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Re: REFLECTOR: duct installation
My initial Ron Davis radiator had a fin area of about 5.5 x 22 inches and
was about 3 inches deep. This is for a 230 HP 3.3 liter/201 cu in Subaru
engine.Even with exhaust augmentors and the prop sucking on the outlet
trumpets (the front face was wide open No inlet horn) I couldn't sustain a
high power level on the engine.I managed a 92 kt airspeed equivalent
manometer reading but I don"t know how many cfm it represented.
My final? size radiator fin area is (7.5x24 by 3 inches deep).Tim England
with a similar HP engine, in the far frozen north gets by with a somewhat
smaller radiator than that.
With my final? size radiator I was able to run wide open until the
temperature peaked around 215 degrees after 5 minutes then back off to 4500
rpm and ran for 15 more minutes with the temperature decreasing slightly to
210 degrees . This on a 90 + degree day.The mannometer reading equated to
around 50 kts (no augmentor this time just prop suction from about 6 inches
away). I also had a 7x8x3 inch heater core in a parallel loop. The heater
loop on a Subaru must remain open at all times.
Turbo Tom in a Contact magazine article suggest :
.9 to 1.3 inches of matrix face for each cid of engine displacement
1.85 to 2.1 inches of matrix cooling volume for each HP
My numbers come out at .89 on area and 2.34 on volume.
I compared numbers with Bayard DuPont (215 HP Ford ) and Charlie Aiersman
2.2l Subaru and came to the same ballpark. Lino Moya graciously provided me
with his dimensions (see attachment) again same approximate ratio.
Russell Sherwood authored a Contact Magazine article on the SVX engine he
is installing in a Glasair. He is the guy who blocked off the radiator to
empirically determine the size required. When I called him to ask radiator
size again the numbers came close to what I'm using.
From: Lino Moya Jeannine Cde Baca <firstname.lastname@example.org>
To: email@example.com <firstname.lastname@example.org>
Subject: Re: Radiator size for an SVX
Date: Sunday, June 14, 1998 10:59 PM
I'm using an aluminum Griffin racing radiator that is 18" x 14" x 2" thick
, it's one of the "off the shelf " sizes you can buy from the racing
parts houses for about $ 150.00 . I also have a 7" x 7" x 1" aluminum
heater core in my cooling loop with a marine bilge fan sucking air through
it for help during ground operations . I'm working on my "Mustang" style
scoop now to go on the belly to cool the beast . This radiator fits between
the legs of my engine mount with no room to spare , it drops below the old
cowl line about 3" (I say old because I had to radically modify the cowl to
accept my exhaust augmentor and the scoop for the radiator ) I'm told by
the racing types that I've asked that I should have more than enough
cooling but I haven't flown it yet so I can't say for sure .
You might try the heater core idea to add to your cooling capacity as we
have done . The heat exchanger we have devised will also provide cabin heat
when necessary through a closed loop system recalculating cabin air only
for cabin heating otherwise it dumps the heated air in the engine
compartment near the exhaust pipe .
Hope this helps
> What are the dimensions of your radiator? Ron Davis racing approved of
> my request for a 24 X 6 X 3 inch thick one but unless I can get more
> airflow on the ground for testing I'm afraid it is too small.I'm revising
> my exhaust augmentation for the belly scoop radiator before I fork out
> big bucks for another rad.