Thread: light twins?
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Old July 25th 05, 02:31 PM
Gordon Arnaut
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Thanks for the info, Rusty.

How much does the 13b single rotor weigh? And how much does it cost to get
the e-shaft shortened?

I think I saw a picture of that drone you mentioned. It's an air-cooled
rotary made by the Israelis, I believe.

I too would love to see a small two-rotor, preferably air-cooled and with
aluminum end housings. That would make a very nice little engine.

There is an outfit here in Canada that is promising to produce some small
rotaries for light planes, but I don't know how far along they are. A German
outfit makes single-rotor go-kart engines, as well as an UL version.

Regards,

Gordon.



"Bellsouth News Server" wrote in message
.. .
Hi Gordon,

Yes, by single rotor, I mean a shortened 13B engine. This requires a few
custom made pieces, primarily the eccentric shaft, but these are probably
going to become more available as the Sport Pilot class of planes comes
online.

Mazda did make smaller engines, but it was a long time ago. The 10A ended
production in 74 I believe. The 12A was a good engine, and it's "only"
been out of production for 20 years. The 13B is by far the most commonly
available engine today, though it won't be too many years before the
Renesis will take over that honor. Unfortunately, the smaller engines
aren't all that much lighter, since it's the rotor housing and rotor that
get narrower. Also, as the 13B advanced, the rotors got lighter, to the
point where a late model 13B rotor is probably lighter than a 10A rotor.
I haven't looked at the weights, so that's just my estimation. Bottom
line is that the 13B, and Renesis are about the only realistic choices for
single rotor conversions at this time.

What would be better than a single, would be a smaller two rotary. There
are any number of these popping up, but like so many other new engines we
see, they just never seem to materialize, and if they do, they're so
expensive that they lose their appeal. There are some very attractive
rotaries made for UAV/target drone use, but they aren't sold for manned
aircraft, and I haven't been able to figure out what the TBO would be.
Can't imagine the life expectancy of a target drone is very many hours :-)
Getting parts for these odd engines would be a problem as well.

Cheers,
Rusty


I'm intrigued by your twin-wankel idea. I appreciate the elegant
simplicity of the wankel design myself and try to keep abreast of what's
happening in the rotary avaition community.

When you say single-rotor, are you talking about a 13b that has been
shortened? I wonder too about the smaller displacement Mazdas -- you
never hear much about those, but I would assume they should be lighter
than the 13b.

Regards,

Gordon.