Originally Posted by M2dude
Now this basic design is not uncommon, F14, F15, Tornado, MIG 25 etc., but the spilled subsonic air in these designs is ejected overboard, giving very little in the way of secondary benefits, and in fact the secondary airflow at all is technically a small waste of energy.
Which is presumably one of the factors in why those designs can't supercruise (not that supercruise was considered a must-have in a fighter of that era), and one of the reasons that once the old girl was supersonic, none of them could catch her.