REFLECTOR:Rotarys, Lycosaurs, etc.
Jim Sower
reflector@tvbf.org
Wed, 05 Nov 2003 10:45:32 -0600
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Al,
I'm on your side here, but I get the impression of a double
standard in parts of your post that I find uncomfortably common
in the general discourse about auto conversions.
<... get better performance and lower cost, no doubt about it;
but the reliability is hard to achieve ...>
Better performance at lower cost I agree with. What
reliability? Admittedly, my own personal experience with three
Lycs (O-235, O-320, IO-360, ALL with less than 500 SMOH when
they came my way) has been abysmal - two jugs on EACH of them
for various reasons, a front seal on the 360, a mag or two,
etc., etc. - ALL within 200 or 300 hours of operation.
But let's not use my experience as typical. Show of hands boys
and girls: how many of us have had, or have a personal friend
who has had, a Lycoming make it to TBO without a major failure?
Now, let's go the other way - tell the truth now - how many have
had or have a personal friend who has had a major failure in
less than, say, 1200 hrs. So much for reliability.
<... pretty stout, reliable engines. Still, their failure modes
are primarily related to valves, connecting rods, and the
occasional crankshaft break ...>
Let's don't forget jugs (worn out/broken rings, cracked heads,
scored barrels, etc. :o)
Rightly enough, you don't count failures of peripherals since
they don't indicate engine problems. Sadly, most of the auto
conversion "failures" ARE failures of peripheral systems, but
nonetheless are attributed to the engine. The type of double
standard that obscures efforts at rational, unbiased
observation.
<... another engine with valves, connecting rods and crankshaft,
stress it to the max, run it at high speeds, and add reduction
gearing; and put it in your airplane ...>
In the 70s, I was in the auto repair business. The life
expectancy of a V8 was 75k - 100k mi. Since then, thanks to CNC
mills, electronic ignition and injection and unleaded gas, any
average car will get a quarter million miles before the body
rots off the chassis with the engine still running strong.
Aircraft engines have NONE of these life extending features.
ALL of the technology in my Lyc was in place, mature and stable
SEVENTY YEARS AGO - like in the HOOVER administration - when
model-T engines were good for 20k or 30k miles. NO substantial
improvements since then other than minor metallurgy. So YES! I
WOULD put one of these engines in my airplane.
<... Do you know of any one of these that has gone 1500 hrs in
an airplane between major malfunctions ...>
Yes. Matter of fact I do. Suppose we turn that around. How
many of us know PERSONALLY of anyone who has achieved that with
Lycs and Conts? I know of two for sure. Don't know if they
actually DID get 1500 hrs with no failures, but they talk as if
they did. Lots of peripheral failures, but no long block
failures. Is it OK if I were to infer from the above that 1500
hours failure free in a Lyc is only twice as common as 1500
hours failure free in a rotary? :o) Bottom line, how many of us
know someone with 1500 hrs in their homebuilt airplane at all?
<... it is very difficult to do a custom auto conversion
installation and achieve a reliability as high as Lyc or
Continental ...>
"Custom" being the key word here. Actually, over the past
several years, more standard and proven conversion packages have
been produced and "packages" are becoming more reliable by leaps
and bounds.
<... in a certified aircraft ...>
When did we start talking about certified aircraft. How about
Lycs and Continentals in homebuilt aircraft? Why is it that
they seem so much less reliable than the same engines installed
in certified planes?
All of that having been said, I find that the reputation for "
proven reliability and dependability" of certified engines is
largely "theological" - that is, it owes a lot more to blind
faith in what we've been told many many times than to rational
examination of all the evidence. Certified engines have
countless failure modes that would be unacceptable to us in say,
our automobiles. The thing is, these failure modes and design
defects have been so well documented and described over the
decades that they have somehow morphed into acceptable
attributes. When a failure occurs, everyone is right there with
"... yeah, the old front seal falls out for reasons best known
to itself syndrome ..." or something of the sort, and the poor
slob who it happened to is left feeling that since it seems so
common, he must have been remiss is not anticipating it and
preventing it. To me, this widespread attitude has all the
intellectual allure of blaming a rape victim for the crime
because she wore a short skirt.
