Built one for a friend and flew it for the first time last week. It is powered with a OS 120 four stroke. Flys great, fast, aerobatic, just keep the speed up on landing. It seems to like being wheel landed rather than a 3-point. Elevator loses effectiveness at low speeds and higher angles of attack making landings touchy. Set up airplane per instructions and it required about 3/4 ounce of lead in the tail to balance. Could have moved the battery back but it was easier to mount a small piece of lead in the tail.