Here's another sad story for you. As an instructor at our club, I'm often asked to maiden airplanes. This one particular day it was a brand new VMAR Beaver arf 40 with a MDS 58 engine. Everything looked good inside and out and the weather was perfect so I took off straight into a light breeze after a long take off run. The model staggered into the air and felt tail heavy. I managed two gentle circuits before it snapped into a spin while banking for the final approach. No time to recover but a big bushy tree saved the day. Lots of witnesses including a few experts and we all studied the model on the bench. The unanamous conclusion was that everything was good to go. As a precaution, we added a few ounces of lead to the nose to get the cg to the front of the recommended range. The next take off had lots of airspeed but the model snapped to the left almost immediately after take-off and was a total write-off. I took the wreckage home and looked it over again. The only thing defect I could find was a slight twist in the left wing (wash in) measured with an incidence meter.
The hobby shop cheerfully refunded the owner's money and I built him a coroplast Spadet with the same motor and radio which he cheerfully flies to this day.