What this K&M graph fig 12-16 is saying is... if you have a wall
behind
your
rad that is less than half the height of the rad away from the
rad you are paying a severe penalty in cooling flow.
In other words a 20 inch high rad must be ten inches in front
of the firewall. Here is a picture of the rad installation
in the Power Sport RV6. Draw your own conclusions.
Are you listening Keith and Ray?
Paul,
Interesting curves -- I received the electronic file of chapter 12
today, and
it is interesting reading.
With your rad under the engine, with the sloping oil pan only a few
(3?)
inches away from the back of the radiator, won't that cause a flow
maldistribution also?
Bill Schertz
KIS Cruiser #4045
I hope you taperd your oil pan. Opps I see you did not. First
is yours. Second is mine.
Not to worry just make your rad a bit wider and move it as low as
you can get it.
Paul Lamar
Not to worry too much Bill. Unlike the test box on the Dodge and
the Power Sport mount on the firewall the air out of the back
side of the Kis rad can go around the sides of the pan. It is not
as restrcted as it would be in an enclosed duct.
Paul Lamar
Bill, here is something that might work even better. Same size rad.
16 by 22 by 2.5. The inlet scoop area is 15 by 5.
Rotate it 90 degrees in the vertical axis and put the inlet duct
on top. Use venetian blind cowl flaps on the bottom.
When the flaps are open the back of the rad then becomes totally
unobstructed. When closed of course you get external diffusion
ahead of the scoop and the consequent streamlining.
The inlet duct length gives room for a K&M style curve.
A incidental advantage is it shields the rad from the exhaust heat
radiation automatically. Should fit in the stock cowl.
Although the bottom of the airplane is generally higher pressure
the pressure is always lower behind a cowl flaps.
Paul Lamar
Paul,
Glad to see you endorse this approach since it is the one that I built a
year ago. Havent gotten the louvered cowl flap built yet but the inlet and
outlet is done just like this.
The only thing I had a problem with here is the oil cooler placement. In
my application the rad is closer to the bottom of the oil pan. Locating the
oil cooler above the rad inlet duct led to restriction of the oil cooler
exit by the oil pan and the PSRU plate. And of course the stock Mazda oil
cooler is far too wide to fit in my skinny cowl, but looks like a good fit
in yours.
Mike Wills
You lucked out Mike :-)
Is that a perfect wedge on top of the rad? I also think you are going
to need the louvers or venetian blind cowl flaps on the bottom
and underneath the rad. Picture below. Don't try to duct it aft
with a 90 degree turn under there. The bottom of the cowl is too
close to the back side of the rad.
A good place for the oil cooler is long ways on the spark plug side
against the cowl with the air coming out the side and again with fixed or
venetian blind cowl flaps. Dave Atkins uses this installation apparently
rather successfully on his RV6. Tracy needs to do the same.
Dave also has a rad under the engine that
could also benefit from underneath louvers. However the entire
cowl is pressurized and air must find its way down over the hot exhaust
pipes and the engine before going into the rad. It needs a wedge shaped
duct added on top of the rad to smooth the flow and inject cooler air.
BTW Dave, are you listening? Put some louvers under the water rad
and try it. You will be amazed.
Todd now has the complete oblique rad header tech paper so download
it from his web site.
Paul Lamar
I knew I had a pic of Dave's oil cooler setup someplace.
Here it is. Mostly. At the bottom of the picture. Underneath
the fuel pumps. BTW Can anybody identify those two guys at Shady
Bend a couple of years ago?
Paul Lamar
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