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If we were talking about an automotive application I agree that it would be
folly to run sans-airfilter. And I qualify my non filtered operation
with the proviso that you must use care when taxiing under certain
conditions. The air is a lot cleaner as soon as you slip the surly
bonds. Flying or taxiing through a sand storm would of course
be disastrous without an air filter.
Only one sample but my first engine (a well used 88 2nd gen) showed
no measurable wear (compared to when first installed) to rotor grooves,
rotor housings, side housings, or side seals after 856 flight hours. The
apex seals had a maximum of .012" of wear measured at height of seal.
This is the least wear I have seen when disassembling a used engine. I've
torn down about 12 so far, all used on cars except for mine, not a big
sample.
Tracy
----- Original Message -----
Sent: Wednesday, February 15, 2006 9:50
AM
Subject: [FlyRotary] Re: Engine failures,
Rotary or otherwise
To clarify the air filter issue. I seem to remember
someone posting a page from the mazda manual regarding apex seal tolerances
after Ed's failure and later confirmed the slot was out of spec. I
remember the manual said to check the air filter. Mazda seems to think running
without a filter or (dirty filter?) will cause rotor apex seal slots
wear. Is this correct?
Bobby
(not doubt I will now build a trailer test stand and run
the engine many hours before it ever goes on the
plane)
Bill;
With
all due respect; I don’t disagree with what you’re saying here, but I do take
offense at you calling Tracy, myself, and others “idiots” because we have
chosen to run without an air filter. My intake is in front of the prop
and above the wing strake. Anyway, why climb on that issue? There
has not been a single aircraft incident that I am aware of that has resulted
from not using an air filter. Let’s pick an issue which has
caused a failure.
I
won’t argue that running without a filter may reduce the engine life; and I
may consider one later. And yes, the engine would eventually fail; every
engine will – filter or no filter - if you run it long
enough.
Al (I
guess it’s past my bedtime)
Rusty,
and Group,
I
understand your comments Rusty, and think you are both right and wrong. I
believe it is easier, for most people, to be successful with a standard
aircraft engine. I DO NOT believe this is because the Lyc, Conti, or whatever
is inherently more reliable. I do believe that the ancillaries are better
developed for "conventional" aircraft engines.
Because
we [FlyRotary or ACRE] are rotary
enthusiasts we hear about EVERY rotary problem. If we heard about every Lyc
problem caused on a daily basis we might never fly spam again! I am not trying
to offer so anecdote to soothe the rotary faithful, as all failures are just
that, failures. I would remind everyone that ALL Lyc installs in certified
aircraft now come with AIR FILTERS!
I'LL
SAY THIS FLAT OUT, IF YOU DON'T RUN A FILTER YOU WILL HAVE A FAILURE! I don't
care if your running a conventional aircraft engine or conversion. Running
unfiltered is simple idiocy.
It
should also be said that for Lycoming to be having crankshaft failures, and a
significant number of them to initiate an AD is not only sad but smacks
of reckless disregard. So saying that the aircooled aircraft engine is super
reliable is simply setting yourself up for a fall. If you look at the
statistics most of the engine failures are "certified" engines simply because
there are more of them!
ANY
ENGINE properly maintained and not operated outside it's normal limits will
work just fine thank you, provided it is not a deficient design to begin with.
The rotary requires a GOOD water and oil cooling system. If you aren't willing
to work on that, stop now and don't hurt the reputation of the rest of us and
go buy a Lycoming. The rewards for a GOOD installation are many but won't
"just happen." As Tracy said you must go in
with the knowledge of the needed systems or you will fail. If you do slipshod
work, Rotary or Lycoming, YOU WILL FAIL. Someone put the old saying on the
site, "How do you eat an elephant?" "One bite at a time!" This is the proper
way of looking at the jobs needed to be successful. You MUST do all the jobs.
(eat every bite) And most importantly you must do all the jobs well. Safety
wire everything even though it's a pain in the ass. If you can't do all the
jobs yourself it's no crime. Get HELP! Buy the redrive from
Tracy. Or buy from
Mistral, or buy them from Marcotte. Build your system up and test it on the
ground. If you overheat your system on the ground don't assume it will be
better in the air! (It might be, but also might not be!) Plan for an adequate
sized radiator. That would be a MINIMUM of 2 cubic inches pre HP, and that
only if you have PERFECT ducting. (3 c.i. per HP would be a safer bet) Don't
expect you are the miracle guy that can change physics for your own
project. Rusty has brought up some good points in pointing out that if
you want to fly soonest buy conventional. Bernie, you can probably rebuild
your system from all new parts for less than the cost of two Lyc cylinders. As
an older guy facing family pressures I can understand how you might not want
to though. This is no crime. Your needs are your own, though I would prefer to
see you go back to the rotary and succeed. We all need to go in with our eyes
open. When setting up race cars and motorcycles I would look at every part
from the stand point what will happen if this part breaks? If the result would
be a crash I would redesign the part until I was SURE it wouldn't break. If
you don't think a part is adequate DON'T USE IT! Your responsibility is to
find a part that IS good enough. Don't just hope that everything will be OK.
Work it out. Run your system enough to be sure of it in the
air. I hope everyone takes this in the spirit intended which is to
have us all come home safe.
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