Nervous about Rotax

Jay,

I hit send to soon. Here are my thoughts from a German perspective:

- The Rotax 912/914 has been in service in Europe for decades now,
inpowered gliders and what's called ultralights here (the LSAs you see
in the US now). People are quite happy with it, the service history
seems completely normal.

- Germany is much smaller, so finding a service center can be much
easier than in the US. However, with the engine becoming more common,
mechanics in the US will have to adapt. They did here.

- The main problem I see is that the 912 doesn't really run well on
diet of Avgas exclusively. OTOH, auto gas contains increasing amounts
of ethanol - and while you can handle part of that with engine design,
choice of gasket and hose materials and so on, you cannot design away
the fact that ethanol will dissolve water which might freeze out at
high altitudes. That's something I would like Rotax to comment on
extensively.

--
Thomas Borchert (EDDH)

Jay Maynard wrote:
On 2008-01-21, Jim Stewart wrote:
On the plus side, plugs cost $3/each and it only takes an hour to do plugs
and oil.

Yeah, but will I have to take it to my nearest Rotax service center to get
that done?

Nope, a one hour job to do it yourself.
I did mine a couple weeks ago. All you
need is a flat-blade screwdriver to get
the cowls off, a wrench for the plugs,
oil drain and magnetic plug and a pair
of safety wire pliers. Feeler gauges to
check the plug gaps and some anti-seize
compound doesn't hurt either.

2000 RPM idle is fine. 2500 is good for warmup.

The comment I got a few times was that idling below 2500 will eventually
result in a broken crank.

My tach is red-banded below 1800 rpm, and yellow
between 1800 and 2000. Running below 1800
for extended time will shorten the life of the
reduction gears. Never heard anything about
broken cranks.

Pluses for the Rotax are no thermal shock issues,

Why not?

Liquid coolant in the heads.

will allegedly run for 30 minutes at 50% power with either oil or coolant
gone, and 5 gallon/hr cruise.

As opposed to 5.5 in the O-200. That's a negligible difference.

Cruise might be, but how long can the O-200
run without oil pressure? This, btw was a
major selling point for me. The common wisdom
with a 912 is that a coolant or lube failure
will still let you fly to a developed airport
and land. The engine might need a rebuild,
but it will keep running and develop at least
partial power.

No mixture control.

What leans the mixture at altitude?

The carbs.

As for support, I've had no problems with my 912 so I don't have any
direct experience. I know that the west coast FlightDesign distributer
has worked closely with Rotax on some safety directive issues and has
gotten parts and support quickly.

If I break a crank, or blow a jug, how long will it take to get parts? I was
told that people are waitiing 6 months for jugs because Rotax is putting all
it can make on new engines.

Can't answer to that. Everyone I know that
has a 912 has had no problems with it.

Call up Lockwood or Airwolf and ask them how
often they sell a crank or a cylinder. Then
ask how long it takes to get one.

On Jan 20, 2:46 pm, Jay Maynard
wrote:

I live in Fairmont, Minnesota, a town of 11000 50 miles from anything. I'd
like the local A&P to be able to do maintenance on the engine, and fix it if
it breaks. I also need to feed it a steady diet of 100LL, as every gallon of
automobile gas sold in Minnesota must have at least 10% ethanol (and that's
supposed to go up to 20% in 2010).

The O-200 also runs best on mogas. They have serious lead fouling
problems.

The cylinders on those small bore continentals aren't exactly known
for their durability either.

That said, I would probably prefer an 0-200 over a Rotax mainly for
the reason you cited -- the universality of its design, anyone can
work on it, etc Just don't think it'll need less work than a Rotax.

On 2008-01-21, xyzzy wrote:
The O-200 also runs best on mogas. They have serious lead fouling
problems.

erf.
Am I hosed, then?

The cylinders on those small bore continentals aren't exactly known
for their durability either.

Yeah, but you hear about O-200s routinely going well past TBO, to 2400 hours
at least (one guy claimed most fo the ones he knew about went to 3000 with
no problems, but I'm not sure how much I believe that). OTOH, the consensus
seems to be that Rotax 912s don't seem to want to make it past 800 or so,
never mind the 1500 rated TBO.

That said, I would probably prefer an 0-200 over a Rotax mainly for
the reason you cited -- the universality of its design, anyone can
work on it, etc Just don't think it'll need less work than a Rotax.

I'm not so sure about that...but, either way, I know I can get it fixed just
about anywhere, unlike the Rotax.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
http://www.hercules-390.org (Yes, that's me!)
Buy Hercules stuff at http://www.cafepress.com/hercules-390

Yeah, but you hear about O-200s routinely going well past TBO, to 2400 hours
at least (one guy claimed most fo the ones he knew about went to 3000 with
no problems, but I'm not sure how much I believe that). OTOH, the consensus
seems to be that Rotax 912s don't seem to want to make it past 800 or so,
never mind the 1500 rated TBO.


My instructors put close to 1500hrs on a rotax in a year with just
routine maintenance. Last time I flew it, it had around 1480hrs. The
plane was a Evektor Sportstar.

I believe Rotaxs can be serviced at Stanton Sport Aviation (KSYN).
Unleaded auto gasoline without ethanol is available in Minnesota at
some gas stations, marinas, and airports, although not at Stanton.

