I am
cross-posting this from Paul's site. I should have posted here
first. I think I was just reading that list when I wrote it.
The initial
response I do not think really addressed the issue asked about but Lee
Hanover did post some info that I followed through with last night. Not
sure of any measurable difference yet, but at least it provides something
proactive. I know some of us monitor both list so sorry for the
redundancy.
As I
state in the post, I do not know how much ducting effects a pusher when
stationary. My buddy with a soob on his RV-7 gets quite a bit of
cooling from the prop.....being up front.
Since,
as was just mentioned, the list has been quit enough to have us question if it
were still up, perhaps this will jump start us a bit.....
Chris
Paul,
What
kind of temps should we be seeing on the ground? On Page 19 of
your
book (I was one of your first purchasers) it mentions even the
P5 1had
trouble on taxi and climb out. No comparison between mine
and a P-51,
but similar concern. I am currently re-reading it again
to gather
potential new insight. Funny, I understand much more of
it now than
when I got it :-). Yes, I understand that it is in
flight that is our
main concern, but it I heat up too much do to a
long taxi or long hold or
while doing run ups, it may prevent my
flying for a while...especially if I
trash an engine. I have this
horrible image of me in the pattern with
steam trailing behind my
plane...yes, better than smoke, but still not
good.
I am currently doing my (hopefully final) high rpm engine
runs
before attempting first flight. I have scheduled
transitional
training with Velocity, Inc in Florida for early
April.
While I seem to maintain reasonable temps while at idle, even
higher
idle of around 2000 rpm, even though I seem to run hotter than I
use
to (may be the addition of the turbo since nothing else major
was
changed), when I run up the engine WITHOUT any air from the prop
in
my pusher aircraft, my temps soar very quickly, perhaps a minute
or
so before I idle back to bring temps down. From the 185/190 to
past
220, sometimes a little more for a couple of seconds when I
throttle
back. I hate going this hot and have only done so to test
full
power twice, but do now wish to trash another set of seals or
worse.
I spoke with another pusher 13b
pusher jockeythat says he has the
same until he gets moving. I
have not had any boil over
though...yet...? I don't know if this is a
bigger problem in
pushers since it does not have the big fan up front
pushing air into
the system or not.
I know a lot changes when you go
faster and that is where I am
thinking some of the ducting "magic" comes
more into play, but since
I am currently limited to a run up area, after a
few minute taxi at
a controlled airport in Houston, I am very stationary
and yesterday
it was "only" 80 degrees out and I had to sit and cool down
before I
ventured to taxi back to the hangar.
My 13b, with water
channel mods, street ported by Mazdatrix, a turbo
with low boost for
testing (3 lbs) as much for muffler use as any
(yes, it made a heck of a
difference). My prop is an in-flight
adjustable 68 inch three blade,
with 45 degree full fine IVO. The
coolant heat exchanger is between
the size of John Slade and Dave
Leonard sat 22 x 19 x 3 = 1254 or a frontal
area of 418. I have two
fans pulling air through the heat exchanger
and the radiator area
where the fans are is cool to the touch with the fans
on right after
shutdown.
I am running up to about 6200 rpm static
with about 32 inch manifold
pressure. I am using Royal Purple synthetic
oil. 50% water to 50%
coolant with some Water Wetter added.
I have a
coolant line from the port on the top of the engine to a
pressure tank,
then to the recovery tank as illustrated on page 39
to help relieve trapped
air. Is there a conventional wisdom other
than this to "burp" the air
out of the system. I have actully
lifted the nose to try to shake air
pockets out.
Again, I am curious as to your and others experiences on
the ground
and taxi as this is before most of the ducting, diffusing
and
wedging comes into play.
As always, your/y'all's input is
appreciated.
Thanks (in
advance)
Chris
Houston
Send me some pictures of what
your rad ducting looks like.
I think you are more likely to have
problems on climb out. Pick a
cool day to do testing and climb out at the
highest speed that is
safe. Keep the climb angle shallow until you see how
well it works.
What are the rad core
dimensions?
Bulents installation worked pretty good but he did
away with the
early turbo.
Air outlets are important as well. The
prop will suck air flowing
over the outlets. Air is somewhat like molasses
in that it tends to
stick to everything including itself.
His wedge
diffuser could have been a bit better.
10 quarts in the oil pan is good
as it takes longer to heat up 10
quarts rather than only five. My O-470 230
HP engine has 12.
Paul Lamar
Do you have the Mazda thermostat
installed? If not, have you plugged the
bypass hole to prevent circulation
through it? The engine will overheat if
this is left out.
Dale
Davies
Try cutting that antifreeze back to 10% just to help with the
boiling point. Try a
Stant 22 pound lever cap. Dump the coolant and
save it.
Refill with just distilled water and Water Wetter or a
teaspoon full of
Dawn dishwashing detergent. Run the system to temp a few
times including some revs to
clean things out. Then Dump that mixture and
refill with 10% coolant and distilled
water and Water Wetter.
The 50/50
idea is for winter time and selling lots of Prestone.
The best coolant is
distilled water.
Lynn E. Hanover
My radiator is 22 x 19 x 3
= 1254. Yes. I need to fly to verifying ducting. However,
I am
currently focusing on ground temps for start up, getting to the active and
run
ups. Not sure how ducting does much at this stage with the fan in the
back.
Yes. I am running a thermostat. Honestly, I am uncertain on which
passage to seal off
in order to remove the thermostat. I would hate to
choose wrong.
Directions/illustrations here would be appreciated. I must
conceded, pulling the
water pump housing is not an appealing thought right
now regardless of how good I
have now gotten at such things on the
rotary.
I think I may drain the coolant tonight. I will go the
distilled with some warer
wetter i think Unless the earth tilts
its axis, Houston is not in direct peril
from
cold.
Chris
Houston