JDAM feature questions?

[Furiz]

In the Wags video, we only see basic link to the TGP and that's it, don't see any option to input coordinates manually, what other options are planned for JDAM deployment, and JSOW for that matter?

And will there be HSD integration with JDAM/JSOW, like a drop zone on the Hornet HSI,  or that's coming later when HSD features are upgraded?

[Donglr]

To add to this question: Wags showed you can set the impact azimuth from 0 to 360°, he left it on 0. What if I don't want to set it, simply letting it impact the way I happen to fly when pressing the pickle button? Do I leave it at 0? Does 0 mean "not used" and 360° actually means north? Otherwise not changing it with approach direction could mean I lose range because the bomb has to steer more and changing azimuth setting with each bomb run seems tedious.

[IkarusC42B Pilot]

-_-

[Badlego]

In the VIS mode demonstration Wags was using a TDC cue on the HUD and it was shown, that the TGP was not slaved to this cue. It is a known bug in the F16, that the HUD cue is off the target position on the ground. Therefore, I assume you will miss your target when aimed with the HUD cue. Is it possible to use the TGP to get the impact point in VIS mode instead (this would make it equal to a TOO mode, just without storing the target points like in the hornet)?

[AvroLanc]

4 hours ago, Donglr said:

To add to this question: Wags showed you can set the impact azimuth from 0 to 360°, he left it on 0. What if I don't want to set it, simply letting it impact the way I happen to fly when pressing the pickle button? Do I leave it at 0? Does 0 mean "not used" and 360° actually means north? Otherwise not changing it with approach direction could mean I lose range because the bomb has to steer more and changing azimuth setting with each bomb run seems tedious.

 

0 means OFF, or no Impact Azimuth specified. The input values run 0-359. In fact, when 0 is set, the Impact Azimuth line on the SMS page should not show at all. 

[Machalot]

2 hours ago, AvroLanc said:

 

0 means OFF, or no Impact Azimuth specified. The input values run 0-359. In fact, when 0 is set, the Impact Azimuth line on the SMS page should not show at all. 

So no 360? Directly north is not available? 

[Donglr]

1 minute ago, Machalot said:

So no 360? Directly north is not available? 

 

I was wondering the same thing. But then I though, meah, just put in 359, how gives a hoot about that one degree, if it's even able to hit that precisely.

[ebabil]

I asked the same question in below the video about the coordinate entering. He replied that " it is based on spi, you can use several methods to set spi."

So how can i set a spi without entering a steerpoint in viper?

[Furiz]

3 hours ago, AvroLanc said:

 

0 means OFF, or no Impact Azimuth specified. The input values run 0-359. In fact, when 0 is set, the Impact Azimuth line on the SMS page should not show at all. 

 

If 0 is OFF then values should run from 1-360 so you have complete compass rose, 0-359 means you are missing 1 degree if 0 = OFF.

Edited June 13, 2021 by Furiz

[BIGNEWY]

Hi,

 

You can also set SPI with the TGP, HUD, and later AG radar. 

 

6 hours ago, Badlego said:

In the VIS mode demonstration Wags was using a TDC cue on the HUD and it was shown, that the TGP was not slaved to this cue. It is a known bug in the F16, that the HUD cue is off the target position on the ground. Therefore, I assume you will miss your target when aimed with the HUD cue. Is it possible to use the TGP to get the impact point in VIS mode instead (this would make it equal to a TOO mode, just without storing the target points like in the hornet)?

No, SPI is set on the HUD per the symbology. TGP is not SOI, so not yet slaved to the SPI. 

[AvroLanc]

17 minutes ago, Furiz said:

 

If 0 is OFF then values should run from 1-360 so you have complete compass rose, 0-359 means you are missing 1 degree if 0 = OFF.

 

I doubt very much the JDAM autopilot can even manoeuvre with enough precision to ensure a hit with -+1 degree. If it can strike within 2 degrees of the selected angle it’s doing well I guess. 
Having 359 as North isn’t going to be a problem. 

[Furiz]

25 minutes ago, BIGNEWY said:

Hi,

 

You can also set SPI with the TGP, HUD, and later AG radar. 

 

No, SPI is set on the HUD per the symbology. TGP is not SOI, so not yet slaved to the SPI. 

 

Hi Bignewy,

we noticed that TGP is not following the Box on the HUD when Wags was moving it, that's our concern cause it was happening in the past that the SPI was not getting updated in a similar way, it would then result in a miss.

 

9 minutes ago, AvroLanc said:

I doubt very much the JDAM autopilot can even manoeuvre with enough precision to ensure a hit with -+1 degree. If it can strike within 2 degrees of the selected angle it’s doing well I guess. 
Having 359 as North isn’t going to be a problem. 

 

+-1 degree can mean hitting a building or getting through to the target, it is very much important.

Edited June 13, 2021 by Furiz

[TobiasA]

The TGP was in area or point track when he went to VIS. AFAIK this behavior is correct. Since the TGP is tracking something it doesn't get slewed to the SPI.

Just wondering- did my previous comment get deleted (if yes, why) or did I forget to actually press "send"?

 

[ebabil]

2 hours ago, BIGNEWY said:

Hi,

 

You can also set SPI with the TGP, HUD, and later AG radar. 

 

No, SPI is set on the HUD per the symbology. TGP is not SOI, so not yet slaved to the SPI. 

 

So we can not send the jdams right to the coordinates like we do with the hornet? 

[llOPPOTATOll]

1 hour ago, ebabil said:

 

So we can not send the jdams right to the coordinates like we do with the hornet? 

Yes thats correct, you can not do that.

