Viper Refuel / rearm and INS alignment

[84-Simba]

Hi guys !

Can someone elaborate step by step how to rearm and refuel on a friendly base with the Viper ?

Last time I tried it was impossible to get my wing fuel tanks to be refueled and the JDAMs were not landing where they should.

I suspect there is a special procedure to get this done.

I don't mind if it's not the real hot rearm/refuel process, I just want to know what to do to avoid to have to deslot / reslot in MP.

[VarZat]

For fuel tanks you need to first take them off, and then take them back on. A seperate fuel tank slider would be a welcome addition.

For JDAMs, you need to make sure you get them powered all the way on and that the target is in the absolute middle of the crosshair. The accuracy has been flaky as of lately with these, but i was able to hit some vehicles when i tried yesterday.

[84-Simba]

Thank you for the fuel tanks.

For the JDAMs, maybe I wasn't clear enough.

The bombs are perfectly accurate on the first flight but after a rearm / refuel they are not anymore.

Also, but I maybe wrong, I think they took more time to be fully aligned and ready to be dropped.

I made 2 flights back to back on the same training range and did pretty much the exact same process regarding my fence in since I have a particular steerpoint to do it.

On the first flight the JDAMs were ready when I arrived on the range.

On the second, I had to make my laser-guided bombs runs until the JDAMs were aligned ... and they missed their targets.

I had a similar experience with 2xGBU-31 penetrators missing completely a concrete shelf on a second flight while they went dead on target on the first flight.

[VarZat]

Hmm that is something to test definitly, sorry i missed the first explanation.

[skywalker22]

5 hours ago, VarZat said:

For fuel tanks you need to first take them off, and then take them back on. 

No need, here is the trick

[VarZat]

Aaah, never got that to work, guess i was missing the under 2500lb part

[Tholozor]

Yea, the external tanks will only fill the same amount that's missing from the internal tanks (i.e. the externals will stop once the internals are full).

[84-Simba]

Thank you guys for all the info on the fuel tanks.

Regarding the INS alignment (which is my main suspect on the JDAMs mishapp), do you guys know if there is a particular process ?

Is there any need to realign ?

Hot or cold mandatory ?

[Tholozor]

Have you tried using the FIX update methods?

[BammBamm]

FIX update methods?  Could you please elaborate or provide a link.

I fought with the ins alignment for hours yesterday watching WAGGS youtube alignment and not getting anywhere near the same result and it is way off when targeting and waypoints by about 6 miles or so.  Mine also gets to about 10 and stops.  I literally followed his instructions to the exact T several time and several game restarts and even a install repair and also a complete reinstall on a seperate machine.  Same results every time.  Am I missing something here?  Is it supposed to stop at 10 now and be off that far? lol.

[rob10]

5 minutes ago, BammBamm said:

FIX update methods?  Could you please elaborate or provide a link.

I fought with the ins alignment for hours yesterday watching WAGGS youtube alignment and not getting anywhere near the same result and it is way off when targeting and waypoints by about 6 miles or so.  Mine also gets to about 10 and stops.  I literally followed his instructions to the exact T several time and several game restarts and even a install repair and also a complete reinstall on a seperate machine.  Same results every time.  Am I missing something here?  Is it supposed to stop at 10 now and be off that far? lol.

Yes, it's changed since that youtube was recorded.  It doesn't go farther than 10.  Shouldn't be off just because it stopped at 10.

[BammBamm]

Ya, it stops at 10 on the right and the left keeps going counting upwards for quite awhile and the RDY flashes continuously after a certain point.

Is there a guide or new procedure to follow?  What FIX is Tholozor referring to?

Thank you,

[84-Simba]

Sorry guys but my OP is not about the alignement procedure per se.

If you just switch to NAV normally in the first flight everything looks normal to me.

My questions were :

- Is the refuel / rearm process demanding an INS re-alignment ?

- Is the refuel / rearm process demanding to be cold or can it be done hot ? (in which case, what is the process in DCS)

 

We now know how to deal with fuel tanks but still remain a potential problem with INS.

@BIGNEWY

@NineLine

@Wags

Do you have any element to enlighten us ?

Again, I'm not debating on whether a process is real or not ... just how it works in DCS.

Thank you guys.

1 hour ago, Tholozor said:

Have you tried using the FIX update methods?

FIX is the in-flight INS recalibration, right ?

Using TGP, FCR, Overfly, etc ...

[Tholozor]

FIX can also be used on the ground. You can create a waypoint on your actual position and update via overfly.

Refueling/rearming shouldn't require you to realign your INS.

[QuiGon]

On 2/11/2023 at 2:06 AM, 84-Simba said:

- Is the refuel / rearm process demanding an INS re-alignment ?

No, it does not.
 

On 2/11/2023 at 2:06 AM, 84-Simba said:

- Is the refuel / rearm process demanding to be cold or can it be done hot ? (in which case, what is the process in DCS)

It can be done hot just fine.
 

