I want to make a second point about the fire extinguisher and bomb bay issue. Most successful aviation extinguishants rely on the principle of oxygen starvation and compartmentalising the aircraft by design. Tappers Dad quoted the avionic bays in other jets and a modern expanding gas. Well, yes, that system will work because the gas expands into a small, sealed bay and starves the bay of oxygen, or if it is not sealed, it will have a limited ventilation system that will account for the needs of the fire extinguishant.
The Nimrod bomb bay is not sealed in flight. The 4 doors close together for aerodynamic purposes and they leave significant air gaps around them. When the doors are closed, the bomb bay heating system continually delivers warm air into the bay. I don't know what the volumetric rate of air exchange is, but 4 distribution ducts, each the size of domestic tumble drier hoses, are delivering air into the bay. The bay does not pressurize, therefore all of that air leaves the bay at the same rate that it goes in, via the gaps around the doors. So, in the event of a fire in the bay, the heating system will be switched off to prevent further oxygen feed. If, by design, a fire extinguisher was then immediately directed into the bay, 4 tumble drier hoses worth of air and extinguishant would be sucked out of the bay through the effects of flying at 200 kts. So, the volume of designed extinguishant that has to be stored in the jet has to be capable of exceeding the amount of bomb bay heating supply, at the outset, and then continue to smother the fire for a sustained period. The heating air is supplied by the 4 engines, so its a big task for any extinguishant to exceed. Impossible, in my opinion.
The people who designed the Nimrod were intelligent and thoughtful and put extinguishers everywhere they believed they could be needed and where they would be effective. I trusted their judgement when I first found out how the aircraft was built and I still do.
Mr Winco and Tappers Dad, as much as we would wish it otherwise, please accept that the Nimrod bomb bay cannot be protected by fire extinguishers while it is empty.