Thought you folks would like to here about my Chippy. Bought it used in 1985 or so with an O.S. .61 four stroke. The plane flew well and very scale like for years. I then decided to try hovering type of manuevers and put in a supertigre .75 two stroke. Not quite enough to hover, so in went a supertigre .91 2 stroke. Hover accomplished!! After a while, I decided to go back to a supertigre .61 two cycleto save on weight and fuel consumption. I put in a 16 oz tank and flew for six more years, flying very scale like manuevers, until 1 month ago I tried to stretch a flat spin One half turn too much and put it in. While the plane is probably repairable, I have decided that she went out the way she deserved to go, and have started stripping her of equipment to put in my new Goldberg Chipmunk, which will be powered by a Thunder tiger .91 four stroke. A 60 two stroke or 81 four stroke will fly that plane just fine, and by the way, isn't that what is recommended for the plane?