for soft-kills, like mines - neither of these weapons can “hard-kill” even a BMP… so, jeeps, trucks, light armor. - can suffer “terminal” , … APC’s and up , just soft “touch”. - maybe not destroyed, but unusable. , but new gen MBT’s - just paint scratch.
just my 2 kopeyke -
Yes. As i said in my previous message. Im not expecting everything in killzone to be killed but expect the actual killzone would be larger. Thats my whole point.
Next thing i will try is flying lower and a bit faster to make canisters still have longitudinal speed when deployed at BA. Setting burst height to a lower setting would decrease the killzone so im not sure about changing BA
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@SyntaxErol
Well, I agree, those (ellipsis) radius-es, maybe should be bit revised… but that “nuke” of AGM-154A in Bms 4.35 was a bit too much.
I was “obliterating” whole SA-10 battalion with just 4 JSOWA… not kinda fair - but now, killzone, for any cluster is about “limited”. - need to play a bit with numbers I guess… radius, damage, hit percent… and even height / dispersion - a bit tricky - as it is a model in the end. -
“All models are wrong but some are useful”
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Eh, which model are you referring at
This:
https://linguasia.com/korean-female-models
(Falcon edition)Or this:
https://omegataupodcast.net/364-physics-beyond-the-standard-model/ -
Tried BA of 3000 2500 and 1000, but no visible change in damage radius or amount
From this acmi screenshot, you can see cbu landed 256 feet from the right tank and it was 258 feet from the left one that was destroyed so a good in-the-middle shot. However, the other tanks were not damaged or hit. So the actual coverage is around 500ft no matter the BA (1000,2500,3000)
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But yes, you’re right that pk is too low, considering it is a line of tanks ~1000ft. They all should get hit at least…, probably soft-killed/unusable… given the weapon and target specs.
Tacview/acmi doesn’t show air-burst, so maybe see BA height?
What is the last recorded bomb altitude… can’t be zer0 ft msl/agl. (shouldn’t be…) -
@jayb Some anecdotal data, if helpful: while flying EMF, I was testing the CBU-87 with loft attacks against a SAM site located on a plateau at about 2600’ MSL. BA values < 2600 produced no spread from the munition. Using a BA around 4000 started to show results, which made me assume that the BA as implemented is in fact MSL, not AGL.
(And—I ask this in total ignorance and happy to be corrected by someone more knowledgeable —wouldn’t that make sense w.r.t. the real thing? It’s a fairly cheap munition with a notoriously high dud rate, so it’s probably set off via some simple barometric trigger, no?)
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@Gadfly that was my thinking too … but if you take one step further – obviously there’s some sort of data-link to update the fusing, based on what you key into the MFD page. it’s possible the avionics could apply the ground-elevation offset, before transmitting BA to the bomb?
could that happen fast enough, reliably enough, for CCIP modes? (and what about MAN release mode?) I have no idea. so, like you I’m inclined to assume it’s MSL, but I can believe AGL if people who know tell me it’s so.
[Edit: wikipedia says it’s “optional FZU-39/B proximity sensor” … which sounds like a little radar-altimeter device]
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@airtex2019 @Gadfly
Tested a little this morning from elevations 200’-6000’ MSL with no difference burst altitudes of 1800’ mostly as @Seifer suggested and then the extreme 3000’ Burst Altitude at both extremes in elevation. Always only two kills even targeting the middle three trucks together that you get in columns. And yes, the simple solution on CBUs is to have a radar altimeter control the burst. -
I would think that it is important to have the radalt active in the jet too. That switch can be overlooked. But I’m with airtex on the BA coming from the jet, likely calculated from active steerpoint
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@Snake122 good thing testing against trucks. The damage can not be messed up from armor values of mbts or ifvs or similar
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@airtex2019 said in The CBU 97/105 Effectiveness (lack there of):
FZU-39/B
[Edit: wikipedia says it’s “optional FZU-39/B proximity sensor” … which sounds like a little radar-altimeter device]yep, seems that’s right.
https://www.bulletpicker.com/pdf/Afghanistan Ordnance ID Guide, Volume 1.pdf#page=236
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@jayb I don’t think the aircraft’s radar altimeter in real life matters. CBU-105 is a bit of a different beast with the data being sent to it, But the non-WCMD CBUs are completely dumb with no data from the aircraft. These are simple stand alone radar altimeters for the burst fuzing.
The other advantage of the trucks is the interval of 3 together before the larger separation distance. The TGP doesn’t like to target the middle one and you kinda have to bump onto it. IMO, all three of these should be taken out but still only 2.
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@Snake122 said in The CBU 97/105 Effectiveness (lack there of):
@jayb I don’t think the aircraft’s radar altimeter in real life matters. CBU-105 is a bit of a different beast with the data being sent to it, But the non-WCMD CBUs are completely dumb with no data from the aircraft. These are simple stand alone radar altimeters for the burst fuzing.
Probably true for real life. But the BMS modelling might require that the Radalt is turned on. We don’t really know until someone with knowledge of how the data and code interact shows up
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@jayb -34 manual page 226 have some insights on this. I dont think its MSl i tested in both near shore and kotan range which is pretty high and observed no change over the covarage.
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@SyntaxErol said in The CBU 97/105 Effectiveness (lack there of):
@jayb -34 manual page 226 have some insights on this. I dont think its MSl i tested in both near shore and kotan range which is pretty high and observed no change over the covarage.
Mav posted a video (for 4.36) about how the SPI altitude can change depending on the sensor - might it be this that causes the discrepancies?
Take a look at
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@CriticalMass well, syatem altitude/range shouldnt effect cbu burst height. Burst height or “altitude” must be a simple radar altimeter onboard the munition, independent of launching aircrafts altitude. The target elevation error may result in bomb falling short or long because of ccrp solution would be wrong but bomb burst is independent of that solution.
Also observed in all shots cbu body landed at exactly where my tgp cross is.