REFLECTOR:Rotarys, Lycosaurs, etc.
Alex Balic
reflector@tvbf.org
Wed, 05 Nov 2003 21:14:35 -0600
Jim,
I had a mercruiser stern drive that put out 280hp from a 350 small block
that we used to use for fishing out in the pacific- 2 hours out, 1-3 hours
trolling, 2 hours back at about 80%. I owned that boat for 6 years, went
fishing most weekends in the summer, and about once/month in the "winter"
so I ended up putting about 650 hours on it, before selling it to a guy that
might still have it 10 years later for all I know, I bought the boat used-
it was an older model Regal, and the hour meter read 1260 when I got it, the
only failure I ever had was the lousy Rochester carb, (didn't fail as much
as just give me worse and worse mileage - which I replaced with an
edelbrock, and a failed water pump ( the scavenging pump, not the
circulator) even with no water flowing, we still drove that thing 8 miles
back into port (at just over idle) and it ran fine after that- didn't even
have to replace any jugs on it. Now that was a crappy, 1970's vintage 350
Chevy with questionable care prior to my ownership- I did take really good
care of it when I got it, but by the looks of the rest of the boat, the
original owner did not.
About the high hour trainers you mentioned, I can believe the numbers,
because the engines tend to do bad things when they are resting all of the
time, an engine that runs daily, and is well cared for should last a long ,
long time...
I used to work for Nippondenso/Toyota, and I can assure you that Japanese
engines are built to tolerances 2 or 3 times (sometimes more ) closer than
American engines, and there QC is second to none (no offence to Mercedes)
they have what is called a zero defects QC system,(which is almost an
accurate statement) every part is checked several times, and I have seen
them fail a piston because it had a lingering fingerprint stain on the face
after degreasing operations ( they claimed that the acid from the oil in the
print would possible affect the metrological integrity of the piston - which
I still think is B.S. by the way ) it was really tough to be a manufacturing
engineer for the Japanese with this kind of mentality, but I certainly
gained their respect. So yes, I will run the hell out of the Subaru that
I have attached to the rear of my Velocity, but I have little fear of it
failing on me. in my somewhat limited flight experience, I have had 3
(flight ending) problems with lycoming engines - fortunately the most major
of them (broken valve stem) happened at run up, but it just as easily could
have happened 10 minutes later. The other two consisted of a failed
alternator (OK, lets not count that one, but it did happen at night) and a
broken carb float that really ruined my day, but fortunately, I was within
gliding distance of the airport, the engine would come back to life
momentarily every 5 seconds or so, and it became unstuck during my somewhat
hasty downwind landing, and later replaced without any fanfare.
I don't know if the "certified" engines are any less failure prone at all,
but one advantage is that they are generally much better cared for then most
auto/boat engines, so you are right, we need an apples to apples comparison-
maybe we can get the NTSB to do a "Castrol" test between a certified and a
conversion, and see what shakes out (all in the interest of safety) I would
be interested in the results.
Alex
-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Jim Agnew
Sent: Wednesday, November 05, 2003 3:39 PM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Rotarys, Lycosaurs, etc.
Let me start by saying that I'm not against auto, rotary,
steam or any other type of conversion.
What I am against is comparisons with aircraft engines in
certified and experimental aircraft against them. First
(see my tutorial about aircraft engine overhauls). Al
mentions 500 hr. SMOH, do you know that an overhaul can
consist of nothing more that seals and gaskets!!! Unless
you know the type of overhaul including the work order you
don't know what was done. In an expert mental engine it is
even worse.
I've seen Lyc's in trainers go 2000-2400 between overhauls
getting the daylights kicked out of them that most engines
wouldn't survive. I've also seen them fail in a lot less
time.
To get real figures you need to start from a common
starting base and abuse all of them alike and maintain them
to the required standards to establish real life.
A closer comparison for automobile engines would be their
use in boats where they get far more abuse and continuous
HP output demands. I'll bet that they don't show any where
near where (personal experience also)the reliability of the
same engine in a car.
Jim
--- Jim Sower <canarder@frontiernet.net> wrote:
> 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 dont 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 wont 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
> > arent 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, thats my 2 cents worth.
> >
> > And, yes; we are building experimental aircraft.
> >
> > Al
> >
> --
> Jim Sower
> Crossville, TN; Chapter 5
> Long-EZ N83RT, Velocity N4095T
>
>
=====
James F. Agnew
Jim_Agnew_2@Yahoo.Com
Tampa, FL
Velocity 173 Elite Aircraft Completed & Flying
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