There was a DIY plan section on F3P foamy's Its called a Bandit. The original plane did not have counter rotating props. Then I found a DIY on counter rotating systems. And decided to try and make one. All info was on RC Groups.
It weighs 104 grams with a 240 mah 2 cell Apprx 32" wing span. Believe it or not the pro's planes weigh about 65 grams.