Oil Duct Opening Size

Chuck wrote:

snips..


It works fine in cool weather. It is marginal above 90F

OAT in a climb.

flew today 61F OAT and the max oil temp was 190F after

full power

takeoff

and 100MPH climb to 7500FT. My inlet is one side of

Van's nostril intake

sq. in. but it reduces to about 10 sq. in at the

oilcooler duct due to

interference with the water pump inlet. I will modify

the water pump

when I

install a new engine, then I can improve the duct.

Jerry, I think you

will

be alright if your first flight is in cold weather and

if you can run

full

power on the ground for 10 minutes without the oil

overheating. I think

you

will find you need more than 3" duct in warm weather.

Chuck Dunlap


Here is a picture of the metal duct Chuck mentioned

feeding air to the

firewall

mounted oil cooler.

Paul Lamar

Chuck,

Hope you don't mind giving some details on your

installation. I was wondering

mostly about the radiator, specifically: How big is your

water radiator? How

big is the air inlet, and how well does it work? I'm

struggling to get all

the heat exchangers to fit under the cowl of my chosen project ;-)

Thanks,

Monty

Here is a picture of Chuck's rad taken at Copper State 2000
unless he has changed it.
I have some pictures of the opening as well but I am sure he
has cleaned it up
since then. I have to give Chuck a economic perseverance
award as he got a bad gear box
from Ross and went ahead and bought a new gearbox from Tracy
to replace it.
Anybody want a slightly defective Ross gear box cheap? :-)>

Paul Lamar

My radiator core size is 10.5 x 20.5 x 2.5 inches, custom made by Griffin.
It was ordered as the biggest size I could fit behind the 13B, angled
against the firewall like Jess Myers RV6 with Chevy V6. I quickly abandoned
that location as I could not keep it cool even at idle speed, so I moved it
up front. Like my oil cooler, it cools fine in weather up to 90F but if I
ever get more power (by raising RPM), I think it will only cool at full
power up to 80F ambient. I can fly if it is over 90F but I have to cut back
on power above about 500ft AGL after full power takeoff to keep temp in the
green. I am looking at replacing it with a bigger unit, since there is
enough room up front. I do not have a photo handy, but the current inlet
under the spinner looks like a "smile" 12 in. across and 4 in. tall in the
center, tapering to the sides. I also want to try moving the inlet forward
to just behind the prop, it is now about 6 in. behind the prop.
Fitting the heat exchangers and hoses is only half the battle; then you get
to fit proper ductwork to make it work! 8-)

BTW the Ross was running fine after I replaced the sun gear it but started
leaking oil at the rear seal because I was in a big hurry and put in a
neoprene seal. It should have had a Viton seal but I did not want to wait
for a special order. I thought neoprene would work because it is rated to
250F but I did not take into account the temp rise at the seal due to
friction of 5500 RPM shaft. Oil temp out of the box was running around 240F.

Chuck Dunlap


 
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