I could go on forever with failures and shortcomings of Lyc and
Cont engines that NONE of us would EVER accept in our
automobiles, but regard as inevitable and therefore somehow OK
in our airplanes.
I find this attitude puzzling in folks who are so unrelenting
regarding quality in the airplane they build.
Man, I DO take the bit in my teeth from time to time, don't I
:o)... Jim S.
Al Gietzen wrote:
> Gentlemen,
> I hope I don't offend with this. But I just spoke with
> Lance Wheeler of NSI the other day and he told me he's getting
> ready to produce a 2.5L (4 cyl) turbocharged Subaru FWF pkg
> that his dyno says puts out 300 hp. I'll bet one thing.
> It'll be a lot quieter than those rotary.
>
> You put a turbo on a rotary and it is pretty quiet as well.
> But I don’t think quiet ranks at the top of the selection
> criteria.
>
> Before I selected the rotary I did a critical review of just
> about every possible engine option. The three main criteria
> were reliability, performance/weight, and cost. At one point
> I was very near choosing the 250 hp turbocharged 2.2L subi
> conversion (I think it was Cross-Flow Aero). Pretty much the
> same thing NSI is offering, just a bit smaller. Performance
> is attractive. When you added it all up, it was quite
> expensive; but after asking a lot of questions, the reason I
> crossed it off was uncertain reliability. Pushing 2 hp/cu.
> in. makes for high stress levels. Running in a race car –
> OK. You can overhaul between races and you can pull into the
> pits when something goes wrong. You can learn a lot about
> engine reliability talking to folks that race cars for a
> living.
>
> Certified aircraft engines are pretty stout, reliable
> engines. Still, their failure modes are primarily related to
> valves, connecting rods, and the occasional crankshaft break.
> And their performance is derated by running them slower to
> eliminate reduction gearing. Do you really want to take
> another engine with valves, connecting rods and crankshaft,
> stress it to the max, run it at high speeds, and add reduction
> gearing; and put it in your airplane? Do you know of any one
> of these that has gone 1500 hrs in an airplane between major
> malfunctions or overhaul?
>
> In my opinion, it is very difficult to do a custom auto
> conversion installation and achieve a reliability as high as
> Lyc or Continental in a certified aircraft. (Uh-oh; now even
> the other auto conversion guys won’t speak to me). You can
> get better performance and lower cost, no doubt about it; but
> the reliability is hard to achieve. The statistics just
> aren’t there. The basic engine can be reliable, but there are
> many first time, one-of-a-kind aspects to most installations.
> Suitable reliability can be achieved, but it takes careful
> scrutiny and engineering every step of the way. And then some
> careful, rigorous testing.
>
> Anyway, that’s my 2 cents worth.
>
> And, yes; we are building experimental aircraft.
>
> Al
>
--
Jim Sower
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T
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Al,
<br>I'm on your side here, but I get the impression of a double standard
in parts of your post that I find uncomfortably common in the general discourse
about auto conversions.
<br><font color="#3333FF"><... get better performance and lower cost,
no doubt about it; but the reliability is hard to achieve ...></font>
<br>Better performance at lower cost I agree with. What reliability?
Admittedly, my own personal experience with three Lycs (O-235, O-320, IO-360,
ALL with less than 500 SMOH when they came my way) has been abysmal - two
jugs on EACH of them for various reasons, a front seal on the 360, a mag
or two, etc., etc. - ALL within 200 or 300 hours of operation.
<p>But let's not use my experience as typical. Show of hands boys
and girls: how many of us have had, or have a personal friend who
has had, a Lycoming make it to TBO without a major failure? Now,
let's go the other way - tell the truth now - how many have had or have
a personal friend who has had a major failure in less than, say, 1200 hrs.
So much for reliability.
