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Bobby,
I knew he had a hand in it somewhere, all those
things Ed mentioned are true as well as the efficiency of the diffuser duct and
if using a wedge diffuser, the angle of the rad to the incoming air. I
think it must be more of an art than science.
Please let us know how it pans out.
George ( down under)
Yes. Ed has been a great help. The formula accurately
predicted my current BTU rejection as compared to the Renesis dyno data
merged with the Eaton M64 SC data. Hope it holds true for the new duct.
However when you change things you never know. I had to enlarge the defuser
duct also so that may have change other things.
Bobby
Bobby,
Is that one of Ed's formulas?
George ( down under)
isn't the
inlet face area supposed to be 30% to 35 % of rad face
area
Based on the data I've collected 26% should give me
the correct heat rejection for climb out at 100 mph. Just have to see if it
actually works.
Bobby
My mistake Bobby, I'm working too
quickly and not concentrating enough. 775 to 800 cu" should be enough rad
volume - however isn't the inlet face area supposed to be 30% to
35 % of rad face area.
I suppose your looking for min
drag?
George (down under)
George,
Have not changed the heat exchangers. Just the
plumbing and shortened the hose loop by about 18 inches. The increase
from 21 to 26% is the opening size to core face ratio. I have about
272 sq in of core face and the opens are now 72 sq in. If this test
doesn't work I will be adding a small oil to air exchanger in parallel
with the oil \ water exchanger with dedicated inlet and reducing my Rad
inlets back to 21% / 58 sq in. Actual core size is about
775 not 800 cu in as I stated earlier.
Glad I have the molds for all this stuff.
Bobby (still wondering about Tracy's
cooling solution)
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On Behalf Of George
Lendich
Sent: Thursday, October 01, 2009 2:53 PM
To:
Rotary motors in aircraft
Subject: [FlyRotary] Re:
Activity
Bobby,
I've seen between 3 to 3.5 cu" per HP, I
guess that depends of how well the cooling is set-up, 800 cu" of Radiator
should do fine for 250hp.
If your previous exchanger was 650 cu" for
250 hp it was undersized. I guessdamated that size form the info you
previously provided.
George (down under)
George,
I have 800 cu in of water to air exchangers. No oil
to air exchanger. At 6800 rpm \ 38" MP I'm producing close to 250 hp.
But 15 hp is used to drive the SC. So about 3.2 cu in per HP. The new
openings are about 72 sq in. The goal is to lower the water temps from
200F to 185F with an OAT of 100F. Oil is running 20F hotter than water.
With the 21% ratio I was only able to maintain 185 HP and keep the oil
temps below 220F \ OAT 95F. It all an experiment.
Bobby
Bobby,
What is your expected HP.
How does 26% of core face equate to 3 cu"
for every HP
i.e. 200 hp = 600 cu"
George (down under)
With any luck I will be back in the
air this weekend. I made several changes including opening my inlets
from 21% to 26% of my core face. Of course it's no longer 105F so will
have to extrapolate the data. Other changes include relocating the
battery back to the stock location, removing 13lbs of tail ballets,
new exhaust manifold and belly mount muffler, CO Detector, exhaust
heat for cabin, O2 system, autopilot, 230 psi water spray for radiator
and manifold injection (yet to be tested), re-plumb the oil to water
exchanger and a fresh pilot bi-annual
today.
Bobby
Anyone out there ??.....................<:)
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