Ed Anderson wrote:

>      Might be able to get that delta T in the near future.
>
SNIP>
>    Now that I think about it, it would appear that I probably should have
the
> coolant temp drop across the radiators equal the air temp increase through
> the radiators, in otherwords both = either  30F or 20F.  Any suggestions?

NO, those delta T's don't have to be equal, and are probably not. The heat
given up by the Radiators IS equal to that absorbed by the air, but the heat
capacity of the air and that of the water are vastly different. Also the
flows are different. The governing equations are

Q = (Mass-air)*(heat-capacity-air)*(delta-T-air) =
(Mass-water)*(heat-capacity-water)*(delta-T-water)

> I had just installed some thermocouples in an attempt to measure the
coolant
> Delta T through the radiators. Won't be able to see what they give until I
> get gear box back on and fly again.

If you can, measure the delta T across EACH radiator, since you have them
plumbed in series. This will give us information on the effect of the
different duct designs you are flying with. Since the water flow is (by
definition and plumbing) identical, the temperature drop across rad-1
compared to rad-2 will give a DIRECT indication of the relative air flows
through the two radiators.

Since I am not bashful about suggesting work for you, the second piece of
information that would help nail things down would be air-temp in front of
rads, and behind rads (both of them).
Bill Schertz