<p><font color="#3333FF"><...</font> <font face="Verdana"><font size=-1><font color="#0000FF">pretty
stout, reliable engines. Still, their failure modes are primarily
related to valves, connecting rods, and the occasional crankshaft break
....></font><font color="#000000"></font></font></font>
<br>Let's don't forget jugs (worn out/broken rings, cracked heads, scored
barrels, etc. :o)
<br>Rightly enough, you don't count failures of peripherals since they
don't indicate engine problems. Sadly, most of the auto conversion
"failures" ARE failures of peripheral systems, but nonetheless are attributed
to the engine. The type of double standard that obscures efforts
at rational, unbiased observation.
<p><font face="Verdana"><font size=-1><font color="#0000FF"><... another
engine with valves, connecting rods and crankshaft, stress it to the max,
run it at high speeds, and add reduction gearing; and put it in your airplane
....></font><font color="#000000"></font></font></font>
<br><font face="Verdana"><font color="#000000"><font size=-1>In the 70s,
I was in the auto repair business. The life expectancy of a V8 was
75k - 100k mi. Since then, thanks to CNC mills, electronic ignition
and injection and unleaded gas, any average car will get a quarter million
miles before the body rots off the chassis with the engine still running
strong. Aircraft engines have NONE of these life extending features.
ALL of the technology in my Lyc was in place, mature and stable SEVENTY
YEARS AGO - like in the HOOVER administration - when model-T engines were
good for 20k or 30k miles. NO substantial improvements since then
other than minor metallurgy. So YES! I WOULD put one of these
engines in my airplane.</font></font></font><font face="Verdana"><font color="#000000"><font size=-1></font></font></font>
<p><font face="Verdana"><font size=-1><font color="#0000FF"><... Do
you know of any one of these that has gone 1500 hrs in an airplane between
major malfunctions ...></font><font color="#000000"></font></font></font>
<br><font face="Verdana"><font color="#000000"><font size=-1>Yes.
Matter of fact I do. Suppose we turn that around. How many
of us know PERSONALLY of anyone who has achieved that with Lycs and Conts?
I know of two for sure. Don't know if they actually DID get 1500
hrs with no failures, but they talk as if they did. Lots of peripheral
failures, but no long block failures. Is it OK if I were to infer
from the above that 1500 hours failure free in a Lyc is only twice as common
as 1500 hours failure free in a rotary? :o) Bottom line, how many
of us know someone with 1500 hrs in their homebuilt airplane at all?</font></font></font><font face="Verdana"><font color="#000000"><font size=-1></font></font></font>
<p><font face="Verdana"><font size=-1><font color="#0000FF"><... it
is very difficult to do a custom auto conversion installation and achieve
a reliability as high as Lyc or Continental ...></font><font color="#000000"></font></font></font>
<br><font face="Verdana"><font color="#000000"><font size=-1>"Custom" being
the key word here. Actually, over the past several years, more standard
and proven conversion packages have been produced and "packages" are becoming
more reliable by leaps and bounds.</font></font></font><font face="Verdana"><font color="#000000"><font size=-1></font></font></font>
<p><font face="Verdana"><font color="#0000FF"><font size=-1><...
in a certified aircraft ...></font></font></font>
<br>When did we start talking about certified aircraft. How about
Lycs and Continentals in <b>homebuilt</b> aircraft? Why is it that
they seem so much less reliable than the same engines installed in certified
planes?
<p>All of that having been said, I find that the reputation for " proven
reliability and dependability" of certified engines is largely "theological"
- that is, it owes a lot more to blind faith in what we've been told many
many times than to rational examination of all the evidence. Certified
engines have countless failure modes that would be unacceptable to us in
say, our automobiles. The thing is, these failure modes and design
defects have been so well documented and described over the decades that
they have somehow morphed into acceptable attributes. When a failure
occurs, everyone is right there with "... yeah, the old front seal falls
out for reasons best known to itself syndrome ..." or something of the
sort, and the poor slob who it happened to is left feeling that since it
seems so common, he must have been remiss is not anticipating it and preventing
it. To me, this widespread attitude has all the intellectual allure
of blaming a rape victim for the crime because she wore a short skirt.
