I have been doing a lot of ground running to check the cooling

system.

With air temp around 80 water temp stays about 200 to 210 and
oil stays about 190 with 1200 to 1400 rpm idle.
When I go to full power at 5500 rpm water temp climbs to 230
whithin a minute, at wich point I back off.
Is this OK or should It be able to cool full power when sitting

still?

Another question. I have a cowl flap. What is the maximum opening
angle that is effective?

 Left evaporator core is water,
right evaporator core is oil. 6" round opening feeds 7" wide

epvaporator

core mounted 5" from firewall that also feeds cabin heat, and boy

does

it pump the heat in!

Lonnie

I assume you are running it like that without the cowl. Correct?
Looks like this scheme will work fine. It is supposed to get
hot if you run full static RPM power on the ground :-)

Perhaps not quite that hot. I can see a few improvements possible
on the evap core near the firewall. It is a bit too close to the

firewall

and the inlet duct needs to be reshaped a bit. If you have room
move it further forward to about ten or twelve inches in front of
the firewall. I'll do a three D later this week. No time today.

My guess is the round pipe
going into the duct is about six inches in diameter. Correct?
That gives about 18 square inches. The evap core is about
7 x 11 (my guess) or about 77 square inches. Which makes the
six inch pipe look a bit small but probably OK. The opening
shape for this on the cowl will be critical.

Are you sure you have all the air out of the system. Is there a
vent from the top of the left evap core? There should be.
Are the rads plumbed in parallel or series? What size is the

plumbing?

Can you mount a couple of thermometers in the center on the back
side of the cores and tell us what they read when the water
temp gets up to 230 F?

Here are the proper coordinates on the inlet duct for the evap.
core near the firewall. It should look like a rectangular
bell when finished. Also the transition from six inch
round to rectangular bell should be smooth. Hard to do
when done in aluminum but easy if done with a foam male
mold and fiberglass.

Paul Lamar

Here are a couple more pics. With the properly shaped inlet
duct and moving the rad away from the firewall could double
the air flow through the core. "a" is the curve you want.
What you have now is "b".

Paul,
All of my testing is with the cowl in place. The ducts in the nose cowl
were made according to these coordinates. The duct on the 7x11
was not. It does have a 6 inch duct and opening. I do get better cooling
when I open the cabin heat door.

The inlet to the front radiator is at the top. I have a vent from the

rear

of the engine to the filler cap area. I am pretty sure all of the air is
burped out, I have done a lot of running with the tail up.

I will put a thermistor on the back of the core and see what the temp

is.

Here is a picture of the nose but  kind of dark.

Any educated guesses on the cowl flap angle? The max I go now is
45 deg. I am sure 90 is too much, but is there anything to gain by
going further?
Lonnie

Good evidence that the rad is too close to the firewall.
45 degrees for the flap is fine. Make sure the sides are
blocked when it is open. Got a flash on that camera? :-)
Just drag a drop light around the front so I can see the openings.

Paul Lamar

Sorry about the picture, it is an old one. Will have to get a digital
camera pretty soon. Here is a drawing I found on the nose cowl.
I wish I had known about placing the cooler so close to the firewall,
will be a lot of work to change it. I am considering maybe getting
a 9x11 core and turning it sideways and exit the air from louvers.

Thanks Ed for your reply. Is there anybody else out there flying that
can tell me at what percent power your engine starts to overheat
on the ground?
Lonnie

The openings look plenty big enough Lonnie.
If everything is sealed it should cool fine. I still think
you may need a vent on the top of the rad. If you get any 
steam bubbles they will accumulate there.

My guess is it is almost good enough to fly.

Paul Lamar

 
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