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Thread: GBU-43/B MOAB v Grand Slam

  1. #1
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    GBU-43/B MOAB v Grand Slam

    A sort of modern v. historic question.

    The BBC are saying that the 21,600lb MOAB munition is the largest non nuclear bomb used in action, but surely Grand Slam, at 22,000lb holds that record. Any ideas?

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    I may be talking/thinking via my backside here but wasn't there a 30,000-plus lb bomb built after Grand Slam? May have been a Russian or US design.

    Anon.

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    Quote Originally Posted by jeepman View Post
    A sort of modern v. historic question.

    The BBC are saying that the 21,600lb MOAB munition is the largest non nuclear bomb used in action, but surely Grand Slam, at 22,000lb holds that record. Any ideas?
    The weight of explosive filling in the Grand Slam was about half its total weight? The MOAB is being quoted as having an explosive weight of 11 tons.
    Martin

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    Still pretty impressive that a prop-driven Lancaster was hauling a 22,000lb load around 70 years ago though!

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    Lots of room for confusion when comparing US / UK bomb weights due to our different definitions of the 'ton'...

    ...an 'Imperial' (long) ton being 2240 pounds and a 'US' (short) ton being just 2000 pounds!

    According to Wikipedia the MOAB weighs in at 22,600lb with a explosive filling of 18,700lb which would make it both the heaviest (conventional) bomb dropped in combat and the one with the most explosive filling.

    The 'blast yield' of the MOAB is quoted as equivalent to 11 'tons' (US tons?) of TNT but that is achieved with a lighter filling of a more powerful explosive.

    The thing that is strange about the use of the MOAB in Afghanistan is that it was stated to have been used against a tunnel or cave complex but the MOAB is not designed to penetrate deep into the ground before exploding (like a Grand Slam is designed to).
    Last edited by Creaking Door; 14th April 2017 at 18:43.
    WA$.

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    If I recall the MOAB is an air/fuel explosive, exploding above ground level. most of the blast is concussive in nature. It easily penetrates tunnels as shock waves. There was a whole show, I think on PBS on its development/testing.

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    Quote Originally Posted by Ian Hunt View Post
    Still pretty impressive that a prop-driven Lancaster was hauling a 22,000lb load around 70 years ago though!
    Mind you the MOAB delivery system design is over 60 years old! Maybe PA474 is actually undergoing a secret MOAB conversion at Duxford LOL!
    I do wonder why the military spends billions on combat aircraft that largely fly in undefended airspace dropping bombs. A fleet of converted airliners dropping 'grand slams' would do the job!

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    It is an air/fuel munition... basically an overgrown PAVE/PAT as used in Vietnam.
    The early weapons used a small primary detonator releasing an aerosol cloud of propane vapour in a cloud that mixed with atmospheric oxygen. The cloud of fuel flowed around objects and into structures and was then ignited by a secondary detonator, causing a massive, fireball blast and pressure wave out to at least three hundred metres.
    Moab is said to contain Tritonal: a mixture of 80% TNT and 20% aluminum powder which improves the speed at which the explosive develops its maximum pressure.Tritonal is about 18% more powerful than TNT alone.

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    Quote Originally Posted by me109g4 View Post
    If I recall the MOAB is an air/fuel explosive.
    No it's filled with an explosive called H6 which is a composite (mixture) of TNT(44%), RDX(29%), aluminium powder(21%) and a balance of paraffin wax. This is reported as being 35% more powerful than TNT alone.
    Last edited by Vega ECM; 14th April 2017 at 09:03.

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    Watched some film of the Project Ruby Anglo/American deep penetration trials after the war using the the Valentin U-Boat pens at Farge as a target. The Heligoland Bunkers were also involved in the trials.
    The weapons dropped from up to high altitudes were inert on the Farge target due to proximity to population - other penetration bombs such as the Disney and Amazon were also tested.

    https://en.wikipedia.org/wiki/Disney...ar_development

    https://www.flightglobal.com/pdfarch...0-%201045.html

    Some of the damage caused on the Valentin bunker can be seen in drone footage of the bunker today…

    https://www.youtube.com/watch?time_c...&v=2yA0CbSCdNU
    Last edited by Bob; 14th April 2017 at 09:07.
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    It is believed only 15 of these MOAB have been constructed. Perhaps Trump just couldn't resist trying out a new toy!

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    Wasn't there something similar used on the Tora Bora cave complex?
    Tony

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    Quote Originally Posted by Old Fokker View Post
    It is believed only 15 of these MOAB have been constructed. Perhaps Trump just couldn't resist trying out a new toy!
    But of course a successful deployment could always unlock the cash for more.....

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    Quote Originally Posted by paulmcmillan View Post
    But of course a successful deployment could always unlock the cash for more.....
    No doubt! Humans are at their most inventive when dreaming up effective ways of killing each other.

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    Wasn't there something similar used on the Tora Bora cave complex?
    This was used then…
    https://en.wikipedia.org/wiki/BLU-82
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    Quote Originally Posted by Tony C View Post
    Wasn't there something similar used on the Tora Bora cave complex?
    That was a 15,000lb "daisy cutter".

