light twins?

Bob Kuykendall wrote:

And further, since most of the patents that cover the Wankel
innovations are now expired or are about to expire, you'd expect to see
other manufacturers adopting the Wankel. That you don't see this tends
to support Corky's argument that for the vast majority of engine
applications the Wankel's disadvantages outweigh its advantages.


If by "vast majority", you mean automobiles, then you a absolutely
correct. An automobile is one of the worst possible applications for a
rotary. The low end torque isn't there, and Mazda has to go through all
sorts of contortions to get some. Rotaries like to rev fast and stay
that way, and really suck at the low end.

Where the engine will shine is situations where the low end grunt is
unecessary, and they can rev to 6000RPM or more and stay there..
Airplanes and power generation are two examples that come to mind.
Expect to see more AIRPLANE ENGINES using the rotary concepts as the
patents run out.

The biggest disadvantages right now is low volume. GM or Ford won't
touch a design that is meant for a few thousand per year. Mechanics
have neither the time nor inclination to learn about an engine they'll
very rarely see. But Lycoming is already working at those sorts of
volumes. It becomes a non issue.

The second quoted problem is a red herring. BSFC. The rotary leans MUCH
better than any piston engine. In actual practice in real airplanes,
fuel burn is indistinguishable.

But the advantages. An engine that will sacrifice itself to get you
home. A $500 rebuild that takes a weekend. Power to weight ratios that
already beat pistons and continue to climb. Did I mention, an engine
that will sacrifice itself to get you home.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

On Wed, 27 Jul 2005 22:47:34 GMT, Ernest Christley
wrote:

The second quoted problem is a red herring. BSFC. The rotary leans MUCH
better than any piston engine. In actual practice in real airplanes,
fuel burn is indistinguishable.

But the advantages. An engine that will sacrifice itself to get you
home. A $500 rebuild that takes a weekend. Power to weight ratios that
already beat pistons and continue to climb. Did I mention, an engine
that will sacrifice itself to get you home.

All good points. I didn't mention this (at least not recently) but I
had a 13B in my shop at one time that I was going to use for my
airplane.

This was a number of years ago before Tracy began developing his
rotory. I had started with a Buick/Olds 215 cid aluminum V8 but had
sold it because it was too hard to find parts for it.

I was getting increasingly nervous about using the 13B because I knew
I had to fabricate my own intake manifold and exaust system. I had
been an auto mechanic who worked on Mazda's, including the RX7's so I
knew something about them. The intake manifold looked to be almost as
big as the engine, which is why all the folks I'd been talking with
were recommending it be junked and a smaller one fabricated.

Remember, this was in the early 90's, not now.

But the thing that really put me off was the heat of the exhaust
system. It ran something like 500 degrees hotter than piston type
exhaust systems and required a thick wall stainless steel system.
Even with such a system, all that heat seemed a little scary to me.

So I sold that and now have the Ford V6 which is running well at this
point and seems to have all the power I need.

Corky Scott