Subject: [FlyRotary] Re: evap core versus radiator


> Posted for "sqpilot@earthlink" <sqpilot@earthlink.net>:
>
> Hi, Kelly.....I found the core at AutoZone. I went to look at one, and the
> information in their catalog was incorrect.  The length and width were
> correct, but the actual core thicknes was not 4 inches. It is 3 inches.
If
> you would like, I can go back to AutoZone and take a look at their catalog
for
> the part number.  If I recall correctly, the unit fits 2000 and 2001 Chevy
> light trucks.  Hope this helps.  Paul Conner
>
> >>
FWIW.  I've been playing around with the equations in K&W and finally
beginning to understand some of them.  Of interest, I cut apart one of the
GM Cores to get some better accuracy on the core dimensions particularly fin
separation and thickenss.  In any case, when you plug the GM core values in
to the K&W equation for a cooler block size cooling 160HP at 120MPH and
assuming losses in the diffuser and ducts (real world consideration),  the
required core size for one GM core  comes out to 94.9 in^2 core area.  Since
the GM core  (94.5 in^2) has slotted fins, the optimum thickenss which
calculates out to 6.87" for smooth fins can be reduced to 2.8".  (Slotted or
corrugated fins have a dramatic effect in reducing cooler core size
required).

So a 9x10.5x3.6 GM core turns out to be pretty close to what the equations
indicate in required for that power and airspeed.  Actually perhaps a bit
thicker at 3.64 inch than optimum at 120 MPH according to the equations. So
the 3" thick core could be a bit closer to optimum if using a GM type core
than the 3.6" core for 120MPH cooling and would probably improve cooling in
the take-off and initial climb phase where there is less dynamic pressure to
force air through the cores.

This not a recommendation at this time, just an observation

Ed Anderson.

A



Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com