fixed CBU-97 falls short (again)

[Marklar]

4 CBU-97s dropped in CCIP mode and all four didn't reach the target. I was aiming at the source of the smoke. You can see on the 2nd picture how far from the target bomblets detonated. In the attached track you can see the other 3 attempts. Does not matter if I drop them with the wind or against, they always fall short. 

f16bombs.trk

[Marklar]

I reported it in general bugs forum but do others experience this issue as well? We used to have this problem several months ago but ED fixed it (after long delay). 

 

[Sinclair_76]

I am submitting a bug report for the CBU-97 in CCRP/LADD as well. 

[Sinclair_76]

CBU-97 CCRP/LADD falls short of target. Compared the CBU-97 with the CBU-87, Mk-84 and the CBU-105 just to be sure. At first glance it seems the CBU-97 canisters bracket the target. Due to the fact the release point is earlier in the sequence the bomblets fall 150m short (guestimate). The CBU-87 bomblets seem to have more momentum and fall on target nicely. The Mk-84 bracket the target and CBU-105 are spot on.

 

 

CBU97 falling short.trk

Mk-84 & CBU-87 trackfile

CBU87 spot on.trk MK84 bracket.trk

CBU-105 trackfile

CBU105 spot on.trk

[KP_Ghost]

Same!

 

[Moonshine]

bump

[Flappie]

If your issue only happens with the F-16C, the problem is not the bomb, it's the aircraft. This thread will soon be moved to the F-16C section.

[Moonshine]

wondering, if it is the aircraft then something with the CCIP and CCRP symbology might be wrong, however, other dumb bombs use the same mode, same symbology and work just fine. maybe someone can test with a different aircraft

Edited August 30, 2022 by Moonshine

[silverdevil]

@Moonshine i have a-10 and f-16. i will try it today at some point if possible. i will find post if it gets moved. now i can add that either with practice or a patch, i am more successful with cbu97 than i was previously.

Edited August 30, 2022 by silverdevil

[Moonshine]

Here my test on the issue, using CBU97 first and then MK82, all in CCIP. see how the cluster bombs all land way short of the CCIP pipper location on release, the mk82 perfectly on target. i doubt it is the planes fault (as in bombing mode bugged)

CBU97 falling short.trk

[Flappie]

I've just checked: this issue is already repored internally. As a Viper problem.

Thanks for the tracks, gents.

Edited August 30, 2022 by Flappie

[Marklar]

It still has not been fixed in today patch.

[Marklar]

I think it has been fixed in the Friday patch but was not mentioned in the change log. I dropped several CBU97s (off and online) and they were more or less on target.

edit: I was wrong. CBU97s are still broken.

Edited October 8, 2022 by Marklar

[Flappie]

I'm not sure what could have fixed this in the latest OB update. Please report back here if you still see the issue.

[Moonshine]

still falls short, see tracks attached.

note: wind set to 0 to avoid drift to better showcase the issue. Target WP was the middle tank of the group of 5.

in both scenarios some tanks were destroyed, however the vast majority of the bomblets did fall short.

CBU97_falls_short_CCIP.trk CBU97_falls_short_CCRP.trk CBU97_CCIP.zip.acmi CBU97_CCRP.zip.acmi

Edited October 8, 2022 by Moonshine
added Tacview

[Marklar]

You are right Moonshine, I did more tests today and they are still broken. Don't know why I had more luck with them earlier this week, maybe strong wind pushed the bomblets towards the target  or I dropped bombs from a steep angle.

[Flappie]

Thank you both. FYI, the bug report is still active.

[silverdevil]

i have been using a bit of kentucky windage and it seems to be mostly successful. i am aiming the pipper past the target with CCIP. also. i saw a video once but am unable to find it. basically when you roll in on the target, aim the aoa indicator about 1000 m  past the target and wait until the pipper is on target.

[void68]

it can be me, but... yes, they fall short, so I aim ahead 200m. Sometimes they hit the 200m offset point exactly. Sometimes they fall 200m short and hit the target. I did not notice an overall constancy!

However perhaps you noticed it too, the CBU97 container hits the target on spot! It's like the bomb's calculation is to reach AGL 0ft on the target, not to open the canister at burst altitude over the target. The higher the BA the worse the offset. What I will test, set the waypoint at BA exactly over the target and see what happens then.

A shame they aren't able to correct this bug for over 2 months, makes low level SEAD almost pointless in CCRP / DTOS mode.

[void68]

So... putting the waypoint AGL+BA and setting the BA to near zero result in a dud, cause no matter at what altitude the waypoint is set, the bomb always refers to ground level, I forgot that.

 

So, burst characteristics / flight path of the CBU-97 vs CBU-87:

While the 87 behaves mostly like a non-burst - it falls like a normal bomb, rotates, bursts open at the BA and as the bomblets are not retarded they follow mostly on their predicted path - the 97 is totally different to that: it falls like a normal bomb, bursts open at the BA and the subammunition is almost instantly retarded, so it does not follow the normal bomb path but remains somewhere between the calculated impact point (of a normal bomb) and where it bursts open. The higher the initial bomb speed the bigger the deviation (as the computer calculates a faster bomb for the remaining distance after the BA). While I noticed around 200ft at 250kts it was around 400ft at 450kts. High speed pull up attacks where with less deviation of course as you tend to lose a lot of speed during a hard PU.

