George, you are talking about the oil cooler inlet? Yes, there is not much
choice in what that looks like. I didn't implement a boundary layer bypass
because it would just lower the oil cooler that much more.

The only first gen to use that oil to water cooler was the 1983. The oil
cooler I had in my plane was a 1982, looks very much like the 2nd gen oil
cooler and is the same size. I had two different 1982 oil cooler in my plane
and they both behaved the same.

Perry

Yes but you also changed the duct at the same time :)

Paul Lamar

Paul, I've modified that oil cooler ducting about 10 times in the last
four years. No significant difference with any of the mods, until the
latest. That tells me for certain there is an internal difference in the
1986 cooler that makes it much more effective. I can send you one of my
1982 coolers if you want to do some experiments to verify :-)

--
Perry Mick

That is true but the outlets were all pretty much in the same
place. I suspect there is a large vortex in front of the fan that
is causing a high pressure on top of the strake in that area.

It would interest me greatly if you instrumented the new set up with
the water manometer. We have plenty of pressure data on your old set up
to compare it to.

I am not saying it is all due to the new ducting. You are undoubtedly right
about the cooler being more efficient. It may not all be about the
new cooler however.

BTW Have you looked inside the 12A cooler through the
fitting holes and observed any fins or turbulators inside the tubes?

Paul Lamar

The ports come out 90 degrees to the long tubes, you would have to stick
a really small mirror in those 8mm ports to see. The only practical way
to know for sure would be to cut one open. This may explain why
non-Mazda oil coolers also do not work as well with the rotary. Ed had a
non-Mazda cooler in the early days that didn't work so well.

--
Perry Mick
Custom Composite Props
mick@bridgingworlds.com
http://www.ductedfan.com

Yes I have a picture of that installation. It was mounted way too
close to the firewall. Also he had a NACA duct initially but he changed 
it at my suggestion and it started working better but not good enough.
Finally he went to the stock cooler and moved it under the engine.
It then had a more or less unobstructed air outlet on the back side.
 
Paul Lamar
 
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