Kevin;
When running without a prop you will
never produce more than a few hp; so the amount of airflow required for cooling
is pretty low. A high speed axial flow fan near the rad should do it. I used
a centrifugal blower from a furnace for doing flow distribution and pressure
drop tests on my radiator and oil cooler. As I recall it put out about 1200
-1400 cfm; which if ducted to your rad would be good to about 40 - 50 hp –
way more than you’ll ever get to without a prop.
Al
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of kevin lane
Sent: Tuesday, May 18, 2010 8:01
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] ground test
cooling
I would like to run my
engine on it's test stand without the prop. I'd like to rig up electric
fans to blow thru the radiators. will I have better luck with a leaf
blower or one of those squirrel cage type blowers? the leaf blower has
high velocity, but it seems the big squirrel cage blowers [like used in forced
air furnaces] move a large quantity of air and may handle back pressure better.
I assume others have already figured this out. I quit when water hit
210°. the leaf blower I had on the water rad didn't seem to make a huge
difference, but my ducting was a pretty poor first attempt.
my tests so far have had
no potential of runaway rpms, plus the MSD ignition has rev limiters, so I am
not worried about that. being killed by a prop is a MUCH more potential
accident. I have a wood prop and is was too scary to be around when
mounted. I don't have water at the airport, so that solution isn't too
easy, I'd have to bring water and pump it. at some point I'm going to
have to address the muffler too. last run got up to 4000rpm. damn
that is loud, even with my noise canceling headsets turned on. my
new s/s exhaust manifold is starting to turn a golden color.