On Feb 13, 5:14*am, Peter wrote:
WingFlaps wrote

Why should that be? Generally, diesels are great at running at high
power for long periods and they are also *the powerplant of choice for
high reliability when fuel consumption is also an issue (ruling out
turbines) -or am I wrong?

Diesels are indeed great in applications where they can be designed
without weight issues e.g. ships and trucks.

It appears that their problems (Thielert specifically - there is no
other diesel actually flying any meaningful hours at present) are to
do with a lightweight car engine - 1.7 litres - being run at 130HP (or
close to it) for 100% of the time. The original car engine would be
running at 20-30HP, maybe 100HP very briefly in a big Merc on a German
motorway (no speed limits). But an aeroplane is a whole different
situation.

They also had some specific issues e.g. corrosion due to the coolant,
but all these can and will be solved.

They are now moving to a slightly different 2 litre design which they
hope will provide that extra bit of ruggedness.

But very significantly Diamond sell only their DA42 twin in the USA,
and, on a twin, engine failures *enroute* are manageable. They wisely
sell the DA40 single with a 180HP Lyco, in the USA.

The old Lycos, OTOH, can run at 75% power continuously and provided
the CHT is well managed (itself a science, as Deakin fans will know,
but no rocket science) it won't fall apart for 2000hrs. They also
don't appear to have any consistent catastrophic failure issues -
ignoring the odd Lyco crankshaft which has been hardened but they
forgot to temper it

A lot of interesting info from you and WingFlaps there Peter. I also
read somewhere recently that the Diamond Twin diesels that uses
Thielerts have limited life on the engine. I can't remember how many
hours, but at the end of the max hour, Thielert will replace your
engines with a fresh rebuild for $25k each, instead of rebuilding
yours for you. In essence, you are actually renting the engine $25k
for that specified hours flown. I suppose this is good and bad. Good
to know your DOC on the engine, bad that you don't get to keep the
core or run the engine past TBO if it was still running good.

Wil