[jandrese]

The aero engine is also air cooled (so no water pump or radiator) and generally simpler all around. But at the end of the day it has a hilariously large displacement for the horsepower delivered. It's not like the thing is using fancy variable timing or partial charge ignition or cylinder deactivation to save fuel either, it has to fill those cavernous cylinders with a combustible mix on every fourth stroke.