reliability: Rotax 503 vs. 582 vs. 912
Paul Folbrecht
aircraft (Sky Ranger, Sky Raider, RANS Coyote..)
Of course the 912 wins hands-down regarding reliability. No question bout
that. But of course I'm not at all convinced I want to pay the $6-$7K
premium. The question comes down to relative reliability. How does the 503
compare to the 582? Logic might dictate that the liquid-cooled 582 would
win but I know they've had problems with shock-cooling. Anyway, are
engine-outs "to be expected" with these two-strokes (over a long period
anyway) or is it possible to make them essentially as reliable as a
four-stroke?
(The aircraft would only be used for relatively short, local flights, but,
still, I want as reliable an engine as possible.)
Mark Smith
I feel that a well maintained two stroke will provide many more flying
miles per dollar than the four stroke. Especially when comparing the 582
to the 912.
My personal favorite would be the 618 but it is no longer available new.
The cost to do a teardown on the 912 will be disasterous cost wise. A
well prepared owner can do his own work on his 582 at very much less
cost than the 912.
And have you checked all the ADs that have come out on the 912 ? What a
bunch of expensive fixes those are !
With about 300 dollars worth of tools, a trained person can tear down a
582 and reassemble it in a day. Costs of parts will be as little as 20
bucks to 300 for piston replacement. I don't subscribe to the Rotax
suggestion of replacing the crank as I use real oil in the injection
system.
CFhek the price on a 912 gasket set,,,,,,,,,,,,,,,,,,,,,,,,
The water cooled two stroke will also have some benifit based on being
lighter, and when 1000 hours are accumulated and you feel it is just
plain time to really replace some serious parts, trade the block in on a
new bare block. You get a new crank, pistons, ignition,
etc,,,,,,,,,,,,,and an initial cost savings of 5000 dollars isn't to be
sneezed at either. Invest this in a good stock for five years and have
just about enough to pay for the trade-in costs.
--
Mark Smith
Tri-State Kite Sales http://www.trikite.com
1121 N Locust St
Mt Vernon, IN 47620 mailto:ma...@trikite.com
1-812-838-6351
Ken Kennedy
> compare to the 582?
I am not qualified to comment on comparing the absolute reliability of
the 503 and 582. However, I can say that relative reliability is a
function of (among other things) how hard the engines might work in a
given application. It is my understanding that the reliability of a 503
goes way down when it is overworked.
Besides the improvements to the 503 over the years, and the generally
better informed maintenance, probably the introduction of the 582 (which
drastically reduced the number of overworked 503s) has been the main
reason for the current excellent reliability record.
IOW, I think a moderately loaded 582 will be more reliable than an
overworked 503. However, if your application does not overload the 503,
this may be the way to go for you.
Cheaper!
MUCH simpler! (How I hate those leaky RV shaft seals!!!!!)
Probably roughly equal reliability.
Lesser performance
> is it possible to make them (two-strokes) essentially as reliable as a
> four-stroke?
Perhaps possible, but not likely for the average operator.
kk
Martha & Russ Oppenheim
been flying two ULs, both with 503s, for about five years, and I've
never had one minute's trouble with either of them. I watch my
temperatures pretty carefully, but neither engine has so much as coughed
on me. Most of my flying is local, but I've done some XCs with both
planes, nothing major, up to around 100 miles.
Martha
Russell Millar
>I am not qualified to comment on comparing the absolute reliability of
>the 503 and 582. However, I can say that relative reliability is a
>function of (among other things) how hard the engines might work in a
>given application. It is my understanding that the reliability of a 503
>goes way down when it is overworked.
That hasn't been the experience here. The 503 is regarded as being
the most reliable engine available, regardless of how hard you work
it! The club bamtum runs a 503 instead of the 582 that was supplied
as standard. It runs very near to flat out all the time. Having said
that I think the newer 582s are supposed to be better. There was
plenty of room for improvement, especially in the crank.
As for the 912. Our latest club machine has one and its very nice,
but I'm not so sure that I would say it is more reliable than a 503
(not that its let us down yet) but a motor that is prone to cracking
crank cases among other things has to be a bit doubtful. In a few
years time these motors should have all thier faults ironed out and
will then be an excellent choice, at a price.
Cheers
Russell
Mark Smith
>
> First off, I'm no mechanic, someone else does that for me. But I've
> been flying two ULs, both with 503s, for about five years, and I've
> never had one minute's trouble with either of them. I watch my
> temperatures pretty carefully, but neither engine has so much as coughed
> on me. Most of my flying is local, but I've done some XCs with both
> planes, nothing major, up to around 100 miles.
