Dukasso

I am using same engine as you, OS-91FX
Where did you locate the extra 750 gr. weight ?,in the firewall or behind.

I was able to balance the plane by moving the rudder servo forward to the servo trail over the wing. But to meet your recommendations on c.g. I'll move the elevator servo too in the same way.

The 135-150 margin for c.g. corresponds to 33%-37% MAC, mean aerodynamoic chord wich seems to me a too backward c.g.,even worse when considering such a short tail (TVC=0.4,Tail Volume Coefficient rather low).

Spinning out of a loop could be caused by too much elevator rate or misaligned half elevators.

I expect to test the plane in about a month or two ,when weather improves