This was designed to the original profile data, minus the uneven base surface. In the end the air reaching the area was too messy to do much good, but still better than having an inlet lower down purely because there was less crap being ingested.
Not often that you see a NACA duct on an F1 car nowadays:
Then there is this abomination. I keep meaning to run CFD on this because everything I read suggests it doesn't work like this.
More NACA
NACANACANACANACA
