well my th fun 51 is tail heavy by about.5 an inch, if i add1 oz of weight up front it will balance fine. my question is is it close enough?
ill add the weight at first for maiden. just want some info on the cgfrom someone who has/had one. i did extend the rudder/elevator by an inch

now for the engine. is a os fp .40 (bushing engine)even cose to a os .40 la engine in power terms?
also is a 11x4a good torque prop for such a small/weak engine or could i use a 11x5?

i am also having a problem turning the back section of the muffler.
the front screw will not turn, i can get the backnut*** off.
if i run the engine for a little and let the muffler heat up will that help?