"Richard Lamb" wrote in message
link.net...
Rich S. wrote:
"Peter Dohm" wrote in message
...

Yes. I know that they do, and new design engines are notorious; as are
design improvements, changes of supplier, etc. And they include plenty
of
reasons for loss of power not caused by the crankshaft!

However, my concerns include, reliability, maintainability, and eventual
replacement; and I think you understand my point.

At this point, the Jabiru 3300 is the only engine that really looks to
me
like a promising replacement; and I really don't know its service
record.
However, albeit at a higher dollar price, its features seem to preserve:
1)
similar or lighter weight, 2) similar or higher power, 3) six cylinder
smoothness, 4) reasonably slow idle, and 5) similar dimmensions.
Additional
benefits are designed in dual ignition and an updraft intake system,
similar
to Lycoming and Continental, which should be more resistant to ice.


Peter..........

Since you answered seriously, I will too. I can agree on the higher
price
and on #1-3 and #5. I don't understand #4 - do Corvairs idle
unreasonably
high? The dual ignition is good if the Jabiru 3300 truly has two
stand-alone
systems. The intake direction is irrelevant if the Corvair is
fuel-injected
or has a heated intake manifold. Updraft carbs are a lot better at
preventing fire as well. The small Continentals will ice up if you look
at
them cross-eyed even with updraft intake.

Rich S.



The Lycoming approach, with the intake manifolds passing through the oil
sump are less inclined to ice up. I'm sure they can be provoked, though.

As for the Corvair's idle? I plain dunno.
I have never seen a Corvair on an airplane - in person.
ANd that kinda is the point here.

The mounted pics I have seen are on a Pietenpol Air Camper, which needs
the weight on the nose. On most other planes that's considered a
Bad Thing (tm). On small short coupled airplanes, it might qualify as
a Very Bad Thing (tm), which is obviously much worse.

Now, I've only *seen* the Jabaru on a plane.
Haven't flown one myself.
But it does look like an engine of fine merit.

Light and simple are high on my short list.

Cost is there too, of course, but it has to take a place in line with
the rest of the conflicting requirements.

The Rotax 912 (which I have flown) is a really sweet set-up.
There is the extra complication (and weight) of the liquid cooled heads.
But it's probably not that big a deal on any two-seater.

From what I've heard, the Jabaru/912 power ratings remind me of the old
Continental A-65/Lycoming 145 days. Both were rated at 65 hp, but the
Continental horses seem a little longer legged.

I'd rank most VW power estimates as Shetland ponies...
I suspect that most people expect a VW to put out like a Rotax, but it
just doesn't work that way.

In the end the final choice will depend on the airframe and the mission.


On the Corvair question...

As I said earlier the Great Plains crank on my 2180 i.e. a way massive
hunk of pure confidence. Just the way an A-65 crank compares to other
small 4 banger non-flying counterparts.

So, why can't someone turn out a new Corvair crank - built to aircraft
service requirements?

The Corvair engine is a 4 bearing block, isn't it?

There is no reason that you _have_ to have a Corvair crank is there?


Richard

Rich,

Whatchit with that BWHAAAAAAaaaaa stuff.
Scared the stuffings outta me.

O thought Badwater was back and I was going to have to spell check my
posts...

I believe that you are correct on all of your points.

The only thing that I really feel compelled to add is that, in the case of
the KR that had a complete crankshaft failure and was "substantially
damaged", the owner had been very agressive in his program to keep the
weight down. I believe that he told me it was less than 200# firewall
forward, which may have even been a record. Even presuming that the weight
excluded the cowling, that is very light, and I have no idea how harmonic
damping was accomplished on any of these engines.

Peter