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Let's try to maintain a little bit of professionalism and courtesy here...
First, I do appreciate honest disagreement. This is America after all. The
fundamental question here is whether one test of one type of a family of
materials (someone's unspecified, undocumented ceramics-on-a-dyno-years-ago
test) applies to all engines and all ceramic coatings for all past, present,
and future development of internal combustion engines. Probably not.
The question is, is it believable that Dick Perry, a retired UAL captain with
ratings from the DC-6 to the 747 would lie about his TIO-360 temperatures and
fuel flows before and after ceramic coatings were applied? This
was the ideal test case that everyone claims to want to see: an almost new
engine that the owner took meticulous data on during and after break in that
suffered a sudden stoppage at idle due to nose gear failure; then was coated
and the same data taken during and after post-ceramic break in. Let's
remember that this is a Grand Champion Kit award winner and an ex fighter
pilot. With 40 years in airliners to boot, he is not some bozo who doesn't
know how to take consistent data. Dynos are nice, 40 years of flying
experience is better; it's the person taking the data that matters. I
understand that his data was published in the Lancair List newsletter a few
months ago; is that forthcoming enough? If anyone has issue with Dick's
methods, call him or Marv Kaye who published the data. He seemed to think it
was pretty impressive (the thoroughness of the data, not just the results).
[ed. note... I do not pass judgement on any material that is submitted to
me for inclusion in the LML or the LNN, it's not my place. I just print
(or allow to be posted) data that's presented and make no claims one
way or the other regarding its accuracy or suitability for any purpose.
Just read the disclaimers on the LML website or at the end of any issue
of the LNN. I am just the messenger. <Marv>]
By the way, it's 7 to 10% power and 15 to 20% fuel flow; the fuel flow
improves more than the power because the primary effect is in reducing the
waste fuel. Since Dick went faster on 10 GPH than he had previously on 12
GPH, this is pretty good correlation to Zehrbach's advertised improvement.
It should be widely stated that the 29% improvement to Jack Watson's
effective HP was due to several effects that Darus Zehrbach and I spent weeks
researching. This did not in fact advance the state of the art of engines by
29% since the O-235 is a very, very long ways from the sate of the art. Even
the resulting engine could stand quite a bit of improvement before it could
even approach the state of the art of a truly modern engine. Simply put, the
thing is such a slug that there's lots of improvement to be had. Considering
that Zehrbach's brochures advertise 7% to 10%, 29% was difficult for Darus to
believe even though the data was there. When something like this happens you
can do one of three things:
A) declare it to be impossible since it is outside your understanding and
call everyone involved stupid liars;
B) accept the data, and demand a reasonable explanation from a qualified
entity (like a professor of thermodynamics);
C) recheck the data source and figure out how the heck it happened.
We chose C. First we went back through multiple engines' worth of data to
see if there was anything special about the O-235. Other than a little
poorer fuel atomization of the carburated vs. low pressure constant injection
which might make up a percent or two, nope. Sealing? Well, the valves were
not in the best of shape and had coking on the back sides that could cause a
3 to 5% loss of volumetric efficiency; and the rings were pretty gummed up.
A little carbon on the top of the pistons could account for a little infrared
absorption. A check with the owner and he admitted that the speed had fallen
by a couple of MPH over the last year or more. Now we were getting
somewhere. Before anyone jumps on these things as major power problems,
remember that the owner had noted only a small decrease in performance since
the engine was new. So, we had about 4 to 6% explained by the previous
condition of the engine and a top end of 10% by the coatings; still not
enough to explain the whole improvement.
Now, an unscrupulous man would take advantage of this much like Fleicshman
and Pons when they claimed cold fusion before they checked the heat of
solution of their experiment (which turned out to be the dominant factor).
Zehrbach is not one to lie, so he pounded on this one until we hit upon the
(now obvious) factor of the fixed pitch prop. If a fixed pitch prop is too
large for the power output of an engine, then RPM will be limited and
efficiency will also suffer. Add power, and the prop comes up into it's
optimum envelope and we get more thrust/HP. The signs of this would be an
increase in RPM and a disproportionate increase in speed with RPM. Bingo.
