RE: Which 20cc - 25cc engine is best
+1 on the Zenoah G26 "Ralph Special". I haven't owned an MLD but I have seen one flying in a Cermark Extra 260 and thought the MLD-28 is pretty darn stought. (It pulled that Extra out of a hover with authority.) I do have the MVVS/EVO 26GT2 and for a 26 it's both light and strong. It turns the same prop as my Zenoah about 1 to 200 more rpms. Where it really shines is with a tuned pipe. That turns it into a real beast. In the end though no one beats Zenoah for durability, + they're right there on power and with a good diet to trim the weight they are a good contender.