CBU-99/Mk.20 Height of Burst option

Ok, guys n gals, I can't get my rockeyes to burst, I've set everything like in the DCS tutorial, the bomb releases but doesn't open. I've tried every height but the pod just hits the deck. This happens in both CCIP and Auto modes. Any ideas? Cheers

 

 

Radar alt switch set

 

1. Mfuze

2. VT

3. Set height

4. Pickle when CCIP cross is over target

I'm having an identical issue (open beta). It applies to all cluster bombs for me. I can't get them to burst in the tutorial either even after following the instructions step by step.

Tried to watch that track or check the mission... needs a mod that I couldn't manage to extract, some .rar that won't open in 7zip or on an Android 7 device... I'm not going to install WinRAR after like 15 years again just for that, sorry... but at least I tried to look into it

Wild guess: Since the HoB is set hard on the Rockeyes at 1500', did you drop them on targets that are positioned above 1500' MSL? I'm pretty sure that the HoB altitudes are barometric.

Hi, sorry about that, I’ll upload a vanilla one. Yes I made sure that the target is below 1500ft.

It’s the same on the Caucasus map on the training mission provided. Following everything that is asked. Bomb releases but just hits the deck.

tempMission.miz.trk

Hi, sorry about that, I’ll upload a vanilla one. Yes I made sure that the target is below 1500ft.

 

It’s the same on the Caucasus map on the training mission provided. Following everything that is asked. Bomb releases but just hits the deck.

After the last patch the fuzing changed but the training mission was not updated it seems, you are setting the EFUZ wrong, it must be set to INST instead of OFF. If you do that it should work absolutely fine. :)

After the last patch the fuzing changed but the training mission was not updated it seems, you are setting the EFUZ wrong, it must be set to INST instead of OFF. If you do that it should work absolutely fine. :)

Thank you, sir! mfuz: v/t and efuz: inst works like a charm. :thumbup:

Will try when I get home from work. Cheers, pal.

Is this the same as with all cluster munitions?

Is this the correct RL procedure now?

Will try when I get home from work. Cheers, pal.

 

Is this the same as with all cluster munitions?

 

Is this the correct RL procedure now?

It works for all clusters. Can't say if it's a correct rl procedure or not.

Ok, cool. Works anyways. Although it does seem to only burst at the same height no matter which vt I enter (judging by the weapons view anyways)

Ok, cool. Works anyways. Although it does seem to only burst at the same height no matter which vt I enter (judging by the weapons view anyways)

Height is fixed at 1500 currently, so you should always set VT to 1500 so that the targeting is accurate.

Cheers Py

This topic came up after a Sunday mission where we had a bunch of issues with the CBU-99.

I ran a quick test this morning against a column of trucks.Set as described above with VT = 1500, but the canisters did not open until 600ft AGL. And the disbursement was very minimal. Maybe 50ft at best. Very ineffective.

This topic came up after a Sunday mission where we had a bunch of issues with the CBU-99.

 

I ran a quick test this morning against a column of trucks.Set as described above with VT = 1500, but the canisters did not open until 600ft AGL. And the disbursement was very minimal. Maybe 50ft at best. Very ineffective.

Y, I understand why, for example, a lantirn pod cannot just be plug and play into avionics. It’s not like that in rl either (though oddly I’d did kind of appear overnight with harrier).

What I don’t understand is how different weapons deploy the same munition with seemingly much different effect, or follow different flight paths, etc., depending on module. Granted a cbu-105 is a much different weapon, being guided and wind corrected. But from an a-10 it is devestating to a column. The AP and AA variants share common bomblets in their respective categories right? It’s just the guidance and such that are different?canisters munitions are the same, so why is the damage different.

Checked yesterday both Mk20 and CBU99, both released around 540ft AGL, not 1500ft - causing small ground print and effect area. If anybody else can test it, please report this as a BUG.

I wonder, when ED will give us proper fuzes and setting of fuze. Now neither of them behave as it is in RL or proclaimed by ED (fixed fuze proximity dispersion at 1500ft).

Its been reported and ignored, as you can see. Only CBU that works well in DCS, is the CBU-97. All others are hard broke for years.

I just did some tests in the stable version to confirm what I had seen before: instead of bursting exactly as it passes 1500 ft, the bomb bursts about 1.2 seconds after it passes that height. This means that the actual burst height is extremely dependant on the weapons vertical velocity (and thus, the release profile). I've had bombs burst at anywhere from 530 ft to 1400+ ft depending on whether i did a steep delivery or a level delivery just above HOF.

And that's why I will normally use the secondary mode if I want anything but a very tight spread pattern.

For the record, currently in the Hornet:

EFUZ must be OFF

MFUZ on PRI will trigger the FMU-140 secondary option, which is 1.2 seconds after release

MFUZ on VT will trigger the FMU-140 primary option, which is some time after passing 1500 ft AGL

AFAIK, there should be a backup for the proximity option where if you release under 1500 ft (ie. the sensor never reaches 1500 ft), burst height becomes 300 ft, but in DCS right now it seems to revert to the 1.2 seconds after release.

I just did some tests in the stable version to confirm what I had seen before: instead of bursting exactly as it passes 1500 ft, the bomb bursts about 1.2 seconds after it passes that height. This means that the actual burst height is extremely dependant on the weapons vertical velocity (and thus, the release profile). I've had bombs burst at anywhere from 530 ft to 1400+ ft depending on whether i did a steep delivery or a level delivery just above HOF.

