Give a possibility to change rockeye/CBU-99 burst height on the ground.

[Rissala]

This is not possible currently. (Set at 1500ft)

The rockeye can be a versatile weapon, but now it isn't.


Edit: Just to clarify, the Rockeye/CBU-99 height fuzes work by setting the burst height on the ground. The HT setting on the plane just changes the attack profile based on the already set height. Therefore the Rockeye/CBU-99 is locked to the default 1500ft burst height limiting its versatility greatly...

Edited October 28, 2021 by Rissala

[Marauder.exe]

Just want to give this a bump after running into this problem. 

At the moment your employment options for CBU-99/Mk 20's are extremely limited and require relatively low altitude and lower airspeeds to guarantee enough time of flight for the bomblets to arm or disperse. The Mk 118 bomblets have no means of retarding airspeed once the canister opens meaning high speed/high altitude release profiles are a non-option. Compared to the BLU-97 bomblets used by the CBU-87/103 which do have a means to retard speed and increase TOF, the height of burst ends up severely impacting the CBU-99/Mk 20/Mk 118's terminal effects. 

These high-speed/high-altitude profiles are a must when engaging in a dense MANPAD/SHORAD environment to ensure you can stay out of their engagement envelope while deploying unguided munitions. 

 

@BIGNEWY or @NineLine is this feature planned or under consideration?

[Rissala]

bump again...
this just makes the MK-20 extremely limited and one of the least used weapons
this is not the case IRL where it was extensively used
maybe this functionality will come with DTC?



Edit: Add a setting in the F8 ground crew menu to change the setting? It could be similar to the head mounted device setting.

Edit 2: The F-16 already has a system in place to change the laser codes IIRC. Why not enable that on the Hornet and CBU-99?

Edited December 8, 2021 by Rissala

[Aarnoman]

+1

[headbreaker_ger]

+1

[Northstar98]

+1 there should be some kind of fuse setting functionality present (either to change the type of fuse or to set them)

Looking at this (page 7), the Mk339 fuse present in the rockeye has 2 time settings, a primary and an option.

The primary is preset at 1.2 seconds, and the option is preset at 4.0 sections, though the function delays for both can be set anywhere from 1.2 seconds to 100 seconds.

[Swift.]

A good that I found this, I was doing some research on this matter recently. In effect for the dispenser we have (ignoring the differences between Rockeye and CBU-99 for now), there should be two fusing options: Mk339 and FMU-140.

Mk339 - Mechanical Time Fuze
This fuse should have to pre-set timings set on the weapon itself, as mentioned above they can be between 1.2 and 50.0 second or 1.2 and 100.0 seconds depending on the version of the fuse we have (Factory pre-set to 1.2 and 4.0 seconds for PRI and OPT respectively). Either of these two timings can be selected in the jet by the use of the Primary or Option fusing setting, these refer to the Tail arming wire (Primary) or the Nose arming wire (Option).

What this timing refers to is a time from release until weapon deployment. Meaning if you drop at 20,000 with a 1.2 second setting the bomb will pop 1.2 seconds after release and if you drop from 5000ft, it will pop 1.2 seconds from release. It is regardless of the height of the weapon.

FMU-140 Dispenser Proximity Fuze
This fuse should have a singular pre-set Height-of-Function that can be set on the weapon itself and a singular arming delay setting. The HOF setting will be in 100s of feet, (300,400,600...3000ft), and the arming delay in seconds (1.2, 4.0, 6.0, 8.0, 10.0). Again this fuse has two arming wires, Primary and Option as above. However with this fuse the Primary mode will make the weapon deploy at the pre-set HOF, except where this height is reached before the arming delay has expired, at which point it will deploy at 300ft HOF. The Option here refers to a hard set 1.2 arming delay followed by a 20ms delay until weapon deployment. 

So in effect, dispenser deployment will occur:
Pri = HOF set in preflight
Opt = 1.22 seconds from release

What do we have in DCS?
Well in DCS the external model for both bomb types indicates a Mk339 fuse, there is an argument to drive the FMU-140 model, but its not enabled by default.