It always helps to mention the type plane the engine is on . Ken noted
that work load or percent full throttle required for level flight type
stuff is a big factor in reliability.
Also, mention the age of the engine, and hours since new.
Both of these factors relate directly to reliability too.
For instance, a 503 with 400 hours and six years old is headed for
trouble regardless of the usage factors. Seals get tired start leaking,
precipitate other problems that will stop the engine.
Also, the 503 got a real shot in the arm in the early 90's with the
heavier crank, and the dual ignition, replacing the points.
Richard Carlisle
>
> Of course the 912 wins hands-down regarding reliability.
I would argue that point. I have 2 503's running on tuned pipes and have
given me no trouble at all. There is a 912 on a Kitfox at our field that
has given its owner quite a bit of very expensive ignition trouble.
If I were looking for more power than a 582 can provide, I would go with a
Turbo Subaru conversion.
Ross
Mark Ambrose
Having flown behind the 582 and 912 and known friends with lots of time on a
503, here's my take on your question. In the first place don't even lump the 503
or 582 in the same category as the 912. There's simply no comparison. I
converted my RANS S-7 with a 582 to the 912 in 1997 and have never regretted the
money I spent. In fact I kicked myself for not doing it sooner. It just seemed
like I was ALWAYS working on the 582 doing something. In fact when I checked the
log books I spent about 2 hours working on that engine for every hour of flight
I logged. The 912 you just change the oil and occasionally the plugs. In
addition 4-strokes burn a lot less gas and oil than 2-strokes.
If money is the the bottom line I would STILL recommend a 4-stroke. Your chances
of an engine failure with a 2-stroke are greater. If you park your airplane in a
tree or smash it into the ground the cost difference between the 2 and 4 stroke
at that point will seem insignificant since your plane will be totaled.
If you still insist on a 2-stroke go with a dual carb Rotax 503 in the tractor
configuration. Statistics have shown this to be the most reliable of the
2-strokes. I personally know a pilot who had 800 hrs on his 503 in a Titan, sold
it (for a 912) and the new owner is STILL flying the 503.
I wouldn't fly behind a 582 at all. Too many problems with the crankshafts. Two
friends had cranks blow on their 582's. I changed mine at 167 hours and the new
crank blew after 40 hrs. We're all flying 912's now going 15-20 mph faster and
without any problems in over 400 hours.
My opinion.
Mark Ambrose
Maryland
Colin Lundy
I'm running a 447 in a Bantam B20 (FMF) out of Te Kowhai (when I can get the
time). Learned to fly there in B22 (SBR) among others, which is 582
powered. . Curious to see your comment about going down in power to the 503
for the club Bantam. I assume it is a B22 for training. Why the switch?
Which club do you belong to?
I'm thinking of going to a 503 in the B20 when the 447 wears out, which may
be soon if the rear c/s seals are going, as I suspect.
Know anyone elsewith a used 503 with not too many hours on it who's changing
up
to a 582?
"Russell Millar" <mil...@clear.net.nz> wrote in message
news:3c32cdd7...@news.clear.net.nz...
Mark Smith
>
> I'm running a 447 in a Bantam B20 (FMF) out of Te Kowhai (when I can get the
> time). Learned to fly there in B22 (SBR) among others, which is 582
> powered. . Curious to see your comment about going down in power to the 503
> for the club Bantam. I assume it is a B22 for training. Why the switch?
> Which club do you belong to?
> I'm thinking of going to a 503 in the B20 when the 447 wears out, which may
> be soon if the rear c/s seals are going, as I suspect.
> Know anyone elsewith a used 503 with not too many hours on it who's changing
> up
> to a 582?
sounds like a better place to buy 582's than 503's !!!
why not just replace the seals in the 447 ? To change motors, you will
need a lot of extra stuff like a motor, etc
Seals are just a few bucks compared to the stuff to go to the
503,,,,,,,,,,,,,
--
Mark Smith
Tri-State Kite Sales http://www.trikite.com
1121 N Locust St
Mt Vernon, IN 47620 mailto:ma...@trikite.com
Colin Lundy
I'd like the extra power so I can cruise at a lower power setting. At the
moment the 447 is revving 5600-5800 (depends on fuel load) to maintain 48-50
knots cruise and it gets thirsty (15-17 litres an hour) at that setting. I
recently replaced the 20-litre fuel tank with a 35-litre home-brew job (
works well ). But the extra weight at full fuel load means I have to work
the 447 that little bit harder.
