411A------------I hadn`t realised that B47s and Vulcans were supersonic unless of course the definition of supersonic has been redefined as Boeing appear to be doing with their current transonic project.I realise that Concorde could not possibly be any good as it was not built in the US.I seem to remember that contemporary American projects fell by the wayside.Maybe they were not able to poach enough European knowhow at that time!