[jojojung]

Gerade eben schrieb llOPPOTATOll:

Yes thats correct, you can not do that.

I think thats only possible with creating a steerpoint at the target

[llOPPOTATOll]

Just now, jojojung said:

I think thats only possible with creating a steerpoint at the target

Yeah, its all off of SPI, you can create four steer point on the target and cycle through them and drop on each, but you cannot just assign coordinates to the bomb like the PP mode in the hornet. Only some export blocks like IAF vipers have the capability to assign coordinates to each bomb.

[Machalot]

4 hours ago, Furiz said:

 

+-1 degree can mean hitting a building or getting through to the target, it is very much important.

 

I agree with @AvroLanc that the azimuth accuracy of the weapon is likely wider than 1 deg, and therefore we shouldn't be relying on a 1 deg wide window to hit a target.

 

However, I agree with you @Furiz that the exclusion of 360 as an ingress heading (if true) is an annoying and unnecessary design choice by MD/Boeing (or ED?).  With an uncertainty window several degrees wide on the ingress heading, it always best to be able to center that window on the desired azimuth.

Edited June 13, 2021 by Machalot
rm unrelated quote

[llOPPOTATOll]

8 hours ago, AvroLanc said:

The input values run 0-359.

Any value between 0 and 360 degrees may be entered; however, an entry of 0 will be considered invalid to the weapon and will cause the weapon to fly from the
release point direct to the target.

[TheBigTatanka]

This is going to be great. Pretty stoked about the attention the viper is getting.

Everyone start making your jdam fallout matrix!

There's a lot i don't know, but the video didn't give me any cause for concern. It would have been nice to see him target off the TGP just to have a warm fuzzy that it's working now..... But i think only good things are coming.

Sent from my Pixel 3 XL using Tapatalk

[Frederf]

It's 0,1-360 for azimuth entry. 0 is for undefined and 1-360 are for the points of the compass defined. If "0" is entered or if using VIS then this is blanked. E.g. I think it was "IMP AZ" instead of "IMP AZ 1°" through "IMP AZ 360°". There is no specified distance the weapon flies straight along the specified azimuth. It can be mid-turn and only achieve desired azimuth at the moment of impact. Azimuth is magnetic north.

 

It's good to know that missile step can pick left/right station similar to AG missiles like Maverick or HARM. You can also use the OSBs on either side as well.

 

While a satisfactory alignment is required to show "RDY" it is possible to launch JDAM during "ALN" marginal alignment state with degraded performance.

 

Weapon-profile association is memorized so multiple weapons can be launched with distinct profiles without pilot selection between releases. By default station 3 gets 1 and station 7 gets 3 but they can be changed. I don't know if BRU-57 was factored into the software to allow 4 weapon release with 4 distinct profiles without pilot interaction between releases. He may have to change stations 3/7 to new programs for the third and fourth releases if he wants each bomb to have a distinct profile.

 

What I'm noticing missing is LAR2 and quite a few HUD features missing. LAR2 is an inner component to the range staple similar to AMRAAM display and indicates compliance with terminal parameters. LAR2 is only displayed in certain conditions depending on weapon, parameters, and airplane positioning. Accompanying LAR2 is information about pitch steering in the form of a loft angle number, turn information in the typical L/R tens-of-degrees and expected altitude at top of loft plus a timer which shows either time to enter LAR2 or time to impact. I also noticed the DLZ was fixed scale at 20nm. It should instead be dynamic maximum tick range at 143% of whatever R1max is so if you're low and slow the tick at the top of the DLZ represents fewer miles than if you are high and fast because R1max is shorter in the former case and longer in the later.

 

Since we're not in the fancier F-16s we're limited to individual "inc-dec" multi target engagement which isn't as fancy as the F-18s one button system but it's pretty easy to use. Four sequential waypoints and it's quite rapid. It's just like A-10 JDAM employment. Make SPI, Kill SPI, one at a time.

[Rubberduck85]

Yeah, its all off of SPI, you can create four steer point on the target and cycle through them and drop on each, but you cannot just assign coordinates to the bomb like the PP mode in the hornet. Only some export blocks like IAF vipers have the capability to assign coordinates to each bomb.

Maybe with markpoints created through TGP one could be able to cycle them after each JDAM release?

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[WHOGX5]

3 hours ago, Rubberduck85 said:

Maybe with markpoints created through TGP one could be able to cycle them after each JDAM release?

Sent from my MI 10 Lite 5G using Tapatalk
 

Yes. It doesn't matter if it's markpoints or not, but markpoints are definitely easier if you don't have pre-planned target steerpoints. Just pickle, next STPT, pickle, next STPT, etc.

[smire666]

1. Pre-planned steerpoints would be OK for me, only if they will be accurate. If you´ll use coordinates from F10, the position is sometimes a few meters out of e.g. building middle (which is NOK for pinpoint strike at smaller target). Otherwise we´ll need TGP for a successfull strike, what generally means: JDAM is fire and forget weapon, also for the targets masked with the weather, but no for Viper...

2. The F/A18 DED symbology (big and small circle) - I don´t need them, as we have a range-bar on the HUD.

3. Different "terminal instructions" for each bomb is a "must."

[SFJackBauer]

3 hours ago, smire666 said:

1. Pre-planned steerpoints would be OK for me, only if they will be accurate. If you´ll use coordinates from F10, the position is sometimes a few meters out of e.g. building middle (which is NOK for pinpoint strike at smaller target). Otherwise we´ll need TGP for a successfull strike, what generally means: JDAM is fire and forget weapon, also for the targets masked with the weather, but no for Viper...

 

Press LAlt+Y two times while on F10 map to get the precise coordinates.