Contrary to this, the fusing settings we have (PRI, VT) appear to be attempting to replicate the FMU-140s settings, but don't match up with the actual functionality or description of the fusings.

What should we have in DCS?

What we should expect is that for the Mk339 fuse to give a Primary and Secondary MFUZ option which refer to those preflighted times, because we cant preflight in DCS I propose we leave them at the 1.2 and 4.0 second defaults as per the real weapon.

And then we should expect the FMU-140 fuse to offer the same Primary and Secondary MFUZ option, this time referring to the time and HOF settings as above, in DCS I propose we use the same 1500ft as we have now for the PRI and the 1.22 for the OPT as in the real world (of course ideally, we'd be able to set the HOF in the kneeboard before engine startup)

TLDR
The CBU-99 and Mk20 fusing we have in DCS is wrong. We should either have 2 options for time of function, or an option for time and an option for height of function.

Edited February 5, 2022 by Swift.

[Rissala]

On 2/5/2022 at 2:30 PM, Swift. said:

A good that I found this, I was doing some research on this matter recently. In effect for the dispenser we have (ignoring the differences between Rockeye and CBU-99 for now), there should be two fusing options: Mk339 and FMU-140.

Mk339 - Mechanical Time Fuze
This fuse should have to pre-set timings set on the weapon itself, as mentioned above they can be between 1.2 and 50.0 second or 1.2 and 100.0 seconds depending on the version of the fuse we have (Factory pre-set to 1.2 and 4.0 seconds for PRI and OPT respectively). Either of these two timings can be selected in the jet by the use of the Primary or Option fusing setting, these refer to the Tail arming wire (Primary) or the Nose arming wire (Option).

What this timing refers to is a time from release until weapon deployment. Meaning if you drop at 20,000 with a 1.2 second setting the bomb will pop 1.2 seconds after release and if you drop from 5000ft, it will pop 1.2 seconds from release. It is regardless of the height of the weapon.

FMU-140 Dispenser Proximity Fuze
This fuse should have a singular pre-set Height-of-Function that can be set on the weapon itself and a singular arming delay setting. The HOF setting will be in 100s of feet, (300,400,600...3000ft), and the arming delay in seconds (1.2, 4.0, 6.0, 8.0, 10.0). Again this fuse has two arming wires, Primary and Option as above. However with this fuse the Primary mode will make the weapon deploy at the pre-set HOF, except where this height is reached before the arming delay has expired, at which point it will deploy at 300ft HOF. The Option here refers to a hard set 1.2 arming delay followed by a 20ms delay until weapon deployment. 

So in effect, dispenser deployment will occur:
Pri = HOF set in preflight
Opt = 1.22 seconds from release

What do we have in DCS?
Well in DCS the external model for both bomb types indicates a Mk339 fuse, there is an argument to drive the FMU-140 model, but its not enabled by default.

Contrary to this, the fusing settings we have (PRI, VT) appear to be attempting to replicate the FMU-140s settings, but don't match up with the actual functionality or description of the fusings.

What should we have in DCS?

What we should expect is that for the Mk339 fuse to give a Primary and Secondary MFUZ option which refer to those preflighted times, because we cant preflight in DCS I propose we leave them at the 1.2 and 4.0 second defaults as per the real weapon.

And then we should expect the FMU-140 fuse to offer the same Primary and Secondary MFUZ option, this time referring to the time and HOF settings as above, in DCS I propose we use the same 1500ft as we have now for the PRI and the 1.22 for the OPT as in the real world (of course ideally, we'd be able to set the HOF in the kneeboard before engine startup)

TLDR
The CBU-99 and Mk20 fusing we have in DCS is wrong. We should either have 2 options for time of function, or an option for time and an option for height of function.

 

Excellent research. So what we have in DCS resembles some weird combination of fuzes and stuff, which in the end does not resemble any real weapon. @BIGNEWY , can you have a look?