The aircraft was very slightly over-prop'd before; the power increase of 17
to 21% pushed the RPM up and gave the engine another 5% just from being spun
5% faster (this was very close to the torque peak). The last few percent
were easily explained by the gain in prop efficiency correlated to the
RPM/velocity data. What a pain. Worth the effort to find the truth and
understand the science behind the data. Fools would choose A and just deny
the data.
Now, I can just hear the cries of "That's it! I knew it was all smoke and
mirrors!". The only problem with that opinion is that there is no way to
explain either Dick Perry's data or Jack Watson's power increase that led to
the RPM gain over the original clean engine. There's also plenty of evidence
of the same ceramics working on perfectly clean engines, much of it here on
the Lancair List. Good data before and after. Sure, flight testing can vary
and my pilot around the course has a fairly consistent +/-1.2 mph in his
times (he's a 20+ year RF-4 recon pilot, LOTS of low level proficiency;
another military trained pilot who is good at collecting statistically
relevant data...). How we account for variances in test conditions in the
real world of professional aerospace is to take a TON of data points.
Statistical averaging tends to cut the noise factor <LOL>. On the MD-11 drag
improvement program, a fix was flight tested to an accuracy of < 0.1% while
the flight conditions varied by several percent. How? Try 250 data points.
It's a lot easier to fly a lot of data points than to try to perfectly
control a single test. Anecdotes? What I have seen is an avalanche. Are
all of the people who have achieved positive results with modern ceramic
coatings liars, thieves, cheats and suckers? Hey, Star Aerospace LLC doesn't
sell ceramics; we BUY them from Zehrbach for our aircraft because they work.
The only real question remaining is why some get better results than others.
I believe Zehrbach gets good results the same way anyone who's successful
does: attention to detail. Simply coating the piston is not going to get
the results of coating the piston, valves, head, intakes, exhausts, adding
solid lubricants to all the sliding surfaces, heat dissipating coatings to
the valve springs, etc., etc., etc. Simply spraying a little alumina on a
piston and declaring that all ceramics are snake oil because this only
resulted in a 1% improvement is pretty funny. Next people will be saying how
no improvements have been made in aircraft engines in 20 years. Really? Was
there no progress from 1920 to 1940? From 1940 to 1960? From 1960 to 1980?
From 1980 to 2000? Guess what, HP/lb. and SFC have improved roughly linearly
on a 20 year average for almost a century. And it's not tapering off. It's
just not all in general aviation(most of the recent progress is in military
drones. It's time for us to get our heads out of our collective.... ummm....
cowlings and look around a little at the world. The trouble is we always can
see the past clearer than the future, so we tend to deny that progress is
continuing.
It's very difficult to see with any clarity what will progress internal
combustion in the next 20 years. It's easier to see what happened in the
last 20 years, but not all that clear since many people are still building
engines based on far older technology directions that have only recently been
abandoned. It's child's play to see what progressed in engines 40 to 80
years ago; that's usually long enough for all the bad ideas to have fallen
by the wayside.
In the future, I'd really like to hear from qualified people on these
subjects who actually have recent experience (the last 5 years) with EFI, EI,
ceramic TBC's, adhesion layers, homogeneous vs. heterogeneous combustion,
combustion radical bonding and nucleation (if you don't know what they are,
you're not qualified to talk about it). We do. People with experience in
the multibillion dollar engine industry of F-1 and Indy cars would be good.
Some rocket engine nozzle and turbopump designers might help.
As for whether TBC's promote or decrease detonation potential, I think that
should be settled by a qualified thermodynamics expert from a major
university. Our chief aerodynamic advisor is a Dean of Aeronautics and our
chief scientific advisor is a Ph.D. of Astronautics and a VP at Boeing. Both
of them are widely published on thermodynamics (this means they WROTE a lot
of the modern theories of thermodynamics) and seem to think we know what
we're talking about. In fact, much of the last few explanations on ceramics
came from them. Hardly the type of people to promote 100 mpg carburetors.
<LOL>
As far as litigation threats, Mr. M and Mr. R have stated their opinions
sufficiently for everyone to know where they stand. No further purpose is
really served by unprofessional and impolite ranting, except that they seem
to enjoy it. They have every right to their own opinions, even though they
seen to discount others. We have stated our opinion fairly clearly and would
like to answer questions from other sources. At this point, it is best for
the rest of the market to speak.
Eric Ahlstrom
Star Aerospace LLC
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Please send your photos and drawings to marvkaye@olsusa.com.
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