Since I admit that I have no background in the physics of aerodynamics,
I'd like to throw out this question to the group.

Those of you familiar with the RV series know that a standard Lycoming
engine without the forward facing sump requires that little forward facing
snorkle inlet at the bottom of the cowl.
However, I'm guessing that the snorkle creates some drag there that
costs a few mph. At least those who seem to know suggest that.
So what's the possibility of feeding the updraft sump with air by
instead installing a flush NACA duct at the same location?

Just wondering out loud.

MJC