My hanger neigbor just sold his CTX because nobody in the general area
could work on the engine. It was sitting in his hanger for a couple
months with the cowling off with an engine problem that couldn't be
repaired. Not sure if it was parts or experience holding it up but he
wasn't happy the last time I talked to him (I didn't snoop too much
into the details).
Robert
KCGZ

On Sun, 20 Jan 2008 18:46:34 GMT, Jay Maynard
wrote:

I spent a day and a half at Sebring looking at aircraft. As I expected,
there are only a few that fit what I'm looking for. Of those, only one (the
AMD Zodiac XLi) uses a Continental engine. Everyone else (and, indeed,
nearly everyone else building an LSA period) uses Rotax 912s.

I'm not fond of the idea of flying behind a Rotax. I know there are lots of
them out there (although I doubt what one guy told me, that there have been
more flight hours on Rotax engines than there have been on Lycomings and
Continentals put together), and I know that lots of folks like them, but I'm
not at all sure they're for me.

I live in Fairmont, Minnesota, a town of 11000 50 miles from anything. I'd
like the local A&P to be able to do maintenance on the engine, and fix it if
it breaks. I also need to feed it a steady diet of 100LL, as every gallon of
automobile gas sold in Minnesota must have at least 10% ethanol (and that's
supposed to go up to 20% in 2010).

I'm told the Rotax runs fast (red line on the Tecnam Sierra I sat in was
5500 RPM, and supposedly everyone recommends idling no lower than 2500), and
that it has very tight tolerances, and demands lots of special tools. Yeah,
it's just different, not necessarily worse - but there's a difference
between that and an O-200, where if I find myself at some random field with
a mechanic, I can be confident he can at least get it running.

The Zodiac's seating looks weird, although I'm reserving judgment until I
get to actually sit in one (the one they had at the show was being delivered
to a customer there today, so they didn't let anyone sit in it, and I didn't
get to go take a demo flight in the one they had there for that purpose).
I'd still like other options, but unless I'm convinced that the Rotax isn't
going to find itself at some point sitting in the hangar while the engine is
shipped off to another state for repair (or, worse, waiting on a replacement
cylinder that never comes because they're all being put on new engines),
there aren't any.

As you said "nearly everyone else building an LSA period" uses Rotax
912s. That fact alone tells you that in a very short time of a couple
years or less every airport will have 912s actively flying if not
already. There must be a hundred or more different model LSAs selling
and selling and selling so 912s will be the most common light engine
over any other. I doubt mechanics will choose to lose all that
potential income by not working on 912s. I read more and more in the
Light-Sport Aircraft group about pilots that find flying too expensive
so they are moving to LSA. Others say they don't want to risk losing
their medical so they just start flying LSA. What ever the reasons are
more and more 912 powered planes are flying so more mechanics are
getting exposure to the Rotax. I've been in the UL and now LSA
flying for twenty three years and don't see anything growing faster
then the LSA side of aviation. Theory says they should only get
better and they work great now. Most of the people on the LSA group
fly with Rotax so ask them some questions.

Have a good day and stay out of the trees!
See ya on Sport Aircraft group
http://groups.yahoo.com/group/Sport_Aircraft/



On Jan 20, 11:46*am, Jay Maynard
wrote:
I spent a day and a half at Sebring looking at aircraft. As I expected,
there are only a few that fit what I'm looking for. Of those, only one (the
AMD Zodiac XLi) uses a Continental engine. Everyone else (and, indeed,
nearly everyone else building an LSA period) uses Rotax 912s.

I'm not fond of the idea of flying behind a Rotax. I know there are lots of
them out there (although I doubt what one guy told me, that there have been
more flight hours on Rotax engines than there have been on Lycomings and
Continentals put together), and I know that lots of folks like them, but I'm
not at all sure they're for me.

I live in Fairmont, Minnesota, a town of 11000 50 miles from anything. I'd
like the local A&P to be able to do maintenance on the engine, and fix it if
it breaks. I also need to feed it a steady diet of 100LL, as every gallon of
automobile gas sold in Minnesota must have at least 10% ethanol (and that's
supposed to go up to 20% in 2010).

I'm told the Rotax runs fast (red line on the Tecnam Sierra I sat in was
5500 RPM, and supposedly everyone recommends idling no lower than 2500), and
that it has very tight tolerances, and demands lots of special tools. Yeah,
it's just different, not necessarily worse - but there's a difference
between that and an O-200, where if I find myself at some random field with
a mechanic, I can be confident he can at least get it running.

The Zodiac's seating looks weird, although I'm reserving judgment until I
get to actually sit in one (the one they had at the show was being delivered
to a customer there today, so they didn't let anyone sit in it, and I didn't
get to go take a demo flight in the one they had there for that purpose).
I'd still like other options, but unless I'm convinced that the Rotax isn't
going to find itself at some point sitting in the hangar while the engine is
shipped off to another state for repair (or, worse, waiting on a replacement
cylinder that never comes because they're all being put on new engines),
there aren't any.
--
Jay Maynard, K5ZC * * * * * * * * *http://www.conmicro.comhttp://jmaynard.livejournal.com* * *http://www.tronguy.nethttp://www..hercules-390.org* * * * * * * (Yes, that's me!)
Buy Hercules stuff athttp://www.cafepress.com/hercules-390