Very interested, and surprised (although apparently there have been hints about this for months) that the RAF is going to get some nuclear strike fighters that can carry nuclear weapons.
In this thread I'm really only interested in the technology aspect, not the politics or wisdom of it, because I find it fascinating.
The weapon it would carry is the B61-12 nuclear bomb. These are old-fashioned gravity bombs, no rocket motor. But depending on the aircraft's speed and altitude, they can be released up to 74km from the target.
Despite not having propulsion, they do have GPS and inertial guidance using control surfaces (fins) on the outer surface. Also, the release of the weapon is controlled by a computer onboard the aircraft which takes into account speed, altitude, angles, climb / dive rate and all that.
This is what I thought was really interesting. The weapon has variable yields - ranging from 0.3 kilotons to 50 kilotons. The Hiroshima atom bomb was a 15 kiloton yield weapon. So that's a bit more than three times the power of the Hiroshima blast at the highest setting.
(http://bikediary.uk/images/b61.jpg)
The weapon itself doesn't come in different strengths - they're all the same, with the same amount of fissile material. You dial in the yield you want with an electronic programmer, like a washing machine or a microwave and the efficiency of the nuclear reaction is adjusted. This means that a low-yield explosion would still be very "dirty", because the bomb contains enough fissile material for a 50 kiloton explosion regardless.
Some of the B61 "family" of nuclear bombs have yields as high as 340 kilotons. But those ones are intended for strategic bombers, and the RAF won't be getting those.
As you say, James, fascinating science for something so obscene.
At one time we had eight nuclear-capable Tornado squadrons but the weapon, the WE.177, was scrapped by Labour in 1998.
There were various versions, the 177A had a relatively modest 10kt yield, the 177B had a 450kt yield.
They were carried by Tornados, Vulcans, Buccaneers and Jaguars.
British Sea Harriers and naval helicopters carried them as well, but only the (lighter) 177A.
They were armed with a simple key, no coded "Permissive Action Links". There was pressure to impose PAL security on them. The Royal Navy resisted this: "It would be invidious to suggest... that Senior Service officers may, in difficult circumstances, act in defiance of their clear orders".
http://news.bbc.co.uk/1/hi/7097101.stm
"To arm the weapons you just open a panel held by two captive screws - like a battery cover on a radio - using a thumbnail or a coin.
Inside are the arming switch and a series of dials which you can turn with an Allen key to select high yield or low yield, air burst or groundburst and other parameters.
The bomb is actually armed by inserting a bicycle lock key into the arming switch and turning it through 90 degrees. There is no code which needs to be entered or dual key system to prevent a rogue individual from arming the bomb."
Amazing facts.