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Scott
The engine is a 2000 hr tbo engine so that is a good thing. I will say I was
suprised to see a motor get that rating right out fo the box. It usually
comes with time but they put it right out there from the get go. They are
billet milled blocks, that is a good thing. No casting to mess up or crack.
When its machined, you know its at spec. I have spoken with several AP's and
an AI and they are all very impressed with the engine. None of them conveyed
that in relation to the Rotax. But not saying that that is 100%
authoritative either. Few have ever seen a motor like a Rotax so its all
greek (er Austrian) to them. But my motor doesn't give me a problem as a
rule when I am restarting after a trip at my home field fuel pump where my
mechanic is familiar with my engine. It happens somewhere else where they
are not seeing things like Rotax very much. They are used to seeing things
like a Jabiru cause its like a Continental or Lycoming. And the tools are
the same size and type they have. When I am flying cross country I don't
encounter alot of airports with auto gas pumps and I'm not going to get far
in a day if every fuel stop I have to find a ride to a gas station and buy
cans of gas, to say nothing of where to store the gas in a LSA.
The weight is much lighter than a continental in the range of 100 pounds,
similar to the Rotax. Its turning fewer rpms. That is a good thing. Yes, I
have had high reving engines in cars also. As I said, low rpm is a good
thing. The Jabiru has direct drive rather than a gear box and a slipper
clutch. There are a few more things to go wrong.
The technology for cooling is more normal. Technology can be a good thing,
but given my choice between something tried and true vs a new idea of
multiple cooling systems, I prefer the simpler system. I think that Jabiru
did a real good job addressing the major issue in homebuilts and in any
aircraft with a few hours on it, the cooling baffles. They molded em of
composite. No more rubber blowing the wrong way or what ever and having a
cylinder get cooked because of lack of air flow. How many coupe engines you
seen with perfect baffling. How many of any kind of aircraft for that
matter. If you talk to folks with experimentals getting the engine cooling
right is a major task.When I saw the Zenith was supporting the Jabiru with a
cowling that tells me that they have done their homework in that direction
as well.
While on power systems in LSA's I'll mention that one of the local LSA's
pitched a blade of the 3 blade lightspeed (german I believe) prop this fall.
Of course it totalled the engine before it could be shut down, a Rotax
turning 5800 rpm at the time... fortuantely over a very nice golf course. It
was a blade defect. I do like metal blades or lacking that a nice laminated
Sesenich has a good history and I noted with interest that the company in
Georgia doing the Zenith 601HL with the continental motor was putting a
laminated Sesenich on the front, not one of the thin composite props. More
than likely it was a fluke, but the plane had 125 hours on it when the blade
went away, no damage history, and had gone through an extensive inspection 2
days before, like an annual. Yea, I know, could have been something there,
but I doubt it. FAA didn't think so either. They declaired it a
manufacturing defect.
Anyway, those were the reasons I was going to go in the Jabiru direction.
I'm sure 10 years from now we will all be comfortable with Rotax mills.
Obviously there are alot of em up there.
On an asside, I do agree with the preference for a metal plane if its going
to be on the flight line. If its private ownership though and not to be used
in training I don't find any problems with composites if they are hangered.
Don't know anyone who is going to pay $80-100+K for a new plane and not
hanger it. I deal with composite structures in one of my other lives (light
weight boat design) and the materials do more than we can ever do with
metals, not just in shapes but structurally. Metal cannot even come close.
The design process takes people really experienced in the medium and the
constuction methods need to minimize the amount of variability in
manufacturing. Methods like vacuum bagging and prepreg fabrics have begun to
take out the previously huge, and I do mean huge variable of the skill of
the laminators and how much time they are give to do their job. The issue in
LSA's will be cost vs gain. How much more useful load and range do you get
by going from aluminum to composite and is it worth it. Again, depends on
the buyer. But just look at the possible range on the CT and you can see
what it can mean. As always, buyer beware. Run the numbers and make sure
they are real world and real and usable. If you go overgross LSA the
theoretical range is not usable and some numbers out there are not adding
up. Witness the Georgia built 601HL. Check their useful load they quote vs
the numbers for the same plane and engine on made from the same materials
the Zenith site just as an example. All that is advertised cannot be truth.
bob branch
99891
----- Original Message -----
From: "scott" <[EMAIL PROTECTED]>
To: "Bob Branch" <[EMAIL PROTECTED]>
Sent: Thursday, December 22, 2005 12:38 PM
Subject: Re: [COUPERS-TECH] Rotax engines
Hello Bob -
I saw my first Jabiru engine the other day. Do you know of a source for
reliability stats?
I work around Rotax engines and they would not be my first chioce for a
LSA.
Thanks
Scott
----- Original Message -----
From: "Bob Branch" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, December 22, 2005 6:56 AM
Subject: Re: [COUPERS-TECH] Rotax engines
----[Please read http://ercoupers.com/disclaimer.htm before following any
advice in this forum.]----
Jerry
A fellow here where I live build a Zenith 701 with the Rotax. He kept it
one
year. Only issue I know of he had with the engine was on one flight the
carb
manifold fractured on one of the carbs. Its plastic. I am not sure, but I
think it was addressed in an AD or whatever the equivalent is on the
motors. Noise wise at least from the ground they are considerably quieter
than a normal aircraft engine even at the higher rpm.
I was also looking at the engine when I was going to do a 601XL project
but
decided on the Jabiru engine for its more normal configuration and the
type
of build of the engine and the fact that it is essentially derated to
bring
most LSA's to their max cruise speed. As such though they can operate at
the
max cruise speed allowed rather than a lower speed. . Its a motor an
american mechanic can addrss pretty easily also which is not really the
case
with the Rotax.
bob branch
99891
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