Hi Paul,

 Do the bell shaped ducts everyone has been talking about add much drag?  I looks like they stick out there quite a ways.  The similar ducts you see on jet fighters and race cars seem to be very snug and tight in comparison.

Robin

I am not sure I follow you Robin. These are strictly internal shapes.
They reduce drag as they improve the cooling of a given size rad core.
The outer inlets can be like a P51 scoop, round inlets on the front
of a cowl or a flush NACA duct opening on the bottom or side of the
the airplane.

This is a picture of Tracy Saylors RV6 which at about 245 MPH is
the fastest RV6 in the country if not the world.

Notice the metal inserts in the air intakes. These are worth 20 degrees F on 
engine cooling improvement over hand made fiberglass intakes of the same diameter. 
They are machined out of aluminum billet on an NC lathe with a very precise 
leading edge airfoil shape turned inside out.  

A larger version of the lower scoop is what I have in mind for the rad air
inlet on my Kis Cruiser.

Paul Lamar
 
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