I have a 41cc engine that i would like to put in a biplane ,not some fast ,but a slow and gentle flight with it, any one can recomment something along those lines?

Yea get a 1/4 scale Sopwith Pup from Balsa USA. I have my US 41 on mine and she is a real ball to fly. Lots of power if I need it and slow enough for a scale landing. I usually fly at just about half throttle and will do a fly by at about quarter throttle. A very gental flyer and loads of fun to fly. Just my $0.02 worth

Another good floater was the Fly Baby Bipe from Balsa USA (I believe). The kit is no longer in production but can still be found once in a while on auction sites and I think plans are available for scratch building also.

I've got a US41 in my lazy ace (the 76" version). While overpowered, it isn't too bad. The next size up lazy ace might be a better choice.