Ground Launched Small Diameter Bomb (GLSDB)

timmymagic said:
TomS said:
And South Korea, I believe.
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I know that the 227mm rockets from M270/HIMARS are compatible with the K239 Chunmoo, but not sure if it works the other way TBH. Interesting if it is the case, particularly for Poland as they've got a split buy of Chunmoo and HIMARS on the way.
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Fair point. I suppose it's possible that there is one-way compatibility but it seems unlikely.
 
TomS said:
timmymagic said:
TomS said:
And South Korea, I believe.
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I know that the 227mm rockets from M270/HIMARS are compatible with the K239 Chunmoo, but not sure if it works the other way TBH. Interesting if it is the case, particularly for Poland as they've got a split buy of Chunmoo and HIMARS on the way.
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Fair point. I suppose it's possible that there is one-way compatibility but it seems unlikely.
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It will depend upon which version of rocket. From what I understand the K239 Chunmoo fires 3 main types of rocket:
  • K33 131 mm unguided rockets
  • KM26A2 230 mm rockets which are based on the M26 227 mm unguided DPICM rocket
  • 239 mm guided rockets
Presumably it would only be the KM26A2s which have any sort of dual commonality.
 
GTX said:
It will depend upon which version of rocket. From what I understand the K239 Chunmoo fires 3 main types of rocket:
  • K33 131 mm unguided rockets
  • KM26A2 230 mm rockets which are based on the M26 227 mm unguided DPICM rocket
  • 239 mm guided rockets
Presumably it would only be the KM26A2s which have any sort of dual commonality.
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The 239mm guided rocket is the same size as GMLRS-ER, which is why I suspect it might also have some commonality, given that Chunmoo launchers can also handle GMLRS-ER.
 
From Defence Updates concerning the GLSDB package that will arrive soon in Ukraine:


The United States has answered President Volodymyr Zelenskiy's plea for weapons that can strike deep behind the front lines of the nearly year-long conflict with Russia.
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The Pentagon has stated that the latest $2.17 billion in aid to Ukraine will include an unspecified number of Ground Launched Small Diameter Bombs (GLSDB).
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The weapon officially referred to as "precision-guided rockets" on the aid package, will significantly aid Ukraine's attempts to retake territory from Russia by giving its troops the capacity to hit targets at distances much greater than the longest-range munitions delivered to Kyiv till now.
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This development was first reported by Reuters. In this video Defense Updates analyzes how GLSDB could be a game-changer for Ukraine?
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Some remarks were deleted from the description concerning political statements.

When I think about it I still find myself scratching my head that once the Boeing/SAAB team successfully demonstrated the concept it wasn't put into production, it uses off-the-shelf components (Except for the adapter that mates the SDB-I to the M26 rocket-motor) so it is very cheap.

I'd be interested to the Boeing/SAAB team extend this concept to include the SDB-II and the SPEAR 3.
 
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Triton said:
Artist's impression of Boeing GL-SDB (Ground Launched Small Diameter Bomb).

Boeing is modifying the Small Diameter Bomb with a rocket motor to be launched from ground-based missile systems such as the M270 MLRS. After the motor launches it to a high enough altitude and speed, the wings will deploy and glide the bomb to its target. The company believes it can fill a gap for long-range precision fires. While typical MLRS systems follow a ballistic trajectory, the rocket-launched SDB can be launched to an altitude and glide on a selected trajectory. Boeing is planning on a demonstration in 2014.
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Source:
defense-update.com

Future Fires to Focus on Precision, Clean Weapons - Defense Update:

In recent years the role of armaments and weapons in military exhibitions is diminishing, reflecting the diminishing role of kinetic effects and the complex public perception as to their role in modern asymmetric warfare. Hence, the armaments and munitions presented at AUSA and the Modern Day...
defense-update.com defense-update.com
en.wikipedia.org

GBU-39 Small Diameter Bomb - Wikipedia

en.wikipedia.org en.wikipedia.org
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AN/AWW-14(V) said:
DO6dya4UMAAdHBd.jpg:large


Saab will test its Ground-Launched Small Diameter Bomb (GLSDB) later this month, with officials hoping the flight will push the 140km mark for the first time.
The last time the system was fired, a 2017 test in the US, the distance reached was short of 100km. Reaching 140km in the latest test would represent close to maximum range for the system.

MSPO 2019: Saab aiming for 40% range bump in next GLSDB test fire | Shephard

Saab will test its Ground-Launched Small Diameter Bomb (GLSDB) later this month, with officials hoping the flight will push the 140km mark for the fir
www.shephardmedia.com
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Ground Launched SDB t be provided to Ukraine.
 
