Theodore James wrote:

Paul,
All of the testing seems to be going well for Jim & Jerry. Jerry's
plane will not be out of the paint shop in time to make the trip to
OSH, and Jim probably will not make the trip alone. Even so they both
expect to make the rounds this summer; Vans homecoming and other west
coast fly-ins. The cooling system is very much the same as the
Powersport installation you are familiar with already, and the cowl is
the one you seen on the James Aircraft web site. There are a few
"tweeks" that are being made and we expect to be able to give everyone
more complete reports soon. We are also sure you will soon get an
opportunity to see first hand.
Regards,
Powersport -Tedd James

Tedd, I have the ultimate solution to your cooling problems. It is so
ridiculously simple I don't know why it did not occur to me six years
ago when you guys first got started with this program. On the other hand 
it took me six years to get to where I am now :)

Your current set up has at least two major problems. 

One; the back side if the rad is too close to the firewall for an 
adequate exit duct. Read Kucheman & Weber chapter 12 COOLING.

Two; the air is heated by the exhaust and the engine BEFORE it flows
through the rad. One degree increase in F is a 1% reduction in cooling 
capacity and this rule of thumb also applies to the ambient air temp 
entering the scoop.

Simply  use a constant area, SEALED duct to carry the cool air to the BACK side 
of the rad and oil cooler. The rad already forms an ideal Kays & London wedge 
shaped diffuser with the firewall. 

NO changes other than some minor ones to the exhaust system will be 
required. Put some louvers in the top side of the cowl above the rad
to let the hot air out. 

This is guaranteed to work under all ambient temperature conditions.

Paul Lamar
 
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