Hey,
It's not a contest. Even Volfy is back on track, so we all agree, don't we?
Core in the discussion is, that theory and pragmatic approach show matching results, with the prime question being: "do you know how to do it?".

Look at Nature. Sharks for example. Their trial and error design has stood up against eons of time. The coolant inlet is in a high pressure zone. The outlet is through the gills in a low pressure region. The series arrangement of gills show, how effective this contraption is when moving at a certain speed. With the shark asleep and zero speed, he relies on jaw pumping action to keep that flow going.

Now look at the Suchoi 26 aerobatic plane design. Incorporated here is all the knowledge gathered in WWII radial fighter planes, and the testing for best performance that went with it. The aircooled radials were well baffled, and when stationary on a start lineup or a ship's deck purely relied on prow wash aerodynamics to keep the engine in a proper operating range. It is no good to start your mission with the engine overheated! Their gills (cowl exhaust baffles) could be regulated to adjust the flow, and hence the engine operating temperature.
Like Dick stated, the prop hardly contributes, because the centre sections were cuffed, and hardly were able to add to the cooling of the engine by providing ram air pressure. Yet there was sufficient pressure difference to sustain a good flow of air through the engine.

With our 3D model airplanes growing in size, and the lack of internal fuel cooling of gas engines, we find ourselves in nearly the same situation as the fighter planes waiting for that take-off signal. There seem to be no shortcuts. Baffling gains importance as sizes increase, because engine swept volume (cube) doubles with available cooling fin area (square) when engine size doubles. Lacking forward speed, we need the low pressure of the air outlet, as well as the generous dimensioning of that outlet to keep gas flow up to par, and resistance to a minimal value.

Emperical values (derived prom field observations) are a ratio of at least 1 for inlet to 1.5 for outlet area. Preferrably 2 for the outlet, where the inlet is in a high pressure region, and the outlet is in a low pressure region.