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triple GBU-12s


twistking

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2 minutes ago, Hardcard said:

Regarding aerodynamic concerns upon release, if those massive cbu canisters don't cause problems, why should gbu-12s?  
Hell, even 3x dumb mk82s are allowed on the inner pylons, if those don't cause problems, why should gbu-12s?

Because the GBU-12 has much larger aerodynamic surfaces than a CBU or slick bomb. With the nose mounted steering fins and pop-out rear stabilizer fins, I can easily imagine a GBU-12 getting thrown around a lot more by aerodynamic forces when released. The large CBUs also weigh twice as much, which would help stabilize them.

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Like you said, extensive testing is performed before clearing these weapons for employment, I would be very surprised if gbu-12s hadn't been thoroughly tested and modified to ensure safe release.

It's entirely possible that testing was carried out, a problem was identified, and it was determined that modifications to the bomb, racks, or aircraft were not worth the cost. Or maybe it was determined that testing such configurations wasn't even worth doing. Think a bit about how tactical jets and weapons are used in the real world. CBUs and slick bombs tend to be released in large numbers all at once. Make a single pass, drop 12x Mk.82s or a bunch of CBUs, then get out. For those weapons carrying large numbers of bombs is useful. But GBUs aren't used that way. They are dropped individually and guided all the way down. In a high-threat environment the aircraft is vulnerable for the entire bomb time of flight, they're not going to make 8 or 10 passes at the target area to drop that many bombs, that'd be ridiculous. In the low-threat environments of Iraq and Afghanistan in the last 20 years that number of weapons was simply not needed, and the inner pylons were always needed for gas to loiter on station. Many XCAS aircraft went on missions with only 2 bombs, clearly that was enough, why would they bother trying to carry 8?. It's entirely possible, likely even, that the USAF considered carrying more than 4x GBU-12s unnecessary for any conceivable mission and not worth the cost of even testing.

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5 minutes ago, Bunny Clark said:

Because the GBU-12 has much larger aerodynamic surfaces than a CBU or slick bomb. With the nose mounted steering fins and pop-out rear stabilizer fins, I can easily imagine a GBU-12 getting thrown around a lot more by aerodynamic forces when released.

Are you sure you didn't get this backwards? 

I'd say that gbu-12s are more stable and easier to steer, precisely because they have that extra set of control fins on the nose. 
I'd expect cbu canisters and mk82s to wobble around a lot more than gbu-12s.

Regarding the practicality of multiple gbu-12s on the inner pylons, like I said, that's a separate matter, I'm only concerned about physical reasons. 

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Just now, Hardcard said:

I'd say that gbu-12s are more stable and easier to steer, precisely because they have that extra set of control fins on the nose. 
I'd expect cbu canisters and mk82s to wobble around a lot more than gbu-12s.

Paveway II is a pretty dumb system, as far as I know it does not actively steer itself away from the aircraft or participate at all in safe clearance. The bomb will fall ballistically until it picks up a laser spot to track. 

Fins help with stability in smooth airflow, but in disturbed flows they can do weird things. If a GBU-12 gets caught in a slipstream along the edge of the fuselage / engine nacelle I can easily imagine it yawing severely or being pulled into the side of the aircraft.

But ultimately my point is we can't just look at the geometry of these things and say that because it looks like it should work it probably will work. If that were the case there would be no intensive weapons separation testing program. If that were the case the incidents in the video I linked to would not have happened - I'm sure no engineer looked at the stores on those aircraft and thought they were probably going to impact the aircraft but decided to fly them anyway. Even with advanced computer 3D modeling and CFD, the F-35 is still going through hundreds of flying hours of weapons separation testing for every desired configuration. Unless someone knows if the USAF did any TER separation tests with GBU-12 on 4 & 6 and is willing to share, we'll only ever be able to speculate. 

 

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1 hour ago, Hardcard said:

I'd say that gbu-12s are more stable and easier to steer, precisely because they have that extra set of control fins on the nose. 
I'd expect cbu canisters and mk82s to wobble around a lot more than gbu-12s.

Gbu-12s fall like any other unguided bomb. That is until the seekerhead picks up the laser signal and the fins are used to steer it on target. In case of the gbu-12s, it's a bang-bang system, meaning the fins gets slammed to one side or another. The ccg can't steer smooth or make small adjustments like a gbu49 for example. 

I'm pretty sure that carrying anything other than fuel tanks and unguided bombs on stations 4 and 6, are not for our F16's (MLU) even so, in all my years in the airforce, only fuel tanks are carried on stations 4 and 6. There are books (country specific) which says what can be loaded on what station, configuration wise and weapon employment

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  • Flaming Cliffs 3                      Black Shark 2                                 Syria
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@Bunny Clark
@Falconeer

So... gbu-12s fall like any other unguided bomb AND do weird things?

What about cbu canisters and dumb bombs with only tail fins? Don't they do weird things in disturbed flows too?

Also, if gbu-12s are so dangerous, why are we allowed to carry one on each inner pylon? 
Seems to me that carrying one is just as dangerous as carrying 2, if this is really the case.

Regarding the country-specific loadout books, I'm guessing they're classified, right?


Anyway, I just want a couple of extra bombs, to hit whatever my JSOW-As and cbu clusters fail to kill.

Also, I could use more than 4x gbu-38s in the viper...


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6 hours ago, Hardcard said:

What about cbu canisters and dumb bombs with only tail fins? Don't they do weird things in disturbed flows too?

Just about anything can  do weird things, it's a matter of how likely a specific weapon is to do something dangerous when dropped from a specific location on the aircraft within certain parameters. The video I posted has several examples of CBU mishaps. 

