You got the answer half and half ;-)

The X means that the Solution X was 10% bigger than the 72"

There was a Weeks Solution built but never a full scale Weeks Solutilon X

The full scale Solution flew awesome, and in it's time was the plane to beat.
It was stored in Kermits hanger in Fl. and in 1992 when hurricane Andrew blew threw, it caused the colapse of the hanger, droping the structure of the building on the Solution and crushing it.


Tom