JDAM question

[Viciam1]

Hi guys,

 

Why do some of my JDAMs not explode and destroy the target and some do? What am I doing wrong?

I see them hit the target but some don't go boom

 

Is it something to do witht the fuse?

 

Thanks in advance.

[durka-durka]

Check to make sure you are in GND mode and not AIR mode.  

 

As for accuracy, the same happens to me.  On every run, if I carry 4 bombs, I will have at least 1/4 miss completely 95% of the time.  2/4 might miss the target, but still be close enough to destroy, and 1/4 will hit dead-on.  This has been tested at level flight from between 10,000 - 25,000 ft, typically 15,000ft.  Full alignment and coordinates punched in via steerpoints using map.

 

I've also tested (not as much) using different pitch or bank angles and it seems the bombs hit half the time, while the other half are off.

[Das Feuer]

JDAM the bomb it self is not fully modeled yet, that means that the fuses don't work at the moment.

You can make sure it would explode by making sure you are in normal ground fuse so press once the OSB next to the fuse selector when it's showing AIR and the it should show GND,

make sure that below it it's saying 0 MSEC that means there is no time fuse, currently time fuses don't work and the AIR fuse doesn't as well.

 

If you still have problems send a message I will try and help.

[TobiasA]

vor 3 Stunden schrieb Viciam1:

Hi guys,

 

Why do some of my JDAMs not explode and destroy the target and some do? What am I doing wrong?

I see them hit the target but some don't go boom

 

Is it something to do witht the fuse?

 

Thanks in advance.

 

Keep in mind that you need absolute precision on the TGP. I have been failing JDAMs pretty regular on vehicles, and came to the conclusion that JDAMs are fine for buildings but for vehicles, paveways rock.

 

As described in the above thread, you need to lase the target shortly for a few seconds before pickling to enable the TGP rangefinder and update the target position. I had regular close misses before, and even with laser ranging, some JDAMs just miss.

[Silvester.E]

Like above seems to work for me perfectly fine! 
 

Point track vehicle at the wheels/ground and just before dropping jdam, lase shortly. 

Edited June 26, 2021 by Silvester.E

[Florence201]

I did AIR burst, TGP to bottom of vehicle chassis, generate coords and input into an SP then drop JDAM. Hit every time 

[Das Feuer]

1 hour ago, Florence201 said:

I did AIR burst, TGP to bottom of vehicle chassis, generate coords and input into an SP then drop JDAM. Hit every time 

It does hit and will destroy if it's a head on collision, but, it wont explode currently AIR fuse or any time delay fuse will not make the bomb explode, it will just impact the ground.

 

[Harlikwin]

People forget that JDAM's CEP was like 11m and at best like 5m... And it depends on how many satellites it can see, and if its being launched in GPS mode or INS mode (i.e. a GPS jammed environment). And that for actual high precision LGB's are better, and that stuff like the GBU54 with a terminal laser seeker was developed to improve accuracy etc.

[TobiasA]

vor 2 Stunden schrieb Harlikwin:

People forget that JDAM's CEP was like 11m and at best like 5m... And it depends on how many satellites it can see, and if its being launched in GPS mode or INS mode (i.e. a GPS jammed environment). And that for actual high precision LGB's are better, and that stuff like the GBU54 with a terminal laser seeker was developed to improve accuracy etc.

This. LGB's are better for vehicles, and they can be used on moving targets as well opposed to the JDAM. The advance of the JDAM is that it is fire and forget on multiple targets per pass and can be dropped through a cloud cover, for actual precision nothing beats LGBs.

Edited June 26, 2021 by TobiasA

[Hawkeye_UK]

On 6/26/2021 at 8:51 PM, Harlikwin said:

People forget that JDAM's CEP was like 11m and at best like 5m... And it depends on how many satellites it can see, and if its being launched in GPS mode or INS mode (i.e. a GPS jammed environment). And that for actual high precision LGB's are better, and that stuff like the GBU54 with a terminal laser seeker was developed to improve accuracy etc.

 

Exactly this.

[Frederf]

The JPF fuze options have no effect currently. AIR/GND/GND DLY it doesn't matter the bomb explodes like any MK-82, simply impact. It is impossible to do anything wrong with the fuzes. Even long AD time setting (25sec) with short TOF (10s) they still explode.

 

I don't know how the GBU-38s won't explode unless you have very short TOF maybe. Not destroying target is usually due to bomb not impacting close enough to target.

[Sinclair_76]

1 hour ago, Frederf said:

The JPF fuze options have no effect currently. AIR/GND/GND DLY it doesn't matter the bomb explodes like any MK-82, simply impact. It is impossible to do anything wrong with the fuzes. Even long AD time setting (25sec) with short TOF (10s) they still explode.

