George,
Actually
the fan is in between the air inlet, and the radiator, so it is pushing air
through the radiator. This is a
pusher airplane, and the inlet scoop is what they call a NACA scoop, but it
also has an extended lip, so not a true NACA.
Steve
-----Original
Message-----
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of George Lendich
Sent: Sunday, August 03, 2008 8:22
PM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Re: Back in the air
Steve,
Thanks
for the photo and reply, yep it's a large fan, that's for sure - I assume it's
sucking on the Rad.
I was
wondering if it wouldn't be better if a large fan was used and it was blowing
on the rad, and it was free wheeling when turned off - if ( in that case) the
restriction would be less.
George
( down under)
George,
I had
considered that. I would assume
that there is definitely some restriction caused by the fan, but I think that
the benefits during extended ground operation, and during climb, probably
outweigh the downside. But, you
are right. The only way to see
how much, is to remove it, and try a takeoff and climb without the fan. It would probably take about an hour
to remove the fan and get the plenum and cowlings
reinstalled.
I will
most likely do this, but I think that I will fly it some more first, and get a
good benchmark on the current set up.
Plus after 3 ½ months of down time, I just want to fly it
some.
Regards,
Steve
-----Original
Message-----
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of George Lendich
Sent: Sunday, August 03, 2008 5:36
PM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Re: Back in the air
Steve,
How large is the
cooling fan, do you think it may be restrictive ( restrict air flow) in the
low speed climb.
Another test would
be to take out the fan and do another test and you would have a better idea of
what the advantages and disadvantages are.
George (down
under)
----- Original
Message -----
To: Rotary motors in aircraft
Sent: Sunday, August 03,
2008 11:33 PM
Subject: [FlyRotary] Back in
the air
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