Has anybody had a problem with the c of g as recommended in the instruction manual. The 2 x 10 oz tanks are behind the c of g and weigh 28 oz (0.8 kg) when full.

Everyone I know has balanced it per the manual. I have never heard of a stablility problem at the mandated CG.

BTW - there is a nice article on the development of that design here:

http://www.top-flite.com/reviews/topa0500-rcr.html

My DC 3 has tanks mounted behind the cg in the center section of the wing due to installing retracts, I balanced with full tanks, I did lots of research on this topic a year ago and I am glad I did. You do not whant to take this plane off tail heavy. I have around 30 flights on it and it flys great with this cg even on one engine. Have fun.

Thank you for your replies fellars. My set up is the same as n9331v and I have come to the same conclusion.I found with full tanks the c of g moved back 5-6 mm so I have added 58 gm in the nose. The reason for my post was a problem on the test flight about 2 weeks ago. After 2 laps of the field at half throttle to trim, the aircraft was positioned for a 30 degree climb with full throttle after which it increased to about 60 degrees with no further control imput. It dropped a wing and entered a spin of 2 turns pulling out about 15 from the ground. Needless to say I landed immediatly thinking something had shifted back but nothing was evident. I have not attempted to fly it since. I just find it strange that the instruction manual tells you to balance with empty tanks ?