From some reports on Ukraine it appears that the Ukrainian army may've received the GLSDB as they conducted several missile strikes against Russian army targets in Mariupol which was something like 50 miles behind the frontlines.
 
NMaude said:
From some reports on Ukraine it appears that the Ukrainian army may've received the GLSDB as they conducted several missile strikes against Russian army targets in Mariupol which was something like 50 miles behind the frontlines.
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Most news reports suggested spring 2023 at the earliest and quite a few said nine months from contract award, which would be September/October timeframe.

www.reuters.com

Factbox: U.S. rocket-powered bomb would double Ukraine's strike range

The United States is expected to send a new weapon to Ukraine, the Ground Launched Small Diameter Bomb (GLSDB), doubling Kyiv's current strike range.
www.reuters.com www.reuters.com


It seems likely that this is something else. Why not renewed drone attacks or special operations forces? Heck, for max secret squirrel factor, the Black Hawk that they just showed off may have been used to test armament kits, so we might be seeing something like a budget DAP at work.

www.thedrive.com

UH-60 Black Hawk Unexpectedly Appears In Ukrainian Military Service

An apparent former U.S. Army UH-60A has appeared in Ukrainian military service, with the shadowy Defense Intelligence directorate.
www.thedrive.com www.thedrive.com
 
TomS said:
Most news reports suggested spring 2023 at the earliest
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Northern spring starts next month so that's not far off.

TomS said:
quite a few said nine months from contract award, which would be September/October timeframe.
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I find that surprising since the US has some 400,000 surplus M26 rocket-motors in storage and the SDB I is already in full-scale production so the only thing new that needs to be manufactured is adapter unit to mate the SDB to the M26.
 
NMaude said:
I find that surprising since the US has some 400,000 surplus M26 rocket-motors in storage and the SDB I is already in full-scale production so the only thing new that needs to be manufactured is adapter unit to mate the SDB to the M26.
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It needs to be productionized -- thus far, all they've done is a few test rounds. It's possible there are a few prototype rounds around, but it's been literally several years years since the last test flight, so I am skeptical. Also, I'd want to put in place some sort of inspection process on the M26s, x-raying them for cracks, etc. They're pretty old, and mostly sitting around waiting for disposal, so not necessarily in great condition. Setting up a reliable procedure for that will take time, especially to do it at scale.

Also, let's consider the source for the claim that GLSDB is in use. It's entirely from Russian sources. Which have also claimed that Russians forces have already destroyed Ukrainian M1 tanks (there aren't any) and started claiming to have destroyed Bradleys long before any reached Ukraine. There were even claims that they must have used ATACMS to hit the Kerch Bridge. Etc.

Why take their statements at face value when there are alternative explanations? We've seen explosions like this happening behind Russian lines for weeks, before anyone started talking about GLSDB. Could just as easily be loitering munitions, saboteurs, etc.
 
Question1
M26 rocket engine has 4 wrap fins to stable by spinning.But SDB can not fly while rotating. So how to?
Question 2
The dimensign of M26 is D227mm, but the cross area of SDB is more than D227mm。That means the launch tube of HIMAS can not contain SDB.So，how to launch the GLSDB?
 
Blueking said:
M26 rocket engine has 4 wrap fins to stable by spinning.But SDB can not fly while rotating. So how to?
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After the M26 rocket-motor has burned out the SDB separates and deploys its' tail-fins then deploys its' wings (Which will dramatically reduce its roll-rate) before using said tail-fins to eliminate any remaining spin.
 
Blueking said:
Question 2
The dimensign of M26 is D227mm, but the cross area of SDB is more than D227mm。That means the launch tube of HIMAS can not contain SDB.So，how to launch the GLSDB?
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The launch tube for MLRS is substantially wider than 9 inches, with interior rails for rifling. The SDB is not much (if any) bigger than the M26 judging from the models I've seen, but there is room on the tube if they need it. Just need to remove some rifling.
 
TomS said:
Blueking said:
Question 2
The dimensign of M26 is D227mm, but the cross area of SDB is more than D227mm。That means the launch tube of HIMAS can not contain SDB.So，how to launch the GLSDB?
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The launch tube for MLRS is substantially wider than 9 inches, with interior rails for rifling. The SDB is not much (if any) bigger than the M26 judging from the models I've seen, but there is room on the tube if they need it. Just need to remove some rifling.
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And the Bomb part of the SDB1 is bout 6 inchs or 155mm in diameter. Seen specs saying 160mms.

