Jerry,
I don't think that 3" is nearly large enough.  You will probalby

need

about 25 sq. in. of intake area (according to Fred Morino) for the
oil
cooling.  The 3" is a really small duct.  Take a look at the
following
numbers:

3" = 7.069
4" = 12.57
5" = 19.63
5.5" = 23.76
6" = 28.27

FWIW, I'm not flying yet.

Ken P.

Ken Powell
kenpowell@aristotle.net

Good point Ken. I missed that.

Paul Lamar

In general, Scat tube is lousy at transfering high velocity air due
to

the

wavy wall.  It dissipates the energy in turbulence so there is
nothing

to

recover pressure with on the other end.

Tracy

There are two kinds of flex tubing. The double wall lined stuff is

smoother inside.

The down side to the double wall stuff is it is not to be used with

suction

as it can separate and plug itself up. For this reason it is not

recommended for

engine air intakes. I agree, the double wall stuff is still not as
smooth as a fiberglas duct made over a smooth male mold. Chuck used a

smooth

metal duct for his firewall mounted oil cooler. Ed may have used the

single wall flex tubing for his installation. Right Ed?

Paul Lamar

Right, it was the single wall stuff as I had also heard about the
double
wall separating and plugging up air ducts.

Ed Anderson

OK with long term hindsight that could be part of your original
problem. The double wall duct would have been better as in a case
like this it is always under positive pressure.

Paul Lamar

Good points!   I will switch from scat to molded fiberglas.    Jerry

 
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