Tallboy/Grand Slam

[gothica7]

Many Thanks for the clips.

Tritonal is 80% TNT and 20% aluminum powder.

What was the diffence then between what was used during WW2 and now? I believe the explosive used in the Grand Slam/Tallboy was Torpex.
It seemed to do the job ok.

Andy

[Taber10]

peregrinvs,
To answer your question, the B61 Mod 11 was specifically developed to penetrate and destroy bunkers. It is the ONLY "recent" US development in the nuclear world that has been fielded, I believe. While not a "tactical" weapon in the sense of "placed" SADMs, artillery fired nuclear projectiles, ground launched missiles, etc. it was certainly "tactical" in its original deployment. Currently, strategies, philosophies and treaties have eliminated the purely tactical weapons.

[HAZORD]

Andy,

There is usually a lot of analysis involved when deciding on which explosive to use in a complex piece of ordnance. If you watch the YouTube video, you can see that they were originally rushed through development and testing of the BLU-28s in much the same way as the first nukes, in that they only had two explosive loaded ones to send to be used in Iraq. Tritonal has been a surplus item in the U.S., since they have been demilling M117 750Lb. bombs, so it was available immediately for loading, whereas Torpex probably isn't being used at all for current ordnance.

When explosive content is limited, and the biggest explosion possible is the desired outcome, then really powerful available stuff that meets the requirements is used. TNT is very powerful, but the addition of the aluminum powder makes it very violent also, and even more powerful. When TNT is detonated, the chemical equation will show that one of the byproducts is oxygen. The aluminum in the mix utilizes this extra oxygen, producing all the extra energy as it turns to aluminum oxide.

An example of the energy available in powdered aluminum can be seen in the solid rocket boosters on the Space Shuttle. The propellant in these boosters is powdered aluminum and ammonium perchlorate (an oxidizer) held together with a binder. All of that energy comes from the burning (oxidizing) of the aluminum powder.

[Tony Williams]

I recall reading something in the last year or two about a new US very heavy bomb which is specifically intended to penetrate huge thicknesses of earth and concrete to reach deep bunkers. Unfortunately I can remember no details, as it's outside my field of interest.

[John D. Bartleson Jr.]

With regard to Torpex, it was used in U/W ordnance but I believe it became obsolete after the great Port Chicago explosion.
Regards,
John

[Speedy]

Hi
(sorry for my English)

I believe the explosive used in the Grand Slam/Tallboy was Torpex.

UK-manufactured bombs (and early US-manufactured) were filled with Torpex. As in other big British bombs, this procedure was a little complicated: the workers first created a 1-in layer of cast TNT around the walls, then loaded Torpex inside this "case". Torpex most popular formula was a mix of 41%TNT, 41% RDX and 18% aluminium.
Later US-made Tallboy-family bombs were filled with Tritonal. It is less sensitive explosive and there was no need to make such protection TNT layer. Also other simplifications were introduced in design.
Torpex is more powerful explosive than Tritonal, but the difference isn't very important, especially if detonate such large amount of explosive as in Tallboy.

[Tony Williams]

The GBU-57A/B is the USAF's big penetrator. It weighs in at 30,000 lb and is dropped by B-2 or B-52 bombers. Boeing received a contract to produce some only a month ago. See: http://directorblue.blogspot.com/201...ption-gbu.html

[Speedy]

Hi
(sorry for my English)
In fact, Tallboy was a little different thing that modern penetrators or WWII AP bombs. AP/Penetrators are very strong and thick-walled. They are designed to destroy target by direct hit. Usually they contained about 20% of explosive (or less). Tallboy was rather strenghten HE/GP bomb than penetrator, only a little stronger than British MC bombs. It contain about 45% of explosive. The original idea of Barnes Wallis was that Tallboy, that near miss his target, buried on impact deeply into the ground, then exploded, creating a strong underground shockwave, "seismic wave", like a small local mini-earthquake. This shockwave could damage the foundations of target (building, bridge, dam etc.) causing the whole structure collapsed. Sometimes it works (Bielefeld viaduct) but AFAIK most targets were destroyed by direct hits.

In the modern era there's no reason for such "earthquake" trick. Today is quite easy to hit any target directly by the guided bombs or missiles.