You're not thinking of the Vulcan with the Pegasus rig slung beneath it are you, BEagle?? (He says vaguely recalling a picture of this and wondering whether he's made it all up).
Edited to add: not made up, but have doubts as to whether it flew.
So as a second guess, how about the Supermarine 517 (hinged rear fuselage and jet pipe)?
Last edited by Archimedes; 2nd Feb 2004 at 08:24.