Originally Posted by solentlife
b) that undercarraige needs to be looked at and possibly more secure, (I'm a great believer in weaker and only break immediate area - not more !)
The under carriage is actually quite sturdy and robust. It breaks off on occasion because it is glued into a 10mm thick section of the foam fuse. This for me has only happened if my landing angle was poor and the front of the wheel pants catch on the runway and drag the carriage off. If it were a regular fix I think I would just remove the wheel pants.
I start at 30% if I have no manual reference to go by. We just assume that the people that wrote the manual went through a whole lot of testing to come to that value. It probably just depends on your flight style I guess. I'm no ace pilot so I like my CG a bit more forward to keep me in the comfort zone.