Torpex is a secondary explosive, 50% more powerful than TNT by mass. Torpex comprises 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for "Torpedo Explosive", having been originally developed for use in torpedoes. Torpex proved to be particularly useful in underwater munitions because the aluminium component had the effect of making the explosive pulse last longer, which increased the destructive power. Torpex was used only in critical applications, e.g. torpedoes and the Upkeep, Tallboy, and Grand Slam bombs. It was also used in the Operation Aphrodite drones. Torpex has long been superseded by H6 and PBX compositions. It is therefore regarded as obsolete, so Torpex is unlikely to be encountered except in old munitions or