Having built quite a few quarter scale Su-27s and not used (or, at least, that's what I remember...), by extrapolating I thought i would be ok with my 1/32...which was not the case..., my friend @johnb!
Surely the extra AB heavy extensions played their role, but I think weight would be needed nevertheless...
This is a weight same as the one I put, not sure how much it weighs, but it's not extremely light ! 🙂