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Old June 17th 04, 11:36 PM
Matt Whiting
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Kyle Boatright wrote:

"Dennis Fetters" wrote in message
...

Rich wrote:

The truth is it's really stupid to design, sell, or fly a helicopter
powered by a small 2-stroke engine.

Anyone dumb enough to fly it kills only themselves.
Anyone dumb enough to design and sell them should feel somewhat
responsible for those who die in them.

Rich



Why? the trouble has never been that one of our Rotax powered engines
quit because it failed from over excursion. Not one Rotax in a Mini-500
failed from the engine wearing out, ever. The only failures that ever
occurred was from failure to jet the engine according to instructions,
using poor fuel below 86 octane, or running out of fuel, or improper
coolant mix or leak, but never the fault of the engine. Nothing beats
the power to weight of a 2-stroke and the ease of maintenance. It was
the right engine.

So where is this the fault of the designer or the aircraft? It was made
plan in instructions, AD's and advisories not to make these mistakes. We
flew the factory helicopters hundreds of hours to prove the design
worked. Sure there were some development problems, but each one was
solved and made available. The truth is that the engine worked well.

Like it or not, your comments are unfounded, uninformed, based on lack
of experience and unappreciated.

Dennis Fetters



Dennis,

Your statement "the trouble has never been that one of our Rotax powered
engines quit because it failed from over excursion (sic)" may be correct,
but I doubt that you have the tear-down reports and expert knowledge to
*prove* the claim. To me, the bigger issue is the one Rich alluded to - 2
stroke engines are notoriously unreliable compared to their 4 stroke
cousins. ALL of the ultralight guys I know with more than a couple of
hundred hours behind 2 strokes have suffered engine events. Seized engines,
partially seized engines, exhaust failures that lead to power loss, etc.
Because of the reliability issue, 2 stroke engines are simply not suitable
for helicopter power plants. You know that, as does anyone else who is
familiar with the history of 2 stroke engines.


Sorry, but that isn't correct. I ran two-stroke motorcycles for years
with no problems. Many outboard engines are two-strokes and they have
excellent reliability records. I think the issues with two-strokes in
aviation has been improper operation.

Matt