RE: Great Planes PT-17 Stearman
The scale of the GP PT-17 is 1:5.4 as near as I can determine so a 1/4 scale engine would be much too big. It comes with 4" tires and 5" tires are about right. The tail surfaces are far from scale as far as not being an airfoil shape. Neither the tail or wings show either a scale or scale looking ribs.