Brit312
Concorde's main landing gear consisted of 3 seperate metal castings . there was the normal two for the oleo and these two were fitted inside the outer casting, which was the one you could see.
As the gear retracted a mechanical linkage , which was driven by the gear's retraction movement, would lift the oleo assembly up into the outer casing, so shortening the length of the leg . If I remember the shortening jack was just to assist in breking the geometric lock of the linkage
Right on the button as usual Brit312, the shortening jack DID just assit breaking of the geometric lock, it was the process of retraction alone that did the actual shortening. Humble aplologies to all for this age induced goof.
And as both yourself and EXWOK pointed out, Air France had a ni-cad based DC power system, the same as G-BOAG.
Dude
