My 1st attempt at the Cessna 140 was a 31"wingspan with a flat wing. It never did fly, but I learned a lot about the building techniques. The plane is built from the 3 view drawings shown here, I loaded the JPG files into Corel Draw and did a bitmap tracing, then output the files to Autocad as DXF format. There I cleaned things up and scaled to the size wanted.

 

 

The plane would not get off the ground, so I experimented with a folded wing with good dihedral and under camber.
The plane still did not fly, although it did get airborne for a few seconds. After evaluating the damages, I decided to build a new plane, this time a 48" wing span. I set the wind incidence to 0 relative to the horizontal stabilizer and the CG slightly forward.

The plane flew, but there are some definite problems. The ailerons were totally unresponsive, in fact they caused the plane to climb and yaw??? Elevator and Rudder worked well, and the plane seems to have plenty of power. I will disconnect and tape the ailerons, and fly it as a 3 channel as an experiment.

 

More on this as it happens. Maybe now that it is flying, I should go back to the flat wing??

I did decide to build a set of floats for this plane but that is another story! Building Floats