Water Cooled Aircraft Engines

I am looking to see the feasibility of a water cooled aircraft engine in the range of 1500 hp, to be used in a small ground attack aircaft design.

My feeling is that (and please blow my feeling out if you can) such an engine would have higher survivability against IR SAMs

Now, I have searched but have failed to find a good comparison in terms of how inefficient a design would be vis-a-vis turbines or air cooled engines. I know somebody wrote a research paper on the Packard X-24, but I don’t have it.

Any information, thoughts, theories, jokes, funny tangential ideas, are welcome.

Yours in searching,

PLA-MKII