So I figure I could get better fuel economy running a more powerful engine
at lower revs. Probably. What do you think?
And yes, the seals are only the first thing to go, but the vertical piston
and big end slack is up to 9 thou, used to be 4 thou about 30 hours ago, so
it's starting to wear . . .
"Mark Smith" <ma...@trikite.com> wrote in message
news:3C3352...@trikite.com...
Paul Folbrecht
"Paul Folbrecht" <paul.fo...@nospam.pobox.com> wrote in message
news:MbtY7.168339$RP1.33...@typhoon.kc.rr.com...
Martha & Russ Oppenheim
GT400. Both planes are about 10 years old, and the 503s are the
original engines on both. Both planes were hangared but not flown for
several years. The Sprint has about 350 hours on it, and the GT (which
I've owned for less time) has about 150 or so hours. (The original
owner built it for his wife, who was afraid of it or something, and
never flew it. He flew it for maybe 30 hours, then hangared it. I
bought it, and put the rest of the hours on it.) On both planes I can
cruise at about 75 percent full throttle for level flight. On the
Sprint, naturally it depends on the weight of the guy I'm taking up.
When I fly alone, with my 120 lbs of concrete in the other seat, I
cruise at about 75 percent. (Both engines have dual ignition.)
Martha
BlueMax
of say...Paul Newman, or Robert Redford (not the wrinkled one...but the way he
was in "The Sting"). Just a thought!!
BlueMax
Martha & Russ Oppenheim
<You know Martha, you should trade in that 120 pounds of concrete for a
wax dummy
of say...Paul Newman, or Robert Redford (not the wrinkled one...but the
way he
was in "The Sting"). Just a thought!!>
Hey, good thought! I'm sure my husband wouldn't mind. I do have a
"co-pilot" on my concrete. Somebody attached a Taco Bell chihuahua onto
the seatbelt that holds my concrete. (I can never trust the guys around
my hangar! They're always putting stuff on my plane.)
John C. Hilbert
the 912, if not more reliable....can use auto or 100LL, 2000 TBO (1000 top
end), AND costs thousands less than a 912, just a little more than a 582,
and weighs about the same for 80 HP.
Chad
"Mark Ambrose" <mark.a...@gsfc.nasa.gov> wrote in message
news:3C33109D...@gsfc.nasa.gov...
Paul Folbrecht
Coyote. Jabiru has a full FWF kit available.
I also wonder why they haven't caught on more.
"John C. Hilbert" <jc.hi...@home.com> wrote in message
news:%prZ7.21227$LQ1.7...@news2.nash1.tn.home.com...
geoff and jodie
seaters are great fun to fly... although getting used to the more positive
use of the rudder required was a mild shock after being able to be a bit
lazy in the Cessna :-)
I expect it's more a matter of marketing, marketing budget and established
market share...
Geoff Hansford
"Paul Folbrecht" <paul.fo...@nospam.pobox.com> wrote in message
news:UHtZ7.189820$RP1.37...@typhoon.kc.rr.com...
M.J.C.
compared to the longer lives of Rotax (for ultralights) and of course
Continental and Lycoming for larger aircraft.
But it's building a solid reputation very quickly and unless their engines
cough up a nasty surprise anytime soon, I'll just bet that the reliability
record it's accumulating, and it's performance specs, will propel the Jabiru
to the top of the list in the next couple or three years for homebuilders.
I was originally going to use a Cont IO-240 for my project but may end up
using the Jab 3300 instead.
M
"Paul Folbrecht" <paul.fo...@nospam.pobox.com> wrote in message
news:UHtZ7.189820$RP1.37...@typhoon.kc.rr.com...
margifa
If you use it following Rotax advise you will not regret to have bought it.
Jabiru is simply better: better than 503 and better than 912.
If you consider reliability regarding to the price you pay, then 912 is not
reliable.
I am considering another engine, Walter Mikron III.
Reliable, of course, and four stroke.
Fabrizio
Paul Folbrecht
useful if it made peak power 500 rpm lower. As it is, the manufacturer of
the current front-runner kitplane for me- Zenith- does not recommend it for
their CH701. The 701 is just too slow for the little prop the 2200 needs to
be effecient. And Zenith DOES like Jabs- the 3300 seems to be their
preferred engine on the 601.
"margifa" <mar...@libero.it> wrote in message
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