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Also, if gbu-12s are so dangerous, why are we allowed to carry one on each inner pylon? 
Seems to me that carrying one is just as dangerous as carrying 2, if this is really the case.

Maybe, maybe not. Bombs don't release from the exact same point relative to the aircraft when mounted directly to the pylon rather than mounted to a rack. The rack itself causes aerodynamic perturbations of the airflow and may have something to do with it. Or, again, it may be totally fine and the USAF just never bothered testing it because they didn't think it was worth the expense. We don't know. 

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Regarding the country-specific loadout books, I'm guessing they're classified, right?

These things aren't generally classified, exactly, but frequently are restricted for public distribution or restricted from overseas distribution - and in the modern day of the internet any document that is shared on-line is essentially shared overseas and immediately becomes a violation of international arms treaties. That's why the forums rules here are so strict about posting documents - there are unclassified publicly available PDFs of the F-16C tactical operation manual available on the internet, for example, but these manuals are still subject to the International Traffic in Arms Regulations (ITAR) which makes "exporting" them illegal. 

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Anyway, I just want a couple of extra bombs, to hit whatever my JSOW-As and cbu clusters fail to kill.

Also, I could use more than 4x gbu-38s in the viper...

Yup. Just realize that it is a "DCSism" - an artificial perception created by the way computer gamers play the sim that doesn't reflect operational considerations in the real world. In real life no single aircraft would be expected to hit more than 4 targets with LGBs in a single flight. If there were more targets that needed hitting, the USAF would just add more aircraft. It is always safer to have 4 aircraft make 1 pass at a target area than have 1 aircraft make 4 passes over a target area. What you need is a wingman, not more bombs. 

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10 hours ago, Hardcard said:

So... gbu-12s fall like any other unguided bomb AND do weird things?

What about cbu canisters and dumb bombs with only tail fins? Don't they do weird things in disturbed flows too?

That would be correct, the first seconds of the bombs falling are identical and *can* do wierd things. Like Frederf mentioned earlier, it can be caused by different reasons like airflow, G's, stuck pistons of MAU12,  you name it.

 

10 hours ago, Hardcard said:

Also, if gbu-12s are so dangerous, why are we allowed to carry one on each inner pylon? 
Seems to me that carrying one is just as dangerous as carrying 2, if this is really the case.

I think a logical reason is to look what's behind the TER, when it's mounted on sta 4 and 6. There is a big old horizontal stabilizer right behind the shoulder station of the TER. When you have a TER on sta 3 and 7, than the inboard shoulder station is also infront of that stabilizer and for that reason, they don't carry 3 Mavericks (in RL). So if anything goes wrong (and it happens even with smaller BDU33 training bombs) that stabilizer gets hit and damaged

 

10 hours ago, Hardcard said:

Anyway, I just want a couple of extra bombs, to hit whatever my JSOW-As and cbu clusters fail to kill.
 

It's not an A-10

 

10 hours ago, Hardcard said:

Also, I could use more than 4x gbu-38s in the viper...

No, you can't as stations 4 and 6 don't have a 1760 interface, which is used to communicate with the bomb


Edited by Falconeer
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  • Flaming Cliffs 3                      Black Shark 2                                 Syria
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On 3/24/2022 at 10:24 PM, Hardcard said:

@Bunny Clark

Notice that, just like gbu-12s, cbu87/97 are also limited to 2 on pylons 3 & 7... yet 3 of them are allowed on the inner pylons (4 & 6), whereas only 1x gbu-12 is allowed.

This is a valuable comment, we should study and correct if necessary. 

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11 hours ago, cofcorpse said:

This is a valuable comment, we should study and correct if necessary. 


I should've kept my mouth shut, shouldn't I?  😅


@DD_Fenrir

Methinks you should've read previous posts and checked the viper loadouts that are currently allowed before making that comment. 

If you had, you would've realized that we're allowed to carry 10x cbus, or 6x cbus and 6x mavericks, which seem kind of "Ace Combaty" to me. 


@Frederf

My thoughts exactly when I was taking those screenshots.


@Bunny Clark
@Falconeer

Thanks, I appreciate your replies.

But, tbh, some of the currently allowed loadouts totally make the viper look like an A-10.

 

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maybe @BIGNEWY could take the matter of this discussion and ask one of ED's SMEs about it. While unfortunately there seems to be more evidence against the triple-loadout, it seems to be less definite than in other loadout-realism discussions. Since we have the loadout-restriction-manager now, it would be possible to allow loadouts that were hypothetically possible. Even if they were not cleared for normal use, who knows if those loadout wouldn't be used in dire circumstances.
To not offend anyone: I would not want even the possibility, if - in reality - it was impossible (!) to safely deploy GBUs from a  triple loadout, but with the loadout-restriction system, it could be fun to explore hypothetically possible loadouts.

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On 3/30/2022 at 10:25 AM, twistking said:

To not offend anyone: I would not want even the possibility, if - in reality - it was impossible (!) to safely deploy GBUs from a  triple loadout, but with the loadout-restriction system, it could be fun to explore hypothetically possible loadouts.

The problem is that unless the USAF ever did any separation testing by actually dropping a bunch of GBU-12s from TER-9s on the inboard stations, we can't really say if it would realistically be safe to deploy them or not. It's one of those things where the only definitive way to know how it would behave is to try it for real. 

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7 hours ago, Bunny Clark said:

The problem is that unless the USAF ever did any separation testing [...] we can't really say if it would realistically be safe to deploy them or not. [...]

As the 16 was so widely exported, maybe some foreign airforce did?
For example who did the seperation testing for the greeks when they decided they wanted HARMs on the inner stations?

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