Excelsior Study 2
Nothing is known about this starship class whose construction seems to date back to the beginning of the 24th century or earlier.

This is one of three or four study models for the Excelsior, built i the course of the pre-production of "Star TrekIII".  The model briefly appeard on screen in TNG: "BEst of Both Worlds".  Unlike the first version above this prototype is already close to the final Excelsior.  It may be a member of the same ship family, but probably doesn't predate the Excelsior.