 

So... they have to develop a totally new calculation scheme for the CBU-97 while all other dumb bombs (including the 87) follow the same glide path while the 97's is abruptly cut-off at BA.

Anybody noticed they changed the bomb mode cylce? From CCIP->CCRP->DTOS to CCIP->DTOS->CCRP... why that?

[silverdevil]

3 hours ago, void68 said:

the subammunition is almost instantly retarded

the CBU-97 submunitions deploy a parachute. wind will affect it. that is a big reason they have CBU-105. a question here is does the bomb not fall as expected? do the submunitions deploy not as expected? do the submunitions not get attracted to the targets? since this bug only affects F-16, it would infer a computer calculation. RL bombs are not perfect either.

[Vortex225]

Edit: adding three short tracks on Caucasus to demonstrate the issue for CCIP, CCRP Loft (i.e., toss bomb), and a level CCRP drop from medium altitude. The CCIP and toss bomb attempts score zero hits and fall notably short. The level CCRP drop gets closer and scores 1 or 2 hits but the majority of submunitions fall short. 

 

This isn't a bug report per se, because the issue (or something related to it) has been reported here.

However, the issue with CBU-97s falling short when using CCRP loft is making it hard to enjoy the new toss bombing symbology for the Viper. They even fall well short of the intended impact point when using CCIP. As I mentioned in the linked thread, it's almost as if they would be on-target if it weren't for the submunition separation and parachute phase, which modifies the normal trajectory below the burst altitude. Other bombs seem to be working great with CCIP and CCRP. CBU-105s also seem to be working as intended.

This is frustrating because the CBU-97 is one of the most capable and entertaining munitions to use in DCS, and it's one of the things that really sets the Viper apart from its multirole peers in the sim. Accurate CBU-97 bombing with the Viper is pretty important in my humble opinion, and I hope this gets fixed soon.

Any word on progress? Thanks in advance!

cbu97_falls_short_CCRP_Loft.trk cbu97_falls_short_CCIP.trk cbu97_falls_short_CCRP_Level_Drop.trk

Edited October 17, 2022 by Vortex225

[=617= Evil]

Hopefully it gets fixed soon. CBUs are so important for DEAD missions, but this can make it extremely frustrating to try to use. Using PRE mode with the 103s and just marking the target a little high/long along your axis of attack is something of a workaround, but not perfect. 

[void68]

On 10/16/2022 at 7:41 PM, silverdevil said:

the CBU-97 submunitions deploy a parachute. wind will affect it. that is a big reason they have CBU-105. a question here is does the bomb not fall as expected? do the submunitions deploy not as expected? do the submunitions not get attracted to the targets? since this bug only affects F-16, it would infer a computer calculation. RL bombs are not perfect either.

Yes, of course I set the mission with zero wind. Furthermore they always fall short, no matter what direction (in case of any wind at least in downwind attack run the bomblets should fall long). They always fall short.

The skeets perform as advertised. If the skeets / bomblets are close to the target they do shoot the molten "rod". It's just that the bomblets are not over the target - while the canister hits the target.

 

Quote

if it weren't for the submunition separation and parachute phase, which modifies the normal trajectory below the burst altitude.

Exactly, the higher the BA and the speed, the worse the deviation.  0 ft BA is a direct hit! But a dud, of course.

 

Quote

Using PRE mode with the 103s and just marking the target a little high/long along your axis of attack is something of a workaround, but not perfect. 

What I do: CCIP "just" aim 200-400ft behind it, it's a matter of training, of course and not really satisfying. CCRP... well, do an evaluation of the situation and then plan from where you will attack. Do a (outside the engagement parameters of the SAM) short simulated attack run and place the SPI a few 100ft behind the target (3D on a 2D screen...), turn away, do a re-run and use the HSI steering setting for the exact radial for the attack run (a bit over-complicated, I admit).

 

Usually it hadn't to be so exact, you can place the SPI behind the target from every direction with a bit of evaluation training or even do it while on the attack run if you do a short pop-up (and instant down) with the backdraw that fine tuning the SPI from low alt into "depth" of field is tricky as each pixel represents a few 10ft or so.

 

Yeah, the CBU97 is IMHO the best against single type SAMs. You can carry up to 10 and take out everything, from high alt through the cloud layer to low level pop-up / lobbing and the bombs can't be shot down by the SA-15 or SA-10. Windy conditions can be a problem, though. But don't forget how adrenaline pumping and satisfying a 10-50ft alt attack run is in comparison to a boring "Magnum" employment...

It's the most important part that needs fixing, ASAP!

Edited October 20, 2022 by void68

[silverdevil]

anyone else seeing an improvement since 2.8? i did my first run today and it appeared to be corrected.

changelog has this

Quote

Fixed: HUD CCIP->CCRP consistently falls short compared to normal CCRP.

i am guessing that is this issue? though i did drop 10 at the same time. :halo: