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A good debate should be educational, and I hope that the discussion of
engines, reliability, octane and such is proving helpful to the
readership. Good data and facts are the best, but not always available.
Clarity of thought is equally important if the debate is to advance
constructively.
I responded separately to George's comments about auto fuel and I concur
with the questions he raises. Better to stay below the height of Pikes
Peak if you want to reduce in-flight entertainment.
Rick wrote in part: "Fred, I can not stay out of this one. I agree
100% with part of your statement, "I believe that control of risk rest
primarily in the hands of the builder and pilot." I have a problem with
the second half of your quote, " not in the engine wherever it may come
from." ... The real truth about the reliability of TSIO-550's and
TIO-540's are that many hundreds of these engines have made TBO with no
problems. Empirical testing and in service flying has proven that the
Cont. and Lycoming engines work well in planes of all types..."
So I think we agree: if it is a mature engine with a long development
and production history and certified to boot (meaning that the design
AND the manufacturing process have been inspected and certified), then
it should have much better reliability than some newer, less developed
design.
I feel compelled to highlight three items.
1) To clarify my assertion: I believe that IF one had all the data, THEN
one would find that experimental airplanes experience engine failures at
a fairly high rate compared to certified aircraft, but this is due
primarily to issues outside of the engine itself. Instead they arise
installation errors and other factors that can (should) be controlled by
the builder. And on the engine itself, I assert that failures usually
come from accessories, not some catastrophic breakage within the guts of
the engine. (I know for a fact that this is the case with turbines.)
Stated another way - If you were to make a pie chart of engine failures
(meaning the prop stops pulling for some reason), most of the pie would
be occupied with things that we as builders and pilots can control.
That is where MOST of your effort should be expended to reduce risk. I
am not suggesting that the "core engine" is unimportant. Merely that it
is more productive to focus most of your effort on a good installation
and careful shakedown testing.
2) Given the history and experience of brands C and L, I still maintain
that it is inexcusable for out-of-the-box new Continental and Lycoming
engines to break crankshafts, shear oil pump drives, and throw
connecting rods. We should expect (and get) MUCH more. Certified
engine reliability is NOT what it should be.
3) To expect that a NEWLY designed package will have the same
reliability as a mature one is simply unrealistic. The prototype will
never be as good as the later, more refined versions. Early production
units would (should) not be as "good" as later production versions
although the recent Continental and Lycoming experience causes one to
review and question this assumption.
The inference of Rick's note is that one should compare the prototype
EngineAir package (or the second or tenth or one hundredth unit?) with
the certified stuff produced for years in quantities of thousands. I
suggest that this is asking a bit much. Using that standard of
performance, nothing new would ever past muster. Anything new
necessarily involves additional risk. But returning to (1) above, MOST
of the risk control resides in the hands of the aircraft builder, engine
installer, and pilot.
I am reminded of a frequent observation in research and development:
"You can always tell the pioneers. They are the ones with the arrows
sticking out of their backs."
Fred Moreno
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