<p>I could go on forever with failures and shortcomings of Lyc and Cont
engines that NONE of us would EVER accept in our automobiles, but
regard as inevitable and therefore somehow OK in our airplanes.
<p>I find this attitude puzzling in folks who are so unrelenting regarding
quality in the airplane they build.
<p>Man, I DO take the bit in my teeth from time to time, don't I :o)...
Jim S.
<p>Al Gietzen wrote:
<blockquote TYPE=CITE><style>
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<div class="MsoNormal" style="margin-right:0in;margin-bottom:0in;margin-left:.5in;
margin-bottom:.0001pt"><span
style='font-size:10.0pt;font-family:Arial;color:black'><font face="Arial"><font color="#000000"><font size=-1>Gentlemen, </font></font></font></span></div>
<div style="margin-left:.5in"><span
style='font-size:12.0pt;font-family:Arial;color:black'><font face="Arial"><font color="#000000"><font size=+0>
I hope I don't offend with this. But I just spoke with Lance Wheeler
of NSI the other day and he told me he's getting ready to produce a 2.5L
(4 cyl) turbocharged Subaru FWF pkg that his dyno says puts out 300 hp.
I'll bet one thing. It'll be a lot quieter than those rotar</span><span style='font-family:Arial;color:blue'></font></font><font color="#0000FF">y.</font></font></span></div>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>You
put a turbo on a rotary and it is pretty quiet as well. But I don’t
think quiet ranks at the top of the selection criteria.</font></font></font></span>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>Before
I selected the rotary I did a critical review of just about every possible
engine option. The three main criteria were reliability, performance/weight,
and cost. At one point I was very near choosing the 250 hp turbocharged
2.2L subi conversion (I think it was Cross-Flow Aero). Pretty much
the same thing NSI is offering, just a bit smaller. Performance is
attractive. When you added it all up, it was quite expensive; but
after asking a lot of questions, the reason I crossed it off was uncertain
reliability. Pushing 2 hp/cu. in. makes for high stress levels.
Running in a race car – OK. You can overhaul between races and you
can pull into the pits when something goes wrong. You can learn a
lot about engine reliability talking to folks that race cars for a living.</font></font></font></span>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>Certified
aircraft engines are pretty stout, reliable engines. Still, their
failure modes are primarily related to valves, connecting rods, and the
occasional crankshaft break. And their performance is derated by
running them slower to eliminate reduction gearing. Do you really
want to take another engine with valves, connecting rods and crankshaft,
stress it to the max, run it at high speeds, and add reduction gearing;
and put it in your airplane? Do you know of any one of these that
has gone 1500 hrs in an airplane between major malfunctions or overhaul?</font></font></font></span>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>In
my opinion, it is very difficult to do a custom auto conversion installation
and achieve a reliability as high as Lyc or Continental in a certified
aircraft. (Uh-oh; now even the other auto conversion guys won’t speak
to me). You can get better performance and lower cost, no doubt about
it; but the reliability is hard to achieve. The statistics just aren’t
there. The basic engine can be reliable, but there are many first
time, one-of-a-kind aspects to most installations. Suitable reliability
can be achieved, but it takes careful scrutiny and engineering every step
of the way. And then some careful, rigorous testing.</font></font></font></span>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>Anyway,
that’s my 2 cents worth.</font></font></font></span>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>And,
yes; we are building experimental aircraft.</font></font></font></span>
<p><span style='font-size:11.0pt;
font-family:Verdana;color:blue'><font face="Verdana"><font color="#0000FF"><font size=-1>Al</font></font></font></span></div>
</blockquote>
<p>--
<br>Jim Sower
<br>Crossville, TN; Chapter 5
<br>Long-EZ N83RT, Velocity N4095T
<br>
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