Here is the VTOL cooling layout.

The fuel tanks are 20 gallons each. I was stunned and pleased on how much volume
I had for fuel with only a 15% thick airfoil. I actually had to cut them down
from 35 gallons 70 gallons total as there was no way we could lift that much fuel.
The two pass rad is 18" by 30" from a late model Dodge pickup.
The oil cooler is in the other wing.
The cooling air ducts run along side the pilot and pax.
The air comes in the bottom of the rad with a Kays & London
wedge diffuser and is sucked out the top with the engine driven fan during takeoff
mode. An exhaust ejector will also work here and is near ideal. I just don't have
it drawn in yet.

This config is idea for an exhaust ejector.