On 2/11/2023 at 2:06 AM, 84-Simba said:

FIX is the in-flight INS recalibration, right ?

Using TGP, FCR, Overfly, etc ...

NO! FIX does not align the INS! FIX just updates your current position based on a known landmark that you need to designate through a sensor of your choice. It's purpose is to get rid of INS drift that accumulates over time, although this should only really happen in missions where there is no GPS available though. So I wonder: Is the mission where you experience this set prior to 1994 (that's when GPS becomes available in DCS) or do you fly on red side?
 

On 2/11/2023 at 2:06 AM, 84-Simba said:

Again, I'm not debating on whether a process is real or not ... just how it works in DCS.

If it's just INS drift a simple FIX should fix it, although that shouldn't be the case if GPS is available as explained above. If you're on the ground you can also always do a full realigment of the INS as well, but you need to input the coordinates of your aircraft's current position on the INS page of the DED for it to work correctly.

Edited February 12, 2023 by QuiGon

[84-Simba]

2 minutes ago, QuiGon said:

No, it does not.
 

It can be done hot just fine.
 

NO! Fix does not align the INS! Fix just updates your current position based on a known landmark that you need to designate through a sensor of your choice. It's purpose is to get rid of INS drift that accumulates over time, although this should only really happen in missions where there is no GPS available though. So I wonder: Is the mission where you experience this set prior to 1994 (that's when GPS becomes available in DCS) or do you fly on red side?
 

If it's just INS drift a simple FIX should fix it, although that shouldn't be the case if GPS is available as explained above. If you're on the ground you can also always do a full realigment of the INS as well, but you need to input the coordinates of your aircraft's current position on the INS page of the DED for it to work correctly.

 

Thank you for detailed answer my friend !

I mark your comment as the solution but I'll restest everything that has been said.

Have a noce day

[RogueRunner]

This actually happened to me today aswell. After a repair, I aligned again until align flashing on the HUD. Bombs wasn't dropping close to where they were supposed to.

[QuiGon]

17 hours ago, RogueRunner said:

This actually happened to me today aswell. After a repair, I aligned again until align flashing on the HUD. Bombs wasn't dropping close to where they were supposed to.

Did you enter your new parking position coordiates on the INS page of the DED within the first two minutes of alignment?

Edited February 13, 2023 by QuiGon

[84-Simba]

As far as I know now :

You can hot rearm/refuel but :

- You have to ditch your external tanks or make the ground crew rearm without and add them again ;

- You can rearm with dumb and laser bombs but you won't be able to change the code ;

- You have to realign completely if you add any GPS guided munitions such as WMCS, JDAMs or JSAWs.

(you'll notice that the INU flag is up on the ADI and that the alignment is 0 on the INS Page)

Note that everytime I tried, the coordinates and altitude were correct on the INS Page. So you just have to confirm the datas with enter and wait.

I usually request ground power and shut the engine down.

I find weird that a re-alignment is needed in this case since the plane knows exactly where it is ...

And off-course the smart munitions are off at this time.

Though I don't know if it is just a DCS behaviour or an actual IRL procedure requirment, maybe something like software or hardware ... or both.

[QuiGon]

9 hours ago, 84-Simba said:

- You have to realign completely if you add any GPS guided munitions such as WMCS, JDAMs or JSAWs.

You sure about that?

I never experienced this when hot-rearming INS/GPS guided munitions, although I haven't done that for a while. It doesn't make sense to me either, as I would think only the weapons itself should require a realignment (or rather a first alignment as they haven't been on the jet before), but not the aircraft INS.

Edited March 3, 2023 by QuiGon

[84-Simba]

8 minutes ago, QuiGon said:

You sure about that?

I never experienced this when hot-rearming INS/GPS guided munitions, although I haven't done that for a while. It doesn't make sense to me either, as I would think only the weapons itself should require a realignment (or rather a first alignment as they haven't been on the jet before), but not the aircraft INS.

 

Yep

[smire666]

You can fill the external tanks under specific circumstances, too. Just two conditions need to be carried out: Aerial-refuelling door opened and internal fuel consumpted at least in the ext. tanks volume...

[skywalker22]

1 hour ago, smire666 said:

You can fill the external tanks under specific circumstances, too. Just two conditions need to be carried out: Aerial-refuelling door opened and internal fuel consumpted at least in the ext. tanks volume...

Yes, correct. Keep the fuel left in internal tank sub 2400lbs before refueling, and you will be able to refuel to 14000 in total!

[smire666]

1 hour ago, skywalker22 said:

Yes, correct. Keep the fuel left in internal tank sub 2400lbs before refueling, and you will be able to refuel to 14000 in total!

Just to be fair, 14000 with all 3 tanks

[84-Simba]

12 minutes ago, smire666 said:

Just to be fair, 14000 with all 3 tanks

Absolutely.

I usually set a conservative bingo but I could eventually dump fuel close to home.

I don't know if it is possible in the Viper nor if it's implemented.

I'll check this out next time.

Good information though

Thx