> Paul,
>
> When I was at the Seven Stock Show, I noticed that all of the rotors
were
> cast iron. Has anyone made aluminum rotors? Is there too much thermal
> expansion to use aluminum? I was also thinking that the rotors could be
> made of a ceramic--low expansion, lighter weight, and possibly lower
cost.
>
> Steve Brazil
>
> I think it is a heat issue. The rotors can run 500 F or more.
> Titanium seems to work but it is expensive.
>
>
> --
> Paul Lamar ...No rotor no motor.
Here is a photo of a lightened Mazda 13b rotor. It can be found on the
website
http://www.der-wankelmotor.de/Motoren/Motoren_Mazda/Mazda_13B/mazda_13b.html
Does anyone know anything about this? It seems to me that not only can
we make the rotors out of a lighter, more durable substance, we can
alter the construction. The rotor does not need to be a solid. It can
have just the material it needs to have. It will be lighter and can
still be reliable.
I do not read German. I do not know if the German written beside the
photo has anything to do with the photo of the lightened rotor. I have
included it, just in case.
http://s12.photobucket.com/albums/a234/JacobPotts/Atom/Rotary%20Engine/?acti
on=view¤t=LightenedRotary13BEngine001.jpg
Les Nordman
This photo only shows the cross section of a stock RX-8 rotor cut in half.
As you can see, there is not a huge amount of excess material in the rotors.
The face of the rotor must be able to hold the maximum combustion pressures
with minimum flexing in order to survive.
On the subject of titanium, I have built many race engine parts out of ti.
It is it's own animal when it comes to designing with it. Any surface that
will see any friction has to be coated with DLC (diamond like carbon) or a
similar coating to prevent galling. The apex seal area would have to have a
steel insert. The other issue would be the rotor running much hotter, as ti
does not transfer heat well and you could run into the case of the seals
overheating.
With enough money for building the investment casting die, we could test
this... but the question remains as to why we need it so much lighter if we
don't plan on spinning the engine above 7500 rpm.
Larry
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