Saw this on ebay in antiques, not the usual category I check.
http://www.ebay.com/itm/Vintage-1940...item19cf1c4b14
Here is my unrestored Air Castle (Spiegel?) FP604 and its schematic.
Air Castle 604.jpgAttachment 173820
As can be seen from the schematic, unlike the Musicaire, mine is a battery "farm set"
. Found at an antique store 35 yrs ago near Altoona in a very rural part of PA.
Now for the question; How many different versions were made
of this set and who really made it?