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That rule of thumb is what I have heard as well. My desire is that over
water with long distances to safety, I would want to have as many
options as practicable. Your admonishment to concentrate on having a
bullet proof radiator system with high quality hoses and a backup water
pump is good advice. I still can't help but look at it as a prop
stopper if it leaks. Perhaps some of you can help me decide if this is
an irrational fear. If the coolant goes by the board (sorry, I've been
listening to Patrick O'Brien's "The Far Side of the World") I want to be
able to continue the flight. That means relying on the oil to cool the
engine. Now we can expect the design characteristics of the rotary to
help such as the aluminum housing/steel rotor interaction to help
prevent seizure; so that's good. I would need to have some excess
cooling capacity built-in to the oil cooling system to handle reduced
power ops; that's another good thing.
My thoughts regarding the intermittent ignition is to limit the heat
generation rate such that the oil with its lower cooling efficiency has
enough time to carry enough of the heat away before the next firing.
Now whether I can do that with reduced throttle setting (each face
fires, but less total heat generated due to reduced charge) and still
have the oil carry away enough heat verses firing every other face (more
heat but longer time for the oil to do the water's job before it fires
again since that face will not fire again until the 2nd revolution, thus
spreading the heat around the rotor.) remains to be seen. I know, I
know, this whole concept remains to be seen.
Another idea...
In looking at the rotary housings it seems that the water jacket in the
engine is simple and straight forward. This leads me to believe that an
internal leak event is very unlikely. Does this correspond with other's
experience? If so, then the failure of an external system is more
likely but just as catastrophic. Would it serve to add some sort of
plates/gaskets on the end plates to divide the water jacket into two
separate systems, thus having redundant radiator systems such that if
one leaks, the other is there to carry some of the load?
Thanks for not crucifying me. Flail away at my ideas though.
-Randy
>-----Original Message-----
>From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of
>John Slade
>Sent: Monday, September 13, 2004 4:55 PM
>To: Rotary motors in aircraft
>Subject: [FlyRotary] Re: Limp home mode
>They say a rotary is cooled 1/3 by oil, 2/3 by water, so theoretically
you
>could use 1/3 power and continue flying, but there's probably more to
it
>than this. I expect that some parts are cooled by more by water than
oil and
>vice versa. Certainly you can turn off one set of injectors (or one set
of
>coils) and lower the power use, but you can also lower power use by
reducing
>throttle. The automatic cadillac system sounds like more of a sales
gimmick,
>and for those who don't know how to do this. The rotary is very good at
>"limping home". It has redundant ignition and fuel injection. I once
saw a
>disassembled engine which "blew" in a drag race, then was driven home
100+
>miles.
>
>Lose of coolant is something you can prevent with quality hoses and
>fittings. Perhaps the more likely scenario is water pump failure for
which
>you can add a backup electric water pump.
>
>John (Sticking with rev 1)
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