would normally impact the front
of the cowling downward into the
radiator duct. This is almost like an
oversized flush NACA-style scoop.
Overall these improvements
have resulted in a significant
reduction in frontal area and
therefore profile drag reduction.
Diamond Aircraft credits this drag
reduction for producing an 8-knot
improvement in cruise speed.
Props and engines
Along with the drag reduction
following the cowling redesign,
Diamond Aircraft also fitted an
improved larger diameter MT
propeller to the 168-hp AE300 diesel
engine. Not only has the new prop
got a larger diameter, but also uses
the latest in propeller aerodynamics
with curved blades of larger chord
that, coupled with a slightly lower
rpm, produces significantly more
thrust than the narrow chord blades
of the NG model. There also seems
to be a slight decrease in noise levels
both internally and externally as I
witnessed personally from beside the
runway on take-off.
The propeller improvements
produced an increase in cruise
speed alone of 3 knots.
When I contacted Austro
Engines, they informed me that thishas resulted in the equivalent thrust
of a 220-hp avgas-fuelled engine while
the AE300 develops only 168 hp.
Yes, the AE300 weighs a bit
more than the Lycoming O-360
powered L360 version of the DA42,
but with the other weight savings
and envelope improvements that
Diamond Aircraft has introduced
in the Dash 6, the weight penalty is
more than made up for.
The Austro AE300 diesel engine
also has a few improvements. The
major one for the owner/operator
is that the time between overhauls
(TBO) has been extended to 1500
hours and in the very near future will
be 2400 hours.australianflying.com.au 41
January - February 2015 AUSTRALIAN FLYINGMAIN: Having been
through a drag-
reduction program,
the new DA42 is
slicker, giving a
higher cruise TAS.
ABOVE: The new
faired coverings over
the flap and aileron
pushrod ends reduce
drag.
TOP: Standard
Diamond cabin layout
is enhanced with new
BMW leather seats.