RE: What is a good engine for a Tower Kaos?
I fly mine with a Rossi 45. Because I had it. It will do anything I want. On FAI 0% fuel.
Instead of spending the big bucks on an OS go with a Magnum or ASP 46 or 52. (Both are old OS engines that OS sold the castings for years ago.) You will not be disappointed. Put a 10x6 prop on it run it a little rich and you will have all the power you will ever need.
I know I will catch flak for that comment. But it is the truth. If/when my Rossi wears out I will put a Magnum 52 with a 10x6 prop with the Rossi mini pipe. If the plane survives.