> Paul,
> Let's change the subject a little bit from props to cooling fans.
> Has anyone suggested shaving off the rotary engine end plates and
installing
> close fitting fans to each end of the engine(one pulling and one sucking
> air) through the water cooling jacket? Milo
>
> Well I hate to disappoint you on this as I don't think there
> is enough surface area to make that work. You still need to cool down
> along the sides of the center and end housing.
>
> Also cooling fans suck HP which increase the fuel burn of the engine.
> The Midwest/Diamond engine suffers from this as did the Porsche
engine used
> in the Mooney. I also suspect this is a factor in the Robinson
Helicopter.
> --
> Paul Lamar ...No rotor no motor.
>
How about let's change the idea up, to air cool a rotary without cooling
fans?
Let's posit that we have an air-cooled rotary engine with no water
jacket. Instead, on the outside of the engine, fins radiate from both
the sides and the ends of the engine, to cool it like the barrel of an
old radial piston engine is cooled. The fins are positioned and
oriented so that air flow is optimized for appropriate cooling and for
air flow in, through, and out of the engine compartment.
No cooling fans, such as the Midwest/Diamond or Porsche engines are
needed, so no power is drained, no unnecessary fuel is used.
Such an air cooled rotary engine would certainly be physically bigger
than its water cooled counterpart, but would not the air cooled rotary
be smaller overall than the water cooled engine and its attendant
radiators, hoses, etc.?
Would not such an air cooled rotary engine be lighter, simpler, more
efficient, more reliable than its water cooled counterpart? How would
we know that it would be or would not be? How would we know that we knew?
Let us also posit that each fin, where appropriate, has within it a
properly-engineered heat sink. Heat sinks have no moving parts, so they
would be reliable. Perhaps heat sink technology could siphon the heat
out from the center housing into fins projecting into the air stream, so
that even the center housing could be cooled.
Would using a technology like a heat sink increase the cooling
effectiveness of each fin? Would not heat sink technology make such air
cooling more efficient? Could such technology help cool a rotary
engine enough? Again, how would we know that it would or would not and
how would we know that we knew?
I would certainly like to hear your thoughts about this. I expect I
will ask of you all, when you post, a lot of questions. Why? Not
because I am trying to be argumentative, but because I do not know all
the answers and I know I do not know. :-)
Les Nordman :-)
I understand. Good idea. I think you mean heat pipe rather than heat sink.
I think it can be made to work. Got a couple of million lying around
you are not using? :)
Paul Lamar ...No rotor no motor.
I'm guessing the two big reasons people want to air cool are
first to get rid of the weight of the coolant and to get rid of
complexity that can lead to failure.
This brings up a related question. How can you increase the
reliability and decrease the weight of the liquid cooling system?
Also, can we assume that most of the technologies that would
make air cooling work better could also be applied to liquid
cooling systems?
Jeff Martin.
The way you increase the cooling system reliability is use high quality
AN plumbing. No automotive parts except the rad cores. The way you decrease
the weight is design and install the cooling system properly.
Paul Lamar
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