 

I don't know how the GBU-38s won't explode unless you have very short TOF maybe. Not destroying target is usually due to bomb not impacting close enough to target.

I've tested fuze setting with the JDAM (GBU-31A) on buildings. While AIR will set the buildings on fire a GND with no delay will destroy it outright. So there appears to be some difference in effect.

[Xavven]

11 minutes ago, Sinclair_76 said:

I've tested fuze setting with the JDAM (GBU-31A) on buildings. While AIR will set the buildings on fire a GND with no delay will destroy it outright. So there appears to be some difference in effect.

 

I confirm this. I'm playing a DCS Liberation campaign and the "Workshop A" is a common factory target. It takes two GBU-31(V)1/B with the GND setting to destroy it. If left on AIR the building will not be destroyed.

[llOPPOTATOll]

12 hours ago, Frederf said:

The JPF fuze options have no effect currently. AIR/GND/GND DLY it doesn't matter the bomb explodes like any MK-82, simply impact. It is impossible to do anything wrong with the fuzes. Even long AD time setting (25sec) with short TOF (10s) they still explode.

 

I don't know how the GBU-38s won't explode unless you have very short TOF maybe. Not destroying target is usually due to bomb not impacting close enough to target.

Setting the arming delay technically shouldn't even change the arming delay of the bomb unless it is equipped with JPF(our jdams arent equipped with JPF) if there is not JPF the arming delay should only be used for HUD LOW cues

[Frederf]

Technically if JPF isn't communicating on 1760 bus the F-16 won't show the JPF menu at all.

 

The remaining menu does have some settings for FMU-143 or FMU-139 but as expected they are for entering fuze details for warning cues and not for programming anything.

 

Thus that AIR or GND DLY are visible at all means that JPF is communicating on bus. Probably ED has no intention of programming two menu logics based on if JPF is present or not. Instead if JPF is always present (expense of JPF not a concern) as it is a valid fuze for all applications (139 is only used for MK84 warheads, 143 only for 109 for example) then it is not needed to program for a condition that never happens.

 

I only tested AIR v GND visually but seeing impact at minimum time acceleration. I figured airburst would explode above ground. If air/gnd configured bombs do different damage that is something I did not check.

[Bunny Clark]

On 7/1/2021 at 12:24 PM, Frederf said:

Probably ED has no intention of programming two menu logics based on if JPF is present or not. Instead if JPF is always present

There were images some time ago of the JPF 3D model being in the game, so I think it's pretty clear at this point that it'll be added for all JDAMs at some point in the future. As you said, probably as the only option. 

[slash11985]

I noticed the lack of precision only in multiplayer server for what concernig the jdam ..If in SP mission the jdam hit pretty close to the target ...hope they solve as soon as they can

[Shrike88]

I understand JDAM's CEP is like 11-5M of an area however until ED fixes and implements a type of better blast damage model and shrapnel against armored vehicles this is moot.  What really needs to be addressed first is the simple damage model of a 1 or a 0 based on if a weapon hits something.  Then the family of GBU series ordinance barely missing according to more accurate real world spec would be less of a waste. 

[Irishlad200000]

Like above seems to work for me perfectly fine! 
 
Point track vehicle at the wheels/ground and just before dropping jdam, lase shortly. 

Why would you lase for a Jdam??

[Sarge55]

He probably means a quick lase to update the target info.  Not to guide like you do for an LGB.

[Jetguy06]

45 minutes ago, Sarge55 said:

He probably means a quick lase to update the target info.  Not to guide like you do for an LGB.

This. The laser gives you a more accurate coordinate designation.

[Wiggo]

Why I CANT change JDAM fuze mode from "AIR" -> "GND" AT ALL? Just bought an f-16, but it seems that that has worked before? How about now? Only thread I found about this BUG (*waving to* @Eagle Dynamics ) was in reddit, which was about update this year, if I understood correctly. (01/2023) How is this now?

[Hobel]

vor 30 Minuten schrieb Wiggo:

Why I CANT change JDAM fuze mode from "AIR" -> "GND" AT ALL? Just bought an f-16, but it seems that that has worked before? How about now? Only thread I found about this BUG (*waving to* @Eagle Dynamics ) was in reddit, which was about update this year, if I understood correctly. (01/2023) How is this now?

It's wip, it'll come back later

 

 

[Wiggo]

1 hour ago, Hobel said:

It's wip, it'll come back later

 

 

Thanks. I thought there has to be error, that I´m not that bad, that not hitting the blinking button, with my mouse.

Edited February 25, 2023 by Wiggo