 

And that's why I will normally use the secondary mode if I want anything but a very tight spread pattern.

 

For the record, currently in the Hornet:

 

EFUZ must be OFF

MFUZ on PRI will trigger the FMU-140 secondary option, which is 1.2 seconds after release

MFUZ on VT will trigger the FMU-140 primary option, which is some time after passing 1500 ft AGL

 

AFAIK, there should be a backup for the proximity option where if you release under 1500 ft (ie. the sensor never reaches 1500 ft), burst height becomes 300 ft, but in DCS right now it seems to revert to the 1.2 seconds after release.

This looks like a mistake. If one mode is supposed to be 1.2 seconds after release, and the other at a set height, it could be they use the same method to detonate, and the 1.2 seconds is stored in there without any conditional. I.e., let's say there's a method "detonate" that tells the bomb to go off after 1.2sec. When in PRI mode, we call bomb.detonate() right away. When we use VT, we call bomb.detonate() at 1500ft. bomb.detonate()

Probably a simple fix, detonate should check mode to apply or not apply the 1.2 second delay.

Pure speculation, of course, but it would be an easy mistake to make.

Made some tests yesterday, and it seems like CBU-99 burst height is now 700 ft, while MK20 is 1500

It'd be nice to see someone from ED confirming if they changed it.

i dont know about you but the agm 154 A kills stuff now and it has the bomblets modeled. Takes out and disables sam sights quite well now.

Made some tests yesterday, and it seems like CBU-99 burst height is now 700 ft, while MK20 is 1500

Is that Single Player mode or M/P?

Online last night, I attacked a Soviet FFG to follow-up a Harpoon strike. The Mk.20 VTs were set to 300ft but they opened at 50ft and dispersion was terrible.

There seems to be a huge problem with this, in between S/P and M/P. Getting ED to test in M/P to confirm for themselves, doesnt appear to be an option.

Is that Single Player mode or M/P?

Online last night, I attacked a Soviet FFG to follow-up a Harpoon strike. The Mk.20 VTs were set to 300ft but they opened at 50ft and dispersion was terrible.

 

There seems to be a huge problem with this, in between S/P and M/P. Getting ED to test in M/P to confirm for themselves, doesnt appear to be an option.

It isn't as simple as that. Speed and dive angle play a HUGE roll in how well the Rockeye works in DCS atm. Just for clarity sake since people tend to agree the VT for the Rockeye on the F/A-18 is hard coded to 1,500 regardless of aircraft setting so I also set my VT to the same 1,500 to match the bomb line and pipper to what the bomb itself is going to do.

I love the Rockeye and use it all the time in MP. If you come in too steep of a dive thus also too fast you won't have much dispersion at all. You can make those drops work but you'd better be a nail driver to do so. If you come in too shallow and slow then it has huge dispersion but tends to not work at all. My best success has been to keep the speed between 400-475 and 30-40 degrees on the dive angle. It has enough of a spread to knock out the target as long as you aim it well enough in those parameters. Even some MBTs like the LeClerc will fall to one Rockeye this way.

Is that Single Player mode or M/P?

Online last night, I attacked a Soviet FFG to follow-up a Harpoon strike. The Mk.20 VTs were set to 300ft but they opened at 50ft and dispersion was terrible.

 

There seems to be a huge problem with this, in between S/P and M/P. Getting ED to test in M/P to confirm for themselves, doesnt appear to be an option.

Two things:

1. Once again, the HOF setting in the STORES page does not have any effect on actual burst height. That is set on the ground, the STORES setting is for HUD symbology and impact point computing.

2. What was your release altitude, dive angle and airspeed ? As mentionned earlier, actual burst height depends on several different factors.

- If you release below 1500 ft, it will burst 1.2 seconds after release

- If you release above that, it will release 1.2 seconds after release if EFUZ is on PRI, or 1.2 seconds after passing 1500 ft if EFUZ is on VT

And in all cases, actual height will depend on the vertical velocity of the bomb (because 1.2 seconds), and thus on the dive angle and airspeed at release.

Also (and obviously) the ground elevation must be taken into account when watching the bomb in external view).

Now I have not tested in the latest Beta, so I cannot comment on if there have been changes, but all of this must be taken into account for any discussion of height of burst.

Quick should be easy to answer questions: when planning the drop, is the pipper point the start of the dispersion? i.e. if I want to hit say three trucks in a row, do I place the pipper just in front of the 1st truck? or on the middle truck and it disperses 'around' the pipper point? Note I always use the about 400 kts and about 25-30 degree dive method.

Two things:

 

1. Once again, the HOF setting in the STORES page does not have any effect on actual burst height. That is set on the ground, the STORES setting is for HUD symbology and impact point computing.

So if the HOF on the ground set to 1500 we have to set it to 1500 in the plane as well otherwise we're not aiming right?

If not - what is the benefit of choosing a 300 HOF if we know it burst at 1500?

Should we (ideally) be able to control the HOF from the ME?

Thanks.

Yes, the 1500' HOF is hard-set on the canister itself, so setting the HOF in the STORES page to anything other than 1500 will provide inaccurate release information, there is no benefit for choosing anything else at this time.

Ideally, we should be able to set the HOF on the kneeboard (similar to setting the LGB laser code on the F-16 and F-5) when on the ground.