We had a guy at our field with a H9 40 size Ultra Stick. Three minutes into it's first flight the piece of wood that has the blind nuts for the wing hold down bolts came loose. Plane went straight in. Both plane and engine were a total loss. To H9's credit, they replaced the plane and engine. I also have the 40 size Ultra Stick and have re-enforced the wing hold down mount. I have flown the heck out of it for almost a year now with no problems.