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    In Gulf War 1, the US built five special deep penetration weapons for dealing with Saddam's deep bunkers. The bodies were made from Howitzer gun barrels packed with explosive and they had guidance fins and laser guidance seeker heads to ensure they hit where intended.

    They were very successful and there is footage of one (a test specimen, I think) which just seems to slip beneath the ground before, after what seems a while, it exploded.

    Not sure if they were rocket powered but they did the job and were much the same as the Disney weapon by the sound of it.

    Anon.

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    Post war trials

    Quote Originally Posted by Bob View Post
    Watched some film of the Project Ruby Anglo/American deep penetration trials after the war using the the Valentin U-Boat pens at Farge as a target. The Heligoland Bunkers were also involved in the trials.
    The weapons dropped from up to high altitudes were inert on the Farge target due to proximity to population - other penetration bombs such as the Disney and Amazon were also tested.

    https://en.wikipedia.org/wiki/Disney...ar_development

    https://www.flightglobal.com/pdfarch...0-%201045.html

    Some of the damage caused on the Valentin bunker can be seen in drone footage of the bunker today…

    https://www.youtube.com/watch?time_c...&v=2yA0CbSCdNU
    IIRC the post war trials involved USAF B29s each carrying 2 Grandslams to the Heligoland bunkers.

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    Project Ruby - if you are interested, a 319 page report on the trials is available as a PDF - http://www.dtic.mil/cgi-bin/GetTRDoc...c=GetTRDoc.pdf
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    The first "Daisy Cutters" were depth charges, used in WWII.
    As far as I am aware.

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    It depends on its purpose, the bunker buster mentioned was designed to penetrate about 200ft and used a small charge as in the confines of a tunnel system it would reek havoc, indeed when they dropped the test one, there was no way to recover it and see if it worked, so the Iraqi drop was the live test so to speak.

    Similarly, to take buildings out and avoid collateral damage they were dropping Laser guided inert concrete bombs that the impact would demolish the building targeted without any blast and drop it on those inside..

    If indeed it was blast it would also probably remove some of the oxygen, the fuel air also does that.

    I can remember watching a film with some old jet in a HAS with some sheep, a simulated 1000lb Nr miss was carried out and when done the narrator was wittering on about how the jet which it showed had survived and with work could be made serviceable in a few days.... All our attention was drawn to the sheep, they were all dead from concussion effect of the blast, and in wartime we were the sheep in the HAS.. We would live, operate and now we knew die in that concrete box.
    Last edited by TonyT; 14th April 2017 at 20:07.

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    Quote Originally Posted by Old Fokker View Post
    It is believed only 15 of these MOAB have been constructed. Perhaps Trump just couldn't resist trying out a new toy!
    Apparently the decision to use it was made by the area commander, though the anti-Trump trolls would have one ignore that.
    There are two sides to every story. The truth is usually somewhere between the two.

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    Quote Originally Posted by farnboroughrob View Post
    A fleet of converted airliners dropping 'grand slams' would do the job!

    Perhaps because the military can't always assume they'll have air superiority? No quite like the days of the RAF doing "air policing" and dropping bombs on unsophisticated, half-clothed "natives".

    The same reason why the spend money on short-field tactical airlifters...moving forces isn't like flying Easyjet on holiday.
    You can't assume there will be nice landing fields.

    In short, a proper military has to be able to go anyplace at any time.
    There are two sides to every story. The truth is usually somewhere between the two.

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    Quote Originally Posted by J Boyle View Post
    Perhaps because the military can't always assume they'll have air superiority? No quite like the days of the RAF doing "air policing" and dropping bombs on unsophisticated, half-clothed "natives".
    Yet here we have the MOAB bomb designed to be luzzed out the back of a slow prop transport?

    There are numerous airliner conversions into military use. AWACS, Elint, ASW and tankers. It does seem uneconomic to have an expensive high-performance jet employed to loiter in airspace, supported by a Boeing 707 made into a tanker. Just stick a bomb bay onto an airliner conversion and have that loiter. We seem to have had several decades of bombing anyone that does not have any credible air defences. Why put wear and tear on expensive military kit when we could do it on a bog-standard airliner airframe? Especially when that airframe could be multi-use.

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    Quote Originally Posted by Creaking Door View Post
    Lots of room for confusion when comparing US / UK bomb weights due to our different definitions of the 'ton'...

    ...an 'Imperial' (long) ton being 2240 pounds and a 'US' (short) ton being just 2000 pounds!

    According to Wikipedia the MOAB weighs in at 22,600lb with a explosive filling of 18,700lb which would make it both the heaviest (conventional) bomb dropped in combat and the one with the most explosive filling.

    The 'blast yield' of the MOAB is quoted as equivalent to 11 'tons' (US tons?) of TNT but that is achieved with a lighter filling of a more powerful explosive.

    The thing that is strange about the use of the MOAB in Afghanistan is that it was stated to have been used against a tunnel or cave complex but the MOAB is not designed to penetrate deep into the ground before exploding (like a Grand Slam is designed to).


    If only we all used the metric system!!



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