Aviation Forum / General / Ultralight / November 2009

HUH??????????

Tell me what "overheating" are you referring to?
What do you mean by "carbon build up"???
How many "failures" have been caused by this *exactly* - seeing you
are making a statement of fact ? And "here" and "overseas"

You don't work for Rotax do you??

Back up your statements *now*.

Nor does the Jab motor.
This is  a bullshit statement.
You know *nothing* of the motor.

You *obviously* are not a L2 .

Nor have *any* idea of what a Jab motor does - or a 912 either for
that matter.

Go back to bed and dream more crap.

Let me tell you: The Jab motor is reliable, easy to maintiant cheap to
operate and has no known major problems. In that almost *all* motors
have *a* problem wiht *some* part of its operation, that is a big plus
for the Jab.

Frankly, I *think* that they are both good motors.

I know the Jab well and *think* that the 912 is also a good motor.
(But not any of the 2 strokes).

Here in Australia, the Jab is *good* because bits are available
ovenight from the makers.
And there are a lot of people who know about them and how to maintain
them.

Hi Richard,

No i don't work for Rotax, and I do agrea with you about the Rotax Two
strokes, like any Two stroke they will give you trouble if you don't
keep up the checks and cleaning of the pistons and heads etc.

With the overheating and cylinder head sealing problems, I'm sure if
you ask any LAME you will find the truth.

I got this off a UK ultralight website and it originates from the UK
air accident branch, Bulletins Oct 2002.  Ref no EW/G2002/06/13
Quote:

The engine was recovered to the AAIB at Farnborough for examination.

The engine was then progressively stripped. On initial examination it
was evident that the engine had completely seized. The number three
cylinder spark plug was damaged so the cylinder head was removed. Upon
removal of the cylinder head it was evident that a catastrophic failure
had occurred. The number three piston was completely destroyed and the
connecting rod was bent. Remains of the piston were still in the
cylinder between the head and the connecting rod (Figure 1 (jpg 95kb)).
The head of the number three exhaust valve was missing, and
subsequently retrieved from the oil sump. The valve stem from the
exhaust valve was stuck in its valve guide. The cylinder and the
cylinder head were extensively discoloured on the lower quarter
indicating several hours of 'blowing' (Figure 2 (jpg 95kb))). There was
also discoloration consistent with overheating around the rockers for
the inlet and exhaust valves on the number three cylinder.

The fins on the cylinder head were distorted indicative of overheating
and the head bolts were interfering with the cylinder head. Inspection
of the bores of the holes for the head bolts revealed deep indentations
from the threads of the bolts, normally these holes are clean with the
threaded portion in the cylinder. This showed that at some point the
distortion of the head from overheating allowed the bolts to interfere
with the head.

There you go Richard, if you research the air accidents branch and type
in Jabiru and read all the reports you will see that the truth is out
there, unless you think level 2 guys know more than the investigators
above, also check out the AUF magazine as there is always a jab engine
failure or two each issue. The above failure is very common, do some
research Richard.

--
greg
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