I am working with Bud on my cooling problem and have his cooling flap installed
- think this is the ticket along with the oil thermostat - which I haven't
installed
yet. I have been experimenting with various tape combinations - my results
are tentative and require some more careful data gathering.
It appears that the oil temp is not much influenced by the amount of tape
covering
the radiator, and is somewhat affected by the outside temperature. In my plane,
the cooling is too good and the plane runs too cool. This is an engine
efficiency
problem, but more importantly in the north, a heater problem. The amount
of tape on the oil radiator doesn't seem to affect the heater output. (Duh,
it is lower than the water radiator and much lower than the heater intake.)
Higher oil temperatures do not seem to affect the water temperatures, at least
in the range I have experimented with.
The water temperature is greatly affected by the amount of tape covering the
water
radiator. At the margin a small change in tape will greatly affect the CHT.
For example, going from covering 1/2 the radiator to 3/4 of the radiator made
the CHT climb from 170 to 270 and resulted in boiling over the radiator (lost
about a cup.) When in cruise in this config (1/2 tape to 3/4 tape) the temps
went from 170 to 180 or so. The heater output was better than when running at
160 with no tape. The high sensitivity in the temps due to the changes in
airflow
at the margin suggests that a permanent (non-cockpit controllable blocking
of the radiator) is not a good idea.
I have put a little sheet metal box around the top right rear of the water
radiator
and that is doing a better job of directing the air. It is however, not yet
sufficient, particularly for she that must be obeyed. I think Bud's idea is
the way to go with a flap, but we put on a wimpy cable (which also doesn't hold
open except with a vise grip)and the flap may be too weak - the result being
when I pull the flap shut the flap doesn't close well - resulting in little
no decrease in airflow - what may be happening is that the air flow is just
speeding
up and I see no different in the CHT with the flap closed or open.
On my to do list:
Need to move coolant temp to show on EIS - presently I don't display water temp
on the EIS or HX - only shows when I get a warning.
I need better data. On the day I tested I either had strange inversion with OAT
at altitude higher than on ground, or engine temp affected OAT sensor in the
carb box.
I may have to seal up the flap better with cowling rubber to cut down the air
flow.
I must repeat to myself it is called an experimental aircraft for a reason.
Gary Leinberger
A237
N388SG
gleinberger@millersville.edu
Lancaster, Pa.
USA
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