What do all the fuzes do?

[fortheiy12]

Between all of the different bombs and their fuse choices, I can't seem to figure out what all of them do besides just change what is going on at the back or the front of the bomb. Could someone explain to me what the fuses do, especially the ones for LDGP and canister munitions?

[Muchocracker]

M904E4 - mechanical nose fuse with safe separation arming delay and impact function delay settings. 

M905 - direction reflection of the 904 but is a tail fuse

FMU-139 - electromechanical tail fuse with arming and function delay. Can be electronically armed in the jet as an instantanious detonation fuse, or use the function delay settings on the faceplate

All 3 of theses are ground crew set and cannot be changed in cockpit minus the caveat with the 139

 

Mk-339 mod 1 - mechanical time clock dispenser fuse that functions the dispenser based on time from release of the weapon. PRI and OPT are 2 different set of function timings

FMU-140 - Radar altimeter proximity dispener fuse that functions on AGL. Vt1 uses the rad-alt. Vt2 uses a backup time based function. Only accesible on the CBU-99

Both of these fuses are ground crew set. You can change with option to use in cockpit. But you cannot change the timings.

 

FMU-143 - electromechanical hard target tail fuse. Used for bunker penetration with a higher 75G impact force activation and (should) have a fixed 60ms function delay. 

FMU-152 - Joint Programmable Fuse. This the only attachable fuse that is fully in cockpit programmable. But only with JDAM's. JPF page is accessd under JDAM DSPLY --> Mission --> JPF. Has arming and function delay settings. Will use the faceplate settings as default if unmodified. 

 

DSU-33 - AGL airburst nose fuse for the mk-80 series warheads. Fixed 20m burst height.

 

This about as condensed of an explanation as i can make it. There are a ton of nuances and caveats but this will get you started

Edited September 23, 2024 by Muchocracker

[Recluse]

16 hours ago, Muchocracker said:

 

DSU-33 - AGL airburst nose fuse for the mk-80 series warheads. Fixed 20nm burst height.

 

 

 

@Muchocracker Should this be 20m burst height?

[Muchocracker]

4 minutes ago, Recluse said:

@Muchocracker Should this be 20m burst height?

It's suppose to be from 5m-25m burst heights selectable from sources but it isn't. Idk why ED did it that way. 

[Recluse]

30 minutes ago, Muchocracker said:

It's suppose to be from 5m-25m burst heights selectable from sources but it isn't. Idk why ED did it that way. 

No, I mean in your post it says "nm" ;looks like 20 nautical miles or nanometers    

Edited September 21, 2024 by Recluse

[Muchocracker]

55 minutes ago, Recluse said:

No, I mean in your post it says "nm" ;looks like 20 nautical miles or nanometers    

 

oh, just a typo. Fixed

[FrostLaufeyson]

2024/9/21 AM7点11分，Muchocracker说：

M904E4 - mechanical nose fuse with safe separation arming delay and impact function delay settings. 

M905 - direction reflection of the 904 but is a tail fuse

FMU-139 - electromechanical tail fuse with arming and function delay. Can be electronically armed in the jet as an instantanious detonation fuse, or use the function delay settings on the faceplate

All 3 of theses are ground crew set and cannot be changed in cockpit minus the caveat with the 139

 

Mk-339 mod 1 - mechanical time clock dispenser fuse that functions the dispenser based on time from release of the weapon. PRI and OPT are 2 different set of function timings

FMU-140 - Radar altimeter proximity dispener fuse that functions on AGL. Vt1 uses the rad-alt. Vt2 uses a backup time based function. Only accesible on the CBU-99

Both of these fuses are ground crew set. You can change with option to use in cockpit. But you cannot change the timings.

 

FMU-143 - electromechanical hard target tail fuse. Used for bunker penetration with a higher 75G impact force activation and (should) have a fixed 60ms function delay. 

FMU-152 - Joint Programmable Fuse. This the only attachable fuse that is fully in cockpit programmable. But only with JDAM's. JPF page is accessd under JDAM DSPLY --> Mission --> JPF. Has arming and function delay settings. Will use the faceplate settings as default if unmodified. 

 

DSU-33 - AGL airburst nose fuse for the mk-80 series warheads. Fixed 20m burst height.

