It is called MA 956.
Since the rotary exhaust temperatures are up around
1800 F it will be needed. One can always cool the exhaust
before it goes to the turbine but that implies a loss
of recovered energy.
Paul Lamar
Ok, that was an excellent tease, what are the characteristics of the
alloy? The weight savings? Is this alloy better than
beryllium/aluminium? How easy is it to machine? Cost?
Steve Ross
I forgot the attachment. The message before this one will have it
If not, I attached it here again and a pdf. BeAl is only good to 700F.
The density of MA 956 is less than steel.
I have no answers to the rest of the questions yet.
Paul Lamar
I just read the attachment, it looks promising! I am going to
enquire about pricing on Monday. How big of a billet would be needed
to carve out a rotor?
Steve Ross
I did not have rotors in mind. I had turbines in mind. Rotors do not run
much over 500 F. BeAl at 700 F would work great for rotors as the
density
is only .07 pounds per cubic inch. Aluminium is .1 pound per cubic inch.
In theory a BeAl rotors would allow 20,000 RPM. Then we would have a
gear
box problem. The weight of the engine would become about 180 pounds,
instead of 200 pounds, with turbo because when you lighten the
rotors the
counter weights become lighter as well.
For turbo compound use the same turbine that boost the manifold
pressure can feed torque to the e-shaft. See the attachment.
The same power to weight ratio, or better, as a turbo prop with half
the fuel burn.
Paul Lamar
I just searched the alloy number and read it. I was thinking
that it has a small thermal expansion and with the high temp
tolerance, it may be good for casting Renesis type end housings
with the side exhaust ports. It should be less prone to cracking
in the port area that I read the Mazda housings are prone to
when turbocharged. Aircraft use is similar in that with the high
duty cycle the port area is subjected to continued high heat.
Dale Davies
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