RE: Difference between Goldberg Falcon 56 and Falcon III?
The reason I would build it lighter is that I have this compulsion to fly my planes with the engines on the LOWER end of the recommended scale and still get a kick flying it around. My 32F is one hot little number. If I were to bolt a 45 size engine in, the weight would not be such a concern. As it was, when I had a Enya 40 in the nose, the batteries and receiver had to get moved to the back of the plane. The plan had excessive power, so I put the 32f back in and put the batteries and receiver in the normal spots. I can still blow the doors off a friend's Great Planes Easy Sport with a TT46.
Even so I would replace the lite ply sides and top and bottom with balsa and just beef up the area of the landing gear. I would keep the trike gear because a tail dragger Falcon won't look like a Falcon.
I would increase the aileron size, maybe make them barn doors, and maybe increase the elevator and rudder size about 1/2". I would definately put individual servos for the ailerons. That way I can use flaperons to slow the thing down for landings.
I found that when I was framing the wings, the big spar that was constructed was a shade too wide. I ended up planing it down slightly in thickness to fit into the rectangular holes in the ribs. Otherwise the plane went togerther reasonable fast. Like I said earlier, the diecutting on mine was so great, but I have a band saw, so it wasn't a big deal.
When you assemble the two wing halves you should have another person helping you as I found it rather a interesting experience when I did it alone. I would also use a 24 hr curing time epoxy for this stage if I did it again, because I'm just so damn slow.
I replaced the supplied wing bolts with 1/4" nylon bolts. I cut a small slice just below the head to encourage breakage in case of a crash.
Have a great time with the Falcon. There is a great number of RC'ers that learned on this plane and probably still fly them. It is a great design with a much vaunted pedigree.
If it turns out that you don't want the plane, give it to me. (sorry, couldn't help myself).