 

This about as condensed of an explanation as i can make it. There are ton of nuances and caveats but this will get you started

 

Excuse me, is there still no fuze explanation document for DCS? The Bf109 fuze took me a lot of time to search for information before I could understand the role of each parameter.

[Skeet]

On 9/21/2024 at 8:25 PM, FrostLaufeyson said:

Excuse me, is there still no fuze explanation document for DCS? The Bf109 fuze took me a lot of time to search for information before I could understand the role of each parameter.

No, there is not a published document like that discusses what the fuses do, the practical use for them, which munitions might be accepting of them, and which would not, etc. At least to my knowledge there is not (hasn't been).  There is a User's Manual, however it has not been updated to include that information, unless it is out just recently, and I have not downloaded.

[kotor633]

Am 21.9.2024 um 01:11 schrieb Muchocracker:

M904E4 - mechanical nose fuse with safe separation arming delay and impact function delay settings. 

M905 - direction reflection of the 904 but is a tail fuse

FMU-139 - electromechanical tail fuse with arming and function delay. Can be electronically armed in the jet as an instantanious detonation fuse, or use the function delay settings on the faceplate

All 3 of theses are ground crew set and cannot be changed in cockpit minus the caveat with the 139

 

Mk-339 mod 1 - mechanical time clock dispenser fuse that functions the dispenser based on time from release of the weapon. PRI and OPT are 2 different set of function timings

FMU-140 - Radar altimeter proximity dispener fuse that functions on AGL. Vt1 uses the rad-alt. Vt2 uses a backup time based function. Only accesible on the CBU-99

Both of these fuses are ground crew set. You can change with option to use in cockpit. But you cannot change the timings.

 

FMU-143 - electromechanical hard target tail fuse. Used for bunker penetration with a higher 75G impact force activation and (should) have a fixed 60ms function delay. 

FMU-152 - Joint Programmable Fuse. This the only attachable fuse that is fully in cockpit programmable. But only with JDAM's. JPF page is accessd under JDAM DSPLY --> Mission --> JPF. Has arming and function delay settings. Will use the faceplate settings as default if unmodified. 

 

DSU-33 - AGL airburst nose fuse for the mk-80 series warheads. Fixed 20m burst height.

 

This about as condensed of an explanation as i can make it. There are a ton of nuances and caveats but this will get you started

 

Just put this kind of information in your official ED manual...The time that was used to open the thread and post the information could just as well have been used to update the manual and publish it with the last patch.

[Muchocracker]

1 hour ago, kotor633 said:

Just put this kind of information in your official ED manual...The time that was used to open the thread and post the information could just as well have been used to update the manual and publish it with the last patch.

Chief. I am not an ED employee. Completely irrelevant

Edited October 8, 2024 by Muchocracker

[MAXsenna]

Does all bombs have fuses now. So a lot of old missions has issues? 

[kotor633]

@MuchocrackerWhat is the reason you call me 'chief'?
Completely irrelevant? Aha...
Then we can only hope that an ED employee reads this and implements it. This information would be interesting for all of us DCS players. And in the forum, things like this are quickly forgotten.

[AndrewDCS2005]

Requested official documentation on fuzes back in May (when it was released) in the following thread.

However, it seems that short blurbs which are shown on mouse hover over the fuze (and copied by Muchocracker in this thread), is all we'll ever get - which is mostly useless anyway as it describes self-evident technical params, not their purpose or best use. I would not expect more than that.

 

[Muchocracker]

5 hours ago, kotor633 said:

@MuchocrackerWhat is the reason you call me 'chief'?
Completely irrelevant? Aha...
Then we can only hope that an ED employee reads this and implements it. This information would be interesting for all of us DCS players. And in the forum, things like this are quickly forgotten.

...same reason anyone calls anyone else "bro"? 

[graveyard4DCS]

Hi. 

Just for info you can have more details about bomb fuze here, and even more related to the F/A-18 case on my personal page.

Enjoy! 

[The_Cokester]

Jesus Christ, I just realized in the CBU fuses, the PRI and OPT are just short for primary and optional meaning you can set both of them in the rearming window and then choose which one you want when in the air. But you can’t change the times for PRI and OPT unless you are on the ground.

