I'm pretty old school so my thinking is on size. The plane I just built is an 80 inch and it's a light weight, it calls for a 1.20FS. To me 80 inches is where I go to my 2.4 40cc gas engine. The cobra is a pretty big plane with two wings and calls for 2+. I'm betting your 1.80 would work very well if you keep the weight down. Now I know why you werre asking about the 50 twin. I do like the DLEs and the cylinders would look cool sticking out of the cowl.