Tom: Now imagine designing, engineering, and servicing one of the three-row "corncobs"! No wonder, with all that stuff going up and down, that the last generation radials, even after half a century of development and refinement, still only got 1,500 to 2,000 hours between overhauls, while jets soon racked up 10,000 hrs. TBO. How the hell they ever managed to cool that third row of pots is amazing.
No wonder, too, that losing an engine on a long flight was not the exceptionally rare occurence that it is today. A long-retired PANAM captain told me once that they used to say, back in the 1950s, that there would never be overseas flights on planes with fewer than four motors, and that when the first jets came in nobody saw any reason to change that dictum.
Then, he told me, in the late 1960s, when the next generation of jet liners was being designed, the ideal number became "more than two, fewer than four," leading to the Trident, B727, L1011 and DC10. Now we are at two turbines, and nobody even thinks twice about flying fo 5,000 miles over water in a B777 etc. So much reserve power, and amazing reliability.