Mike,
I think the CG was probably most of your problem. 15cm behind the aft CG point is a lot on a 40-sized plane.

i agree... 15cm IS a lot! but it was 15mm...

Not really ... Mike's plane is actually 40 cubic inches!!! Hahahahaaaaaaa ...

I got the Black Horse Sukhoi 40, let's see how it holds up against the Phoenix ... I am installing a TT .61 into it to get the nose back down again (BHs are notoriously tail heavy, actually they are just heavy!).

Sheesh, my first typing error and you're all over it!! LOL

I just read a review in RCM&E (UK magazine) about the blackhorse sukhoi 40 model. Allegedly a VERY well built plane. The author had balanced the plane in the range provided by the manual, but on initial flight, he commented on a VERY sensitive elevator response, meaning a rearward CG. After adding 6oz lead to the nose, it flew quite well... so just beware the CG on the sukhoi.
Bloody nice looking aeroplane!

mike