[Phantom711]

@The_Cokester

Yes, and for the Mk20 it gets even trickier since it does not dispense based on altitude, but on „time after release“. So you need to know your altitude above the target prior the flight or adjust your altitude in flight accordingly. Then you need to do the math by yourself or find a website that calculates the time of fall of an object and then substract a couple of seconds from that for your desired dispense (like 2-5sec I would say).

[Muchocracker]

1 hour ago, Phantom711 said:

@The_Cokester

Yes, and for the Mk20 it gets even trickier since it does not dispense based on altitude, but on „time after release“. So you need to know your altitude above the target prior the flight or adjust your altitude in flight accordingly. Then you need to do the math by yourself or find a website that calculates the time of fall of an object and then substract a couple of seconds from that for your desired dispense (like 2-5sec I would say).

You don't have to. The Bombing computer accounts for it in both CCIP and AUTO.

[Phantom711]

vor 1 Stunde schrieb Muchocracker:

You don't have to. The Bombing computer accounts for it in both CCIP and AUTO.

I don´t see how this would work. The Mk339 Mod1 is the only fuze that can be selected. In the fuze menu. It is a timed fuze and you have to select the time for the PRI and OPT fuze setting (function delay) on the ground (or mission editor). 

 

Once in the air, there are no other options to be set, like a burst hight.

So I just did a quick test, where I flew significantly below my calculated altitude, had the tgt designated via ATFLIR and as expected, the Mk20 just impacted the ground without dispensing the submunitions.

Of course, I had tested this before while adhering to the calculated parameters and the submunitions expanded on that one.nullnull

Edited December 16, 2024 by Phantom711

[Muchocracker]

15 minutes ago, Phantom711 said:

I don´t see how this would work. The Mk339 Mod1 is the only fuze that can be selected. In the fuze menu. It is a timed fuze and you have to select the time for the PRI and OPT fuze setting (function delay) on the ground (or mission editor). 

 

Once in the air, there are no other options to be set, like a burst hight.

So I just did a quick test, where I flew significantly below my calculated altitude, had the tgt designated via ATFLIR and as expected, the Mk20 just impacted the ground without dispensing the submunitions.

Of course, I had tested this before while adhering to the calculated parameters and the submunitions expanded on that one.nullnull

That is the DUD cues being bugged and i believe has been reported previously, and it's a problem with a bunch of weapons. The SMS gets told what the timings are when the weapons codes are loaded by the ordinance handlers. 


 

Edited December 16, 2024 by Muchocracker

[Phantom711]

@Muchocracker

But it‘s not a DUD. It works perfectly fine if you use it correctly.

It simply is the way that fuze works. It dispenses after a certain time. If you put in 20sec it dispenses 20sec after release.
How would the computer account for that if you fly too low? Again…there is no option anywhere to set a dispense hight. It doesnt have any type of altimeter.

https://cat-uxo.com/explosive-hazards/fuzes/mk-339-fuze

Or do you mean you would get a DUD cue if the computer calculates, that the bomb would not have sufficient time to dispense before impact? 

Edited December 16, 2024 by Phantom711

[Mapi]

Am 21.9.2024 um 18:11 schrieb Recluse:

@Muchocracker Should this be 20m burst height?

20 ft

Real: 5 - 35 Feet (80%)

Edited December 16, 2024 by Mapi

[Muchocracker]

1 hour ago, Phantom711 said:

 

Or do you mean you would get a DUD cue if the computer calculates, that the bomb would not have sufficient time to dispense before impact? 

Yes. That is what the jet should be doing

[Tholozor]

2 hours ago, Phantom711 said:

The Mk339 Mod1 is the only fuze that can be selected

 

You can select the FMU-140 on the CBU-99 version of the Rockeye.

[Phantom711]

vor 34 Minuten schrieb Muchocracker:

Yes. That is what the jet should be doing

Fair enough. But still, all you could do is climb, until the DUD cue is gone. Now you would at least know that the canister will dispense the submunition prior impact. But I still think one should have an idea of it before and calculate the timings.

 

vor 17 Minuten schrieb Tholozor:

You can select the FMU-140 on the CBU-99 version of the Rockeye.

Thanks. Yeah, I‘m well aware of that, that‘s why I was specifically referring to the Mk20. The CBU-99 is definitely more user-friendly with the FMU-140.