Check out http://www.geocities.com/Pentagon/Qu...0/engine9.html
a real radial. I've seen these running with the top of a cylinder
blown off and the only way to tell it was BMEP was a little low and
you could see it on the ingnition analyzer.

The biggest reason we all fly jets is without all those zillions of
reciprocating parts they are a hundred times more reliable.