Capt'n,
That Ryobi look so clean that one has to admire it, I wish they came in bigger displacement with the same inline design.
I see yours has electronic ignition, would like to expand on it?, what size prop are you using on it and what rpm are you getting? have you installed it on an airframe and flown it or are still admiring it on the ground? Any idea how heavy and what size airplane this engine would be able to handle comfortably?. It is kind of difficult to make up the type of mount you have on it, but as you say a flat plate mounted with metal tubing spacer should do the job on almost any installation. And yes, my weedeater is a Snapper with a Ryobi 31 cc, that runs very well, only gallon and a half fuel through it, I am ever so tempted to disect it!! (Isn't it a sick thought?)

w8ye (man, you have a hard name to remember!)

I will keep your email for future reference with the information on Mr. Bowman, thanks much! I was checking your photo gallery and noticed that you have a Homelite 30cc exactly like the one I featured above (the one on the left), only difference being that mine is a 25cc displacement, and you are using it on an Ugly Stick type airplane, what size airplane was this and how much did it weigh ?, were you satisfied with the engine performance on that size airframe?, can you expand on what changes you made to it, seems the muffler is different from the stock one, what about the carburator?, how were you able to fit a prop hub to that long shaft?
were you able to crank this engine by hand or did it need help from the Heavens! Do you believe the 25 cc power to weight ratio is worth the work to convert?