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