3 cylinder water cooled vs 2 cylinder air cooled thoughts on possible conversion

[freebeard]

The Meredith_effect is off-topic.

The duct must be travelling at a significant speed with respect to the air for the effect to occur.
[snip]
The air expands and decreases temperature as it passes along the duct, before emerging to join the external air flow. Thus, the three processes of an open Brayton cycle are achieved: compression, heat addition at constant pressure and expansion. The thrust obtainable depends upon the pressure ratio between the inside and outside of the duct and the temperature of the coolant.[1] The higher boiling point of ethylene glycol compared to water allows the air to attain a higher temperature increasing the specific thrust.

The Hurricane and Spitfire predated the P-51 by four years.

No help when your idling in traffic.

[Autobahnschleicher]

Regardless of the Meredith effect (wich isn't realy significant at the speeds we're going anyway) water cooling is more efficient in cars as it has far lower parasitic losses than air cooling in cars.
Allthough a ducted radiator has proven to massively reduce cooling losses, Porsche 911 (996) for example has less than 1% of its aerodynamic drag in cooling losses, where as aircooled Porsches wasted some ~10% of their engines power output on their blower alone.

[cRiPpLe_rOoStEr]

Originally Posted by Autobahnschleicher

Meanwhile a water cooled engine can run without a fan running in most situations.

Unless they resort to thermosyphon effect, the water pump shall not be neglected.