The thing that amazes me about Stanley Hooker was he was a theoretical aerodynamicist, and "not much of an engineer."
But on the development of the Merlin with the two stage supercharger he did something absolutely brilliant and went to air-to-liquid aftercooler. Normally an aerodynamics guy would continue to do as he had been doing and focus on further refinement of the airflow to eke out whatever small gains in efficiency would be possible. But by going to liquid cooling he solved a whole host of problems. In other words, he thought "out of the air box."
His brilliance is shown best by the fact that nobody else implemented this same idea. Take a look at the attached article from the March 1943 Aviation Magazine. Intercooler design is discussed but it is all air-to-air stuff. The P-51B would be coming off the production lines a very few months later.
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