Lets back up for a minute and consider putting the oil cooler in there the
long way. It has almost been working for Tracy with less than an ideal
air intake duct. Tracy's would work better if it had a NACA intake duct
on the top of the RV4 cowling IMHO.

Todd Carrico wrote:

I am not sure if a NACA duct will work well in that area.  NACA ducts
work best off of undisturbed boundary layer air.  I would guess that the
boundary layer on top of the cowl would be very think [thick or thin?] and 
very turbulent. My guess anyway.  Also, it is on the opposite side of the climb.

What about Ducting air from a conventional opening just behind the prop?
The duct could be formed on the inside of the cowl using the cowl as one
side of the duct.  Then treat it the same as the NACA, with the curved peice
to distribute the airflow.

Something to ponder...

tc

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