Morgans wrote:

"Cy Galley" wrote in message
newsiFEc.5861$Oq2.2704@attbi_s52...
NACA vents are some what difficult to get to flow.

I had read somewhere, that NACA ducts are poor at pushing air through
something as restrictive as a radiator. Add to that, the side of a cowl is
not a high pressure area, (lower than the front of the cowl, as a matter of
fact)

Push comes to shove, your friend may have to do a total rethink on the
setup.
--
Jim in NC

---


Way back when he started doing the NACA inlets, I made the same
comments, refering to Bingelas and Jim Clement.

But hey, when somebody wants to do something, they gonna do it.

We clamped a 3" extension to the outlit lip and re-ran the test.
No change in altimeter readings and no noticible difference in the
tufts.

Does sound like the inlets are not in-letting, doesn't it.

Refering back to the photos (ain't digital cameras wonderful!) there
is also some indication that the big opening in the cowling is not
letting much air in. I'll add some shorter hair deeper in the opening
and take another look.

Next (easy) step is probably remove the Scat tubes and see if the
cowling internal pressure is any better at letting air into the
radiator enclosure.

After that, only thing I can think to do is remove the enclosure
and ReDo (the true meaning of R&D).

So far as our (net) research indicates, there are few other Zodiacs
with an internal radiator setup. All the earlier ones have the rad
hanging below the cowl.

Thanks guys.

Richard