I added the lower MM rear cross tube and adjusted the dims
to conform to the Van's RV4 dwgs I just found.
On the RV 4 I think it is wise to make the rad larger
and move the oil cooler up to the cool side.

Both Tracy Crook and Dave Atkins run their oil coolers
in this position. Dave uses exit louvers on the outside
of the cowl and Tracy dumps the hot air back into
the cowl which IMHO is not as good as the exit louvers.
Dave's oil cooler duct and diffuser shields the oil
cooler from the hot air under the cowl while Tracy's
oil cooler is exposed to the hot air. IMHO Tracy made
the same mistake on his 20B powered RX8 radiator mounted
in the same position :) One degree F increase on the air
going into the cooler is a one percent decrease in
cooling capacity. Both systems consume the same amount
of volume under the cowl. Which system has the least
aerodynamic cooling drag is open to speculation.

I'll bet it is hard to measure. I wish these two guys
would get in an air race with each other. It would
be good PR for the rotary.


BTW David these have not been processed by gimp.
They are right out of the Rhino renderer.

Paul Lamar ...No rotor no motor.

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