MOAB vs. Grand Slam

[Vitorio]

Yertis said:

I was getting slightly irked when listening to the news last night at reports of 'MOAB' being "the largest non-nuclear bomb ever dropped", or words to that approximate effect. By my reckoning Grand Slam was about 5% heavier, but whatever. Question is, given the apparent need for such a weapon, do we (as in us or US) still possess the ability to construct a Grand Slam, and aside from sliding it out the back of an MC130, any aircraft capable of dropping it accurately?

largest non nuke ever is wrong either way, but it is the largest non-nuke in the US arsenal (which is what the various news outlets should have reported)

As for which is biggest, the Russians reportedly tested their own version of the fuel air explosive, nicknamed "the father of all bombs" rumored to have four times the yield of the MOAB.

[IforB]

The Grandslam is probably closer to the GBU-57 MOP or Massive Ordnance Penetrator. That is the US bunker buster bomb. It comes in at 14tonnes (30,000 lbs) though I don't think they've dropped one in anger.

Edited by IforB on Friday 21st April 12:55

[Shakermaker]

TEKNOPUG said:

GBU-43 MOAB is 22,600lbs so heavier than Grand Slam. And 11tonnes to 6.5tonnes TNT equivalent.

According to an internet meme I saw the other day, which of course makes it the height of truth and accuracy, but the MOAB page has been updated on Wikipedia to give it a higher weight than the Grand Slam, previously it was "only" 21,000lbs or similar, but now it all of a sudden was the 22,600 you have quoted.

[Vitorio]

Shakermaker said:

According to an internet meme I saw the other day, which of course makes it the height of truth and accuracy, but the MOAB page has been updated on Wikipedia to give it a higher weight than the Grand Slam, previously it was "only" 21,000lbs or similar, but now it all of a sudden was the 22,600 you have quoted.

A simple google turned up a globalsecurity.org article which mentions both 21.600 and 21.700 within the span of a paragraph...

Either way, "heaviest" in terms of bombs also could refer to blast yield.

[Ayahuasca]

Eric Mc said:

Don't forget, Grand Slams and Tallboys were designed to actually miss the target.

I understood that they were designed to hit the target, but later it was found that a near miss caused more damage.

On a related note, some anti-ship torpedoes are designed to 'miss' too. Rather than hit the target ship as you might expect, they explode underneath their target. The idea is to cause a huge hole in the water under the ship's hull. The hull, being in part unsupported by water, breaks its back and sinks.

[gregs656]

Ayahuasca said:

I understood that they were designed to hit the target, but later it was found that a near miss caused more damage.

On a related note, some anti-ship torpedoes are designed to 'miss' too. Rather than hit the target ship as you might expect, they explode underneath their target. The idea is to cause a huge hole in the water under the ship's hull. The hull, being in part unsupported by water, breaks its back and sinks.

You're right that some are designed to explode under the keel, but it is the pressure wave of the explosion lifting the ship that causes the damage, not the ship being unsupported in the water.



bit more info here: https://chuckhillscgblog.net/2011/03/14/what-does-...

[eharding]

Some third party analysis of the after-effects of the MOAB strike:

https://stories.alcis.org/after-the-dust-settles-d...

[aeropilot]

Ayahuasca said:

I understood that they were designed to hit the target, but later it was found that a near miss caused more damage.

Correct.

Tallboy and Grand Slam were designed as deep penetration bombs, hence the one-piece hardened steel nose, needed to penetrate the massively thick concrete roofs of the German U-Boat pens, and the underground factories being built/used by the Germans as protection from Allied bombing.
The earthquake effect meant that for some structures, a near miss was sufficient to cause the required damage, such as at the dome of the V2 rocket facility at Wizernes in the case of Tallboy, and the Bielefeld Viaduct in the case of Grand Slam.
Tallboys were also used to attack the Tirpitz, with direct hits from 3 of them resulting in her capsizing after the final attack in Nov 44.

[slartibartfast]

On the subject of the Grand slam there was a story about there being one as gate guard at RAF Scampton and it was there for years until they tried to move it and find it was still filled with H.E.

[aeropilot]

slartibartfast said:

On the subject of the Grand slam there was a story about there being one as gate guard at RAF Scampton and it was there for years until they tried to move it and find it was still filled with H.E.

Correct.

[steve j]

Vitorio said:

A simple google turned up a globalsecurity.org article which mentions both 21.600 and 21.700 within the span of a paragraph...

