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Information wanted please on RDX bomb

ROBIN BIRD

Well-Known Member
I have details of a WW11 trial of a 100 lb anti submarine bomb fitted with RDX instead of TNT. It does not state what RDX was but the explosion was 'quite staggering for a comparatively small bomb.'



Robin Bird researching the Marine Aircraft Experimental Establishment during WW11.
 
Hi Robin,
It is my understanding that RDX is Hexogen but i await correction from one of our more knowledgeable members.
Best Weasel.
 
RDX is said to stand for Royal Demolition Explosive, while other sources say Research Department Explosive and is known by a number of names, cyclonite being one of them. Its original name was Hexpgen given to it by the Germans who invented it. On explosive power scales, TNT is rated with a power factor of 1. C4 plastic explosive is RDX mixed in with a plasticizer. C4 has a power factor of 1.34, and has a very high detonation velocity making it good for shaped charges and shattering dense materials like steel. So, RDX is 1/3 more powerful than TNT. It is combined with other explosives in different percentages to make a number of other military explosive types for differing applications.

The British experimented with it in bombs in the 1930's in search of a stronger blast to take out submarines. The Germans used Hexogen as the main filler in the high explosive shells fired from the MK108 aircraft cannon in the ME262 Jet Fighter.
 
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Thank you The trials were conducted by the Marine Aircraft Experimental Establishment in Scotland. I understand RDX was added to Torpex in some bouncing bombs including those used in the Dambusters raid
 
Torpex was a mixture of RDX, TNT and powered aluminium.
RDX was widely used in ww2, both by the British and the Americans. Try to put a hand on the following book: "The Secret History of RDX: The Super-Explosive that Helped Win World War II" - Colin F. Baxter, The University Press of Kentucky, 2016 - quite enjoyable to read and informative

From a ww2 US publication:
RDX (Cyclonite Cyclotrimethylenetrinitramine)
RDX is the most powerful and brisant of the military high explosives, and it is considered much too sensitive to use alone. It seems to be about half way between Tetryl and PETN in mixtures of other explosives and inerts which reduce the sensitivity to a safe range, while the mixtures have a very high brisance and power due to the RDX. It has excellent stowage qualities, but, because of its sensitivity, it is shipped immersed in water like an initiating explosive.
The velocity of detonation is 28,000 feet/second at a density of 1.70. Its Laboratory Impact Value is 34. Its Bullet Impact Value is 0. Its color is white.

Torpex
Torpex is one of the explosives developed during this war to be used mainly in underwater ordnance. The original Torpex (Torpex 1) was a mixture of 45% RDX, 37% TNT, 18% Aluminum powder (1% wax added). It is used in mines, torpedo warheads, and depth bombs. Torpex is more sensitive than TNT; its bullet impact and drop test sensitivities are of the same order as those of Tetryl. It is quite stable in stowage, though it produces gas, causing pressure in the case. It is insensitive enough to stand all normal handling. Its melting point is low enough for it to be cast-loaded.
Its velocity of detonation is 24,000 feet/second at a density of 1.72. It is 141% as powerful as TNT. Its Laboratory Impact Value is 53. Its Bullet Impact Value is 48. Its color is slate gray.

DBX (Depth Bomb Explosive)
DBX is another aluminized RDX mixture, and its name suggests its intended use. It is 21% RDX, 21% Aluminum Nitrate, 40% TNT, 18% Aluminum. It was designed to replace Torpex, which is closely resembles in sensitivity, strength, brisance, and energy of shock in water, but half of the strategic RDX in Torpex is replaced by Ammonium Nitrate in DBX. It will probably not be used, as the present supply of RDX seems adequate to meet the demand. DBX can be cast, though its melting range of 98-105 degrees Celsius is about the upper limit.
Its velocity of detonation is 22,300 feet/second at a density of 1.68. It is 143% as powerful as TNT under water. Its Laboratory Impact Value is not given. Its Bullet Impact Value is 51. Its color is gray.
 
thank you for the info. In the test I have recorded DBX was used in a 100lb bomb and totally demolished the derelict house used as a target! Much to the surprise of those conducting the trial on behalf of the MAEE
 
There are all manner of explanations as to the meaning of RDX. However, it's Research Department Explosive.

TimG
 
The most important reason for mixing RDX with other explosives and also aluminum, graphite, wax and paraphene is desensitizing as RDX is much more sensitive than TNT to shock and friction.
 
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