On 22 May, 05:37, Greg Copeland wrote:
On May 21, 8:54 pm, Paul kgyy wrote:

Anybody know whether the Diamond DA40 is available with diesel power
in the U.S.? I checked the website and the only engine is the ancient
Lycoming IO360.

Hmm. Not sure why you put it that way. The IO360 is well know for
being rock solid. Diesel aircraft engines typically cost you useful
load because of their weight and the fuel is heavier to boot. A
double whammy on useful load isn't exactly exciting. IIRC,

On top of all that, the energy density for 100LL is some
20% higher (IIRC; or was it 40%) which means fuel consumption is 20%
higher for the same HP rating.

It seems that you do not recall correctly.
Quite a lot of people disagree with these numbers.
Chevron for example seem to think that the
difference in enengy density between kerosene and
aviation gasoline is rather smaller than either of
your figures. The inherent efficiency of the
diesel at part throttle does the rest.

http://hypertextbook.com/facts/2003/EvelynGofman.shtml

Everyone else that I have read on the subject
(other than yourself) seems to reach the
opposite conclusion regarding range/payload.