Titanium and its alloys have really low thermal conductivity.
which could
limit
it's use for the rotor which has thick sectiond that must be
cooled. We
actually
used titanium for thermal isolators in some rocket applications -
it has
lower
conductivity than ceramic alumina - Vance
Vance,
While I'm sure your correct about thermal conductivity of Ti. The
other side
of the coin is that it retains it's strength to a much higher
temperature
than
many light alloys. Since the rotor is oil cooled as well I believe
it could
be
done, with the problem being the cost of course. I think Doug is
being
really optimistic if he thinks $500.00 per rotor is possible.
$2000.00 would
be more likely. Not logical when you could run an engine hard and
replace
the entire "block" for less than that!
Yes
I am aware of the thermal characteristics of Ti. Actually I thought it
might
be a benefit though of course that would mean more heat has to be
absorbed
through the housings even if we do go with aluminum side housings.
As soon as I can get an estimate on the inner gear weight I'll ask our
diecast people to give me some numbers. Higher revs for aircraft
rotaries
may not be so desirable at this point in the game as it tends to
introduce
so many variables.
I should know by tomorrow if Mazda has tried Ti or flame sprayed
AL.rotors
in any tests so far.
Doug in Japan
Jerzy Krasinski wrote:
Alumina is listed with a very wide range of thermal conductivity.
Well sintered alumina has thermal conductivity close to that of
crystalline sapphire, and that one is not too bad, especially at lower
temperature.
Porous alumina can be pretty bad.
Pure titanium is not too bad in sense of thermal conductivity, but not
too strong.
Alloys of titanium are much stronger, but much worse in sense of thermal
conductivity.
I wonder what titanium alloy would you consider for the rotor?
Jerzy
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