Marc Wiese wrote:

Also if someone has a NACA duct and they claim it is working
fine and instrumented with a water manometer I will fly there and
help them take the data.

Here is one of 2 I am working on, the scoop is the 2nd mod, vgs next, am
using a dual needle pressure gauge for differentials. This is an
intercooler. The other I am working on is an oil cooler.
[Marc Wiese]

What is a dual needle pressure gauge?
That is not a true NACA duct Marc. It is sort of a hybrid 
sans boundary layer air bleed.

At what speed are you testing it?  What pressure are you seeing
in front of the intercooler. What pressure behind the intercooler.
Looks like it has a nice air outlet duct.

Have you checked the pressure at various points around the front
face of the intercooler? You really should make a water manometer
and check half a dozen pressures or more at various points in the system 
simultaneously. Unless of course you have half a dozen dual needle 
pressure gauges.

Paul Lamar
 
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