CoroCub - a little bigger one.
Background:
I needed an engine test-stand for playing with gas-glow conversion. I got everything running fine on the bench, so I needed a plane for them. I have some ARFS in the box but I didn't want to trash them. And it does not fit right: 200+ dollars plane for 25 dollars engine. I wanted something easy, fast and cheap to build, that will be easy and fun to fly, that will glide well and survive less than perfect off-airport landings. That's why my decision was to build a SPAD. The only thing I found that would fit my needs was [link=http://www.spadtothebone.com/SPAD/corocub/Corocub_1.htm]CoroCub[/link].
Plane:
The orignal plane designed on SPAD website was to small. I wanted testbed for engine 25cc or more. So I increased the size by 25% and that would make a quarter scale Clipped Wing J3 Cub. I had only white 2mm coroplast, so I decided to make it not a yellow, but white and maybe blue (will be painted).
Plans
When drawing the plane on the sheet of 4mm coro for units I din not use"inches" but "flutes" instead. This way I was sure, that every cut wil end between the flute's wall. Fitting entire design into one sheet 4'x8' of 4mm coro I made the fuselage exactly 48 inches long. The rest fit just fine without further modifications.
Modifications
Of course there are modifications. I have that kind of problem, that I can not build a plane straight from plans and I always have to modify something. The first mod was in the fuselage. I made it with a little longer nose part so I shouldn't have a problem with balancing the plane even when I use very light engine. There is much easier to add 4 oz of lead on the tail than 1 lb at the firewall. The second and the most imortand mod was to make two wing halves. There is no way I will fit one piece 86 inch wing into my truck. This requirement change the entire wing design. And at last, but not least I used more plywood than you may expect in simple SPAD. Instead of using bamboo sticks I used pieces of flywood. This way I got extra "hard points" in the coroplast.
The building posts below.