Mark James Boyd wrote:

Interesting article. Too bad (for US pilots) it uses
the "despised in the US" rotax engine. But this is
a real favorite in Europe, I'm told.


I also despise this Rotax engine, although not being an
US pilot. Since we bought our Super Dimona 5 years ago
we never had a season without engine problem(s). The last
season we spent 26000 euros on repairs/exchange. We had
to hire another Dimona for towing during the long period
we had to wait for the replacement engine. The good news
is that hiring another tug was cheaper than using our
own one, but this opportunity is going to stop as the
owner is selling the plane.

Maybe the Rotax is a very good engine for ultralights,
or even for the Dimona used as a touring motor glider,
but when used as a tug, the stress seems to be to high
for this engine, at least in the conditions of my club
(20 club gliders and 5 private owners using aerotow, we
add the second tug, a Rallye, when more than the half
fleet is waiting for launch). The version of the Super
Dimona used as tug is model HK36 115 TTC (I think the TC
means turbo charged). The maximum time during which
the full power (115 HP) is allowed is 5 minutes, but during
a good soaring day, each flight is a 5 minutes climb at full
power followed by 1 minute descent and landing, and I can
understand that the engine doesn't like that.