Ejector cooling (not sure why the posters are calling the device an eductor - that term is reserved for machines that use a current of fluid to move bulk solids) is well worth pursuing. It isn't much pursued because:

1. people follow plans, even if a design has a history of cooling problems

2. ejector cooling is poorly documented in textbooks even though it's been worked on for decades, and research on unsteady-flow ejectors is ongoing.

Bruce Carmichael, Mr. Low Speed Aerodynamics, comments in one of his books that cooling drag in typical light aircraft is MANY TIMES what theory predicts it should be, so as other aspects of light airplanes become cleaner and more efficient cooling is the obvious drag abatement target.

The immediate benefit of ejector cooling is reliable static cooling during taxi and runup, without stealing precious shaft power for an auxiliary cooling fan.

Marc de Piolenc