Had a long talk with Dick MacCoon (Mr. RPM) at OSH in the Pulsar tent
during a thunder storm. Dick is the originator of the Chevy V8 turbo big block
based Thunder Engine for aircraft. Dick spent ten million and ten years
trying to make it work including $100,000 for a new forged crankshaft die.
Then Orenda in Canada bought the project for an undisclosed amount
and borrowed 30 million from the Canadian tax payers. The project
just closed its doors after another ten years stiffing the Canadian 
taxpayer for the 30 million. Seems nobody wanted a 1000 pound firewall 
forward package with only 600 HP and a 1200 hour TBO for $100,000.

Sounds like our GAT program where we spent 100 million on the Williams
turbo fan and 10 million on the Continental diesel. Don't give any money to the
government as they just waste it. It is not their money so they don't care how
they spend it. There is another such Chevy V8 powered AC program in NASA 
as we speak that I will talk about shortly.

Anyway I'll get to the point. Dick has a few rules of thumb for cooling
liquid cooled aircraft engines. He says 2 cubic inches of rad volume
are necessary for every HP. That means we should be cooling with 400
cubic inch rads and right now it is taking 500 to 600. We are not
doing a good enough job on the scoops and ducts.

Another rule is the outlet area should be 150% of the inlet area.
Many of our installations are violating that rule as well.

Dick also subscribes to the old diffuser angle rule that states 
the diffuser wall angle must be 7 degrees or less. K & M has modified
this rule with the bell shaped diffuser duct. I guess Dick missed
the K & M book Aerodynamics of Propulsion when it was published in 1953.
In both cases the diffuser length would be out of the question
for mounting the rad under the cowl. Fortunately Kays & London
book Compact Heat Exchangers (still in print) came up with the 
oblique diffuser answer.

Paul Lamar
 
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