Designing a cooling system

[robtek]

You might specialice on the He-100 or the He-177 prototype.
Those planes had a condensation cooling system.
When the water -steam - mix left the engine the water was separated and pumped
back to the water - inlet of the engine.
The separated steam was guided to surface-coolers, which were part of the upper planking of the wings where the lower temperatures (air-press reduction over the wing) helped to condensate the steam.
The condense-water then was brought back to the water - inlet of the engine.
The major point for this system is reduced drag, the malus that it is easily shot doesn't count here, me thinks.