The first batch of B.2’s were not originally capable of carrying Blue Steel- when that weapon became available those aircraft underwent the mod programme to allow them to carry the weapon while those on the production line had the mods incorporated before issue. It was originally intended that roling between Blue Steel and conventional would be a quick change thing however practical realities proved different. Although the cabling etc was installed in the bomb bay as were the extra fuel gallery connections swapping between roles would turn out to be a right pain. Not only were the bomb bay doors replaced but a cooling, hydraulic and electrical package needed fitting plus the nose and tail fairing panels needed fitting to replace the original panels. Given the amount of work needed to rerole it was decided that the Blue Steel aircraft would remain unchanged especially as getting the bomb doors off was a nightmare- only did this once – never again. The list of mods required was quite extensive and included seperate items for the front and rear spar- mountings for the services crates plus changes to the switching titles for the bomb bay doors which became fin gap doors- in fact the last aircraft to carry the fin gap door tags didn’t change until early 1974. Just to make life even more complicated some aircraft such as XM575 had a partial Skybolt panel fit in the Nav area so it sported relics at one time of conventional, Blue Steel and Skybolt.

Cheers
Mad Jock