Thanks for the input guys. The plans build a 50" model but they can easily be enlarged to 1/5 or even 1/4 scale. The plan is by Frank Roberts. What puzzles me is why this model was labeled as a Douglas "O-41A" seeing that the O-41 designation was assigned to Thomas-Morse at least seven years before the plan was drawn. I have pics and some views of the O-47 and the O-43, both being Douglas designs. Could this Douglas "O-41" plan be a fluke or perhaps Mr. Roberts actually drew plans of the modified O-46? Compare the pics below to the ones in my first post. The B/W pic is the O-43. The color pic is the O-46. Opinions?