The corrosion you see here is very untypical of a rotary and I tend to agree
with Don as to it's electrolysis origin.
The rotary is not in the same ball park as automotive piston engines.
It is also far superior to any aircraft piston engine due alone,
if nothing else, a lack of exhaust valves.
Paul Lamar
Paul,
Thanks for accepting me to this forum, I expect to learn a lot
about the practical application of the rotary engine to homebuilt aircraft
here; I have already learned a number of aero-application specific
arrangements.
Indeed I am well aware of the mechanical differences between piston
and rotary engines but both are still Carnot process engines (the colloquial
suck, squeeze, bang, blow) that need to get the fresh air and fuel in as
efficiently as possible at the proper mass ratio, burned to maximum effect,
have the exhaust gases removed from the chamber with the minimum of energy
losses and most critical to their usefulness, extract useful work from the
high energy fluids (combustion gases). Effective ECUs and
reliable/effective fuel and cooling systems are equally essential to both
engine formats as are ignition and other ancillary systems; hence my comment
that "... many of the principles are the same ...". Yes the application and
physical formats of the combustion chambers and the intake/exhaust "systems"
could not be any more different but the engines as a whole share the same
thermodynamic fundamentals.
That being said I wholeheartedly agree that the rotary engine should
easily outperform any piston engine (auto or airplane, 4 or 2 stroke) in
terms of reliability as measured by MTBF, MTTR, MTTO, MTTRTO etc.. They are
inherently smoother and their higher rpm capabilities speak to greater power
to weight ratios and outright power per unit effective displacement. I also
think that once "standard" installations have been developed they hold the
potential to draw away a significant portion of the certificated engine
market.
Okay, so my first questions to the list.
Is there any move afoot to pool efforts/resources and conduct any
"accelerated age" testing of the most popular rotary engines on a dynamic
brake so as to determine their actual long term performance and develop
actual reliability statistics? While it would undoubtedly be prohibitively
expensive to build an altitude chamber, or rent time in one, it should be
cost effective to pool resources and conduct simulated flight profiles on a
dynamic brake in a test cell with interim cool down profiles. Perhaps Mazda
themselves or commercial suppliers and machine shops involved in aero-rotary
engines might be interested in helping fund or conduct such tests.
Certainly 80 - 100 operating hrs per week in a test cell should be doable
and a simulated life of 2000 hrs could be completed in less than 6 months.
After such test cell evaluation perhaps an actual flight test programme
could be conducted to determine actual altitude effects.
Perhaps naive questions but ones I think need to be asked, otherwise
everyone using a rotary is a "pioneer" breaking "new ground". That
situation IS NOT conducive to gaining a more widespread acceptance of rotary
engine use in homebuilt and general aviation circles. Certainly I, and no
doubt many others, would feel more comfortable if such tests were completed
and dependable data were made available
Thanks and Cheers
Good Building and Flying
Carl
Carl P. Lindon B.Eng., CD.
Lieutenant (Navy)
DGIIP/DIRAP
Work
e-mail:
lindon.cp@forces.gc.ca
Home
e-mail: carllindon at rogers dot com
Not that I know of. Hard to wear something out that will run full power
day in and day out for years. Expensive too if for no other reason than the
gas cost. In racing, rotaries last ten times as long as piston engines.
Nobody has worn one out in an airplane so far. If properly
maintained in automotive service they go well over 300,000 miles.
I have owned six rotary powered cars since 1972. I never wore one out yet.
Sure the rubber O-rings melted in my RX2 but Mazda immediately replaced then
with silicone. A common occurrence in cars is to have the cheap nylon
apex seal lubrication lines harden and crack after about ten years.
If you replace these every ten years the engine should run nearly forever.
Also burning Mobil 1 or better yet new Idemitsu Rotary Engine Oil your
apex seal slots should stay clean and not cause the apex seals to stick
which occasional happens when cheap oil is used.
Turbo engines fail when people start to crank up the boost and
allow the engine to detonate. In that case the apex seals are known
to fracture.
Keep the cooling system in good shape by changing the
anti freeze every couple of years and have the cooling system flushed
every ten years. Replace all rubber hose every ten years whether they
need it or not.
Your upholstery will wear out long before the engine. If it is in the
North East the body will rusted out long before the engine wears out.
Paul Lamar
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