Years ago, Don Edberg while at Stanford did a study and I beleive he had access to the wind tunel at Nasa Ames and he found that a Monokote covered panel was less drag then a primed/panted panel. At the time Don was very competitive sailplane pilot and if I'm not mistaken was on a Worlds team. Obviously a moulded airframe will have less drag overall but I think this has more to do with more accurate airfoil sections and skin hinging that the technique provides.


On the other end of the theory, lots of boat guys run a rough bottom. The theory is that at speed, water adheres to the rough surfave and the boat glides with water on water. I know when I go pylon racing, on of the fastest guys out there has a finish close to 150 grit sandpaper. Personally, I also think that at our model speeds it dosent make alot of difference.