I’ve had my plane torn apart for about 3 ½ months rebuilding the cooling
system, in between vacation, wife’s projects, and problems fitting in the
radiator. I installed a custom made
radiator, replacing two evaporator cores that I was using. The evaporator cores provided only marginal
cooling for the turbo 13B, in a pusher aircraft
In order to install the new radiator, I also had to relocate almost all of
the fuel system components, and I replaced the aluminum lines connecting the fuel
pumps to filters to regulator with SS braided AN hose/fittings.
Due to the extensive changes, I had at least an hour, maybe hour and a
half of ground testing, including four high speed taxi’s up to rotate speed.
The new cooling system also has a cooling fan which I was able to integrate
into the plenum holding the radiator.
At 95 F degrees OAT, and turning the fan on at about 190 F degrees
coolant temperature, The fan maintained 180 F for 20 minutes of ground
operation, including some high power testing.
This morning OAT was about 78 F, which is very good for North Carolina
in August, I wanted something less
than 95 F for the first test of the new cooling system. I did not use the cooling fan for taxi
or takeoff, as I wanted to see what the cooling was without the fan. I took of and climbed up to about 1200’
AGL. The coolant was up to about
205, and oil at 185. I leveled off
and reduced the throttle to normal cruise power. I watched the coolant temperature for a little while (maybe
15-20 seconds), and it seemed to stay at the 205 F reading. I wish now that I’d been a little more
patient, but I kicked on the cooling fan, and the temperature came down pretty
quickly to slightly above 180 F. I
turned the fan off again and the temperature stayed right there. I did power up and climb another 300
feet or so, but really didn’t push it too hard on the first flight. The temperature didn’t really move too
much during the brief climb. All
other systems ran perfectly and it was a very nice flight. I did stay within gliding distance of
the runway the whole flight, but based on zero squawks on this flight, the next
one will be longer.
While I would like to have seen a little better performance, I was happy
with the improved cooling over the old system. Climbing to pattern altitude old the old system at today’s temperature
would have been 215 – 220F. On the
next flight, I’ll take off using the cooling fan, and see what kind of numbers
I get with it. I hope to see
something more in the 185-190 range, but I’ll have to see what the real number
are.
Steve Brooks
Cozy MKIV N75CZ
Turbo rotary