Assuming that not including the wings assembly the entire bomb is in all likelyhood LESS them 200mm or roughly 8 inchs. And I have Seen specs saying its 7.5 inch/190mm at the widest point.

Which is roughly an inch in a half two inchs, either way more then 30mms of spare space with the Rifling.

So there is more then enough room for it.
 
Saab and Boeing are not saying exactly how this works (and I can't find a patent) but I suspect the interstage between the M26 rocket and the SDB payload has a despin function, either during launch or after booster separation.
 
TomS said:
It needs to be productionized -- thus far, all they've done is a few test rounds.
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True however I wouldn't surprised if the Boeing/SAAB team drew up such plans after the successful conclusion of the tests.

TomS said:
Also, I'd want to put in place some sort of inspection process on the M26s, x-raying them for cracks, etc. They're pretty old, and mostly sitting around waiting for disposal, so not necessarily in great condition. Setting up a reliable procedure for that will take time, especially to do it at scale.
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That's a good idea but I'm sure that no doubt Boeing already has plans in place to set up the x-raying of the available M26 rocket-motors. Now as to the condition of the rocket-motors that really depends on how well they were stored. In addition to x-raying M26s for crack I imagine that once Boeing has obtained the number of motors they want I could see them randomly selecting a few and test-firing them to see how they perform.

TomS said:
Saab and Boeing are not saying exactly how this works (and I can't find a patent) but I suspect the interstage between the M26 rocket and the SDB payload has a despin function, either during launch or after booster separation.
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While that's possible IMO I think that's more likely that the rate of rotation will be slowed by the deployment of the tail-fins and the wings due to conservation of angular-momentum with any residual rolling being dampened out by the control-fins.
 
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NMaude said:
About bloody time! With the GLSDB will Ukraine be able to reach targets in Crimea?
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Some of it, yes. Dzhankoy will be in range for instance. Lugansk city also, Mariupol, Berdyansk etc. And Taganroy airbase in Russia's Rostov region.
 
timmymagic said:
Pretty certain that the US will have received assurances that actual Russian territory will be off limits unfortunately..
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Generally yes, but there was that exemption for returning fire. So hypothetically if Russian aircraft took off from there to launch an attack against Ukraine, they could return fire when they land.
 
Interesting to note it was pretty much a direct hit, indicating that enemy EW did not have much effect. Also interesting is that it was 60km behind enemy lines, so the Grads were not in a position where they could even hit their own front line troops, let alone the enemy.

View: https://www.youtube.com/watch?v=BgkcXf30j88
 
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Once the GLSDB is deployed in large numbers the Ukrainians can start attacking and destroying Russian ammunition dumps, command HQs, armoured vehicle and truck parks, supply warehouses, barracks radar sites, SAM sites and various electronic warfare sites that were out of range of the GMLRS missiles.
 
NMaude said:
Long overdue! Anyway I hope the US DoD orders something similar with the SDB-II as since it has a seeker it can be used against moving targets.
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SDB-II is more complicated to use .... you need to provide target info (templates, characteristics) for its seeker to do matching and tracking ....
 
NMaude said:
Long overdue! Anyway I hope the US DoD orders something similar with the SDB-II as since it has a seeker it can be used against moving targets.
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SDB2 is Raytheon-made, not Boeing, and needs a different interstage adapter due to different shape tailcone.
 
NMaude said:
I'm aware of that and given how the GLSDB has performed so far I can see the US Do9D signing a contract with Raytheon to develop an adaptor compatible with the SDB-II.
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Gotcha!

And yes, I definitely see the DoD dropping a contract with Raytheon for GLSDB2s.

Edit: Frankly, Raytheon would likely be wise to throw some company money at making that interstage without a contract...
 
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Has there been any recent news concerning the GLSDB in Ukraine or in general? I wonder if the US DoD is considering doing a version using the SDB II instead?
 
NMaude said:
Has there been any recent news concerning the GLSDB in Ukraine or in general? I wonder if the US DoD is considering doing a version using the SDB II instead?
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The US military has expressed no interest in any version of GLSDB, as far as I am aware. ER GMLRS achieves the same range and is already in procurement.
 
TomS said:
The US military has expressed no interest in any version of GLSDB
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Maybe not the US military however there are certainly foreign customers who're users of the M142 and/or the M270 who'd definitely use it, Ukraine for example would love to have such a system.

Scott Kenny said:
GL-SDB2 has sensors and targeting capabilities that ER GMLRS does not have.
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This! For one thing the SDB2 can be used to attack moving targets as it has a terminal homing seeker.
 

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