Either way, "heaviest" in terms of bombs also could refer to blast yield.

Blast yield is generally governed by CWR, charge weight ratio and of course the type of filling, the RAF used a lot of Amotol, then later Baratol during WW2. A 1,000lb HC, high capacity bomb has a thin casing, resulting in maximum blast, a 1,000lb AP, armour piercing bomb has a thick casing, resulting in a smaller blast. Of course Grandslam and Tallboy had a low CWR to ensure deep penetraion with the thicker case and hardened ogive.

[slartibartfast]

aeropilot said:

slartibartfast said:

On the subject of the Grand slam there was a story about there being one as gate guard at RAF Scampton and it was there for years until they tried to move it and find it was still filled with H.E.

Correct.

so not urban myth?
I live in Lincoln and not far from RAF Scampton.

[aeropilot]

slartibartfast said:

aeropilot said:

slartibartfast said:

On the subject of the Grand slam there was a story about there being one as gate guard at RAF Scampton and it was there for years until they tried to move it and find it was still filled with H.E.

Correct.

so not urban myth?

Correct, its true.

From memory, was late 50's (or maybe very early 60's?) when they had to move the gate guardians because of road works or something like that, and they got a standard RAF 8 ton capacity crane to lift the Grand Slam (thinking it was empty) and the crane wouldn't budge it. Aah, its filled with concrete then.............until someone in the team then thought, err......surely not, best check and got the Scampton armourers out to check by removing fuse etc., and they found it was as live as the day it was made! So, it was made safe and then transported to one of the coastal ranges, and blown up. I think there was some sort of investigation, but I don't think they ever found out how a live GS had spent nearly 15 year sitting on gate guardian duties at Scampton!!

[steve j]

aeropilot said:

Correct, its true.

From memory, was late 50's (or maybe very early 60's?) when they had to move the gate guardians because of road works or something like that, and they got a standard RAF 8 ton capacity crane to lift the Grand Slam (thinking it was empty) and the crane wouldn't budge it. Aah, its filled with concrete then.............until someone in the team then thought, err......surely not, best check and got the Scampton armourers out to check by removing fuse etc., and they found it was as live as the day it was made! So, it was made safe and then transported to one of the coastal ranges, and blown up. I think there was some sort of investigation, but I don't think they ever found out how a live GS had spent nearly 15 year sitting on gate guardian duties at Scampton!!

It`s not the only time that this has happened, in the late 1970s, a 1,000lb training bomb at RAF Halton was found to have an explosive filling. It was removed quite quickly and disposed of .

[davepoth]

Yertis said:

Amazing what there is to learn, when you start looking. B29 with Grand Slam:

US Grand Slam was called T-14, Check out the T-12, 43,000lbs for the B36, also B29 could carry two Tallboys under the wings.

Here's a video of the B-36 with the T-12. Typo at the beginning I think, as that's a big bomb.

https://www.youtube.com/watch?v=S5tYPD0eafM

[anonymous-user]

davepoth said:

Here's a video of the B-36 with the T-12. Typo at the beginning I think, as that's a big bomb.

https://www.youtube.com/watch?v=S5tYPD0eafM

the bomb dropped looks different.

[grumpy52]

steve j said:

aeropilot said:

Correct, its true.

From memory, was late 50's (or maybe very early 60's?) when they had to move the gate guardians because of road works or something like that, and they got a standard RAF 8 ton capacity crane to lift the Grand Slam (thinking it was empty) and the crane wouldn't budge it. Aah, its filled with concrete then.............until someone in the team then thought, err......surely not, best check and got the Scampton armourers out to check by removing fuse etc., and they found it was as live as the day it was made! So, it was made safe and then transported to one of the coastal ranges, and blown up. I think there was some sort of investigation, but I don't think they ever found out how a live GS had spent nearly 15 year sitting on gate guardian duties at Scampton!!

It`s not the only time that this has happened, in the late 1970s, a 1,000lb training bomb at RAF Halton was found to have an explosive filling. It was removed quite quickly and disposed of .

I think lots of stuff that would wake you up if it got upset was mislaid at the end of the war .
A farming family had a cache of all sorts of stuff for the British resistance in a cellar of one of their farm buildings.
They contacted the MOD many years after the end of the war (60s) and said were they going to collect it . They claimed they had no record of it but would inspect it .
All new and unused equipment and ordinance it filled several trucks .