ORIGINAL: ho2zoo
---- it is because of the large right-thrust of the engine. It does help a lot to do your take-off with a long roll at 1/2 or so throttle.
Another problem one of the students had was that the wing was very loose even when the wing bolt was screwed in as far as it would go. The wing would rock back and forth with a 1/4 inch gap between the bottom of the wing and the fuselage. We were very concerned about it coming off in flight.
The large right thrust can indeed cause a drift to the right, both on take-off and in flight at full throttle, but it is entirely manageable.
The wing floppiness is due to failure to properly engage the threaded receptacle with the wing hold-down bolt. If the wing is correctly installed, it can be cranked down quite tightly & will not come off in flight under the most extreme aerobatics..