Thanks for the info Gary but if I understand you correctly, you are implying that the diesel doesn't need as much cooling.  So why does the SMA air cooled diesel have double the intake area compared to the standard C182?

And another note is that it was designed to get rated HPat 2200 RPM which increases the potential efficiency of the prop when compared to the standard 2500-2700 RPM.  I say potential because they have yet to tweek the prop and are instead using a standard issue model so that is not at its full potential.

And last, are the Lancair IV and ES's prone to being nose heavy or tail heavy? Even if the extra output and fuel consumption are attractive, ballasting the tail could wipe out those differences.

Dan Newland
Super ES