I have a ready to Fly /wet Biplane at 26lbs......Using the fish-o meter I am getting 24lbs of pull (thrust) from my engine....But my vertical ( assuming from drag) is very very limited.......What effect does the extra wing and such play into this drag factor......I knoweven if I had 30lbs of thrust ...I don't think the vert would be great.......I've heard that there is no such thing as an overpowered Biplane.....I'm believing it......But I'm trying to figure the Max limit to get best performance from the airframe.....Oh yea...wing area is about 2000sq in

My guess is you're having to fly around at almost full throttle all the time? If so, it's probably not a thrust issue, but one of speed, and you need to try a steeper pitch prop. I've got a plane with similar characteristics and if I go strictly for thrust, I run in to the same problem, but with the right prop, she'll carrying through extended up lines quite well.