RE: Fox .50
To the best of my recollection, the Hawk and the original Eagle came out in the late Sixties or early to mid Seventies. Eventually, Tower Hobbies began selling the baffle piston equipped Eagle as their housebrand engines. I don't recall seeing the Hawk around at that later time. I could be confusing the Hawk series with the older .59 series too.
I'm a baffle piston Eagle fan. Mine have ran without problems. I can't say the same for the later editions of Fox Eagles that utilized schneurle porting. Head button problems and the like. I do not consider myself knowledgable in the geneaology of the various Fox engine lines.
Ed Cregger