I kind of preferred the old concept of the undersides of the folding bits being the "sails." Just seems a bit overly elaborate for a propulsion system to me. Great work with the execution though.
Maybe that's why they're unique to this class. You can drop the ship on a dime over 50 lightyears but it's a bitch to maintain and repair. And God help you if one of the grids gets knocked out of alignment.